Forum RUFOn

Resurse => Stiri => Topic started by: pri3st3ss on 13 April 2007, 21:07:59

Post by: pri3st3ss on 13 April 2007, 21:07:59
am sa postez aici tot ce iese din sfera Hubble, SPITZER , precum si noi afirmatii privind planetele care nu au propriul lor topic :lol:

eclipse of a supermassive black hole

 April 12, 2007: NASA's Chandra X-ray Observatory has observed a remarkable eclipse of a supermassive black hole, allowing a disk of hot matter swirling around the hole to be measured for the first time.

The supermassive black hole is located in NGC 1365, a spiral galaxy 60 million light years from Earth. It contains a so-called active galactic nucleus, or AGN. Scientists believe that a black hole at the center of the AGN is fed a steady stream of material from a surrounding disk. Matter just about to fall into a black hole should be heated to millions of degrees before passing over the event horizon, or point of no return. This super-heated disk material glows brightly in the X-ray part of the electromagnetic spectrum where Chandra can see it. ( fig 1)

The disk of gas around the central black hole in NGC 1365 is much too small to resolve directly with a telescope. However, the disk was eclipsed by an intervening cloud. By recording the time taken for the disk to go in and out of eclipse, scientists were able to estimate the diameter of the disk.

"For years we've been struggling to confirm the size of this X-ray structure," said Guido Risaliti of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass, and the Italian Institute of Astronomy (INAF). "A serendipitous eclipse enabled us to make this breakthrough."

The Chandra team directly measured the diameter of the X-ray source as about seven times the distance between the Sun and the Earth or 7 AU (astronomical units). For comparison, if such a disk were placed in our own solar system, it would swallow all the planets out to Mars and most of the asteroid belt as well.(fig 2)
According to these measurements, the source of X-rays is about 2 billion times smaller than the host galaxy NGC 1365 and only about 10 times larger than the estimated size of the black hole's event horizon. This is consistent with theoretical predictions.

"Thanks to this eclipse, we were able to probe much closer to the edge of this black hole than anyone has been able to before," said co-author Martin Elvis from CfA. "Material this close in will likely cross the event horizon and disappear from the universe in about a hundred years, a blink of an eye in cosmic terms."

In addition to measuring the size of this disk of material, Risaliti and his colleagues were also able to estimate the location of the dense gas cloud that eclipsed the X-ray source and central black hole. The Chandra data show that this cloud is one hundredth of a light year from the black hole's event horizon--much closer than anyone expected. So this is a bit of a puzzle.

"AGN [are among] the brightest objects in the cosmos and they are powerful probes of the early history of the Universe. It's vital we understand their basic structure," said Risaliti. "It turns out that we still have work to do to understand these monsters."

fig 3: An artist's concept (not to scale) of Chandra observing the black hole eclipse
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 19 April 2007, 21:50:47
Space shield to block radiation

British scientists are planning to see whether a Star Trek-style deflector shield could be built to protect astronauts from radiation.
They argue that magnetic shields could be deployed around spacecraft and on the surfaces of planets to deflect harmful energetic particles.
Several countries' space agencies have announced their intentions to resume human exploration of the Solar System.
Scientists hope to mimic the magnetic field which protects the Earth.
Details have been presented at the Royal Astronomical Society's National Astronomy Meeting in Preston, UK.

There are a variety of risks facing future space explorers, not least of which is the cancer-causing radiation from cosmic rays and solar flares that astronauts will encounter when they venture beyond the Earth's protective magnetic envelope, or magnetosphere.    
The Earth's magnetosphere deflects many of the energetic particles from space; others are largely absorbed by the atmosphere.

Between 1968 and 1973, the Apollo astronauts were only in space for about 10 days at a time.
They were simply lucky not to have been in space during a major eruption on the Sun that would have flooded their spacecraft with deadly radiation.
Crew members on the International Space Station can retreat to a thick-walled room during times of increased solar radiation.

Stable field

But these protective shelters would not be practical on long-duration space journeys, since the "drip-drip" of energised particles is thought to be as harmful to the health of astronauts as large solar storms.
Potentially damaging solar activity is hard to predict
The harmful particles come from the Sun, in the form of the solar wind, and from sources outside our Solar System.
To create the deflector shield around a spacecraft or on the surface of a planet or moon, scientists need to generate a magnetic field and then fill it with ionised gas called plasma.
The plasma would held in place by a stable magnetic field (without the magnetic field, the plasma would simply drift away). This shield could be deployed around a spacecraft or around astronauts on the surface of a planetary body such as the Moon.
As energetic particles interact with the plasma, energy is sapped away from them and they slow down.
"You don't need much of a magnetic field to hold off the solar wind. You could produce the shield 20-30 kilometres away from the spacecraft," explained Dr Ruth Bamford, from the Rutherford-Appleton Laboratory in Didcot, UK, one of the scientists on the team.
Dr Mike Hapgood, from the Didcot-based research centre, told BBC News: "The nice thing is that magnet technology is really quite evolved here on Earth. The question is can you take it into space?'"
The team from Rutherford-Appleton plans to build an artificial magnetosphere in the laboratory. They would eventually like to fly a test satellite which would test the technology in space.

'Shields on'

The idea has been likened to the deflector shields which protect the USS Enterprise and other spacecraft in Star Trek. Like their fictional counterparts, these shields could also be switched on and off.
The planned moon base will be exposed to solar radiation
An artificial magnetosphere could come in handy anywhere in the Solar System where humans would need to be for long durations.
A permanent Moon base, of the type Nasa plans to build, could be buried under lunar soil to protect the occupants and equipment from space radiation. But inhabitants will still be vulnerable when venturing outside in their spacesuits.
"Our warning systems aren't very good [for solar flares]. You might be able to say: 'this is a dangerous period in terms of solar activity', but you might be on red alert for weeks," said Dr Hapgood.
"If you've got a problem, you might not want to wait a week to fix it. You might want a device to deploy on the surface as a shield that would blunt the effect of a flare at ten minutes' notice, it adds an extra level of safety."
The idea for the shields draws on technology pioneered in experimental nuclear fusion reactors. Nuclear fusion is not yet a mature technology.
It works on the principle that energy can be released by forcing together atomic nuclei rather than by splitting them, as in the case of the fission reactions that drive existing nuclear power stations.
At the Jet experimental fusion facility at Culham in the UK, magnetic fields were used to keep plasma away from the interior wall of the reactor.
This represents a reversal of that technology: "We want to use the same technique to keep an object in the middle away from plasma that's on the outside," said Dr Bamford.
But the plasma needed to protect against particles from the solar wind and elsewhere would actually be weaker than that generated in experimental fusion reactors like Jet.
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 20 April 2007, 21:52:37
Pipe organ' plays above the Sun

Immense coils of hot, electrified gas in the Sun's atmosphere behave like a musical instrument, scientists say.
These "coronal loops" carry acoustic waves in much the same way that sound is carried through a pipe organ.
Solar explosions called micro-flares generate sound booms which are then propagated along the coronal loops.
"The effect is much like plucking a guitar string," Professor Robert von Fay-Siebenbuergen told BBC News at the National Astronomy Meeting in Preston.
The corona is an atmosphere of hot, electrically-charged gas - or plasma - that surrounds the Sun. The temperature of the corona should drop the further one moves from the Sun.
But, in fact, the coronal temperature is up to 300 times hotter than the Sun's visible surface, or photosphere. And no one can explain why.

Fiery fountains

The coronal loops arch hundreds of thousands of kilometres above the Sun's surface like huge fiery fountains, and are generated by the Sun's magnetic field.
As solar plasma travels from the photosphere into the loops, it is heated from about 6,000 Kelvin (5,700C) to upwards of one million Kelvin.
Solar explosions called micro-flares can release energy equivalent to millions of hydrogen bombs.
These blasts can send immensely powerful acoustic waves hurtling through the loops at tens of kilometres per second, creating cosmic "organ music".
"These loops can be up to 100 million kilometres long and guide waves and oscillations in a similar way to a pipe organ," said Dr Youra Taroyan, from the Solar Physics and Space Plasma Research Centre (SP2RC) at the University of Sheffield.
The sound booms decay in less than an hour and dissipate in the very hot solar corona.
Professor von Fay-Siebenbuergen, who is director of SP2RC, said that studying how plasma is heated to such high temperatures in coronal loops could speed up the technological development of industrial-scale nuclear fusion on Earth.

'Star on Earth'

Nuclear fusion is the same process which powers the Sun and other stars. Unlike the burning of fossil fuels, fusion reactions produce no carbon dioxide, the greenhouse gas blamed by scientists for warming the planet.
Fusion works on the principle that energy can be released by forcing together atomic nuclei rather than by splitting them, as in the case of the fission reactions that drive existing nuclear power stations.
In the core of the Sun, huge gravitational pressure allows this to happen at temperatures of around 10 million Celsius.
At the much lower pressure that is possible on Earth, temperatures to produce fusion need to be much higher - above 100 million Celsius
In nuclear fusion experiments, powerful magnetic fields can be used to isolate hot plasma from the walls of a containment vessel.
This reduces the conductive heat loss, allowing the electrified gas to be heated to high temperatures.
The most promising magnetic confinement systems are ring-shaped; called a torus.
Professor von Fay-Siebenbuergen said a coronal loop could give clues to improving nuclear fusion because it could be regarded as a half-torus.    ascultati muzica universului!!!!!!
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: darkness on 02 May 2007, 13:27:14
unde esti,priestess,ne lasi in urma cu  stirile??

Today NASA released stunning new images of Jupiter and its moons taken by the New Horizons spacecraft. Views include a movie of a volcanic eruption on Jupiter's moon Io; a nighttime shot of auroras and lava on Io; a color photo of the "Little Red Spot" churning in Jupiter's cloudtops; images of small moons herding dust and boulders through Jupiter's faint rings--and much more: gallery.

"We'll be analyzing these data for months to come," says Science Mission Directorate Associate Administrator and New Horizons Principal Investigator Alan Stern of NASA Headquarters. "We have collected spectacular scientific products as well as evocative images."
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 20 May 2007, 21:32:16
Planeta cu "gheata calda"

Observatorul spatial elvetian OFXB a confirmat descoperirea unei exoplanete, situata la 30 de ani-lumina de Terra, compusa in principal din "gheata calda" ultracomprimata, stare fizica inexistenta pe Pamant.
Denumita GJ436b, planeta este de 22 de ori mai mare decat Terra, fiind compusa in principal din apa. Ea are un nucleu din roca si se presupune ca este inconjurata de hidrogen.

cine mi-a dus dorul sa ridice mana :lol:
i`m back,reloaded
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 20 May 2007, 21:48:58
Astronomers using NASA's Hubble Space Telescope have discovered a ghostly ring of dark matter that formed long ago during a titanic collision between two massive galaxy clusters. The ring's discovery is among the strongest evidence yet that dark matter exists. Astronomers have long suspected the existence of the invisible substance as the source of additional gravity that holds together galaxy clusters. Such clusters would fly apart if they relied only on the gravity from their visible stars. Although astronomers don't know what dark matter is made of, they hypothesize that it is a type of elementary particle that pervades the universe.

This Hubble composite image shows the ring of dark matter in the galaxy cluster Cl 0024+17. The ring-like structure is evident in the blue map of the cluster's dark matter distribution. The map was derived from Hubble observations of how the gravity of the cluster Cl 0024+17 distorts the light of more distant galaxies, an optical illusion called gravitational lensing. Although astronomers cannot see dark matter, they can infer its existence by mapping the distorted shapes of the background galaxies. The map is superimposed on a Hubble Advanced Camera for Surveys image of the cluster taken in November 2004.

This Hubble Space Telescope composite image shows a ghostly "ring" of dark matter in the galaxy cluster Cl 0024+17.

The ring-like structure is evident in the blue map of the cluster's dark matter distribution. The map is superimposed on a Hubble image of the cluster. The ring is one of the strongest pieces of evidence to date for the existence of dark matter, an unknown substance that pervades the universe.
The map was derived from Hubble observations of how the gravity of the cluster Cl 0024+17 distorts the light of more distant galaxies, an optical illusion called gravitational lensing. Although astronomers cannot see dark matter, they can infer its existence by mapping the distorted shapes of the background galaxies. The mapping also shows how dark matter is distributed in the cluster.

Astronomers suggest that the dark-matter ring was produced from a collision between two gigantic clusters.

Dark matter makes up the bulk of the universe's material and is believed to make up the underlying structure of the cosmos.

The Hubble observations were taken in November 2004 by the Advanced Camera for Surveys (ACS). Thanks to the exquisite resolution of the ACS, astronomers saw the detailed cobweb tracery of gravitational lensing in the cluster.

