A powerful stellar explosion that has shattered the record for the most distant object visible to the naked eye was detected by NASA's Swift satellite on Wednesday.

The explosion, known as a gamma-ray burst, also ranks as the most intrinsically bright object in the universe ever observed by humans.

Astronomers reported Wednesday that they had made the first detection of an organic molecule, methane, in the atmosphere of a planet outside our solar system and had confirmed the presence of water there, clearing the way for a bright future of inspecting the galaxy for livable planets, for the chemical stuff of life, or even for life itself.

Under the right conditions, water can combine with organic chemicals like methane to make amino acids, the building blocks of life as we know it. While the presence of these chemicals was not a big surprise and while the planet in question — in the constellation Vulpecula — is too hot and massive for living creatures, the result left astronomers elated at their improving powers of celestial discernment.

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What do you call an absence of darkness? Dark matter is supposed to be spread throughout the universe, but a new study reports a spiral galaxy that seems to be empty of the stuff, and astrophysicists cannot easily explain why.

In the outer regions of most galaxies, stars orbit around the centre so fast that they should fly away. The combined mass of all the observable inner stars and gas does not exert strong enough gravity to hold onto these speeding outliers, suggesting some mass is missing.

Most astronomers believe that the missing mass is made up of some exotic invisible substance, labelled dark matter, which forms vast spherical halos around each galaxy. Another possibility is that the force of gravity behaves in an unexpected way, a theory known as modified Newtonian dynamics, or MOND.

In the spiral galaxy NGC 4736, however, the rotation slows down as you move farther out from the crowded inner reaches of the galaxy. At first glance, that declining rotation curve is just what you would expect if there is no extended halo of dark matter, and no modification to gravity. As you move far away from the swarming stars of the inner galaxy, gravity becomes weaker, and so motions become more sedate.

The rotation measurements only stretch 35,000 light years out from the galactic centre, which is not far enough to confirm that first impression. So a team of astronomers in Poland developed a more sophisticated analysis.

Joanna Jalocha, Lukasz Bratek and Marek Kutschera of the Polish Academy of Science in Krakow have found a way to splice the rotation curve together with another measurement: the density of hydrogen gas far from the galactic centre.

According to their combined mathematical model, ordinary luminous stars and gas can indeed account for all the mass in NGC 4736.

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Astronomers using telescopes on Mauna Kea have found an extremely rare quartet of stars that orbit each other within a region smaller than Jupiter's orbit round the Sun.  The quartet appears as a speck of light even when viewed with the world's most powerful telescopes but its spectrum reveals not one, but four distinct stars arranged in two pairs.  Astronomers are now struggling to work out whether they could have been born that way, or were forced together by a dense disk of gas in their youth.

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MOSCOW (AFP) - Russia plans to participate in a European mission to investigate Jupiter's moon Europa and search for simple life forms, the Interfax news agency reported on Monday, quoting a senior researcher.

The head of the Space Research Institute, Lev Zelyony, said a project to explore the giant gaseous planet Jupiter would shortly be included in the programme of the European Space Agency (ESA) for the years 2015 to 2025.

"The main task is to explore its satellite Europa, on which under a thick layer of ice a liquid water ocean has been detected," said Zelyony. Russia is to participate in the programme, called Laplace after French astronomer Pierre-Simon Laplace, and has suggested landing a craft in one of the fissures in Europa's icy crust.

Having landed, the craft would melt some of the ice and search for life forms, he said.

"Where there is an ocean, life could arise. In this respect, after Mars, the Europa satellite is probably the most intriguing place in the solar system," said Zelyony.

Russia has gradually been reviving its space research programme, which all but collapsed after the Soviet Union fell apart in 1991. Moscow has been cooperating closely with the ESA as part of this revival.

At the end of this year an upgraded Russian Soyuz rocket is due to be launched for the first time from the ESA's Kourou launchpad in French Guiana.

Last October Moscow also signed a deal with Washington to provide the US space agency NASA with instruments for scanning the Moon and Mars for water.

news.yahoo.com/s/afp/20080107/sc_afp/russiaesaspaceresearch

A jet of highly charged radiation from a supermassive black hole at the center of a distant galaxy is blasting another galaxy nearby -- an act of galactic violence that astronomers said yesterday they have never seen before.

