Strange, New Worlds

Young planets forming around cool stars may have a different life-forming mix of chemicals than early Earth did

The most common type of star in our galaxy is also a kind which we can't see in the sky with the naked eye. They aren't bright enough. They are M-dwarf stars, and they are significantly dimmer, smaller and cooler than our sun.

Now, observations made with NASA's Spitzer Space Telescope, a space-based infrared observatory, suggest that planets orbiting these cool stars may contain "prebiotic" material -- the elements required for the formation of life, but not the same kind of chemistry present on Earth when life sprang forth some 4 billion years ago.

Spitzer detected hydrogen cyanide -- an organic, prebiotic precursor to amino acid -- around stars like our sun, but none were found near cooler stars.

Adenine, a chemical element of DNA found in all living things on Earth, can be made when five hydrogen cyanide molecules combine.

We now know the chemistry of some of these young exoplanets is different. And that suggests that if life does form on another world, it could look a lot different too.

Then again, life could very well be jump-started by a mix of chemicals brought over by a meteorite, a.k.a. Panspermia.

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image: artist's conception of a hypothethical young planet orbiting a cool star (Image credit: NASA/JPL-Caltech)