Is the moon 100 million years younger?

The moon is quite a bit younger than scientists had previously believed, new research suggests. The leading theory of how the moon formed holds that it was created when a mysterious planet — one the size of Mars or larger — slammed into Earth about 4.56 billion years ago, just after the solar system came together.

However, new analyses of lunar rocks suggest that the moon, which likely coalesced from the debris blasted into space by this monster impact, is actually between 4.4 billion and 4.45 billion years old. The finding, which would make the moon 100 million years younger than previously thought, could reshape scientists' understanding of the early Earth as well as its natural satellite, researchers said.

Scientists know the solar system's age (4.568 billion years) quite well. And they can pin down the formation times of relatively small bodies such as asteroids precisely, too, by noting when these objects underwent extensive melting — a consequence, in part, of the heat generated by the collision and fusion of these objects' building-block "planetesimals."

Scientists keep getting better and better estimates, however, as they refine their techniques and technology improves. And those estimates are pushing the moon's formation date farther forward in time. The moon is thought to have harbored a global ocean of molten rock shortly after its dramatic formation. Currently, the most precisely determined age for the lunar rocks that arose from that ocean is 4.360 billion years, the researchers said.

And here on Earth, scientists have found signs in several locations of a major melting event that occurred around 4.45 billion years ago. So, evidence is building that the catastrophic collision that formed the moon and reshaped Earth occurred around that time, rather than 100 million years or so before, the researchers said.

To read more about the research and findings, click here.

Life on Mars: Absence of methane challenges theory

Nasa’s Mars Rover Curiosity has failed to find a key chemical on the Red Planet challenging the theory of life on Mars. This latest discovery has added a new twist to the debate about possible life on Mars.

According to data collected by the robot, the Martian environment lacks methane. This comes as a surprise to researchers as previous information had indicated positive detections. Crucially, this reduces the possibility that life ever survived there.

Over the past decade, scientists using Mars satellites and telescopes on Earth have reported plumes of methane in the Martian atmosphere. These small but potentially crucial amounts of methane would have indicated the possibility of life on the Red Planet. On Earth, the vast majority of methane in the atmosphere is caused by organic life. The rover is now 14 months into a planned two-year mission to search for signs of organic life.

However, not all scientists are convinced that methane is missing there. And according to the twitter account of the Rover itself, there is still a chance that life once existed on Mars. On 19 September, one of its messages read “Lack of methane doesn’t mean Mars never supported life. Plenty of Earth organisms don’t produce the gas.”

And the debate is still open. It’s hoped an upcoming Indian mission will provide further information on the question. India’s Mars Orbiter Mission, scheduled to be launched at the end of October, will explore the existence of life on the Red Planet.

To read more about India's mission to Mars, click here.

Venus and Moon meet up in spectacular encounter

Venus and moon shared a dazzling celestial meet-up that wowed stargazers around the world Sunday evening (Sept. 8).Skywatchers snapped photos and at least one time-lapse video of Venus and the moon as the pair shined together in the night sky.

Venus and the moon shared what astronomers call a "conjunction," when two celestial objects appear near each other when viewed from Earth. The Venus-moon sight occurred about 45 minutes after sunset on Sunday in what was their closest encounter of the northern summer, fall or winter.

Some observers got a particularly special cosmic treat. From certain locations on Earth, the moon appeeared to hide Venus it passed between Earth and the more distant planet in what scientists call an "occultation." Although the unique sight couldn't be seen around the world, some stargazers in the Southern Hemisphere also got an incredible view of the conjunction.

Click here to watch the video.

To read more and view photos, click here.

Strange brown dwarfs: Little 'failed' stars or big planets?

Is it time for a stellar identity crisis? Astronomers studying cold brown dwarfs have found that the boundary between star and planet might be much blurrier than once thought. These strange 'failed' stars, described online in the journal Science, could help shed light on the atmospheres of distant exoplanets.

Scientists have managed to find out a lot about stars and their atmospheres by studying their light, including their temperatures and their distances, reports Los Angeles Times. But that’s easier said than done for exoplanets: The operating ground rules are very different between a massive, hot, bright star and a very small, cool, dark planet. So these brown dwarfs, which sit on the scale between normal stars and gas-giant planets, can bridge the gap in scientists' knowledge.

There could be a whole lot of them in the sky, too -- so many that some scientists suggested they could help partly explain the mysterious Universe-wide effects attributed to dark matter. These brown dwarfs are essentially the D-listers of celestial Hollywood – their career goals to become stars never quite took off. That’s because these relative lightweights never became dense enough in their cores to start their hydrogen-fueled nuclear fusion engines.

Ultra-cool brown dwarfs, described in the last two years using NASA’s Wide-field Infrared Survey Explorer telescope, are the coldest of the bunch, and very dim and small. They generally sit right around the borderline between a tiny star and a really big gas giant – 13 Jupiter masses.

But brown dwarfs are easier to pick out in the sky than exoplanets, said study coauthor Adam Kraus, an astronomer at the University of Texas at Austin. And given the number of properties the two share, studying these brown dwarfs and their atmospheres could help astronomers understand exoplanet atmospheres too.