Object Names: CL0024+17, ZwCl 0024+1652

Image Type: Astronomical

Credit: NASA,

si un ghid util pt iunie
isn`t it amasing!!! :-o
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: lylyt_ice on 20 May 2007, 23:44:47
pri3st3ss,cred ca toti ti-am dus dorul ,fara posturile tale rufonul este rece, fara suflet.Ai facut tu ce ai facut si ne-ai prezentat pana si o planeta de "GHEATA CALDA"
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 21 May 2007, 21:44:52
hehe,doar sunt RADIO COSMOS,nu? :lol:

uite,pentru ca ti-a fost dor de mine, iti ofer un cadou...sunt de fel generoasa :wink:

Five-Star" Rated Gravitational Lens

NASA's Hubble Space Telescope has captured the first-ever picture of a group of five star-like images of a single distant quasar.
The multiple-image effect seen in the Hubble picture is produced by a process called gravitational lensing, in which the gravitational field of a massive object — in this case, a cluster of galaxies — bends and amplifies light from an object — in this case, a quasar — farther behind it.

Although many examples of gravitational lensing have been observed, this "quintuple quasar" is the only case so far in which multiple quasar images are produced by an entire galaxy cluster acting as a gravitational lens.
The background quasar is the brilliant core of a galaxy. It is powered by a black hole, which is devouring gas and dust and creating a gusher of light in the process. When the quasar's light passes through the gravity field of the galaxy cluster that lies between us and the quasar, the light is bent by the space-warping gravity field in such a way that five separate images of the object are produced surrounding the cluster's center. The fifth quasar image is embedded to the right of the core of the central galaxy in the cluster. The cluster also creates a cobweb of images of other distant galaxies gravitationally lensed into arcs.

pt poza 3 - Globular Cluster with Multiple Stellar Populations

This Hubble telescope image of a dense swarm of stars shows the central region of the globular cluster NGC 2808.

Astronomers were surprised when Hubble spied three generations of cluster stars. The discovery is far different from the standard picture of a globular cluster. For decades, astronomers thought that cluster stars formed at the same time, in the same place, and from the same material, and have co-evolved for billions of years.

Globular clusters are the homesteaders of our Milky Way Galaxy, born during our galaxy's formation. They are compact swarms of typically hundreds of thousands of stars held together by gravity.

All the stars in NGC 2808 were born within 200 million years very early in the life of the 12.5-billion-year-old massive cluster. Of the about 150 known globular clusters in our Milky Way Galaxy, NGC 2808 is one of the most massive, containing more than 1 million stars.

pt im 4--Comet Galaxy' Being Ripped Apart By Galaxy Cluster
Space Telescope, in collaboration with several other ground- and space- based telescopes, has captured a galaxy being ripped apart by a galaxy cluster's gravitational field and harsh environment.

The finding sheds light on the mysterious process by which gas-rich spiral-shaped galaxies might evolve into gas-poor irregular- or elliptical-shaped galaxies over billions of years. The new observations also reveal one mechanism for forming the millions of "homeless" stars seen scattered throughout galaxy clusters.
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: darkness on 22 May 2007, 16:55:41
Planeta cu "gheata calda"

cine mi-a dus dorul sa ridice mana :lol:
i`m back,reloaded

i missed ya,girly!
pri3st3ss,cred ca toti ti-am dus dorul ,fara posturile tale rufonul este rece, fara suflet.Ai facut tu ce ai facut si ne-ai prezentat pana si o planeta de "GHEATA CALDA"
de acord cu lylyt si uite,ridic labuta :lol:(

welcome back!!!
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 22 May 2007, 21:17:55
Andromeda Galaxy (M31):
A New Look at a Close Neighbor

The Andromeda Galaxy is a large spiral galaxy very similar to our own Galaxy, the Milky Way. Also known as Andromeda Galaxy (M31), the Andromeda Galaxy is over 65,000 light years in diameter and approximately 2.9 million light years from Earth.

Andromeda, the nearest major galaxy to the Milky Way, is shown here in this wide-field optical image from Kitt Peak. The central region of Andromeda is shown in a composite image, with X-rays from NASA's Chandra X-ray Observatory (blue) combined with the optical image. Astronomers believe that Andromeda, also known as Andromeda Galaxy (M31), and the Milky Way will merge in a few billion years.

In the composite image, hot, X-ray bright gas is seen to envelop the central region of Andromeda. Point sources are also prominent, mostly from pairs of stars that are interacting with each other.
Many of these double stars are thought to include white dwarfs that are pulling large amounts of material away from a companion star. When the amount of gas being dumped onto the white dwarf gets too high a thermonuclear explosion occurs on the surface of the white dwarf, emitting bright X-rays.

By taking multiple observations of these so-called novae with Chandra and ESA's XMM-Newton observatories, a team of astronomers studied how long the burst of X-ray emission lasts. They found that several novae are bright in X-rays for surprisingly short periods of time, suggesting that the corresponding nova explosions were missed in earlier
observations. Such short periods of bright X-ray emission, according to theoretical calculations, indicate that the white dwarfs have relatively high masses. This makes them good candidates for progenitors of Type Ia supernovas, where a white dwarf reaches a mass limit and undergoes a thermonuclear explosion and is completely destroyed. The high masses suggested by the short X-ray outbursts suggests that the white dwarfs do not have to gain very much mass before reaching their limit and being destroyed. A long-running goal in stellar astrophysics has been to identify the elusive stars that explode as Type Ia supernovas.

SN 2006gy:
NASA's Chandra Sees Brightest Supernova Ever
- imaginea 4

According to observations by NASA's Chandra X-ray Observatory and ground-based optical telescopes, the supernova SN 2006gy is the brightest and most energetic stellar explosion ever recorded and may be a long-sought new type of explosion. The top panel of this graphic is an artist's illustration that shows what SN 2006gy may have looked like   
if viewed at a close distance. The fireworks-like material in white shows the explosion of an extremely massive star. This debris is pushing back two lobes of cool, red gas that were expelled in a large eruption from the star before it exploded. The green, blue and yellow regions in these lobes shows where gas is being heated in a shock front as the explosion material crashes into it and pushes it backwards. Most of the optical light generated by the supernova is thought to come from debris that has been heated by radioactivity, but some likely comes from the shocked gas.
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 30 May 2007, 19:30:08
Blue Moon over North America  

May 30, 2007: At 9:04 pm Eastern Daylight Time on May 31st, the full moon over North America will turn blue.

Not really. But it will be the second full moon of May and, according to folklore, that makes it a Blue Moon.If you told a person in Shakespeare's day that something happens "once in a Blue Moon" they would attach no astronomical meaning to the statement. Blue moon simply meant rare or absurd, like making a date for "the Twelfth of Never."

But "meaning is a slippery substance," writes Philip Hiscock of the Dept. of Folklore, Memorial University of Newfoundland. "The phrase 'Blue Moon' has been around a long time, well over 400 years, and during that time its meaning has shifted

The modern definition sprang up in the 1940s. In those days the Maine Farmer's Almanac offered a definition of Blue Moon so convoluted even professional astronomers struggled to understand it. It involved factors such as ecclesiastical dates of Easter and Lent, tropical years, and the timing of seasons according to the dynamical mean sun. Aiming to explain blue moons to the layman, Sky & Telescope published an article in 1946 entitled "Once in a Blue Moon." The author James Hugh Pruett (1886-1955) cited the 1937 Maine almanac and opined that the "second [full moon] in a month, so I interpret it, is called Blue Moon
Surveying the last four centuries of literature and folklore, "I have counted six different meanings which have been carried by the term," recounts Hiscock. In song, for instance, Blue Moons are a symbol of loneliness; when love conquers all, the Blue Moon turns gold. (See old Elvis records for more information.) "This makes discussion of the term a little complicated," he says.

I had never paid any real attention to the term 'Blue Moon' until one October evening in 2003," he recalls. "I had my telescope set up in the backyard and the moon began rising in the east with a strange blue tint I had not seen before."

The cause of the blue was probably tiny droplets of water in the air. "The air was damp and heavy with moisture," notes King. When water droplets are about 1 micron (one millionth of a meter) in diameter, they strongly scatter red and green light while allowing other colors to pass. A white moonbeam passing through such a misty cloud turns blue.

Clouds of ice crystals, fine-grained sand, volcanic ash or smoke from forest fires can have the same effect. "The key," notes atmospheric optics expert Les Cowley, "is that the airborne particles should all be of very similar size, a micron or so in diameter." Only then do they scatter the correct wavelengths of moonlight and act as a blue filter.

There are other reasons for blue Moons, he notes. "Our eyes have automatic 'white balances' just like digital cameras. Go outdoors from a cozy cabin lit by an oil lamp (yellow light) and the Moon will appear blue until your eyes adjust."

im 1. The first full moon of May 2007, photographed May 2nd by Tony Wilder of Wisconsin. May's second full Moon on May 31st will probably look as gray as this one, although according to folklore, it is "blue."
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: Nox on 30 May 2007, 20:44:23
Wow, interesant! Nu stiam ca exista asa ceva in realitate (ca luna se poate vedea in albastru), credeam ca e doar imaginatia mea.  :mrgreen:
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 30 May 2007, 20:50:55
nici eu nu stiam...
stiam ca in popor se numeste asa,dar ca de fapt e gri,dar vad ca tipul asta din texas a fotografiat-o albastra... o fi  fost ceva in atmosfera?!

What about Europe? Because of time zones, this week's full Moon occurs over Europe on June 1st rather than May 31st. In Europe, therefore, it is the month of June which has two full Moons, and a Blue Moon on June 30th
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: Nox on 30 May 2007, 22:25:24
More info:

Although the full moon occurring Thursday, May 31, 2007, will look like an ordinary full moon, it will actually be a bit extraordinary—a blue moon.

What is a Blue Moon?
There are in fact two definitions for a blue moon. According to the more recent definition, a blue moon is the second full moon in a calendar month. For a blue moon to occur, the first of the full moons must appear at or near the beginning of the month so that the second will fall within the same month (the average span between two moons is 29.5 days). May 2007 will have two full moons: the first on May 2, the second on May 31—that second full moon is called the blue moon.

Note that the May 31 date applies to most of the Western Hemisphere, including the United States. In the Eastern Hemisphere, the full moon in question will occur on June 1. For that half of the world, the blue moon will be on June 30, 2007.

The Other Kind of Blue Moon
An older definition for the blue moon is recorded in early issues of the Maine Farmer's Almanac. According to this definition, the blue moon is the third full moon in a season that has four full moons. Why would one want to identify the third full moon in a season of four full moons? The answer is complex, and has to do with the Christian ecclesiastical calendar.

Some years have an extra full moon—thirteen instead of twelve. Since the identity of the moons was important in the ecclesiastical calendar (the Paschal Moon, for example, used to be crucial for determining the date of Easter), a year with a thirteenth moon skewed the calendar, since there were names for only twelve moons. By identifying the extra, thirteenth moon as a blue moon, the ecclesiastical calendar was able to stay on track.

For a fuller explanation see For more background information on the controversy over the two definitions of blue moon, see the Sky and Telescope article, "What's a Blue Moon?" In it they explain how the two different definitions of a blue moon came about—including their own role in introducing the second, modern definition.

A Star Rating for the Modern Blue Moon
Although Sky & Telescope calls the modern blue moon definition "trendy" and a "mistake," the fact that there is an older, preexisting (and more complicated) definition does not necessarily make it the more interesting or meaningful definition. Charting the "third full moon in four full moons" in a season isn't everyone's idea of an fascinating enterprise. The modern, "trendy" definition, however, points to an intriguing astronomical phenomenon—every so often two moons can manage to position themselves in the same month. Given that full moons occur once every 29.5 days, this is quite an accomplishment!

How Often Does a Blue Moon Occur?
Over the next twenty years there will be a total of 17 blue moons, with an almost equal number of both types of blue moons occurring. No blue moon of any kind will occur in the years 2006, 2011, 2014, and 2017.

The more recent phenomenon, where the blue moon is considered to be the second full moon in a calendar month, last occurred on July 31, 2004. Two full moons in one month may occur in any month out of the year except for February, which is shorter than the lunar cycle.

The other, older blue moon event, which happens when there are four full moons in a season, last occured in August 2005. Since this type of blue moon is reckoned according to the seasons, it can only occur in February, May, August, or November, about a month before the equinox or the solstice.

Twice in a Blue Moon
The rare phenomenon of two blue moons (using the more recent definitition) occurring in the same year happens approximately once every 19 years. 1999 was the last time a blue moon appeared twice, in January and March.

The months of the double blue moons are almost always January and March. That is because the short month that falls in between them, February, is a key ingredient in this once-every-nineteen-year phenomenon. For January and March to each have two full moons, it's necessary for February to have none at all. Since February is usually 28 days long, and the average span between full moons is 29.5 days, if a full moon occurs at the end of January, it's possible for the next full moon to skip February entirely and fall in the beginning of March.

