Beyond Neptune lies the Kuiper Belt, a massive asteroid belt twenty times the size of the one between Mars and Jupiter. In this frigid, unforgiving environment, organic molecules might still survive, suggesting life's building blocks are everywhere in the universe.
The Kuiper Belt isn't just a uniform collection of icy, frozen rocks. Instead, astronomers can detect lots of different colors in the belt's bodies, including reds, whites, and blues. Thanks to a new computer model, scientists now have a pretty good idea what's creating all the reds: there are organic molecules in the Kuiper Belt, buried just beneath the surface of the various objects.
NASA physicist John Cooper is quick to point out this doesn't mean there's life in the Kuiper Belt, but the reality is almost as exciting:
"We're not saying that life is produced in the Kuiper Belt. But the basic chemistry may start there, as could also happen in similar Kuiper Belt environments elsewhere in the universe, and that is a natural path which could lead toward the chemical evolution of life."
Some of the Kuiper Belt's objects appear to be far enough away that the Sun's ions don't turn their surfaces black with radiation exposure. Instead, the ions blast the millimeter-thick top layer away to reveal the much thicker reddish second layer, which is then cooked by the cosmic radiation. This process then would transform water ice, carbon, methane, nitrogen and ammonia - all materials that would need to be on the objects to account for the reddish color, according to the computer models - into organic molecules, such as formaldehyde and ethane.
Cooper says these objects are in a sweet spot where these reactions can take place, and that it's possible even more complex reactions occur:
"If there wasn't any cooking at all, we would just see primordial ice, and the object would appear bright and white. And if there was too much radiation we would just see black crust. When you take the right mix of materials and radiate them, you can produce the most complex species of molecules. In some cases you may be able to produce the components of life - not just organic materials, but biological molecules such as amino acids."
If organic molecules really can survive in so cold and inhospitable an environment as the Kuiper Belt, then they could be pretty much anywhere in the universe - and, indeed, they probably are everywhere. For more on how the Kuiper Belt objects get their different colors, check out the original article.