New Way of Looking for 'E.T.' Devised

With more than 300 exoplanets discovered thus far and hundreds others to be found soon by the Kepler Space Telescope, astronomers are now considering methods of investigating their surface, in a bid to discover signs of life. Naturally, sending probes to these worlds is unfeasible, on account of the fact that some of them are hundreds or thousands of light-years away. It would take several generations for a craft to reach its destination, and astronomers cannot wait that long.

Hopefully, they won't have to, thanks to a new technique developed by a Space Telescope Science Institute (STSI) science team. It revolves around looking for signs of photosynthesis, the basic process that allowed for our planet to develop in such a manner that life became possible. In other words, it's vegetation that actually allows for life to develop. But the issue for the team has been finding a method of identifying those exoplanets that have at least a very thin atmosphere.

“When you look at objects in the solar system, what's a high-probability way of determining whether or not that planet has life? Circular polarization has the potential to be a signature of life,” STSI Astrobiologist Neill Reid explains, as quoted by Wired. The basic principle of this investigation method is fairly simple – analyzing the way in which photons in an exoplanet's atmosphere behave. That is to say, they usually travel up and down, but when they hit other molecules, they tend to engage in a corkscrew-like motion. By using a sophisticated spectrometer, researchers could potentially identify what molecules the photons collide with, as each such interaction has its own signature.

The new study, which was published on Monday in the journal Proceedings of the National Academy of Sciences (PNAS), also argues that installing spectrometers on earth- and space-based telescopes should be a standard procedure from now on, as such a complex would constitute “a powerful remote sensing technique for generic life searches.” Bacteria and microbes will be the main targets of any future study of exoplanets around us, as evolutionary biologists have determined that they are the organisms most likely to be found in the Universe. Their resilience comes from the fact that they are very simple in structure and able to adapt to the most vicious conditions.