14 DAY TRIAL // Astronomers believe that developing a telescope capable of detecting the signature of light bouncing off alien atmosphere could enable the detection of extrasolar planets that may be inhabitable. They say that the necessary type of atmosphere (i.e. one like Earth's) has a specific signature.
An added benefit to using this approach is that scattered light also encodes a vast volume of data about the physical conditions of the atmosphere in question. These include the chemical composition, which is the most important thing for experts to find out.
According to the latest investigations on the factors affecting exoplanets, it would appear that even some of the worlds located in their parent stars' habitable zones may not be inhabitable after all. Factors such as extreme radiations or huge tidal forces can make planets useless to life.
In fact, atmospheric analyses are the deal-breakers of astronomical studies. Even if an exoplanet fulfills all the other conditions necessary for being cataloged as habitable, a lack of atmosphere, or the presence of an unsuited one, could negate all the other positive aspects.
At this point, most studies dedicated to extracting data from scattered light are collected of edge-on, transiting systems. But this approach is very limiting, University of California in Santa Cruz (UCSC) astronomer Sloane Wiktorowicz says.
“We know of many other planets that do not transit their host stars, and we therefore know almost nothing about those atmospheres. Less than 10 percent of the known exoplanets have had their atmospheres detected,” he explains.
One of the main reasons for this is that the planets themselves – regardless of whether they are gas giants or rocky worlds – are several thousand times dimmer than their parent stars. Light from the latter simply drowns out whatever light the former may scatter, Daily Galaxy reports.
This is why astronomers are currently trying to use an observations technique called linear polarimetry to conduct their investigations. Unlike regular methods, this one detects light that is polarized in specific manners.
If the light bouncing off an exoplanetary atmosphere is polarized, then its polarization would be different from that of the parent star, which does not scatter from any obstacle. This means that the faint light bouncing off exoplanets could be identified even among much brighter light from the parent star.