One way to determine whether distant worlds may be home to extraterrestrials is to seek out the presence of biosignatures, molecules that indicate the existence of past or present life, in the exoplanet's atmosphere. (The chemical composition of the atmosphere affects its color spectra, observable with telescopes.) According to new MIT research, one biosignature may be a stinky, poisonous gas found in swamps, bogs, and even some animals' bowels. From MIT:

MIT researchers have found that phosphine is produced by... anaerobic organisms, such as bacteria and microbes, that don’t require oxygen to thrive. The team found that phosphine cannot be produced in any other way except by these extreme, oxygen-averse organisms, making phosphine a pure biosignature — a sign of life (at least of a certain kind).

In a paper recently published in the journal Astrobiology, the researchers report that if phosphine were produced in quantities similar to methane on Earth, the gas would generate a signature pattern of light in a planet’s atmosphere. This pattern would be clear enough to detect from as far as 16 light years away by a telescope such as the planned James Webb Space Telescope. If phosphine is detected from a rocky planet, it would be an unmistakable sign of extraterrestrial life.

“Here on Earth, oxygen is a really impressive sign of life,” says lead author Clara Sousa-Silva, a research scientist in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “But other things besides life make oxygen too. It’s important to consider stranger molecules that might not be made as often, but if you do find them on another planet, there’s only one explanation.”

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Very quickly. Before it, and you, freeze.

On Cyprien Verseux's Twitter account, wonderful snapshots of fun with food on the bleak, frozen ice sheets of Antarctica. Read the rest

Deep below a mile of ice at the Martian south pole lies a lake of liquid water, according to a team of Italian scientists led by Roberto Orosei. Read the rest

A new study in the International Journal of Astrobiology posits that beached whales may sometimes be influenced by solar storms. Read the rest

Turns out that long stints in outer space affect levels of cerebrospinal fluid. That explains why many astronauts who had 20/20 vision before space missions needed glasses upon return, according to a paper presented this week. Read the rest

Researchers at UT Austin have analyzed a deep depression on Mars that differs from a typical crater. The Hellas depression may in fact be an ancient ice cauldron, where a glacier forms over an active volcano, creating a chemical-rich environment that could support life forms. Read the rest

SETI Institute chief astronomer Seth Shostak bet hundreds of people at Boing Boing: Ingenuity that we'll hear from an extraterrestrial within 25 years. Find out why.

Researchers at the Universidad de Buenos Aires recreated conditions found on the surface of Jupiter's moon Europa in the lab, and then proved that some Earth organisms are capable of surviving in that extreme environment. At least, for three hours. It's one experiment in a growing body of work aimed at proving that Earth could seed other planets with life. Read the rest

Look Ma, no SETI. 10 other ways to search for intelligent life in the Universe. (Via Sarah Zielinski) Read the rest