Once in a Blue Moon
"Blue moon" appears to have been a colloquial expression long before it developed its calendrical senses. According to the Oxford English Dictionary, the first reference to a blue moon comes from a proverb recorded in 1528:

If they say the moon is blue,
We must believe that it is true.

Saying the moon was blue was equivalent to saying the moon was made of green (or cream) cheese; it indicated an obvious absurdity. In the 19th century, the phrase until a blue moon developed, meaning "never." The phrase, once in a blue moon today has come to mean "every now and then" or "rarely"—whether it gained that meaning through association with the lunar event remains uncertain.


alte info:
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 05 June 2007, 11:45:14
Venus Flyby

The spacecraft is MESSENGER, and the planet is Venus. On June 5, 2007, MESSENGER will fly past Venus just 338 km above the planet's surface--and it will shoot a 20 Watt laser into the clouds.
MESSENGER is on a mission to Mercury, not Venus. But the spacecraft must pass by Venus for a gravity assist en route. In passing, researchers hope to learn a few things about Earth's "evil twin," an Earth-sized world with sulfuric acid clouds, a choking carbon dioxide atmosphere, and a surface hot enough to melt lead.

"We are treating the Venus flyby as a full dress rehearsal for the first flyby of Mercury in January 2008," says Sean Solomon, the mission's principal investigator at the Carnegie Institution of Washington. "All of the spacecraft's science instruments will be turned on during the flyby."

Of particular interest is the laser experiment, which aims to measure the location of Venus' cloud decks. "It could either fizzle or be a major result," says Ralph McNutt, MESSENGER's project scientist at the Johns Hopkins University Applied Physics Lab. "We've never sent a laser to Venus before. This could give us some unique information about the planet's clouds."

In addition to the laser, MESSENGER will scrutinize Venus using high-resolution cameras, a suite of spectrometers ranging in wavelength from infra-red to gamma-rays, an energetic particle counter and a magnetometer. Data from these instruments may shed new light on the chemistry of Venus' atmosphere and how it interacts with the solar wind.

Unlike Earth, Venus has no global magnetic field to protect it from solar wind. A gale of charged particles traveling 300 km/s (almost a million mph) hits Venus with full force, and to some degree this erodes the planet's atmosphere.

Cold object delights astronomers

Astrophysicists have found a star-like object with a surface temperature just one tenth that of the Sun.
The cold object is known as a brown dwarf: a "failed" star that never achieved the mass required to begin nuclear fusion reactions in its core.
This one - called J0034-00 - is thought to have a surface temperature of just 600-700 Kelvin (up to 430C/800F).
It is the coldest solitary brown dwarf ever seen, according to the British team that discovered it.
This find further tests the boundary between high-mass gas planets, like Jupiter, and the smallest brown dwarfs.

'Needle in a haystack'

"Physically, stars, brown dwarfs and the gas planets are all the same thing - they're just blobs of gas with different mass," said Dr Steve Warren, of Imperial College London, who led the project.
"And as this work progresses, we're going to start finding things between the stars which have the masses of planets, and what are we going to call them?"
Te brown dwarf was first spotted by his colleague Dr Daniel Mortlock.
"Identifying an object like J0034-00 is a more challenging version of finding a needle in a haystack," he said.
"In this case it was like looking for a piece of slightly reddish straw rather than a nice shiny needle."
It has a mass of just 15-30 times that of Jupiter and a similar diameter.
It was spotted in the early stages of the world's deepest ever near-infrared sky survey - using the UKIRT telescope in Hawaii.
Using four filters, the telescope produces 2,000 images a night - a vast amount of material to sift through.
The reason for the filters is to get an idea of the colour of objects in the sky.

'Billion times nearer'

Dr Mortlock had been looking for distant quasars when he found the brown dwarf.
"One of the interesting objects that turned up there didn't have quite the right colours for a quasar, and that was J0034-00," he said.
"The peculiar thing was it was a billion times nearer than the quasars we were actually looking for, and it looks almost identical in terms of the colours," added Dr Warren.
More observations, made at the Gemini South Telescope in Chile, were needed to work out its temperature and likely mass.
It is still too early to say exactly how far away it is from Earth, but the research team believes it could be about 50 light-years.
And that is not so far, compared with the distance from some of the stars that can be seen with the naked eye.

planeta Venus, fotografiata de Galileo in 1990
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 18 June 2007, 23:31:11
Pluto status suffers another blow

Pluto has suffered yet another blow to its status.
Not only has it been demoted from planet to "dwarf planet", research now shows that it cannot even lay claim to being the biggest of these.
A study has confirmed that the dwarf planet Eris - whose discovery prompted Pluto's relegation from planet to dwarf - outranks it in mass.
The US team, whose work is published in the journal Science, described their finding as "Pluto's last stand".


The discovery of Eris, formerly known as 2003 UB313, marked the beginning of the end for Pluto as a planet.
Previous measurements from the Hubble Space Telescope confirmed that Eris was larger in diameter than Pluto, leading the International Astronomical Union (IAU) to rule in 2006 that Pluto could no longer be classed as a planet.

First seen in 2003 but finally recognised in 2005
Given the designation 2003 UB313 until formal naming
Highly elongated orbit around Sun lasting 560 years
Currently positioned some 14.5 billion km from Earth
Has extremely frigid surface temperature of -250C
May have thin atmosphere when closest to Sun
Is accompanied by a satellite called Dysnomia

A new category of dwarf planets was adopted, into which Pluto, Eris and another body called Ceres, which is located in the asteroid belt, were placed.
Eris lies some 14.5 billion km from Earth in a region of space known as the Kuiper Belt. It has a highly elongated orbit around the Sun that lasts 560 years.
It also has a moon, which is called Dysnomia, and scientists used this satellite, along with the Keck Observatory, Hubble Space Telescope to calculate its mass.
The researchers, led by Eris' discoverer Mike Brown from the California Institute of Technology, discovered that the more distant world has 27% more mass than Pluto.

They wrote: "In addition to being the largest, Eris is also the most massive known dwarf planet."
So if Pluto qualified as a full-fledged planet, then Eris certainly should too. Astronomers attending the International Astronomical Union meeting in 2006 worked to settle this dilemma. In the end, we lost a planet rather than gaining one. Pluto was demoted and reclassified as a dwarf planet along with Eris and the asteroid Ceres, the most massive member of the asteroid belt.

Adding insult to injury for the former ninth planet, Brown has now determined that Eris is also more massive than Pluto. This new detail was determined by observations of Eris’ tiny moon Dysnomia. The Hubble Space Telescope and Keck Observatory took images of the moon’s movement, from which Brown precisely calculated Eris to be 27 percent more massive than Pluto. In fact, if you scooped up all the asteroids in the asteroid belt they would fit inside Eris, with a lot of room to spare.

Currently, Eris is more than three times farther from the Sun than Pluto. It is so cold out there that the dwarf planet’s atmosphere has frozen onto the surface as a frosty glaze. The coating gleams brightly, reflecting as much sunlight as fresh fallen snow. The path Eris takes around the Sun is shaped like an oval rather than a circle. In about 290 years, Eris will move close enough to the Sun to partially thaw. Its icy veneer will melt away revealing a rocky, speckled landscape similar to Pluto’s.

Double Explosion Heralds The Death Of A Very Massive Star - imagine

 Eta Carinae may be about to explode. But no one knows when - it may be next year, it may be one million years from now. Eta Carinae's mass - about 100 times greater than our Sun - makes it an excellent candidate for a full blown supernova. Historical records do show that about 150 years ago Eta Carinae underwent an unusual outburst that made it one of the brightest stars in the southern sky. Eta Carinae, in the Keyhole Nebula, is the only star currently thought to emit natural LASER light. This image, taken in 1996, resulted from sophisticated image-processing procedures designed to bring out new details in the unusual nebula that surrounds this rogue star. Now clearly visible are two distinct lobes, a hot central region, and strange radial streaks. The lobes are filled with lanes of gas and dust which absorb the blue and ultraviolet light emitted near the center. The streaks remain unexplained. Will these clues tell us how the nebula was formed? Will they better indicate when Eta Carinae will explode?
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 21 June 2007, 23:52:24

South is toward the top in this colorful close-up view of the Great Carina Nebula (NGC 3372), famous star-forming region of the southern sky. Covering an area surrounding the dusty Keyhole Nebula (NGC 3324) near picture center, the image spans about 40 light-years within the larger Carina Nebula at an estimated distance of 7,500 light-years. Like the more northerly Orion Nebula, the bright Carina Nebula is easily visible to the naked-eye. But the dramatic colors in this telescopic picture are mapped colors, based on three exposures through narrow filters each intended to record the light emitted by specific atoms in the gaseous nebula. Sulfur is shown in blue, hydrogen in green and oxygen in red hues. The Carina Nebula is home to young, extremely massive stars, including the still enigmatic variable Eta Carinae, a star with well over 100 times the mass of the Sun. Highlighted by diffraction spikes, Eta is just above and right (east) of the Keyhole.
"This provides strong evidence that SN 2006gy was, in fact, the death of an extremely massive star," said Dave Pooley of the University of California at Berkeley, who led the Chandra observations.

The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding. This large mass loss is similar to that seen from Eta Carinae, a massive star in our galaxy, raising suspicion that Eta Carinae may be poised to explode as a supernova. Although SN 2006gy is intrinsically the brightest supernova ever, it is in the galaxy NGC 1260, some 240 million light years away. However, Eta Carinae is only about 7,500 light years away in our own Milky Way galaxy.

si acum... pentru cei care cred ca evenimentele cosmice au legatura cu Biblia - ori invers, sau orice tip de varianta - propun acest link:  ,

( We continue to study just what all of this means. Probably the most significant cosmic thing to ever happen in our life time. If this is what the ancient writers meant as the 7th Angel then indeed we are on the brink of a major event. Even if you cannot accept Eta Carina as the 7th Angel, be aware of the possibilities for earth when it explodes. There is nothing anyone can do about it, but we all should be aware)

Domnul acela spune ca,daca Eta Carinae va eploda, vom fi capabili sa citim noaptea fara sa aprindem luminnile...In plus, e posibil sa realizeze ceva ce noi nu am reusit inca: sa distruga stratul de ozon..
vizionare placuta!
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 27 June 2007, 13:19:38
NASA'S Swift Sees Double Supernova In Galaxy

 In just the past six weeks, two supernovae have flared up in an obscure galaxy in the constellation Hercules. Never before have astronomers observed two of these powerful stellar explosions occurring in the same galaxy so close together in time.

The galaxy, known as MCG +05-43-16, is 380 million light-years from Earth. Until this year, astronomers had never sighted a supernova popping off in this stellar congregation. A supernova is an extremely energetic and life-ending explosion of a star.

Making the event even more unusual is the fact that the two supernovae belong to different types. Supernova 2007ck is a Type II event – which is triggered when the core of a massive star runs out of nuclear fuel and collapses gravitationally, producing a shock wave that blows the star to smithereens. Supernova 2007ck was first observed on May 19.

In contrast, Supernova 2007co is a Type Ia event, which occurs when a white dwarf star accretes so much material from a binary companion star that it blows up like a giant thermonuclear bomb. It was discovered on June 4, 2007. A white dwarf is the exposed core of a star after it has ejected its atmosphere; it’s approximately the size of Earth but with the mass of our Sun.

"Most galaxies have a supernova every 25 to 100 years, so it’s remarkable to have a galaxy with two supernovae discovered just 16 days apart," says Stefan Immler of NASA’s Goddard Space Flight Center. In 2006 Immler used NASA’s Swift satellite to image two supernovae in the elliptical galaxy NGC 1316, but both of those explosions were Type Ia events, and they were discovered six months apart.

The simultaneous appearance of two supernovae in one galaxy is an extremely rare occurrence, but it’s merely a coincidence and does not imply anything unusual about MCG +05-43-16. Because the two supernovae are tens of thousands of light-years from each other, and because light travels at a finite speed, astronomers in the galaxy itself, or in a different galaxy, might record the two supernovae exploding thousands of years apart.

Supernova 2007ck  is a Type II event, and Supernova 2007co (right) is a Type Ia event. The image is a combination of red, green, and blue pictures taken on June 9 and 12 by the Ultraviolet/Optical Telescope on NASA's Swift satellite, which was designed primarily to study another type of stellar explosion gamma ray bursts. (Credit: Stefan Immler NASA/GSFC, Swift Science
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 10 July 2007, 21:53:13
o uimitoare cometa verde, VZ13  , trece pe langa constelatia Draco..uitati-va spre nord cu binoclul
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 11 July 2007, 23:43:49
NASA's Spitzer Finds Water Vapor on Hot, Alien Planet

A scorching-hot gas planet beyond our solar system is steaming up with water vapor, according to new observations from NASA's Spitzer Space Telescope.

