Getbig Main Boards > General Topics

NASA and current Astronomy

<< < (2/10) > >>

Raymondo:

--- Quote from: shizzo81 on October 03, 2013, 02:40:37 PM ---Way too many planets and solar systems to not have other life out there. Mathematically impossible.

--- End quote ---

The right term is astronomically improbable  :)

Gregzs:
http://www.reuters.com/article/2013/11/04/us-space-exoplanet-idUSBRE9A311820131104

One in five Milky Way stars hosts potentially life-friendly Earths: study


One out of every five sun-like stars in the Milky Way galaxy has a planet about the size of Earth that is properly positioned for water, a key ingredient for life, a study released on Monday showed.

The analysis, based on three years of data collected by NASA's now-idled Kepler space telescope, indicates the galaxy is home to 10 billion potentially habitable worlds.

The number grows exponentially if the count also includes planets circling cooler red dwarf stars, the most common type of star in the galaxy.

"Planets seem to be the rule rather than exception," study leader Erik Petigura, an astronomy graduate student at the University of California at Berkeley, said during a conference call with reporters on Monday.

Petigura wrote his own software program to analyze the space telescope's results and found 10 planets one- to two-times the diameter of Earth circling parent stars at the right distances for liquid surface water.

The telescope worked by finding slight dips in the amount of light coming from target stars in the constellation Cygnus.

Some light dips were due to orbiting planets passing in front of their parent stars, relative to Kepler's line of sight.

Extrapolating from 34 months of Kepler observations, Petigura and colleagues found that 22 percent of 50 billion sun-like stars in the galaxy should have planets roughly the size of Earth suitably positioned for water.

A positioning system problem sidelined Kepler in May. Scientists are developing alternative missions for the telescope. More than a year of data already collected by Kepler, which was launched in 2009, still has to be analyzed.

In another Kepler study, the telescope found 3,538 candidate planets, 647 of which are about the size of Earth, said astronomer Jason Rowe, with the SETI Institute in Mountain View, California.

Of the 3,538 candidates, 104 are at the right distance from their parent stars for water, he said.

"When exoplanet hunting started, everyone expected solar systems to look just like ours," Rowe said. "But we're finding quite the opposite, that there's a wide variety of systems out there. If you can imagine it, the universe probably makes it."

The research was published in this week's Proceedings of the National Academy of Sciences and presented on Monday at a Kepler science conference at NASA's Ames Research Center in Moffett Field, California.

Gregzs:
http://newswatch.nationalgeographic.com/2013/10/30/new-found-earth-sized-exoplanet-doomed/

New-found Earth-size Exoplanet Doomed

Astronomers announced this week that they have spotted a rocky Earth-size planet beyond our solar system, the smallest alien world accurately sized by observers to date. However, the super-hot planet is no second Earth, and according to theories, the distant world some 700 light-years away from Earth shouldn’t exist.

The planet, Kepler-78b, was first discovered by its namesake NASA space telescope. The planet is about 20 percent larger than the Earth, with a diameter of 9,200 miles, and it weighs almost twice as much.

Using the world’s largest ground-based telescopes, two independent research teams have now confirmed the planet’s mass and density by measuring “wobbles” of its sun-like host star, seen as the exoplanet orbits around it. They report the confirmations in the journal Nature.

Unfortunately, Kepler-78b is not Earth 2.0, however, because it turns out that it circles its star at a scorching distance of one million miles. A year on this fast-paced little world lasts only 8.5 hours.

“It’s Earth-like in the sense that it’s about the same size and mass, but of course it’s extremely unlike the Earth in that it’s at least 2,000 degrees hotter,” says co-author Josh Winn, an astronomer at MIT.

“It’s a step along the way of studying truly Earth-like planets.”

The problem astronomers have with their finding is that according to what we understand about planet formation, this hot lava world couldn’t have formed so close to its star, nor could it have moved there.

“This planet is a complete mystery,” says study co-author David Latham, an astronomer at the Harvard-Smithsonian Center for Astrophysics. “We don’t know how it formed or how it got to where it is today. What we do know is that it’s not going to last forever.”

Astronomers have a quandary on their hands.  They don’t believe the planet could have formed in its current orbit because then Kepler-78b would have been inside the much larger, younger star. At the same time, it couldn’t have formed farther out and migrated inward, because it should have been drawn on a swirling kamikaze dive straight into the star.

“How it came to reside in its current 8.5-hour orbit is uncertain,” says planetary scientist Drake Deming of the University of Maryland in a commentary accompanying the studies. “Among the more exotic possibilities is that it is the remnant core of a disrupted gas giant,” he writes.

