Alien Life May Be "Weirder" Than Scientists Think, Report Says

Think life on Earth is weird? It might be even weirder on distant planets and moons, according to a new report.

Instead of thriving on water, extraterrestrial organisms might live in a sea of liquid methane. Or instead of getting energy from the sun, they might thrive on hydrochloric acid.

These possibilities could revolutionize future space missions in search of life elsewhere in the solar system, says the report, issued today by the National Academy of Sciences (NAS).

The report concludes that scientists need to consider an expanded list of characteristics that define life, including so-called "weird" life-forms that may thrive where Earth organisms couldn't.

Instead of dispatching spacecraft to dig into the subsurface of Mars, considered a prime candidate for primitive life because of its watery past, the report says the probes may have better luck on Saturn's moon Titan, which has seas of liquid methane and ethane.

In fact, the report concluded that Titan is the most likely candidate in the solar system for weird life.

"It's a carbon world, so there's plenty of different kinds of carbon compounds there, and the possibility is that there may be the carbon compounds that make up life," said John Baross, an oceanographer at Seattle's University of Washington, who lead the report team.

Different Life

Baross chaired the committee that prepared the report released by the National Research Council, an arm of the NAS.

The report probes the question: How might life on distant worlds be different than life on Earth?

"We don't want to not recognize a life form because it doesn't exactly resemble Earth life," Baross said.

Since these characteristics make life on Earth possible, scientists have long assumed they are required for life elsewhere in the universe. But advances in biology and biochemistry in the last decade show that the basic requirements for life may not be so concrete, according to Baross.

Seth Shostak is a senior astronomer at the SETI Institute in Mountain View, California, which is dedicated to the search for alien life. He was not part of the report but said the premise is "very justified."

"Let's be a little more broad-minded. Let's not just look for life as we know it," Shostak said.

"The only problem," he added, "is it's very difficult to look for life as you don't know it, because you don't know how to look for it. I think that's what motivates this study."