The planet, called HD 189733b, swelters as it zips closely around its star every two days or so. Astronomers had predicted that planets of this class, termed "hot Jupiters," would contain water vapor in their atmospheres. Yet finding solid evidence for this has been slippery. These latest data are the most convincing yet that hot Jupiters are "wet."

"We're thrilled to have identified clear signs of water on a planet that is trillions of miles away," said Giovanna Tinetti, a European Space Agency fellow at the Institute d'Astrophysique de Paris in France. " Tinetti is lead author of a paper on HD 189733b appearing today in Nature.

Although water is an essential ingredient to life as we know it, wet, hot Jupiters are not likely to harbor any creatures. Previous measurements from Spitzer indicate that HD 189733b is a fiery 1,000 Kelvin (1,340 degrees Fahrenheit) on average. Ultimately, astronomers hope to use instruments like those on Spitzer to find water on rocky, habitable planets like Earth.

"Finding water on this planet implies that other planets in the universe, possibly even rocky ones, could also have water," said co-author Sean Carey of NASA's Spitzer Science Center at the California Institute of Technology in Pasadena. "I'm excited to tell my nephews and niece about the discovery."

The new findings are part of a brand new field of science investigating the climate on exoplanets, or planets outside our solar system. Such faraway planets cannot be seen directly; however, in the past few years, astronomers have begun to glean information about their atmospheres by observing a subset of hot Jupiters that transit, or pass in front of, their stars as seen from Earth.

Earlier this year, Spitzer became the first telescope to analyze, or break apart, the light from two transiting hot Jupiters, HD 189733b and HD 209458b. One of its instruments, called a spectrometer, observed the planets as they dipped behind their stars in what is called the secondary eclipse. This led to the first-ever "fingerprint," or spectrum, of an exoplanet's light. Yet, the results came up "dry," probably because the structure of these planets' atmospheres makes finding water with this method difficult.

Later, a team of astronomers found hints of water in HD 209458b by analyzing visible-light data taken by NASA's Hubble Space Telescope. The Hubble data were captured as the planet crossed in front of the star, an event called the primary eclipse.

Now, Tinetti and her team have captured the best evidence yet for wet, hot Jupiters by watching HD 189733b's primary eclipse in infrared light with Spitzer. In this method, changes in infrared light from the star are measured as the planet slips by, filtering starlight through its outer atmosphere. The astronomers observed the eclipse with Spitzer's infrared array camera at three different infrared wavelengths and noticed that for each wavelength a different amount of light was absorbed by the planet. The pattern by which this absorption varies with wavelength matches that created by water.

"Water is the only molecule that can explain that behavior," said Tinetti. "Observing primary eclipses in infrared light is the best way to search for this molecule in exoplanets."

The water on HD 189733b is too hot to condense into clouds; however, previous observations of the planet from Spitzer and other ground and space-based telescopes suggest that it might have dry clouds, along with high winds and a hot, sun-facing side that is warmer than its dark side. HD 189733b is located 63 light-years away in the constellation Vulpecula.

Other authors of the Nature paper include Alfred Vidal-Madjar, Jean-Phillippe Beaulieu, David Sing and Nicole Allard of the Institute d'Astrophysique de Paris: Mao-Chang Liang of Caltech and the Academia Sinica, Taiwan; Yuk Yung of Caltech; Robert J. Barber and Jonathan Tennyson of University College London in England; Ignasi Ribas of the Institut de Ciències de l'Espai, Spain; Gilda E. Ballester of the University of Arizona, Tucson; and Franck Selsis of the Ecole Normale Supérieure, France. JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, Pasadena. JPL is a division of Caltech. Spitzer's infrared array camera was built by NASA's Goddard Space Flight Center, Greenbelt, Md. The instrument's principal investigator is Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass.

Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 12 July 2007, 13:16:24
Astronomers claim galaxy record

The detections were made at the Keck Observatory
Astronomers say they may have detected the light from some of the earliest stars to form in the Universe.
They have pictures of what appear to be very faint galaxies that shone more than 13 billion years ago, a mere 500 million years after the Big Bang.
The remarkable claim dramatically exceeds the current, broadly accepted record for the most distant detection.
The Caltech-led team behind the work recognises there will be sceptics but says it believes its data is strong.
It has published details in The Astrophysical Journal; and the group leader, Professor Richard Ellis, has been arguing the case at a conference in London, UK.
"We've had these galaxies for over a year and we have gone back to the telescope and revisited them, to prove their signals are robust," he explained.
"We feel confident now that we have done all that is humanly possibly to show the community that these galaxies are at these great distances," Professor Ellis told BBC News.

Big zoom

The international team of astronomers found its six "candidate" galaxies using one of the 10m Keck telescope twins sited on Mauna Kea, Hawaii.
The researchers employed a technique known as gravitational lensing to achieve the detections.
This makes use of the gravity of relatively nearby objects (in this case galaxy clusters) to magnify the light coming from much more distant objects (the six candidates).

More details
Astronomers from Caltech (California Institute of Technology) have helped pioneer this field; and they say they know how to select just the right "zoom lens" to see back into the required period in cosmic history.  - im 1
The team then further refined its search by only looking for a very narrow wavelength of light where its target galaxies - if they existed - would be expected to shine.

It has taken three years' painstaking work to make and check the observations.
"Using Keck II, we have detected six faint star-forming galaxies whose signal has been boosted about 20 times by the magnifying effect of a foreground cluster," said Caltech co-worker Dan Stark.
"That we should find so many distant galaxies in our small survey area suggests they are very numerous indeed."

It's a crowd

This is perhaps the most significant implication of the study.
Astronomy is now engaged in a major drive to tie down the timings of key events in the early Universe.
Scientists would like to see extensive evidence for the very first populations of stars. These hot, blue giants would have grown out of the cold neutral gas that pervaded the young cosmos.

Peering at a distant epoch 

The behemoths would likely have burned brilliant but brief lives, producing the very first heavy elements.
They would also have "fried" the neutral gas around them to produce the diffuse intergalactic plasma we detect between nearby stars today.
But this theory demands the earliest star-forming phase in the Universe was a busy one - and the significance of the latest study is that it suggests the numbers of stars required did indeed exist.
"The area of sky we surveyed was so small that for us to find anything at all suggests to us these objects must be very numerous," Professor Ellis told the BBC News website.
"Obviously it's a bit of a stretch to estimate a population from just six objects - but if you went out into a London street, looked at one piece of pavement and found six people standing there, I think you could reasonably conclude London was a crowded place."

Redshift hunters

It has been known for a while that the Caltech-led group had some very interesting pictures. In the past 12 months, knowledge of their existence has been shared at scientific conferences and hinted at by popular publications such as Time Magazine and the BBC News website.
But Ellis and colleagues have deliberately held back from formal publication of their work. Theirs is a field which has burned the reputations of others who have rushed forward with announcements that could not be confirmed by subsequent, independent observation.
Even so, to get an idea of how big a leap in detection is now being claimed can be illustrated by the "ruler" astronomers use to describe far-off sightings.
They will often be heard referring to "redshift". It is a measure of the degree to which light has been "stretched" by the expansion of the Universe. The greater the redshift, the more distant the object and the earlier it is being seen in cosmic history.
The current, widely accepted distance record-holder is the IOK-1 galaxy detection announced last year which had a redshift of 6.96. Its light was being seen when the Universe was little more than 700 million years old (Current estimates have the Universe coming into existence about 13.66 billion years ago as a "hot soup" of elementary particles).
Getting to this mark was a process of steady, incremental steps through redshifts in the lower-sixes and fives. The Caltech-led group has now suddenly jumped into the redshift region of eight to 10.

Dr Andy Bunker is a high-redshift hunter with Exeter University, UK. He has worked with the Ellis group in the past but was not involved in this study.
He commented: "Richard is a careful worker and he knows the burden of proof is very high.

"His group is aware of the history of the field and that's why they are being a little bit cagey; but I think this is a significant paper and unlike many that have gone before, I believe this will stand the test of time and at least some of the six candidates will be confirmed by others in due course."
The Caltech-led group hopes soon to get some confirmation of its own by looking at a different wavelength of light using the Spitzer Space Telescope and through the use of a new spectrograph instrument which is being installed at the Keck.
A refurbished Hubble Space Telescope is expected to be able to reach up to redshift 10; and its successor, the James Webb Space Telescope, due for launch early in the next decade, should be capable of redshift 15 observations.
Richard Ellis, the Steele Professor of Astronomy at Caltech, Pasadena, US, delivered a talk at the From IRAS to Herschel and Planck Conference. The meeting was organised to celebrate the 65th birthday of Royal Astronomical Society President Professor Michael Rowan-Robinson.  - im 2


im 1 - Images of the cluster fields with the newly located candidates marked. Three clusters gave up six candidates. Each foreground galaxy cluster acts as a "zoom lens". Magnification is predicted to be strong along "critical lines" (black lines). The Keck was used to search specifically these regions.

im 2 - Even the powerful Keck struggles to see the greatest distances
It uses a trick - a gravitational zoom lens to magnify far-off objects
The candidate galaxies are among the first to form in the Universe
Their stars would have helped end a period dubbed the 'Dark Ages'
In this cold phase the Universe was filled with neutral gas atoms
The stars of the 'Cosmic Renaissance' changed their environment
These giants' nuclear cores synthesised the first heavy elements
Their intense ultraviolet light also 'fried' the neutral gas atoms
The resulting plasma - free electrons and protons - is evident today
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 13 July 2007, 13:50:34
The origin of perennial water-ice at the South Pole of Mars

Thanks to data from ESA's Mars Express mission, combined with models of the Martian climate, scientists can now suggest how the orbit of Mars around the Sun affects the deposition of water ice at the Martian South Pole.
Early during the mission, the OMEGA instrument (Visible and Infrared Mineralogical Mapping Spectrometer) on board Mars Express had already found previously undetected perennial deposits of water-ice. They are sitting on top of million-year old layered terrains and provide strong evidence for a recent glacial activity.
However, only now a realistic explanation for the age of the deposits and the mechanism of their formation could finally be suggested. This was achieved thanks to the OMEGA mapping and characterisation of these ice deposits, combined with the computer-generated Martian Global Climate Models (GCMs). 
The mapping and spectral analysis by OMEGA has shown that the perennial deposits on the Martian South Pole are of essentially three types: water-ice mixed with carbon dioxide (CO2) ice, tens-of-kilometres-wide patches of water-ice, and deposits covered by a thin layer of CO2 ice.
The discovery of the ice deposits of the first type confirms the long-standing hypothesis that CO2 acts as a cold-trap for water-ice. But how were the other two types of deposits, not ‘trapped’ by CO2, accumulated and preserved over time?
Franck Montmessin, from the Service d'Aéronomie du CNRS/IPSL (France) and lead author of the findings, explains how the deposits of water ice at the Martian's poles 'behave'. "We believe that the deposits of water-ice are juggled between Mars’ North and South Poles over a cycle that spans 51 000 years, corresponding to the time span in which the planet's precession is inverted." Precession is the phenomenon by which the rotation axis of a planet wobbles.Montmessin and colleagues came to the conclusion by turning back time in their Mars climate computer model. This was done by changing the precession together with other orbital information.  - fig 2
The scientists set the clock 21 000 years back, when the closest vicinity of the planet to the Sun corresponded to the northern summer – a situation opposite to that of today.
The model has shown that water at the North Pole was in an unstable condition and was easily transported to the South Pole in the form of water vapour, to then re-condense and freeze on the surface. Up to 1 millimetre of water ice was deposited at the South Pole every year. After Mars has spent more than 10 000 years in that climatic configuration, this accumulation led to a layer up to 6-metre thick.
About 10 000 years ago the precession cycle was inverted, and started to return to its current configuration. Water-ice at the South Pole became unstable, and was forced to progressively return back to the North.
About 1000 years ago, by a not-yet-well explained trigger mechanism, the erosion of the water-ice deposits at the South pole was blocked as soon as layers of CO2 ice were deposited on the water-ice and trapped it, as OMEGA has observed them.
Note for editors
Mars is currently experiencing 'Southern summer' – that is, water ice is more likely to accumulate at the North Pole.

Types of ice deposits at the South Pole of Mars - fig 1
Water-ice accumulation rate at Martian South Pole - fig 2
Recent evolution of water-ice at the south pole of Mars -  fig 3
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 13 July 2007, 22:17:34 - cate ceva despre luna

in imagine : This  image was taken by the Far Infrared Surveyor instrument on Japan's Akari spacecraft. It shows star-forming regions in the constellation Cygnus, one of the brightest regions in the Milky Way.
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 18 July 2007, 23:40:09
X-ray satellites discover the biggest collisions in the Universe

 The Bullet Cluster is a much-studied pair of galaxy clusters, which have collided head on. One has passed through the other, like a bullet travelling through an apple. In the Bullet Cluster, this is happening across our line of sight, so we can clearly see the two clusters.