Because it has the tightest orbit around a star ever seen, one thing researchers know for sure is that Kepler-78b’s days are numbered. The extreme gravitational pull from its star will draw it ever closer in, ripping the entire planet apart in about three billion years.

Gregzs:
http://xfinity.comcast.net/articles/news-science/20131121/US-SCI--Monster.Cosmic.Explosion/

'Monster' cosmic blast zipped harmlessly by Earth

WASHINGTON (AP) — Astronomers call it the monster. It was the biggest and brightest cosmic explosion ever witnessed. Had it been closer, Earth would have been toast.

Orbiting telescopes got the fireworks show of a lifetime last spring when they spotted what is known as a gamma ray burst in a far-off galaxy.

The only bigger display astronomers know of was the Big Bang — and no one, of course, was around to witness that.

"This burst was a once-in-a-century cosmic event," NASA astrophysics chief Paul Hertz said at a news conference Thursday.

But because this blast was 3.7 billion light-years away, mankind was spared. In fact, no one on Earth could even see it with the naked eye.

A gamma ray burst happens when a massive star dies, collapses into a brand-new black hole, explodes in what's called a supernova and ejects energetic radiation. The radiation is as bright as can be as it travels across the universe at the speed of light.

A planet caught in one of these bursts would lose its atmosphere instantly and would be left a burnt cinder, astronomers say.

Scientists might be able to detect warning signs of an impending gamma ray burst. But if a burst were headed for Earth — and the chances of that happening are close to zero, astronomers say — there wouldn't be anything anybody could do about it.

NASA telescopes in orbit have been seeing bursts for more than two decades, spotting one every couple of days. But this one, witnessed on April 27, set records, according to four studies published Thursday in the journal Science.

It flooded NASA instruments with five times the energy of its nearest competitor, a 1999 blast, said University of Alabama at Huntsville astrophysicist Rob Preece, author of one of the studies.

It started with a star that had 20 to 30 times the mass of our sun but was only a couple of times wider, so it was incredibly dense. It exploded in a certain violent way.

In general, gamma ray bursts are "the most titanic explosions in the universe," and this one was so big that some of the telescope instruments hit their peak, Preece said. It was far stronger and lasted longer than previous ones.

"I call it the monster," Preece said. In fact, one of the other studies, not written by Preece, used the word "monster" in its title, unusual language for a scientific report.

One of the main reasons this was so bright was that relative to the thousands of other gamma ray bursts astronomers have seen, the monster was pretty close by cosmic standards. A light-year is almost 6 trillion miles.

Most of the bursts NASA telescopes have seen have been twice as distant as this one. Other explosions could be this big, but they are so much farther away, they don't seem so bright when they reach Earth, the studies' authors say.

Astronomers say it is incredibly unlikely that a gamma ray burst — especially a big one like this — could go off in our galaxy, near us. Harvard's Avi Loeb, who wasn't part of the studies, put the chances at less than 1 in 10 million.

Our galaxy doesn't have many of the type of star that lends itself to gamma ray bursts, said Charles Dermer, a co-author of the studies and an astrophysicist at the U.S. Naval Research Laboratory.

"The chance of anything happening and being dangerous is virtually nil," Dermer said.

Also, because a burst is concentrated like a focused searchlight or a death beam, it has to be pointing at you to be seen and to be dangerous.

"Either it's pointed at us or it's not," Preece said. "If it's not, yay! Civilization survives and we see maybe a supernova. If it were pointed at us, then it matters very much how far away it is in our galaxy. If it's in our local arm, well, we had a good run."

Some theorize that a mass extinction on Earth 450 million years ago was caused by a gamma ray burst in a nearby part of our galaxy, but Dermer said that's unlikely.

We don't see gamma ray bursts from the surface of Earth because the atmosphere obscures them and because most of their light is the type we cannot see with our eyes. That's why NASA has satellites that look for them.

This burst was so bright telescopes on Earth saw a brief flash in the constellation Leo.

For scientists, this was a wow moment.

"These are really neat explosions," said Peter Michelson, a Stanford physicist who is the chief scientist for one of the instruments on a NASA gamma ray burst-spotting telescope. "If you like fireworks, you can't beat these. Other than the Big Bang itself, these are the biggest there are."

The burst "is part of the cycle of birth and life and death in the universe," Michelson said. "You and I are made of the stuff that came from a supernova."

Gregzs:
NASA’s Juno spacecraft captured this amazing video of the Moon orbiting Earth as it passed by our planet on October 19th, 2013. Using a camera designed to track faint stars, Juno captured the images — which were later assembled into a video — at a distance of about 600,000 miles. As it passed by Earth, the spacecraft accelerated to more than 8,800 mph in order to reach Jupiter by July 4th, 2016.

Navigation

[0] Message Index

[#] Next page

[*] Previous page