Using images from the orbiting Chandra X-Ray Observatory and other sources, scientists said the extremely intense jet from the larger galaxy can be seen shooting across 20,000 light-years of space and plowing into the outer gas and dust of the smaller one.

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http://eng.cnews.ru/news/line/indexEn.shtml?2007/11/22/276238

Alexander Novgorodov, the reader of the portal R&D.CNews from Moscow Region, has pointed to an object of unusual morphology found on Mars images made by the spacecraft Mars Reconnaissance Orbiter.

On the images taken from the orbit an unusual mountain formation is depicted, which seems to have resulted from weathering (erosion) and is located amid the frozen ocean. The given formation drop-like shape (in section), its evidently erosion origin and the unusual structure at the base, which might be conventionally called a 'door' for its physical resemblance, are of interest.

The object unusual form and the presence of a 'door' do not mean the mountain formation is of artificial origin. The mentioned peculiarities are of primary interest because of their morphology.

The other images sent by our reader depict another formation of unusual shape resembling a pyramid with a regular polygon at the base.

Exploding Comet 17P/Holmes is now larger than Jupiter. Astronomer Eric Allen of Quebec's Observatoire du Cégep de Trois-Rivières combined images he captured on three consecutive nights (Oct. 25, 26 and 27) and placed them beside a picture of Jupiter scaled to the same distance as the comet:

The diaphanous and curiously spherical cloud surrounding the comet's core is now large enough to swallow the King of Planets! It's gotten so big, in fact, that many observers say they can see it without a telescope. "I estimate the comet's brightness at magnitude +2.2 and last night I could see the disk easily with the naked eye," reports Martin McKenna of Maghera, Northern Ireland. "I saw the disk, too," says Doug Zubenel of Lincoln County, Kansas. Bill Smith of puts the comet "at magnitude +2.1--nearly as bright as Polaris"--and notes that "to the naked eye, it is no longer a simple point of light." [sky map] What would make a comet explode in this fashion? Actually, a better question is, what would make a comet explode twice in this fashion? This is the second time Comet 17P/Holmes has erupted. The first was in 1892, an outburst that led to the comet's discovery by British astronomer Edwin Holmes. The answer may be sinkholes. There is growing evidence that some comets and asteroids may have a porous internal structure akin to, say, swiss cheese or a honycomb. Suppose one of the chambers of the honycomb suddenly collapsed, exposing many square kilometers of fresh cometary ice to sunlight for the first time. A flurry of sublimation would ensue with mega-jets of dusty gas emerging from the sinkhole to create a cloud around the comet much as we see now. Twice = two sinkholes, one in 1892 and one in 2007. Because no one can see the comet's nucleus--it is small, far away and hidden inside a Jupiter-sized debris cloud--this "explanation" is no more than conjecture. The true events at the core of Comet Holmes remain unknown. Grab your telescope and savor the mystery!

SpaceWeather.com

www.guardian.co.uk/science/2007/apr/25/starsgalaxiesandplanets.spaceexploration

The Earth-like Gliese 581C circles a star in the constellation of Libra that is cooler than our sun. Photograph: European Southern Observatory/AP

Scientists have discovered a warm and rocky "second Earth" circling a star, a find they believe dramatically boosts the prospects that we are not alone.

The planet is the most Earth-like ever spotted and is thought to have perfect conditions for water, an essential ingredient for life. Researchers detected the planet orbiting one of Earth's nearest stars, a cool red dwarf called Gliese 581, 20 light years away in the constellation of Libra.

Measurements of the planet's celestial path suggest it is 1½ times the size of our home planet, and orbits close to its sun, with a year of just 13 days. The planet's orbit brings it 14 times closer to its star than Earth is to the sun. But Gliese 581 burns at only 3,000C, half the temperature of our own sun, making conditions on the planet comfortable for life, with average ground temperatures estimated at 0 to 40C. Researchers claim the planet is likely to have an atmosphere. The discovery follows a three-year search for habitable planets by the European Southern Observatory at La Silla in Chile.

"We wouldn't be surprised if there is life on this planet," said Stephane Udry, an astronomer on the project at the Geneva Observatory in Switzerland.

Two years ago, the same team discovered a giant Neptune-sized planet orbiting Gliese 581. A closer look revealed the latest planetary discovery, along with a third, larger planet that orbits the star every 84 days. The planets have been named after their star, with the most earthlike called Gliese 581c. The team spotted the planet by searching the "habitable zone".