The optical image from the Magellan and the Hubble Space Telescope shows galaxies in orange and white in the background. Hot gas, which contains the bulk of the normal matter in the cluster, is shown by the Chandra X-ray image, which showst the hot intracluster gas (pink). Gravitational lensing, the distortion of background images by mass in the cluster, reveals the mass of the cluster is dominated by dark matter (blue), an exotic form of matter abundant in the Universe, with very different properties compared to normal matter.

This was the first clear separation seen between normal and dark matter.

Credits: X-ray: NASA
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: calinahanna on 19 July 2007, 14:37:57
Ca efect estetic e mai mult decat bestial... in sensul bun al cuvantului, bineinteles...
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 24 July 2007, 14:25:22
Astronomers Find Highly Elliptical Disk Around Young Star

Dust and debris parade in an extremely misshapen ring around the young star, HD 15115. The disk, seen edge-on with NASA's Hubble Space Telescope, is the dense blue line extending from the star to the upper right and lower left of the image. The disk appears thicker at upper right than at lower left, evidence of its lopsided structure. Astronomers think the disk's needle-like look is caused by dust particles following a highly elliptical orbit around the star
Astronomers using the Hubble Space Telescope and W. M. Keck Observatory have found a lopsided debris disk around a young star known as HD 15115. As seen from Earth, the edge-on disk resembles a needle sticking out from the star.
Astronomers think the disk's odd imbalanced look is caused by dust following a highly elliptical orbit about the star. The lopsided disk may have been caused by the gravity of planets sweeping up debris in the disk or by the gravity of a nearby star.

The observations were made by Paul Kalas, James Graham, and Michael P. Fitzgerald, all from the University of California at Berkeley. Their paper appeared in The Astrophysical Journal Letters.

"The lopsided disk presents a host of new challenges for theorists," said Kalas.

Debris disks are produced by dust from collisions among protoplanetary bodies, which are the building blocks of planets. These dusty disks can be affected by planets nearer to the star, much as Jupiter's gravity affects asteroids in the asteroid belt.

This discovery is consistent with models for planetary upheavals in our own solar system, where Neptune may have originally formed between Saturn and Uranus. Neptune was eventually kicked out to its present location by a gravitational dance between Saturn and Jupiter before their orbits stabilized. "Therefore, we speculate that if such a planetary upheaval were occurring around HD 15115 at the present time, it could explain the highly asymmetric disk," Kalas said.

This might happen through a powerful gravitational interaction between planets that kicks one or more planets into highly elliptical orbits, or even ejects them into interstellar space. When the planet's orbit becomes elliptical through a violent upheaval, the rest of the disk can be disturbed into an elliptical shape, according to Kalas.

Kalas also is studying whether the gravity of a star known as HIP 12545, located about 10 light-years from HD 15115, may have created the disk's lopsided shape due to a close encounter in the past.

Dusty disks are known to exist around at least 100 stars, but because of the difficulty in observing material within the glare of a star, less than a dozen have been studied closely.

HD 15115 and HIP 12545 are among nearly 30 stars that belong to the Beta Pictoris Moving Group. Moving groups are expanded clusters of stars believed to have a common birthplace and age that are traveling loosely together through space.

The dusty disk around HD 15115 was first inferred by observations at infrared wavelengths in 2000 and its existence confirmed in 2006 when the Hubble Space Telescope (HST) resolved the disk in reflected light for the first time. The disk was investigated further using Keck adaptive optics in 2006 and 2007.

"The disk was seen in the HST data, but its appearance was so extraordinary we could not be certain that it was real. It took follow-up observations at Keck to confirm that it was a real disk," Kalas said.

Credit: NASA, ESA, and P. Kalas (University of California, Berkeley)
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 31 July 2007, 22:20:50
New Type Of Active Galaxy Discovered

An international team of astronomers using NASA’s Swift satellite and the Japanese/U.S. Suzaku X-ray observatory has discovered a new class of active galactic nuclei (AGN).

By now, you’d think that astronomers would have found all the different classes of AGN — extraordinarily energetic cores of galaxies powered by accreting supermassive black holes. AGN such as quasars, blazars, and Seyfert galaxies are among the most luminous objects in our Universe, often pouring out the energy of billions of stars from a region no larger than our solar system.

But by using Swift and Suzaku, the team has discovered that a relatively common class of AGN has escaped detection…until now. These objects are so heavily shrouded in gas and dust that virtually no light gets out.

"This is an important discovery because it will help us better understand why some supermassive black holes shine and others don’t," says astronomer and team member Jack Tueller of NASA’s Goddard Space Flight Center in Greenbelt, Md.

Evidence for this new type of AGN began surfacing over the past two years. Using Swift’s Burst Alert Telescope (BAT), a team led by Tueller has found several hundred relatively nearby AGNs that were previously missed because their visible and ultraviolet light was smothered by gas and dust. The BAT was able to detect high-energy X-rays from these heavily blanketed AGNs because, unlike visible light, high-energy X-rays can punch through thick gas and dust.

To follow up on this discovery, Yoshihiro Ueda of Kyoto University, Japan, Tueller, and a team of Japanese and American astronomers targeted two of these AGNs with Suzaku. They were hoping to determine whether these heavily obscured AGNs are basically the same type of objects as other AGN, or whether they are fundamentally different. The AGNs reside in the galaxies ESO 005-G004 and ESO 297-G018, which are about 80 million and 350 million light-years from Earth, respectively.

Suzaku covers a broader range of X-ray energies than BAT, so astronomers expected Suzaku to see X-rays across a wide swath of the X-ray spectum. But despite Suzaku’s high sensitivity, it detected very few low- or medium-energy X-rays from these two AGN, which explains why previous X-ray AGN surveys missed them.

According to popular models, AGNs are surrounded by a donut-shaped ring of material, which partially obscures our view of the black hole. Our viewing angle with respect to the donut determines what type of object we see. But team member Richard Mushotzky, also at NASA Goddard, thinks these newly discovered AGN are completely surrounded by a shell of obscuring material. "We can see visible light from other types of AGN because there is scattered light," says Mushotzky. "But in these two galaxies, all the light coming from the nucleus is totally blocked."

Another possibility is that these AGN have little gas in their vicinity. In other AGN, the gas scatters light at other wavelengths, which makes the AGN visible even if they are shrouded in obscuring material.

"Our results imply that there must be a large number of yet unrecognized obscured AGNs in the local universe," says Ueda.

In fact, these objects might comprise about 20 percent of point sources comprising the X-ray background, a glow of X-ray radiation that pervades our Universe. NASA’s Chandra X-ray Observatory has found that this background is actually produced by huge numbers of AGNs, but Chandra was unable to identify the nature of all the sources.

By missing this new class, previous AGN surveys were heavily biased, and thus gave an incomplete picture of how supermassive black holes and their host galaxies have evolved over cosmic history. "We think these black holes have played a crucial role in controlling the formation of galaxies, and they control the flow of matter into clusters," says Tueller. "You can’t understand the universe without understanding giant black holes and what they’re doing. To complete our understanding we must have an unbiased sample."In the newly discovered type of AGN, the disk and torus surrounding the black hole are so deeply obscured by gas and dust that no visible light escapes, making them very difficult to detect. (Credit: Aurore Simonnet, Sonoma State University.)

The discovery paper will appear in the August 1st issue of the Astrophysical Journal Letters.

Post by: pri3st3ss on 20 February 2008, 21:57:20
In noaptea zilei de 20/21 februarie 2008 va avea loc prima eclipsa a anului 2008 vizibila din Romania si ultima eclipsa totala de Luna a deceniului intai din secolul XXI. Aceasta eclipsa va fi deosebit de frumoasa, faza de totalitate durand aproape 50 de minute. In Romania eclipsa este asteptata cu nerabdare urmand eclipsei din 3/4 martie 2007 cand conditiile meteorologice nu au permis observarea eclipsei dar si pentru ca dupa aceasta eclipsa urmatoarea eclipsa totala de Luna vizibila din Romania se va produce pe 15 iunie 2011.

Seria Saros

Eclipsa de Luna din 21 februarie face parte din seria Saros 133 fiind a 26-a eclipsa din cele 71 ale seriei. In aceasta serie eclipsa din 21 februarie 2008 este a 6-a eclipsa totala. In total seria produce 21 de eclipse totale
In noaptea de 20/21 februarie Luna se va afla pe teritoriul constelatiei Leo si va trece printre stelele Regulus (alfa Leonis, m=+1.35) si 31 Leonis (m=+4.37). De asemenea la doar 3° nord-est de Luna se va afla planeta Saturn (m=+0.2). Discul lunar va avea diametrul aparent de 31.5'. Luna va rasari in seara zilei de miercuri, 20 februarie la ora 17.15 la est-nord-est. Apoi, Luna va trece la meridian la ora 00.27 avand altitudinea maxima de 53°. Eclipsa de Luna va incepe sa fie vizibila in jurul orei 03.00 cand pe discul lunar va incepe sa fie observata penumbra terestra. De precizat ca pentru a observa penumbra terestra e nevoie de un cer bun si experienta in domeniu. Dupa acest moment eclipsa se va desfasura conform datelor din tabelul urmator:

Momentul eclipsei Ora de iarna
Intrarea Lunii in penumbra 02h36m35s
Inceputul eclipsei partiale 03h43m19s
Inceputul eclipsei totale 05h01m10s
Faza maxima  05h26m05s
Sfarsitul eclipsei totale 05h50m57s
Sfarsitul eclipsei partiale  07h08m47s
Iesirea Lunii din penumbra  08h15m39s

Eclipsa totala de Luna din 21 februarie 2008 va avea un farmec deosebit pentru ca se produce la sfarsitul noptii terminandu-se cu apusul Lunii in crepusculul de dimineata. Astfel in Romania Luna va apune cand penumbra Pamantului se va afla inca pe discul acesteia. Totusi in zonele cu orizont vestic inalt (munti, vegetatie, etc) Luna va disparea inca in eclipsa partiala.

Desfasurarea eclipsei

Eclipsa de Luna din 21 februarie 2008 va debuta la ora 02.37 cand Luna va incepe sa se cufunde in penumbra terestra. Totusi, cum am amintit si mai inainte, penumbra nu se va putea observa pe discul lunar numai in jurul orei 03.00 cand va acoperi o suprafata suficient de mare pentru a iesi in evidenta nuanta mai inchisa a zonelor aflate in eclipsa. In acest moment Luna se va afla la sud-vest la o altitudine de 41°. Dupa aceasta, eclipsa va fi tot mai evidenta prin scaderea luminozitatii discului lunar dinspre est.

Eclipsa prin umbra incepe la ora 03.43 cand estul discului lunar dispare in intuneric. Din acest moment eclipsa a inceput in adevaratul sens al cuvantului si poate fi observata de oricine si din orice loc cu cer senin si cu Luna pe cer. In acest moment Luna a mai coborat pe cer avand o altitudine de 35° si aflandu-se foarte aproape de steaua 31 Leonis. Mai precis la ora 03.45 steaua se va afla la doar 24' de centrul discului lunar si la numai 8' de limbul sud-vestic al astrului noptii. Cu ochiul liber steaua 31 Leonis se va gasi exact sub Luna aflata in eclipsa. In continuare eclipsa avanseaza si umbra Pamantului va parea ca inainteaza tot mai mult pe discul Lunii dinspre est. In realitate, in spatiu Luna se cufunda in interiorul umbrei planetei noastre apropiindu-se de eclipsa totala. Odata cu trecerea minutelor, lumina dimprejur va scadea treptat, cerul se va intuneca iar obiectele mai putin stralucitoare vor deveni tot mai evidente. Astfel, obiectele deep-sky (galaxiile, nebuloasele, roiurile de stele) se vor putea observa in conditii mai bune.

Putin dupa ora 5 (mai precis la ora 05.01) incepe eclipsa totala. Intreg discul lunar se va afla cufundat in interiorul umbrei Pamantului. Din acest moment cerul va fi la fel de negru ca intr-o noapte fara Luna si va recomand sa mai aruncati cate un ochi la obiectele deep-sky prezente pe cer. Discul lunar va avea o culoare rosiatica insa nuanta sau nuantele exacte nu se pot calcula. Culoarea exacta a Lunii in timpul eclipsei totale depinde foarte mult de starea, din acel moment, a atmosferei terestre care poate permite mai mult sau mai putin trecerea luminii rosii in interiorul conului de umbra. De-a lungul timpului au fost observate eclipse totale de Luna in care culoarea discului lunar a variat de la galben-orange, la rosu, maroniu sau chiar negru. Sa vedem ce surpriza ne rezerva aceasta eclipsa de Luna.

