The Search for Another Earth
EmailTo astronomers looking for life elsewhere in the universe, the holy grail would be an Earth-like planet orbiting in the so-called "habitable zone" around its host star, where the temperature might be right for liquid water. That is why they have taken a special interest in Gliese 581, a small star about 20 light-years away in the constellation Libra. It seems to have a busy solar system, with at least four known planets. The, er, star of the show is the outermost planet, designated 581d, which was identified in 2007. It’s on the large side, about seven times as massive as Earth, but it’s a good distance from its sun. Its year is equal to about 67 of our days. Now a French team, using a telescope at the European Southern Observatory in the arid mountains of Chile, says 581d is almost definitely in the right place for liquid water. It may even be a once-icy world whose orbit has decayed and brought it closer to the star, so that it could, conceivably, be covered by an ocean. And there’s more, announced today at a conference in Britain. The smallest planet, Gliese 581e, is only 1.9 times as massive as Earth. It’s probably a pretty hellish, hot place, with a "year" of less than 32 Earth days — but the astronomers are impressed they were able to detect it. They cannot see any of these worlds; instead, they measure how much the planets’ gravity causes their star to "wobble" in space. 581e changes its star’s velocity by 7 km per hour — about walking speed. Why, people often ask, do we make earthly assumptions in the search for life elsewhere? Because anywhere you point a spectrometer (an instrument for measuring the light, given off or absorbed by something), they see the same chemical signatures. A rock on Mars resembles a rock in Earth. An astrobiologist friend quipped, "The chemistry books on Proxima Centauri say exactly the same things ours do." (Image: artist’s conception of Gliese 581 system, courtesy ESO/L. Calçada.)
Space Station Flies Over Eastern U.S. at Night 
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Forget the chemistry books, I want to see what the sci-fi fiction and graphic novels look like on Proxima Centauri.
Posted by: Will | April 21, 2009, 4:55 pm 4:55 pm
Very cool stuff. Quit spending money on bombing people and stick on these types of things. Even better, don’t spend it and give it back to us.
Posted by: Huh | April 21, 2009, 4:59 pm 4:59 pm
20 light years? We better get moving, humans, especially Republican humans, are quickly making this planet uninhabitable.
Posted by: plantain_11 | April 21, 2009, 5:30 pm 5:30 pm
lets hope they find a new earth soon, ’cause this one is going to heck in a handbasket real quick, thanks Mr. Obama
Posted by: Dennis | April 21, 2009, 5:47 pm 5:47 pm
581d seems to be rotating pretty fast for a planet 7 times our size. Barely enough time for one season. No sooner than your alarm goes off, its time to come back home and get ready for bed.
Posted by: tendergroins | April 21, 2009, 5:50 pm 5:50 pm
Life here on Earth lately isnt so great lately (human life I mean) why do we feel the need to ruin the rest of the universe?
Posted by: omgnoway | April 21, 2009, 6:18 pm 6:18 pm
James Webb Space Telescope 2013!!!Now w got a target!
Posted by: cool. | April 21, 2009, 6:35 pm 6:35 pm
Hey, maybe Obama should take a trip there..he can tell the people there just how bad America is too!!!
Posted by: rfchir81 | April 21, 2009, 6:36 pm 6:36 pm
Their planet may be dieing. That’s possibly why they’re checking our’s out.
Posted by: Daniel | April 21, 2009, 6:36 pm 6:36 pm
help!!!! come and get me!
Posted by: sos | April 21, 2009, 6:41 pm 6:41 pm
20 light years? We better get moving, humans, especially Democrat humans, are quickly making this planet uninhabitable.
Posted by: lew | April 21, 2009, 7:01 pm 7:01 pm
What a fascinating discovery. It’s a shame that so many people feel the need to turn every story into an opportunity for political discourse. Whether left or right, they are fools if they can’t look up to the stars in amazement and humility.
