Exoplanets and Alien Life

For hundreds of years, man hoped to find some form of life in our Solar System, but sadly, after a lot of research and development and careful scanning and observation, things just didn't seem to fit. Every planet was chalked out for some vital condition that it could not satisfy. However, at this point, what we must realise is that what we are looking for is not some form of civilisation that is alien to us, for all we know of life is the way we humans biologically know it. We can definitely not rule out the possibility of the existence of an alien life form that has a totally different set of conditions to be able to sustain themselves. But, since looking for such forms of life would be nothing less than a wild goose chase, we narrow down our search to only those forms of life that are more or less similar to us biologically.

Once scientists laid down some fundamental basis to define life, and some basic characteristics were identified, they went ahead in the quest to search for life beyond our solar system.

In the simplest terms, an extrasolar planet (also referred to as an exoplanet) is a planet beyond the solar system. As of today, there are 257 exoplanets that have been identified. This count only includes those planets that have been observed to be revolving around particular stars. Rogue planets and interstellar planets are not included in this count.

As far as detection of exoplanets is concerned, direct imaging is not an option. However, a host of other alternative indirect methods are available, including transit method (most commonly used), astrometry, radial velocity or Doppler method (this technique has proved to be the most productive one), eclipsing binary, and many more.

Most exoplanets known today orbit stars very similar to our sun. Firstly, this is because most of these search programs tend to focus on such stars. Secondly, those stars that are of lower mass are less likely to have planets, and even if they do, the planets themselves are quite small and therefore hard to detect. Lastly, the stars that are much hotter than our sun produce a photo-evaporation effect that inhibits planetary formation. Kepler Mission is probably one of the biggest leap that mankind has taken in this direction and it is expected to yield tremendous amounts of information about exoplanets that will take us a step closer to detecting alien life forms.

Detection of life (other than an advanced civilization) at interstellar distances, however, is a tremendously challenging technical task that will not be feasible for many years, even if such life is commonplace. So till then, lets just say, WE RULE THE WORLD...

Image details:

This artist's illustration shows an icy/rocky planet orbiting a dim star. Astronomers detected an extrasolar planet five times as massive as Earth circling a red dwarf, a relatively cool star. The distance between the planet, designated OGLE-2005-BLG-390Lb, and its host is about three times greater than that between the Earth and the Sun. The planet's large orbit and its dim parent star make its likely surface temperature a frigid minus 364 degrees Fahrenheit (minus 220 degrees Celsius). OGLE-2005-BLG-390Lb looking at it's sun.
Image Source : NASA and the European Space Agency

-Mohit Gidwani