Πέμπτη, 30 Σεπτεμβρίου 2010

Could 'Goldilocks' planet be just right for life?

WASHINGTON – Astronomers say they have for the first time spotted a planet beyond our own in what is sometimes called the Goldilocks zone for life: Not too hot, not too cold. Juuuust right.

Not too far from its star, not too close. So it could contain liquid water. The planet itself is neither too big nor too small for the proper surface, gravity and atmosphere.

It's just right. Just like Earth.

"This really is the first Goldilocks planet," said co-discoverer R. Paul Butler of the Carnegie Institution of Washington.

The new planet sits smack in the middle of what astronomers refer to as the habitable zone, unlike any of the nearly 500 other planets astronomers have found outside our solar system. And it is in our galactic neighborhood, suggesting that plenty of Earth-like planets circle other stars.

Finding a planet that could potentially support life is a major step toward answering the timeless question: Are we alone?

Scientists have jumped the gun before on proclaiming that planets outside our solar system were habitable only to have them turn out to be not quite so conducive to life. But this one is so clearly in the right zone that five outside astronomers told The Associated Press it seems to be the real thing.

"This is the first one I'm truly excited about," said Penn State University's Jim Kasting. He said this planet is a "pretty prime candidate" for harboring life.

Life on other planets doesn't mean E.T. Even a simple single-cell bacteria or the equivalent of shower mold would shake perceptions about the uniqueness of life on Earth.

But there are still many unanswered questions about this strange planet. It is about three times the mass of Earth, slightly larger in width and much closer to its star — 14 million miles away versus 93 million. It's so close to its version of the sun that it orbits every 37 days. And it doesn't rotate much, so one side is almost always bright, the other dark.

Temperatures can be as hot as 160 degrees or as frigid as 25 degrees below zero, but in between — in the land of constant sunrise — it would be "shirt-sleeve weather," said co-discoverer Steven Vogt of the University of California at Santa Cruz.

It's unknown whether water actually exists on the planet, and what kind of atmosphere it has. But because conditions are ideal for liquid water, and because there always seems to be life on Earth where there is water, Vogt believes "that chances for life on this planet are 100 percent."

The astronomers' findings are being published in Astrophysical Journal and were announced by the National Science Foundation on Wednesday.

The planet circles a star called Gliese 581. It's about 120 trillion miles away, so it would take several generations for a spaceship to get there. It may seem like a long distance, but in the scheme of the vast universe, this planet is "like right in our face, right next door to us," Vogt said in an interview.

That close proximity and the way it was found so early in astronomers' search for habitable planets hints to scientists that planets like Earth are probably not that rare.

Vogt and Butler ran some calculations, with giant fudge factors built in, and figured that as much as one out of five to 10 stars in the universe have planets that are Earth-sized and in the habitable zone.

With an estimated 200 billion stars in the universe, that means maybe 40 billion planets that have the potential for life, Vogt said. However, Ohio State University's Scott Gaudi cautioned that is too speculative about how common these planets are.
 
Vogt and Butler used ground-based telescopes to track the star's precise movements over 11 years and watch for wobbles that indicate planets are circling it. The newly discovered planet is actually the sixth found circling Gliese 581. Two looked promising for habitability for a while, another turned out to be too hot and the fifth is likely too cold. This sixth one bracketed right in the sweet spot in between, Vogt said.
With the star designated "a," its sixth planet is called Gliese 581g.
 
"It's not a very interesting name and it's a beautiful planet," Vogt said. Unofficially, he's named it after his wife: "I call it Zarmina's World."
 
The star Gliese 581 is a dwarf, about one-third the strength of our sun. Because of that, it can't be seen without a telescope from Earth, although it is in the Libra constellation, Vogt said.
 
But if you were standing on this new planet, you could easily see our sun, Butler said.
 
The low-energy dwarf star will live on for billions of years, much longer than our sun, he said. And that just increases the likelihood of life developing on the planet, the discoverers said.

"It's pretty hard to stop life once you give it the right conditions," Vogt said.

Δευτέρα, 27 Σεπτεμβρίου 2010

DNA barcode library to launch in Toronto


OTTAWA (AFP) – An international consortium of geneticists on Saturday will activate a DNA barcode library in Toronto representing almost 80,000 species, the International Barcode of Life Project (iBOL) announced.

The aim is to eventually build a digital identification system for all life on Earth to reduce the time and cost of species identification.

