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Hubble sees Pluto changing color, ice sheet cover
Thursday, February 4, 2010
Spurned Pluto is changing its looks, donning more rouge in its complexion and altering its iceball surface here and there.
Color astronomers surprised.

Newly released Hubble Space Telescope photos show the distant one-time planet — demoted to "dwarf planet" status in 2006 — is changing color and its ice sheets are shifting.
The photos, released by NASA Thursday, paint a Pluto that is significantly redder than it had been for the past several decades. To the layman, it has a yellow-orange hue, but astronomers say it has about 20 percent more red than it used to have.
The pictures show icy frozen nitrogen on Pluto's surface growing and shrinking, brightening in the north and darkening in the south. Astronomers say Pluto's surface is changing more than the surfaces of other bodies in the solar system. That's unexpected because a season lasts 120 years in some regions of Pluto.
"It's a little bit of a surprise to see these changes happening so big and so fast," said astronomer Marc Buie of the Southwest Research Institute in Boulder, Colo. "This is unprecedented."
From 1954 to 2000, Pluto didn't change in color when it was photographed from Earth. But after that, it did. The red levels increased by 20 percent, maybe up to 30 percent, and stabilized from about 2000 to 2002, Buie said. It's not as red as Mars, however, Buie said.
Buie said he can explain the redness, but not why it changed so dramatically and so recently. The planet has a lot of methane, which contains carbon and hydrogen atoms. The hydrogen gets stripped off by solar winds and other factors, leaving carbon-rich areas on the surface, which tend to be red and dark.
The Hubble photos were taken in 2002 and the analysis took a few years. But why Pluto changed so quickly was such a mystery that Buie held off for years on announcing what he had found, worried that he might be wrong. However, since Pluto's moon Charon hadn't changed color in the same telescope images, he decided the Pluto findings weren't an instrument mistake.
His analysis also found that nitrogen ice was shifting in size and density in surprising ways. It's horribly cold on Pluto with, paradoxically, the bright spots being the coldest at about -382 degrees Fahrenheit. Astronomers are still arguing about the temperatures of the warm dark spots, which Buie believes may be 30 degrees warmer than the darker areas.
Part of the difficulty in figuring out what is going on with Pluto is that it takes the dwarf planet 248 years to circle the sun, so astronomers don't know what conditions are like when it's is farthest from the sun. The last time Pluto was at its farthest point was in 1870, which was decades before Pluto was discovered. Unlike Earth, Pluto's four seasons aren't equal lengths of time.
Buie's explanation makes sense, said retired NASA astronomer Stephen Maran, co-author of a book on Pluto. "Pluto is interesting and poorly understood, whether it qualifies as a planet or not," he said.

http://news.yahoo.com/s/ap/20100204/ap_on_sc/us_sci_pluto

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posted by Surono Karti @ 9:42 PM   0 comments
Hubble telescope shows earliest photo of universe
Tuesday, January 5, 2010
The Hubble Space Telescope has captured the earliest image yet of the universe — just 600 million years after the Big Bang, when the universe was just a toddler.


Scientists released the photo Tuesday at a meeting of the American Astronomical Society. It's the most complete picture of the early universe so far, showing galaxies with stars that are already hundreds of millions of years old, along with the unmistakable primordial signs of the first cluster of stars.

These young galaxies haven't yet formed their familiar spiral or elliptical shapes and are much smaller and quite blue in color. That's mostly because at this stage, they don't contain many heavy metals, said Garth Illingworth, a University of California, Santa Cruz, astronomy professor who was among those releasing the photo.




"We're seeing very small galaxies that are seeds of the great galaxies today," Illingworth said in a news conference.

Until NASA's Hubble telescope was repaired and upgraded last year, the farthest back in time that astronomers could see was about 900 million years after the Big Bang, Illingworth said. Hubble has been key in helping determine the age of the universe at about 13.7 billion years, ending a long scientific debate about a decade ago.

As far back as Hubble can see, it still doesn't see the first galaxies. For that, NASA will have to rely on a new observatory, the $4.5 billion James Webb telescope, which is set to launch in about four years.

"We are on the way to the beginning," said astrophysicist Neil deGrasse Tyson of the American Museum of Natural History. "Every step closer to the beginning tells you something you did not know before."

The new Hubble picture captures those distant simpler galaxies juxtaposed amid closer, newer and more evolved ones. The result is a cosmic family photo that portrays galaxies at different ages and stages of development over the course of more than 13 billion years.

Tyson, who was not involved in the Hubble image research, said most people only like their own baby pictures, but Hubble's photo is different: "These are the baby pictures for us all, hence the widespread interest."

http://news.yahoo.com/s/ap/20100106/ap_on_sc/us_sci_hubble_photo_11

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posted by Surono Karti @ 6:00 PM   0 comments
NASA: Planet-hunting telescope unearths hot mysteries
NASA's new planet-hunting telescope has found two mystery objects that are too hot to be planets and too small to be stars.


The Kepler Telescope, launched in March, discovered the two new heavenly bodies, each circling its own star. Telescope chief scientist Bill Borucki of NASA said the objects are thousands of degrees hotter than the stars they circle. That means they probably aren't planets. They are bigger and hotter than planets in our solar system, including dwarf planets.