Faza maxima a eclipsei se va produce la ora 05.26. Luna se va afla cel mai aproape de centrul petei de umbra a Pamantului: limbul nordic se va gasi la 7' sud de axa conului de umbra in timp ce limbul sudic se va afla la doar 3' de limita sudica umbrei terestre. Astfel in acest moment pe discul lunar lumina va fi mai intensa in zona sudica iar culoarea acestuia nu va fi uniforma. De asemenea aspectul Lunii eclipsate poate varia odata cu trecerea timpului de aceea va recomand sa estimati valoarea Danjon a eclipsei de mai multe ori in timpul totalitatii. Magnitudinea eclipsei in faza maxima va fi de 1.1062. Luna se va afla deasupra orizontului vestic la o altitudine de 18°.

Dupa aproape 50 de minute de eclipsa totala, la ora 05.50, Luna incepe sa paraseasca umbra terestra iar faza totala a eclipsei se termina. Discul lunar incepe sa reapara in zona estica a acestuia. Luna mai coboara spre orizont ajungand la altitudinea de 15° deasupra orizontului vestic. Simultan cu cresterea luminii Lunii la vest, la est va creste lumina crepusculului de dimineata care a inceput la ora 05.39. Cu trecerea minutelor Luna ia din nou aspectul unei seceri si se apropie tot mai mult de orizontul vestic.

La ora 6.30 Luna stapaneste orizontul vestic de la o altitudine de 6° fiind inca acoperita in raport de 50% de umbra terestra. Luna se apropie incet de apus dar si de sfarsitul eclipsei partiale. Acesta se produce la ora 07.09 dar, pentru unele zone ale tarii la aceasta ora Luna deja va fi apus (in functie de locatie si de orizontul vestic). Apusul Lunii se produce in jurul orei 07.15. Tot in jurul acestui moment la sud-est va rasari Soarele.

Eclipsa de Luna va continua si dupa apusul Lunii pana la ora 08.15 cand Luna va parasi si penumbra terestra. Cu aceasta ia sfarsit eclipsa totala de Luna din 21 februarie 2008.

Sfaturi pentru observarea eclipsei

Pentru a observa in conditii bune eclipsa de Luna din 21 februarie 2008 trebuie sa va alegeti un loc de observare unde orizontul vestic sa fie cat mai jos. Astfel veti putea observa faza partiala finala a eclipsei cat mai mult inainte de apusul Lunii. De asemenea pentru a putea admira cu adevarat spectacolul cerului din noaptea de 20/21 februarie va recomand sa va deplasati in afara localitatilor, in locuri cu poluare luminoasa cat mai mica.

In timpul eclipsei constelatiile de primavara sunt bine plasate pentru a fi observate. Astfel cerul va fi vegheat de stelele Regulus, Spica, Arcturus, Alphard (alfa Hydrae), Antares, Vega, Deneb si Altair. De asemenea si planetele vor fi prezente pe cer in timpul eclipsei: Saturn se va afla destul de aproape de Luna, Marte apune la 04.30, Jupiter rasare la 05.10, Mercur si Venus in jurul orei 06.15 fiind la o distanta de doar 4°.

Pentru observarea eclipsei recomand folosirea unui instrument de orice fel: binoclu, luneta sau telescop. Bineinteles ca si cu ochiul liber totul va arata superb insa instrumentele vor arata detalii fine ale fenomenului. Incercati sa folositi grosismente cat mai mici pentru a avea o imagine de ansamblu. Eu recomand sa observati eclipsa la 30-40x dar puteti sa mergeti pana pe la 75x. E bine sa aveti campul in telescop macar 50'-55' (cam 1.7-1.8 diametre aparente lunare).

sursa  :

P.S. : rog varcolacii sa nu consume luna cu prea mult sare,zahar si alcool :-D :wink:
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 22 March 2008, 20:27:23
spiral galaxy NGC 4565

This image was created by median combining 7 x 90 second unfiltered images taken with a Takahashi Epsilon 250 with SBIG ST-8XE CCD. The image has been cut down to be 20 x 20 arc minutes in size.The edge-on spiral galaxy NGC 4565 is a celestial showpiece - far superior to some of the Messier entries. This view resembles what we would see of our own Milky Way if seen from outside near its galactic equatorial plane. NGC 4565 is about 31 million light years distant.
( im 1 )

Star explodes halfway across universe

The explosion of a star halfway across the universe was so huge it set a record for the most distant object that could be seen on Earth by the naked eye.
A star 7.5 billion light years away exploded, giving off the brightest gamma-ray burst afterglow ever seen.
 The aging star, in a previously unknown galaxy, exploded in a gamma ray burst 7.5 billion light years away, its light finally reaching Earth early Wednesday.
The gamma rays were detected by NASA's Swift satellite at 2:12 a.m. "We'd never seen one before so bright and at such a distance," NASA's Neil Gehrels said.
It was bright enough to be seen with the naked eye.
However, NASA has no reports that any skywatchers spotted the burst, which lasted less than an hour.
Telescopic measurements show that the burst -- which occurred when the universe was about half its current age -- was bright enough to be seen without a telescope.
"Someone would have had to run out and look at it with a naked eye, but didn't," said Gehrels, chief of NASA's astroparticles physics lab at Goddard Space Flight Center in Greenbelt, Md.
The starburst would have appeared as bright as some of the stars in the handle of the Little Dipper constellation, said Penn State University astronomer David Burrows. How it looked wasn't remarkable, but the distance traveled was.The 7.5 billion light years away far eclipses the previous naked eye record of 2.5 million light years. One light year is 5.9 trillion miles.
"This is roughly halfway to the edge of the universe," Burrows said.
Before it exploded, the star was about 40 times bigger than our sun. The explosion vaporized any planet nearby, Gehrels said

Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 23 March 2008, 19:38:26
Un pas inainte in cautarea vietii extraterestre

NASA a identificat, in premiera, o molecula organica pe o planeta din afara sistemului nostru solar. Poarta numele de HD 189733b, are dimensiunea lui Jupiter si este situata la 63 de ani-lumina, in constelatia Vulpecula (Vulpea). Un corp ceresc ca oricare altul, pina cind a devenit, gratie unor cercetatori NASA, prima planeta extrasolara in atmosfera careia s-a gasit o molecula organica. Mai mult, molecula in cauza este cea de metan (combinatie de carbon si hidrogen), substanta care, in anumite conditii, joaca un rol crucial in chimia prebiotica, adica in reatiile chimice considerate necesare pentru ca viata, asa cum o stim, sa apara. Descoperirea, realizata cu ajutorul telescopului spatial Hubble, apartine unei echipe conduse de Mark Swain, de la Laboratorului NASA de Propulsie Jet din Pasadena, California, care-i mai include pe Gautam Vasisht, de la acelasi institut, si pe Giovanna Tinetti, astrobiolog in cadrul University College London. Rezultatele cercetatarii au aparut in editia de azi a publicatiei “Nature”, noteaza site-ul NASA.

Pe linga metan, atmosfera planetei contine si apa, insa oamenii de stiinta exclud posibilitatea prezentei vreunei forme de viata, deoarece HD 189733b are o orbita mai apropiata de steaua careia ii da tircoale decit cea pe care este inscrisa planeta Mercur (prima planeta din sitemul solar) fata de Soare. In consecinta, atmosfera planetei se ridica la peste 900 de grade Celsius, temperatura apropiata de punctul de topire al argintului. Viata n-ar rezista in asemenea conditii, explica Giovanna Tinetti, citata de “BBC Online”: “Desi metanul descoperit este un produs organic, n-a fost generat de organisme vii. Este mult prea cald acolo pentru asa ceva”. Chiar daca nu au dat de viata, cercetatorii n-au de gind sa se lase cu una, cu doua, asa cum explica astrobiologul: “Am fi prea aroganti sa ne imaginam ca sintem singurele creaturi din univers”.

Studiul celor trei reprezinta trecerea de la simpla identificare a exoplanetelor (planetele situate in afara sistemului nostru solar), la determinarea compozitiei chimice a atmosferei lor. “Putem acum sa analizam structura chimica a atmosferei exoplanetelor. Este o descoperire foarte importanta”, a declarat, ieri, Mark Swain, in cadrul unei conferinte de presa, dupa cum noteaza “New York Times”. Mai mult, el a subliniat, pentru “The Telegraph”, ca “masuratorile efectuate sint un pas important spre scopul final, acela de a stabili toate conditiile atmosferice ale unei planete, precum temperatura, presiunea, intensitatea vintului si caracteristicile straturilor de nori”. In prezent, oamenii de stiinta cunosc doar masa si orbitele celor in 270 de exoplanete descoperite. “La 13 ani dupa descoperirea primei exoplanete, incepem sa adunam suficiente date despre corpurile ceresti pentru a le putea acorda titlul de lumi”, a declarat profesorul Adam Showman, de la Universitatea Arizona, care nu a participat la proiect. El a subliniat ca, pentru ca viata sa fie posibila, metanul trebuie sa fie insotit de oxigen, lucru care nu este valabil in cazul HD 189733b.

Pentru a determina compozitia atmosferica a planetei, cercetatorii au asteptat ca ea sa se pozitioneze in fata stelei pe care o inconjoara, din punctul de vedere al unui observator terestru. Cind razele stelei au maturat planeta, gazele atmosferice si-au lasat amprenta pe respectivul flux de lumina. Metoda numita spetroscopie, care separa lumina in componentele din care este alcatuita, a dezvaluit amprenta chimica a metanului. “Spetroscopia va fi aplicata, eventual, si in cazul unei planete mai reci, potential locuibile”, a spus Swain. Scopul ultim al echipei pe care o conduce este sa identifice molecule prebiotice in atmosfera planetelor situate in “zonele locuibile”, unde temperaturile sint potrivite pentru ca apa sa se pastreze in stare lichida, si nu sa se evapore sau sa inghete.

Cercetatorii cauta Evul Intunecat al cosmosului

Oamenii de stiinta vor incerca sa studieze perioada in care universul nu primea lumina de la nici un astru, pentru a-i intelege evolutia.O echipa de cercetatori si ingineri condusi de Laboratorul de Cercetare Navala din SUA va studia, in cadrul proiectului Dark Ages Lunar Interferometer (DALI), cum sa conceapa un telescop pe Luna care sa descoasa ultima era neexplorata din istoria universului, mai precis primele 100 de milioane de ani din tineretea sa, anunta publicatia „Science Daily“.
Desi cerul de noapte este plin de stele, acestea nu s-au format imediat dupa Big Bang. A existat o perioada, botezata Evul Intunecat, in care universul nu era luminat de nici o stea. Cel mai abundent element din cosmos, materie prima pentru formarea stelelor, planetelor si a oamenilor, este hidrogenul. Din fericire, atomul de hidrogen poate produce un semnal in spectrul undelor radio la 21 cm, lungime de unda mult mai mare decit poate cuprinde ochiul uman. Daca aceste prime semnale ale atomilor de hidrogen din Evul Intunecat pot fi detectate, astronomii pot proba cum au evoluat primele stele, primele galaxii, precum si universul modern. Intrucit universul se extinde, semnalele venite de la acesti atomi de hidrogen indepartati in timp vor fi extinse la lungimi de unda mai mari, de citiva metri.
Desi observatiile astronomice bazate pe lungimi de unda radio au o istorie lunga in spate, aceasta portiune a spectrului electromagnetic este folosita masiv pentru diferite transmisiuni civile si militare, toate fiind de milioane de ori mai limpezi decit semnalul hidrogenului cautat de astronomi. In plus, straturile superioare ale atmosferei Pamintului sint ionizate, ceea ce distorsioneaza semnalele astronomice in drumul lor spre telescoapele pamintene. Fara atmosfera si scuturi din partea Pamintului, partea indepartata a Lunii prezinta un mediu ideal pentru un telescop care sa studieze Evul Intunecat. In cadrul proiectului DALI, oamenii de stiinta si inginerii vor investiga constructia de noi antene si de dispozitive electronice care sa supravietuiasca conditiilor aspre de pe Luna si configurarea unei tehnologii pentru ridicarea telescopului selenar in viitorii zece ani.

Harta oxigenului din Soare
Oamenii de stiinta au masurat compozitia de oxigen de la nasterea sistemului solar, descoperire vitala pentru reconstituirea evolutiei mediului nostru cosmic inconjurator, informeaza BBC. Naveta spatiala Genesis de la NASA a petrecut mai mult de doi ani in spatiu colectind oxigen din cele mai indepartate straturi ale Soarelui, care reflecta compozitia norului de praf si gaze, cunoscut sub numele de nebuloasa solara, din care sistemul solar s-a format acum 4,6 miliarde de ani.
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 05 April 2008, 15:46:59
A fost descoperitã o planetã "bebeluº"

O planetã embrion, aflatã încã în primele stadii de formare, a fost descoperitã închisã într-un "uter de gaz" în vecinãtatea unei stele tinere, au anunþat astronomii britanici.
Protoplaneta, cunoscutã sub numele de HL Tau b de la numele stelei-pãrinte, HL Tau, ar putea avea doar câteva sute de ani, fiind astfel cea mai tânãrã planetã observatã vreodatã. Este posibil sã ajungã un gigant gazos, similar cu Jupiter ºi Saturn, ºi va oferi o nouã perspectivã asupra modului în care planetele formeazã cercuri de gaz ºi praf în jurul stelelor.
Descoperirea a fost fãcutã în timp ce o echipã de cercetãtori studia steaua HL Tau, aflatã în constelaþia Taurus, la o distanþã de 520 de ani luminã.