To mark the world?s largest biodiversity genomics initiative, Toronto's CN Tower -- the tallest free-standing structure in the Western Hemisphere -- is to be illuminated as a giant bar code, iBOl said.

"We are witnessing alarming rates of species extinction," said iBOL scientific director Paul Hebert.

"But efforts to reverse that trend are hampered by huge gaps in our knowledge about the distribution and diversity of life. DNA barcoding promises a future where everyone will have rapid access to the names and biological attributes of every species on Earth."

DNA barcoding, which identifies species using a short DNA sequence from a standard location on the genome, will also be a vital tool for conservation and for monitoring species that have adverse impacts on human health and economic wellbeing, he said.

More than 25 countries are involved in the project.

Work over the past five years has produced barcode records for almost 80,000 species.

By 2015, consortium members are expected to have entered DNA barcode records from five million specimens representing half a million species into the interactive Barcode of Life Data System (BOLD) databank, and eventually all of Earth's animal, plant and fungal

Σάββατο, 25 Σεπτεμβρίου 2010

Big Bang is a fact... But...

Actually I had this question for a long time. Since we all know everything started with the Big Bang how from a single point galaxies end up colliding with each other. Of course taking account the gravities of the celestial bodies, black holes etc help in a galactic billiard which make our universe a very dangerous space. On the other hand the design of the universe puzzles me. Especially since in every day life, we follow the rules of the universe. Math, Physics, chemistry etc. So since the universe is expanding it kinda tells us that distance is a good thing... I won't expand on this... just some food for thought.

Facebook and Twitter Fails, MineCraft and Ubuntu Wins - PCWorld Podcast #92

This week on the PCWorld Podcast, we take a look at Facebook's big outage and the odd Twitter hack that disrupted the social media world briefly. Then we dive into news from Nvidia's GPU Technology Conference to see how the coming wave of graphics upgrades will speed up everyday computing.

Editors Nate Ralph and Jason Cross have become fiendishly addicted to a little game called MineCraft, and tell us why we should all check it out this weekend.

Finally, Nate walks us through his recent foray into Ubuntu Linux. (Yes, he can still play MineCraft on it.)

You can also stream the podcast via QuickTime:
Subscribe to the PCWorld Podcast on iTunes or via the PCWorld Podcast RSS feed. You can reach us at iTunes.

Παρασκευή, 24 Σεπτεμβρίου 2010

3-D Supernova Simulation Aims to Solve Astronomy Puzzles

Most stars end their lives in a whimper - our own sun will almost certainly be one of them - but the most massive stars go out with an impressive bang. When that happens, creating what's known as a Type II supernova, the associated blast of energy is so brilliant that it can briefly outshine an entire galaxy, give birth to ultra-dense neutron stars or black holes, and forge atoms so heavy that even the Big Bang wasn't powerful enough to create them. If supernovas didn't exist, neither would gold, silver, platinum or uranium. The last time a supernova went off close enough to earth to be visible without a telescope, back in 1987, it made the cover of TIME.

Given the Type II supernovas' cosmic importance, you might think astronomers would have figured out how they work - and in a general way, they have. But when it comes to the most critical few moments of the detonation process, says Princeton theorist Adam Burrows, you'd be wrong. "We've been working on this for about 50 years," he explains, "but every time we think we've nailed it, the answer turns out to be ambiguous or wrong." (There's an entirely different kind of a supernova by the way, called a Type I, which astronomers don't fully understand either, but that's a different story.)

Thanks to a new, powerful supercomputer simulation, though, reported in the current Astrophysical Journal, Burrows and a group of colleagues at Princeton and Lawrence Berkeley National Laboratory, in California, are convinced they're getting closer. "We're not there yet," he says, "but victory is in sight." (See pictures of earth from space.)

To understand what Burrows, lead author Jason Nordhaus and the others have done, you first have to understand the most basic fact about a star, which is that it's essentially a thermonuclear reaction - an H-bomb - held in place by its own powerful gravity, which goes on for many billions of years. The nuclear furnace in a star's core welds atoms together, transforming hydrogen into slightly heavier helium. In very massive stars, the helium is forged, in turn, into carbon and oxygen and on up the periodic table until the star's core has been transformed into iron.

That's the end of the road. Nuclear fusion stops, and without the enormous energy generated by that process, the core caves in on itself. "It's as if the earth had suddenly collapsed to the size of New York City," Burrows told TIME in 1987. "At this point the rest of the star is oblivious. It doesn't know the core has collapsed and that it's doomed." (See the top 50 space moments since Sputnik.)