But because brown dwarfs don’t shine the way that successful stars do, it’s hard to judge a lot of their characteristics, including one of the most basic – how far they are. So the researchers decided to directly measure the distances of 16 brown dwarfs with a different method, using NASA’s Spitzer Space Telescope as it trailed behind the Earth.

As Spitzer moves, it watches how the brown dwarfs 'move' in front of the background stars. It’s the same reason your finger seems to 'jump' against the background if you hold it up and look at it with one eye closed and then quickly switch to the other eye. Each eye has a slightly different perspective because it’s in a slightly different position on your face.

And just as your two eyes’ slightly different perspectives allow your brain to determine depth, the scientists used Spitzer’s snapshots of the same brown dwarf from different positions to calculate the failed star's distance. It's a painstaking but time-tested method known as the parallax method.

The researchers found that these failed stars were between 20 and 50 light years away. They also ended up being hotter than expected. Many of the ultra-cool brown dwarfs are thought to be room temperature, but the brown dwarfs surveyed here were around 260 to 350 degrees Fahrenheit.

"The coldest brown dwarfs (and by extension, the extrasolar planets that closely resemble them) have their appearance shaped by many properties, and not just by their temperature," said Kraus, who co-wrote the report with Trent Dupuy of the Harvard-Smithsonian Center for Astrophysics. "We need to understand the influence of these other properties (such as chemical composition, cloud cover, and surface gravity) in order to interpret the many exoplanet discoveries that we expect to see from ongoing and future discovery programs."

Perhaps the planet-star boundary needs to be redrawn – but not in terms of mass, Kraus added. Size should not matter as much. What should matter is how they formed.

To read the entire story, click here.

Monster storm on Saturn reveals water and hidden layers

A massive storm rages on Saturn once every 30 years, which mixes up the atmosphere and reveals some of its hidden secrets. The most recent mega-storm arrived on the ringed planet about 10 years ahead of schedule, from December 2010 to August 2011, said Lawrence Sromovsky, a planetary scientist at the University of Wisconsin-Madison.

The storm grew quickly from a small white dot first detected by NASA's Cassini probe on Dec. 5, 2010, to a spot about the size of Earth by the end of the month, writes Deborah Netburn for the Los Angeles Times. By the end of January 2011, the storm had totally encircled the planet at a latitude of 30 degrees. The mega-storm raged on for seven more months, releasing static electric charges indicative of lightning and causing fierce vertical winds that blew up to 300 mph.

The storm also allowed scientists a rare opportunity to glimpse the hidden layers of Saturn's thick atmosphere. Scientists have hypothesized that Saturn's atmosphere is stacked like a layer cake, with water vapor clouds at the bottom, followed by a layer of ammonia hydrosulfide clouds and pure ammonia clouds near the top. But this structure has been difficult to observe because the surface of Saturn is obscured by a thick haze that is difficult to penetrate.

The storm temporarily changed all that. As the storm's fierce winds cut through the haze, Cassini was able to observe the cloud tops in near-infrared light, revealing a very different infrared color signature than the one produced by haze particles in the surrounding atmosphere. Sromovsky and his team recently analyzed that data and discovered that cloud particles at the top of the storm were probably made of water ice, ammonia ice and a third substance that might be ammonium sulfide. This is the first time that water ice has been detected on Saturn.

To know more about the research and other details, click here.

Did a meteor kill megafauna and trigger prehistoric climate shift?

Scientists have discovered new evidence that an extraplanetary body came down over Canada around 12,900 years ago, possibly triggering the death of the giant animals then roaming the North American continent, and starting a cooling spell that helped drive mankind towards agriculture and civilization.

During the Younger Dryas climactic period, which kicked off around 13,000 years ago, world temperatures fell sharply, with parts of the northern hemisphere dropping around five degrees Centigrade in a decade or less. The effects lasted for over a thousand years before temperatures warmed up again.

The Younger Dryas has been cited as a reason why North America lost the unique megafauna that roamed the continent, including huge saber-toothed cats, a giant sloth, and colossal camels. The cold period is also thought to have spurred the shift from hunter-gathering to agriculture as the means of production for humanity.

The prevailing theory as to what caused the Younger Dryas is that the climate was altered by the draining of Lake Agassiz, a vast fresh-water lake the size of the Black Sea that was dammed by glaciers in the center of the North American continent. When this vented, it sent an enormous amount for fresh water into the Atlantic and Arctic seas, which could have disrupted warming sea currents.

But an alternative theory suggests that the continent may have undergone a series of bombardments from asteroids or comets, triggering the cooling period. One 4km-wide crater from around that time, the Corossal crater, has already been spotted in Canada.

Professor Mukul Sharma, from Dartmouth University said his team has found direct evidence of another massive impact. Sharma studied core samples from six different sites along the Eastern seaboard, looking for spherules, which are crystalline rocks formed by temperatures of 2,000°C. These can only be formed naturally by volcanoes or impacts – forest or coal fires don't burn hot enough – and Shama's team found concentrations of these indicating that an impact had occurred in Quebec at around the time the Younger Dryas started.

The composition of the spherules differs from the element concentration that would have come from the Corossal crater. Sharma says the team now needs to find another crater to account for the new data, and are looking for a suitable target, according to the paper published in the Proceedings of the National Academy of Sciences.

How did scientists find conclusive proof that the impact caused humans to develop agriculture? Read more from this link.