"The universe keeps making strange things stranger than we can think of in our imagination," said Jon Morse, head of astrophysics for NASA.

The new discoveries don't quite fit into any definition of known astronomical objects, and so far don't have a classification of their own. Details about the mystery objects were presented Monday at a meeting of the American Astronomical Society in Washington.

For now, NASA researcher Jason Rowe, who found the objects, said he calls them "hot companions."

How hot? Try 26,000 degrees Fahrenheit. That's hot enough to melt lead or iron.

There are two leading theories for what the objects might be and those theories cover both ends of the cosmic life cycle:


_Rowe suggests they are newly born planets. New planets have extremely high temperatures, and in this case Rowe speculates they might be only about 200 million years old.

_Ronald Gilliland of the Space Telescope Science Institute says they could be white dwarf stars that are dying and stripping off their outer shells and shrinking.

The primary focus of the Kepler telescope's three-year mission is to find out how common other planets — especially Earth-like planets — are in the universe. To do that, it is scanning a small chunk of the sky, about one four-hundredth of the night sky with more than 150,000 stars to look for planets.

The telescope in just six weeks found its first five confirmed planets, slightly more than astronomers expected from such a quick search. There are hundreds of other candidates that need confirmation.

The five planets are all much larger than Earth, much closer to their stars than Earth is to the sun, and way too hot for life, Borucki said. A couple of these planets are close to 3,000 degrees.

"Looking at them is like looking at a blast furnace," Borucki said. "Certainly, no place to look for life."

One of the newly discovered planets is so airy that "it has the density of Styrofoam," Borucki said.

"There's going to be all kinds of weird stuff out there," said Alan Boss of the Carnegie Institute of Washington, who wasn't part of the research. "This is an unparalleled data set. The universe really is a weird place. It's fantastic."

http://news.yahoo.com/s/ap/ap_on_sc/us_sci_space_mystery

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posted by Surono Karti @ 12:52 AM   0 comments
Russia may send spacecraft to knock away asteroid
Thursday, December 31, 2009
Russia's space agency chief said Wednesday a spacecraft may be dispatched to knock a large asteroid off course and reduce the chances of earth impact, even though U.S. scientists say such a scenario is unlikely.
Anatoly Perminov told Golos Rossii radio the space agency would hold a meeting soon to assess a mission to Apophis. He said his agency might eventually invite NASA, the European Space Agency, the Chinese space agency and others to join the project.

When the 270-meter (885-foot) asteroid was first discovered in 2004, astronomers estimated its chances of smashing into Earth in its first flyby, in 2029, at 1-in-37.
Further studies have ruled out the possibility of an impact in 2029, when the asteroid is expected to come no closer than 18,300 miles (29,450 kilometers) from Earth's surface, but they indicated a small possibility of a hit on subsequent encounters.
NASA had put the chances that Apophis could hit Earth in 2036 as 1-in-45,000. In October, after researchers recalculated the asteroid's path, the agency changed its estimate to 1-in-250,000.
NASA said another close encounter in 2068 will involve a 1-in-330,000 chance of impact.
Don Yeomans, who heads NASA's Near-Earth Object Program, said better calculations of Apophis' path in several years "will almost certainly remove any possibility of an Earth collision" in 2036.
"While Apophis is almost certainly not a problem, I am encouraged that the Russian science community is willing to study the various deflection options that would be available in the event of a future Earth threatening encounter by an asteroid," Yeomans said in an e-mail Wednesday.
Without mentioning NASA's conclusions, Perminov said that he heard from a scientist that Apophis is getting closer and may hit the planet. "I don't remember exactly, but it seems to me it could hit the Earth by 2032," Perminov said.
"People's lives are at stake. We should pay several hundred million dollars and build a system that would allow us to prevent a collision, rather than sit and wait for it to happen and kill hundreds of thousands of people," Perminov said.
Scientists have long theorized about asteroid deflection strategies. Some have proposed sending a probe to circle around a dangerous asteroid to gradually change its trajectory. Others suggested sending a spacecraft to collide with the asteroid and alter its momentum, or hitting it with nuclear weapons.
Perminov wouldn't disclose any details of the project, saying they still need to be worked out. But he said the mission wouldn't require any nuclear explosions.
Hollywood action films "Deep Impact" and "Armageddon," have featured space missions scrambling to avoid catastrophic collisions. In both movies, space crews use nuclear bombs in an attempt to prevent collisions.
"Calculations show that it's possible to create a special purpose spacecraft within the time we have, which would help avoid the collision," Perminov said. "The threat of collision can be averted."
Boris Shustov, the director of the Institute of Astronomy under the Russian Academy of Sciences, hailed Perminov's statement as a signal that officials had come to recognize the danger posed by asteroids.
"Apophis is just a symbolic example, there are many other dangerous objects we know little about," he said, according to RIA Novosti news agency.
___
AP Science Writer Alicia Chang contributed to this story from Los Angeles.

http://news.yahoo.com/s/ap/eu_russia_asteroid_encounter

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posted by Surono Karti @ 1:35 AM   0 comments
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