But the rest of the star soon learns. Like Wile E. Coyote standing in thin air above a deep canyon, it pauses - then plummets. When the outer layers slam into the collapsed core, the impact generates a massive shock wave of matter, blasting outward. And here's where astrophysicists' ignorance sets in. Powerful as it is, this shock wave alone isn't energetic enough to create the blinding flash of a supernova. Something must be supplying the shock wave with extra power. And that something, theorists have long believed, comes from a blast of subatomic neutrinos, generated in the heat and pressure of the core collapse. The neutrinos slam into the shock wave and that provides the turbocharge. (Comment on this story.)

Here's the problem: neutrinos are so ethereal that only they pass right through the shock wave without sufficiently perturbing it. And in the most sophisticated computer simulations to date, which render supernovas in two dimensions (that is, using a flat circle to represent a spherical star) the amount they transferred simply wasn't sufficient.

But the new simulation by Nordhaus, Burrows and the others renders a star in 3-D. That makes things look different. "Over the past decade and a half," says Burrows, "we've learned that [shock waves] have all sorts of instabilities." In other words, they churn, and this simulation lets the scientists examine the effect of that churning in detail. It appears that the instabilities give neutrinos more of a chance to mingle with the matter in the shock wave and transfer enough of their considerable energy to create the signature flash that can be seen halfway across the universe. (See pictures of Saturn.)

This still doesn't explain the process fully, Burrows notes. "We still need to model the neutrino physics better," he says - a step so complicated that it will require tens to hundreds of times more computer power than the scientists currently have available. Once they get there, theorists could finally end up explaining just about everything supernova-related, from the birth of neutron stars and black holes to the creation of heavy elements, in detail.

"We'll do the physics better," says Burrows. "But that won't change this effect." What it will change is our knowledge base, which will finally include an explanation of what may be the most extraordinary phenomenon known to science.

Πέμπτη, 23 Σεπτεμβρίου 2010

Distant Spiral Galaxy May Reveal Clues About Our Milky Way


A beautiful spiral galaxy 60 million light-years from Earth could help astronomers better understand our own Milky Way because of a trademark central bar-like structure.
The galaxy, NGC 1365, is one of the most-studied barred spiral galaxies. It is sometimes called the Great Barred Spiral Galaxy because of its strikingly perfect form.  
Now, a new photo released by the European Southern Observatory today (Sept. 22) shows the galaxy in exacting detail, and may help astronomers who are trying to determine if our own Milky Way contains a central bar. [New photo of the Great Barred Spiral Galaxy.]
Barred galaxies like NGC 1365 are actually quite common, scientists said. According to recent estimates, two thirds of spiral galaxies are barred, and recent observations have contributed evidence of a bar in the Milky Way.
Astronomers have used NGC 1365 to study how spiral galaxies form and evolve. By examining the complex flow of material within the galaxy, researchers can pinpoint how these processes affect the reservoirs of gas from which new stars can form.

Galaxy bar exam

The galaxy NGC 1365 has a straight bar packed with stars at its center, with two visible outer spiral arms. The entire galaxy is laced with delicate dust lanes, and close to the center is also a second spiral structure.
The new image of the galaxy was taken with the powerful HAWK-I camera on ESO's Very Large Telescope at the Paranal Observatory in Chile. It was captured in infrared light, which cuts through the dust that obscures parts of the galaxy when viewed in visible light.
The photo reveals a clear glow from the vast number of stars that are located in both the bar and spiral arms.
NGC 1365 is located within the constellation of Fornax (the Furnace). The entire galaxy, including its two huge outer spiral arms, spans approximately 200,000 light-years wide. One light year is the distance light travels in one year, or about 6 trillion miles (9.7 trillion km).

A bar in space

The huge bar structure within NGC 1365 disturbs the shape of the galaxy's gravitational field, which causes regions of gas to compress and trigger star formation. Many huge young star clusters trace out the main spiral arms and each contains anywhere from hundreds to thousands of bright young stars that are less than 10 million years old.
In the photo, most of the tiny clumps that are visible are actually star clusters, but the galaxy is too remote for single tars to be seen individually.
The galaxy's bar consists primarily of older stars long past their prime, but many new stars are born in the stellar nurseries of gas and dust in the inner spiral close to the nucleus.
The bar also funnels gas and dust gravitationally to the very center of the galaxy, where astronomers have found evidence to support the presence of a supermassive black hole, well hidden among myriads of intensely bright new stars.