Recent research makes extraterrestrial life seem more likely

Life would probably look more like mold than E.T., scientists say
Wednesday, December 8, 2010 | 6:32 p.m. CST; updated 8:15 p.m. CST, Wednesday, December 8, 2010
This image provided by NASA of Saturn's moon Enceladus was made by the Casini spacecraft during a fly-by on Aug. 11, 2008. Areas that are greenish in appearance are believed to represent deposits of coarser grained ice and solid boulders that are too small to be seen at this scale. The whitish deposits represent finer grained ice. (AP Photo/NASA)



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"The evidence is just getting stronger and stronger," said Carl Pilcher, director of NASA's Astrobiology Institute, which studies the origins, evolution and possibilities of life in the universe. "I think anybody looking at this evidence is going to say, 'There's got to be life out there.'"




What last week's findings did were both increase the number of potential homes for life and broaden the definition of what life is. That means the probability for alien life is higher than ever before, agree 10 scientists interviewed by The Associated Press.

Miracles vs. proof

Seth Shostak, senior astronomer at the SETI (Search for Extraterrestrial Intelligence) Institute in California, ticks off the astronomical findings about planet abundance and Earthbound discoveries about life's hardiness.

"All of these have gone in the direction of encouraging life out there, and they didn't have to."



"And astronomers tend not to believe in miracles," he said.


But, says NASA astrobiologist Chris McKay, who has worked on searches for life on Mars and extreme places on Earth, "There are real things we can point to and show that being optimistic about life elsewhere is not silly."

Sextillions of new worlds

First, there's the basic question of where such life might exist. Until a few years ago, astronomers thought life was only likely to be found on or around planets circling stars like our sun. So that's where the search of life focused — on stars like ours.

That left out the universe's most common stars, red dwarfs, which are smaller and dimmer than our sun. Up to 90 percent of the stars in the universe are red dwarf stars. And astronomers assumed planets circling them would be devoid of life.

But three years ago, NASA got the top experts in the field together. They crunched numbers and realized that life could exist on planets orbiting red dwarfs. The planets would have to be closer to their star and wouldn't rotate as quickly as Earth. The scientists considered habitability and found conditions near these small stars wouldn't be similar to Earth but would still be acceptable for life.

That didn't just open up billions of new worlds, but many, many times that.

Last week, a Yale University astronomer said he estimates there are 300 sextillion stars — triple the previous number. That's the number 3, followed by 23 zeros.

Lisa Kaltenegger of Harvard University says scientists now believe that as many as half the stars in our galaxy have planets that are two to 10 times the size of Earth — "super Earths" that might sustain life.

Then the question is how many of those are in the so-called Goldilocks zone — not too hot, not too cold. The discovery of such a planet was announced in April, though some scientists are challenging that.

Star bucks: Betting on alien life

The other half of the equation is: How likely is life? Over the past decade and a half, scientists have found Earth life growing in acid, in Antarctica and in other extreme environments. But nothing topped last week's news of a lake bacterium that scientists could train to thrive on arsenic instead of phosphorous. Six major elements have long been considered essential for life — carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. This changed that definition of life.

By making life more likely in extreme places, it increases the number of planets that are potential homes for life, said Kaltenegger, who also works at the Max Planck Institute in Germany.

Donald Brownlee, an astronomer at the University of Washington, is less optimistic because he believes what's likely to be out there is not going to be easy to find — or that meaningful. If it's out there, he said, it's likely microbes that can't be seen easily from great distances. Also, the different geologic and atmospheric forces on planets may keep life from evolving into something complex or intelligent, he said.

If life is going to be found, Mars is the most likely candidate. And any life is probably underground where there is water, astronomers say. Other possibilities include Jupiter's moon Europa and Saturn's moons Enceladus and Titan.

There's also a chance that a telescope could spot a planet with an atmosphere that suggests photosynthesis is occurring, Kaltenegger said. And then there's the possibility of finding alien life on Earth, perhaps in a meteorite, or something with an entirely different set of DNA.

And finally, advanced aliens could find us, or we could hear their radio transmissions, McKay said. That's what the SETI Institute is about: listening for intelligent life.

That's where Shostak puts his money behind his optimism. At his public lectures, Shostak bets a cup of coffee for everyone in the audience that scientists will find proof of alien life by about 2026. The odds, he figures, have never been more in his favor.

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Louis Schneebaum December 8, 2010 | 8:03 p.m.


Misinformation. Arsenic and Phosphorous reside next to one another on the periodic table (i.e they're chemically very similar). These bacteria are able to substitute arsenic in the absence of phosphorous (which is a necessary element for all life). It's not that astounding. They're evolutionarily young and living in an extreme environment - they survive.

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Ellis Smith December 9, 2010 | 7:45 a.m.

It's difficult not to notice that this furor has erupted just as NASA faces serious reductions in funding and an uncertain future. :)

But let us never speak ill of NASA, particularly if we happen to be MS&T, where classroom and laboratory facilities for one of America's largest Aerospace Engineering programs have recently been more than doubled. (You remember reading about that in the Columbia newspapers, don't you?)

NASA has been very good to MS&T: three NASA Astronauts, all of whom spent time in space (Sandra Magnus also on the space station) and one of whom (Janet Kavandi) is now high up in the NASA organization.

Good Lord, Martha! Do they actually have female students at MS&T? Well I never! (Seriously, 27% of the student body.)

Back to the article, if it can't crawl, sit up, walk, speak, and at least do simple arithmetic, how much of a "life form" is it? Seriously, these discoveries are important, but what everyone wants to meet is someone at least remotely resembling us. Statistically such life forms should exist, but making contact is another matter.

Beam us up, Scotty.

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