Sursa TimesOnline

M17 - bright nebula in Scutum

This image was created by median combining 7 x 90 second H alpha images taken with a Takahashi Epsilon 250 with SBIG ST-8XE CCD. The image has been cut down to be 30 x 30 arc minutes in size.M17 (NGC 6618) is a region of star formation and shines by excited emission that has been caused by the high energy radiation of the young stars embedded in the nebula.

Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 07 April 2008, 20:48:03
Solar System's 'look-alike' found

Almost 300 planets have now been found outside our Solar System

Astronomers have discovered a planetary system orbiting a distant star which looks much like our own.
They found two planets that were close matches for Jupiter and Saturn orbiting a star about half the size of our Sun.
Martin Dominik, from St Andrews University in the UK, said the finding suggested systems like our own could be much more common than we thought.
And he told a major meeting that astronomers were on the brink of finding many more of them.
The St Andrews researcher said this planetary system, and others like it, could host terrestrial planets like Earth. It was just a matter of time before such worlds were detected, he explained.
Dr Dominik told BBC News: "We found a system with two planets that take the roles of Jupiter and Saturn in our Solar System. These two planets have a similar mass ratio and similar orbital radius and a similar orbital period.
"It looks like this may have formed in a similar way to our Solar System. And if this is the case, it looks like [our] Solar System cannot be unique in the Universe. There should be other similar systems out there which could host terrestrial planets."
Dr Dominik presented his work at the Royal Astronomical Society's National Astronomy Meeting in Belfast.

Ultimate goal
The newfound planetary system, which orbits the star OGLE-2006-BLG-109L, is more compact than our own and is about five thousand light-years away.
Although nearly 300 extrasolar planets have been identified, astronomers have consistently failed to find planetary systems which resemble our own. Dr Dominik said only 10% of systems discovered so far are known to host more than one planet.
But he explained that all the techniques currently used to find exoplanets were strongly biased towards detecting gas giant planets orbiting at short distances from their parent stars.
The OGLE planets were found using a technique called gravitational micro-lensing, in which light from the faraway planets is bent and magnified by the gravity of a foreground object, in this case a another star.
"It's a kind of scaled-down version of our Solar System. The star the planets are orbiting is half as massive as the Sun and they orbit half as distant to their host star as Jupiter and Saturn orbit around the Sun," said Dr Dominik.
He said that the ultimate goal for exoplanet researchers was to find habitable Earth-like and Mars-like planets. This aim was achievable, he said, because technology was improving all the time.
"I think it will happen quite soon," he said, adding: "Micro-lensing can already go below Earth mass and it has detected more massive planets in the habitable zone. So in the next few years, we will see something really exciting."
Dr Dominik said there was competition between teams of astronomers using micro-lensing and those who favoured the transit technique, which seeks to detect new planets when, from our point of view, they pass directly in front of the parent star they are orbiting. The planet blocks a tiny fraction of the star's light, causing the star to periodically dim.
But he added that there was little chance to detect Earth-like worlds in OGLE-2006-BLG-109L because the system was too distant for current techniques to resolve planets the size of our own.

Mysterious White Rock Fingers on Mars    -im
 What caused this unusual white rock formation on Mars? Intrigued by the possibility that they could be salt deposits left over as an ancient lakebed dried-up, detailed studies of these fingers now indicate that this is not correct. The light material appears to have eroded away from the surrounding area, indicating a very low-density composition, possibly consistent with volcanic ash or windblown dust. The stark contrast between the rocks and the surrounding sand is compounded by the sand's unusual darkness. This picture was taken from the Mars Express spacecraft currently orbiting Mars. Planetary scientist Emily Lakdawalla, among others, has followed her curiosity about this unusual Martian landform into a fascinating investigation that is eloquently described in the Planetary Society Weblog. The mysterious white rock spans about 15 kilometers across inside a larger crater that spans about 100 kilometers.

Credit: G. Neukum (FU Berlin)
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 10 April 2008, 20:36:44
Nasa probe pictures Phobos moon   - im 1

Nasa's Mars Reconaissance Orbiter (MRO) has captured two stunning images of the Red Planet's biggest moon Phobos.
Stickney Crater, a 9km (5.5 mile) -wide depression that is the largest feature on Phobos dominates the pictures.
The images also show a series of grooves and crater chains; the formation of these features is the subject of debate among scientists.
MRO was launched from Florida in August 2005 and entered orbit around the Mars in March 2006.
It is mapping the Martian surface with high-resolution cameras with a view to choosing landing sites for future missions.
It will also study Mars' weather, climate, geology and atmosphere.
MRO's High Resolution Imaging Science Experiment (HiRISE) camera acquired two dramatic views of Phobos on 23 March 2008, one at a distance of 6,800km (4,225 miles) from the Martian moon and another at 5,800km (3,603 miles).
The two images were taken within 10 minutes of each other and show roughly the same features, but from a different angle so they can be combined to yield a stereo view.

Get into the groove
Some scientists believe the grooves and crater chains that can be seen in the pictures are related to the formation of the Stickney impact crater.
However, others think they may have formed from ejecta from impacts on Mars that later collided with Phobos.
In the MRO images, surface rocks near the rim of Stickney appear bluer than the rest of Phobos. Based on analogy with rocks on our own Moon, this could mean this surface is fresher, and therefore younger, than other parts of Phobos.
Phobos was discovered in 1877 by the American astronomer Asaph Hall. Both Phobos and Mars' other moon Deimos are thought to be captured asteroids.
Phobos' orbit around Mars is dropping by about 1.8m (5.9ft) every 100 years. This means that in 50 million years it will either crash into Mars or break up into a ring.
Russia has been working on an unmanned spacecraft that will return samples of soil and rock from the surface of Phobos. The mission, called Phobos Grunt, has a provisional launch date of October 2009.
The unique, fist-sized Kaidun meteorite, which fell to Earth at a Russian military base in Yemen in 1980, is claimed by some researchers to be a piece of Phobos.

Cercetãtorii spanioli au identificat cea mai micã planetã din afara sistemul nostru solar
Oamenii de ºtiinþã spanioli au descoperit cea mai micã planetã din afara sistemului nostru solar identificatã pânã acum. Savanþii sunt convinºi cã acesta este un pas important cãtre descoperirea unor noi planete asemãnãtoare Pãmântului.
Botezatã GJ 436c, planeta este de aproximativ cinci ori mai mare decât Pãmântul ºi se aflã în Constelaþia Leului la o distanþã de 30 de ani luminã de Calea Lactee.
Pentru identificarea astrului cercetãtorii spanioli au folosit o metodã diferitã faþã de cea utilizatã în mod curent. Ei au analizat distorsiunile magnetice produse de o altã planetã, aflatã în acelaºi sistem solar. Metoda este similarã celei folosite acum un secol, când a fost descoperit Neptun.
Mare parte dintre cele 280 de corpuri cereºti descoperite pânã acum sunt giganþi gazoºi, asemãnãtori cu Jupiter. Tehnicile folosite la descoperirea planetei întãresc speranþele astronomilor în gãsirea altor civilizaþii.
Deºi diferenþele între GJ 436c ºi Pãmânt nu sunt foarte mari, spaniolii spun cã planeta nu prezintã condiþii prielnice dezvoltãrii vreunei forme de viaþã. GJ 436c este, deocamdatã, cea mai micã planetã din afara sistemului nostru solar descoperitã pânã în prezent.
Sursa: Realitatea TV

Astronomii au descoperit "geamãnul" sistemului nostru solar

Astronomii au descoperit un sistem solar îndepãrtat care seamãnã foarte mult cu sistemul nostru solar.
Pânã acum cercetãtorii au identificat, la o distanþã de circa 5.000 de ani luminã, douã planete, foarte asemãnãtoare cu Jupiter ºi Saturn, care orbiteazã în jurul unei stele având jumãtate din dimensiunile Soarelui.
Oamenii de ºtiinþã cred cã acesta ar putea fi începutul unei serii de descoperiri, care vor duce în final la identificarea unor planete pe care ar putea exista viaþã.

Sursa: Daily Mail

M80 - Globular Cluster in Scorpius  - im 2
This image was created by median combining 7 x 90 second unfiltered images taken with a Takahashi Epsilon 250 with SBIG ST-8XE CCD. The image has been cut down to be 20 x 20 arc minutes in size.Discovered in 1781 by Messier M 80 (NGC 6093) is one of the most densely packed globular clusters. At a distance of 32000 light years it has a diameter of about 95 light years

Omega Centauri Looks Radiant in Infrared  - im 3
A cluster brimming with millions of stars glistens like an iridescent opal in this image from NASA's Spitzer Space Telescope. Called Omega Centauri, the sparkling orb of stars is like a miniature galaxy. It is the biggest and brightest of the 150 or so similar objects, called globular clusters, that orbit around the outside of our Milky Way galaxy. Stargazers at southern latitudes can spot the stellar gem with the naked eye in the constellation Centaurus.
Globular clusters are some of the oldest objects in our universe. Their stars are over 12 billion years old, and, in most cases, formed all at once when the universe was just a toddler. Omega Centauri is unusual in that its stars are of different ages and possess varying levels of metals, or elements heavier than boron. Astronomers say this points to a different origin for Omega Centauri than other globular clusters: they think it might be the core of a dwarf galaxy that was ripped apart and absorbed by our Milky Way long ago.
In this new view of Omega Centauri, Spitzer's infrared observations have been combined with visible-light data from the National Science Foundation's Blanco 4-meter telescope at Cerro Tololo Inter-American Observatory in Chile. Visible-light data with a wavelength of .55 microns is colored blue, 3.6-micron infrared light captured by Spitzer's infrared array camera is colored green and 24-micron infrared light taken by Spitzer's multiband imaging photometer is colored red.
Where green and red overlap, the color yellow appears. Thus, the yellow and red dots are stars revealed by Spitzer. These stars, called red giants, are more evolved, larger and dustier. The stars that appear blue were spotted in both visible and 3.6-micron-, or near-, infrared light. They are less evolved, like our own sun. Some of the red spots in the picture are distant galaxies beyond our own.
Spitzer found very little dust around any but the most luminous, coolest red giants, implying that the dimmer red giants do not form significant amounts of dust. The space between the stars in Omega Centauri was also found to lack dust, which means the dust is rapidly destroyed or leaves the cluster.

Image Credit: NASA/JPL-Caltech/ NOAO/AURA/NSF

im1 : This image of Martian moon Phobos was taken by the High Resolution Imaging Science Experiment (HiRISE) camera onboard the Mars Reconnaissance Orbiter. On the right, the photo provides a detailed view of the impact crater Stickney.The 9km-wide Stickney impact crater is the most prominent feature on Phobos

im 2 : M80 - Globular Cluster in Scorpius

im 3
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 10 April 2008, 20:56:56
Natal Microcosm - im1
Spitzer's infared eyes reveal a star-forming region, hidden to regular telescopes by thick dust clouds. Astronomers study images like this to learn about star birth. A cluster of three young stars makes up the bright center. The reddish bowl, or arc, traces the outer surface of the cloud encasing the young stars.
Messier 31   - im 2
A galaxy is like an extended family of a star. NASA's Galaxy Evolution Explorer studies these stellar families with ultraviolet light, which reveals young stars.
The blue regions in Messier 31 show where young, hot stars are forming along the galaxy's spiral arms. The central orange-white "bulge" of old, cooler stars formed long ago.
This image provides astronomers with a wonderful example of how galaxies develop.
The 'Terrible Twos' - im 3
Young stars, like toddlers, want to start showing their independence. This Spitzer view shows a stellar version of the "terrible twos" - the stars are beginning to move away from their formative cloud, seen in red and green. Jets can be seen coming off the young stars as they make their way into the cosmos.
This nebula is 1,000 light-years from Earth in the constellation Perseus.