Posted by: John | April 21, 2009, 7:11 pm 7:11 pm
Hey John,
You are absolutely right buddy.
Posted by: Scott | April 21, 2009, 7:25 pm 7:25 pm
NASA must need more money from Congress.
They did the same thing a few yrs back by saying they found a Mars rock that had a fossil of some type of worm.They got the money from Congress and the went,oops…My bad.
They think people will believe anything.
Posted by: Christian Conservative | April 21, 2009, 7:38 pm 7:38 pm
Quick! Inhabit it, subjugate and drive to extinction any life forms, plunder all natural resources, cover the surface in McDonald’s, McMansions and Megachurchs then look for another habitable plant to occupy and destroy!
Posted by: I Am Who Am | April 21, 2009, 7:48 pm 7:48 pm
Where can I buy a ticket to this new earth . . . and the sooner the better.
Posted by: rplat | April 21, 2009, 7:56 pm 7:56 pm
Christian Conservative,
I think your only problem is that NASA may actually prove that evolution is TRUE and that God did create the Universe with “A BIG BANG” and then allowed us to evolve, and not “IN SEVEN DAYS”.
Posted by: Steve_NJ | April 21, 2009, 8:08 pm 8:08 pm
DANG
i did my science current event yesterday
and this EVENT is posted today?
Posted by: duke | April 21, 2009, 10:58 pm 10:58 pm
I have to agree with tendergroins on this one. So what if a planet can hold water? If a planet has no stable “seasons,” how can anything grow, unless it is stuck in eternal spring/summer?
Also, the g-forces on this planet are probably astounding. 7 times larger than Earth, you say? Do the math, it doesn’t look pretty.
Posted by: K-Chan | April 22, 2009, 8:19 am 8:19 am
The point in finding it is not for Human habitation. But in search of life outside our planet. I can’t wait to find that. Just think of the societal changes that’ll come about.
And just because it’s year is 67 days, doesn’t mean it has bad seasons. It’s tilt may not be large enough to give noticable seasons. Come on people, have you already forgotten 2nd grade? A planet needs a tilt on it’s axis of rotation to have seasons. Not a 365 day long year. And so what if it has a 12 day spring or whatever, if life evolved there, it evolved to deal with that. It wasn’t put there for us. How arrogant.
Posted by: Lawrence | April 22, 2009, 8:54 am 8:54 am
When I read my first astronomy book in the 2nd grade, the human race knew almost nothing about the Universe. In my life time we have orbited the earth, landed on the moon, sent probes passed all the planets except Pluto, it was a planet when Voyager was launched, and now we are finding planets around distant stars using detective measures that would make CSI proud. In that same time nothing new has been learned
about religion except that most of the stories In the Bilble have been proven to be inaccurate. Research on the Dead Sea Scrolls, suppressed for years,
has put new light on the vague meaning of the scriptures. And stop hating on Obama, you lost, get over it. Even if we sent Hanity, Beck and O’Rieley into space there still wouldn’t be any intelligent life out there….lol
Posted by: blackie | April 22, 2009, 3:04 pm 3:04 pm
If the distance light travels in a year is a “light year”, and you multiply it times 20, what we’re seeing happened 20 years ago, right? “They cannot see any of these worlds; instead, they measure how much the planets’ gravity causes their star to “wobble” in space.” WHAT?!
Posted by: Gerald | April 27, 2009, 5:49 pm 5:49 pm
STEVE NJ – while you think you are COOL & SMART in bashing Christian Conservative, on the note of the “seven days” … God also says in His word to anyone who would listen, that to Him, “a day is as a thousand days and a thousand days as one” — TIME is a tool and not a constrant to the universe’s creator. A “God evolution” or not, there remains the condition of ones eternal conscious/soul. If you would refute good and bad in the world, then it is YOU with blinders on. There are more “Jesus followers” in science than not.
Posted by: a Monsanto Bio-Eng. | May 11, 2009, 8:03 pm 8:03 pm