Scientists Have Identified Exoplanets With The Same Life-Giving Properties As Earth

Thursday, 02 August 2018 - 2:23PM
Space
Astrobiology
Thursday, 02 August 2018 - 2:23PM
Scientists Have Identified Exoplanets With The Same Life-Giving Properties As Earth
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Image Credit: Maxpixel
Exoplanets with the same life-giving chemical properties as Earth have been identified in a new study out of the University of Cambridge, published yesterday in the journal Science Advances. The secret sauce? "Let there be light."

The study lead by Paul Rimmer, an astrophysicist from the University of Cambridge, focused on planets that are Kepler candidates. These are rocky planets that measure below a certain size threshold and orbit their host stars at a very precise distance: close enough to maintain stable levels of liquid water, but not so near that it evaporates into the cosmos.



But once you have those details in hand, what comes next? How do you transform dormant earth and water into a breathing organism?

Astronomers turned to an earlier study by John Sutherland – an organic chemistry professor who co-authored the current paper – for answers.

Sutherland had hypothesized that meteorites carried carbon down to Earth that reacted to atmospheric nitrogen, forming hydrogen cyanide. This compound, in turn, interacted with solar ultraviolet radiation to form the primordial soup from which RNA and DNA precursors first sprang.

This became the inspiration for today's groundbreaking study. "I came across these earlier experiments, and as an astronomer, my first question is always what kind of light are you using, which as chemists they hadn't really thought about," said Rimmer. "...and then realised that comparing this light to the light of different stars was a straightforward next step."

From there, it was a simple matter of replicating the circumstances in Sutherland's study, running the conditions under varying levels of UV light. The results were clear: light – and a very specific amount of it – is a critical component in the formation of life.

Astronomers then measured the relative ultraviolet output of possible host stars and found that stars similar to our Sun provide the perfect amount of ultraviolet light. Cooler stars fall below this threshold – and even if they release solar flares, those could fry fledgling microbes on a planet's surface.

This led to an entirely new classification of planets in the search for alien life: the abiogenesis zone, which builds upon the concept of a habitable zone by adding parameters for UV light in addition to ambient temperature and liquid water.

It's a high point in the unlikely partnership between exoplanet research and organic chemistry, revealing how collaboration between multiple scientific disciplines could accelerate our search for alien life, and that understanding our own origins may help us discover our neighbors look awfully familiar.
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