Death Becomes Her - im 4
Knowing how stars die is just as important as knowing how they form and develop. This image shows the remnant of a once massive star that died in a violent supernova explosion more than 300 years ago. This false-color view of Cassiopeia A shows the dead star and a surrounding shell of material that was blasted off as the star died.
Images from Spitzer, the Hubble Space Telescope and the Chandra X-ray Observatory were combined to create this view
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 11 April 2008, 20:54:10
Cel mai rece obiect cosmic

Astronomii francezi ºi canadieni au descoperit cel mai rece obiect cosmic. Este vorba de o stea piticã maro, mult mai mare decât Jupiter ºi care se aflã la o depãrtare de 40 de ani-luminã depãrtare de noi. Rezultatul este cu atât mai important cu cât poate duce la o mai bunã înþelegere a diferenþelor între stele ºi planete.Descoperirea a fost posibilã prin observaþii care s-au realizat cu telescoape situate in Hawai si Chile. Este vorba de o stea piticã maro care are o temperaturã de aproape 350 de grade Celsius ºi o masã de aproape 15-30 de ori masa lui Jupiter. Se aflã la aproximativ 40 de ani-luminã de sistemul nostru solar ºi este un obiect izolat, adicã nu orbiteazã vreo stea. Corpul ceresc proaspãt descoperit seamãnã mai mult cu o planetã gigant decât cu stelele pitice maro; ºi asta din cauza temperaturii joase ºi din cauza prezenþei amoniacului. Este foarte posibil prin urmare sã reprezinte prototipul unei noi clase de pitice maro. Aceasta ar putea deveni clasa celor mai reci obiecte cosmice.
Rezultatul are implicaþii ºi în ceea ce priveºte studiul planetelor extrasolare, în special în modelarea atmosferei exoplanetelor.

Credit: Canada-France-Brown-Dwarf-Survey 2008
Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 22 June 2008, 21:29:53
O româncã a descoperit o fãrâmã din materia lipsã din Univers

Brãileanca Aurora Simionescu, de 24 de ani, doctorand la Institutul Max-Planck din Germania, a fãcut parte dintr-o echipã de astrofizicieni de la institutul german ºi de la alte douã institute olandeze care a detectat pentru prima datã un fragment din masa de “materie obiºnuitã” încã necunoscutã oamenilor.
Românca explicã pentru importanþa descoperirii. Universul este compus, în proporþie de 95%, din substanþe cu compoziþie încã necunoscutã: materie întunecatã (21%) ºi energie întunecatã (75%). Restul, circa 4 - 5%, este format din aºa-numita “materie obiºnuitã”, barionicã (protoni, neutroni etc.), din care suntem fãcuþi ºi noi. “Dar, dacã numãrãm toate obiectele – de exemplu stele, galaxii º.a.m.d –, ºi adunãm toate masele acestor obiecte, nu ajungem la aceste procente, ci la jumãtate din ceea ce s-ar aºtepta. ªi atunci întrebarea este: unde e restul?”, explicã Aurora Simionescu pentru
Ideea din spatele descoperirii i-a venit tinerei românce în vara anului trecut, într-o discuþie cu colegii de cercetare. În plus, observaþia ei este ºi parte a tezei de doctorat pe care o va prezenta Universitãþii din München ºi a fost fãcutã cu ajutorul telescopului XMM-Newton, cu raze X, al Agenþiei Spaþiale Europene, folosit întâia oarã în 1999.
“Teoriile de pânã acum preziceau cã acest rest se aflã în diferite filamente, de densitate foarte redusã, ºi cã densitatea din univers este dispusã într-un fel de pânzã de pãianjen, nodurile acestei pânze fiind clustere de galaxii, zone foarte populate, foarte dense, ºi conectate între ele de filamente”, ne explicã doctorandul român.
Acum, echipa din care ea a fãcut parte a detectat în premierã un asemenea filament, mai precis un “pod” de gaz cald ºi foarte puþin dens ce leagã douã grupuri de galaxii, Abell 222 ºi Abell 223, aflate la o distanþã de aproximativ 2, 3 miliarde de ani luminã de Pãmânt. “Existã foarte multe astfel de filamente care acoperã o suprafaþã mult mai mare decât nodurile, iar teoria era cã barionii care ne lipsesc sunt în astfel de gaze”, spune Aurora Simionescu pentru
Observaþia confirmã astfel teoriile anterioare ºi dã cercetãtorilor mai multã încredere în înþelegerea universului, precum ºi posibilitatea dezvoltãrii de noi teorii, întãreºte ea. Rãmân totuºi multe necunoscute, continuã doctorandul, cum ar fi proprietãþile exacte ale filamentelor cu pricina.
“Noi nu am putut identifica acum decât gazul cel mai dens ºi cel mai fierbinte din acest filament. Ceea ce vedem noi în emisie nu este tot gazul din filament, ci doar o parte a lui. Aceasta este o constrângere observaþionalã a modelelor pe care le vom folosi de acum încolo, pentru cã aceastã observaþie spune: în acest filament trebuie sã avem un model care prezice cã gazul cel mai fierbinte va avea aceastã temperaturã ºi aceastã densitate”.
Aurora Simionescu ne prezintã ºi planurile de viitor ale institutului german în aceastã direcþie. “Trebuie sã existe foarte multe filamente în Univers, pentru cã altfel nu am ajunge la acei 50% de barioni care ne lipsesc. Primul pas va fi sã folosim acest telescop pentru a observa alte sisteme cu o geometrie asemãnãtoare cu cel pe care l-am observat acum ºi sã confirmãm cã ºi în alte sisteme vom detecta aceleaºi proprietãþi”, completeazã ea.
Acesta pregãteºte ºi lansara de misiuni care sã caute exclusiv dupã astfel de filamente ºi care sã le poatã detecta, totodatã, ºi pe cele cu geometrie diferitã de cea a “podului” de gaz proaspãt descoperit.
Brãileanca a ajuns doctorand la Max Planck în septembrie 2002, dupã faze naþionale la olimpiadele de fizicã ºi sesiuni de comunicãri, dar mai ales dupã o bursã de un an în SUA, în clasa a XI-a, când rezultatele ei au intrat într-o bazã de date internaþionalã, fiind apreciate de Universitatea Internaþionalã Bremen. “Am primit materiale de la aceastã universitate, m-am înscris, am primit ºi o bursã de la ei. Mi-au acoperit taxa de ºcolarizare ºi costurile pentru cãmin”.
Nimeritã în a doua promoþie a restrânsei universitãþi, tânãra ºi-a ales dublã specializare: fizicã, pe de o parte, ºi ºtiinþele pãmântului ºi astrofizicã, pe de altã parte. La prima specializare erau doar 12 studenþi înscriºi, la a doua în jur de zece. “Bineînþeles cã atunci e o relaþie cu totul altfel cu profesorii decât ne imaginãm la o facultate mai mare, cum ar fi Politehnica din Bucureºti. E foarte uºor sã-þi cunoºti profesorii”.
Tocmai din acest motiv crede ea cã a fost recomandatã de decanul din Bremen, fost director al Institutului Max Planck, dupã absolvirea din 2005, pentru un doctorat la instituþia germanã. “La câþiva elevi care eram nici nu a fost relativ foarte greu”, spune ea.
Aurora Simionescu a fost admisã direct la doctorat. “Neavând un master, a trebuit sã dau niºte examene la Universitatea din München pentru a fi admisã în mod oficial de cãtre ei ca doctorand. Cercetarea o fac la Institut, dar ei nu au autoritatea academicã de a conferi gradul de doctor. Dupã aceastã cercetare voi scrie o tezã de doctorat, pe care o voi preda universitãþii, iar profesorii de la universitate o vor evalua”.
Teza de doctorat o va realiza în colaborare cu un coleg din Olanda, Norbert Werner, coordonator al studiului privind noua descoperire, publicat în revista americanã ,,Astronomy and Astrophysics Letters’’.
Românca s-ar întoarce în þarã doar dacã vor fi pompate fonduri serioase în cercetare: “Mi-ar plãcea sã mã întorc în România. Din pãcate, în momentul acesta, condiþiile pentru studiul astrofizicii ºi pentru cercetare nu sunt tocmai optime, dar sper cã prin aderarea la Uniunea Europeanã vor exista investiþii ºi în acest domeniu. Când vor exista aceste investiþii ºi va fi nevoie de specialiºti, atunci bineînþeles cã va fi o posibilitate mult mai atractivã”.

S-au descoperit încã trei Super-Terre

Planetele asemãnãtoare cu Terra ar putea deveni un lucru obiºnuit, sunt de pãrere cercetãtorii europeni.
Cele trei Super-Terre descoperite recent au de 4,2, 6,7, respectiv 9,4 ori masa planetei noastre. Ele se rotesc în jurul stelei HD 40307, cu perioade de 4,3, 9,6 ºi 20,4 zile. Aceasta este mai micã decât Soarele nostru, ºi se aflã la 42 de ani-luminã de constelaþiile Doradus ºi Pictor. Dacã ar fi orbitat în sistemul nostru solar, planetele ar fi fost situate mai aproape de Soare, decât de Mercur, scrie
Alãturi de grupul celor trei, Michel Mayor, de la Observatorul elveþian din Geneva, ºi colegii lui au mai descoperit alte douã sisteme solare, tot cu planete mici. Gemenii” Terrei ar putea deveni un lucru obiºnuit, a fost concluzia cercetãtorilor europeni, prezentatã la o conferinþã din Franþa.
Peste 300 de exoplanete au fost descoperite pânã acum. Cele mai multe sunt uriaºe, asemãnãtoare lui Jupiter sau Saturn. Cele mici, copii ale Pãmântului, au fost mai greu de observat însã. Cu noile tehnologii, astronomii le pot observa acum ºi pe acestea. “E clar cã, momentan, vedem doar vârful aisbergului în aceastã privinþã”, spune Mayor.

Title: Raspuns: DE-ALE COSMOSULUI...
Post by: pri3st3ss on 24 March 2011, 22:28:59
Hubble has taken this stunning close-up shot of part of the Tarantula Nebula. This star-forming region of ionised hydrogen gas is in the Large Magellanic Cloud, a small galaxy which neighbours the Milky Way.

What looks like a cosmic wonderland to some resembles a spindly space spider to others. The Hubble Space Telescope has just captured a new close-up picture of the famous object, known as the Tarantula Nebula.
The nebula is a vast star-forming cloud of gas and dust in our neighboring galaxy, the Large Magellanic Cloud. In this picture, we see a close-up of the Tarantula’s central region, glowing brightly with charged gases and young stars.
The wispy arms of the Tarantula Nebula were originally thought to resemble spider's legs, giving the nebula its name. The part of the nebula visible in this image from Hubble’s Advanced Camera for Surveys is crisscrossed with tendrils of dust and gas churned up by recent exploding stars, called supernovas.
These supernova remnants include NGC 2060, visible above and to the left of the centre of this image, which contains the brightest known pulsing star, or pulsar.

The tarantula’s bite goes beyond NGC 2060. Near the edge of the nebula, outside the frame, below and to the right, lie the remains of supernova SN 1987a, the closest supernova to Earth to be observed since the invention of telescopes in the 17th century.
Hubble and other telescopes have been returning to spy on this stellar explosion regularly since it blew up in 1987, and each subsequent visit shows an expanding shockwave lighting up the gas around the star, creating a pearly, necklace-like of glowing pockets of gas around the remains of the star.
Together with dying stars, the Tarantula Nebula is packed with young stars that have recently formed from the nebula’s supply of hydrogen gas.
These toddler-stars shine forth with intense ultraviolet light that energizes the gas, making it light up red. The light is so intense that although it's around 170 000 light-years away, and outside the Milky Way, the Tarantula Nebula is nevertheless visible without a telescope on a dark night to Earth-bound observers.
This nebula might be far away, but it is the most luminous example of its type that astronomers have observed in the local universe.

A compact and extremely bright star cluster called RMC 136 lies above and to the left of this field of view, providing much of the radiation that powers the multi-colored glow. Until recently, astronomers debated whether the source of the intense light was a tightly bound cluster of stars, or perhaps an unknown type of super-star thousands of times bigger than the sun.


si inca ceva interesant   :  6 Everyday Things That Happen Strangely in Space    :wink:

   on Earth, flames rise. In space, they move outward from their source in all directions. Here's why:
The closer you are to the Earth's surface, the more air molecules there are, thanks to the planet's gravity pulling them there. Conversely, the atmosphere gets thinner and thinner as you move vertically, causing a gradual decline in pressure. The atmospheric pressure difference over a height of one inch, though slight, is enough to shape a candle flame.
That pressure difference causes an effect called natural convection. As the air around a flame heats up, it expands, becoming less dense than the cold air surrounding it. As the hot air molecules expand outward, cold air molecules push back against them. Because there are more cold air molecules pushing against the hot molecules at the bottom of the flame then there are at its top, the flame experiences less resistance at the top. And so it buoys upward.
When there's no gravity, though, the expanding hot air experiences equal resistance in all directions, and so it moves spherically outward from its source.

               mai multe aici
Post by: pri3st3ss on 15 March 2013, 17:18:49
pentru cei care nu au vazut minunata cometa.... "as seen from the STEREO Behind spacecraft. Following in Earth's orbit, the spacecraft is nearly opposite the Sun and looks back toward the comet and Earth, with the Sun just off the left side of the frame."

si un video:

ScienceCasts: Sunset Comet (