European Southern Observatory yesterday discovered Proxima Centauri b, the closest Earth-like exoplanet (planet which does not orbit our sun) till date. Many theories have said that some day humans may have to leave Earth to look for a ‘second home’, and planets like this certainly look promising if ever that day comes. Whether we succeed in space travel or not, these discoveries are significant because they indicate that somewhere else in the universe, life may exist. This is not the first such significant discovery and we, at Reacho, had a look at other such planets which were discovered in the last 5 years, owing to advancement in technologies, that lie in the Conservative Habitable Zone (where water, and maybe life, could exist):.
(Note: 1 light year = distance travelled by light at 3,00,000 km/s in one year. All images are concept arts)
Proxima Centauri b
Discovery date: 24/08/2016
Distance from Earth: 4.224 light years
As mentioned above, this is the closest Earth-like planet ever discovered, giving rise to hope that if ever space travel becomes feasible, a visit to this planet may become possible. It is slightly bigger than Earth and has temperature suitable for liquid water. Further studies on this one are expected to reveal more details as to its characteristics and structure
Gliese 667 Cc
Discovery date: 21/11/2011
Distance from Earth: 23.62 light years
This planet is perhaps the most Earth-like planets ever found, with a slightly hotter equilibrium surface temperature. It is close to its star and, like many below in the list, has one side locked facing towards its star. It could sustain life if it has a thick atmosphere and being quite close, presents a relatively better prospect for future research.
Comparison with Earth
Discovery date: 06/01/2015
Distance from Earth: 1120 light years
Kepler-442b is said to be one of the most Earth-like planets ever found, in terms of size and temperature. It is closer to its star than Earth is to the sun, which indicate a much longer day than Earth. Its star, however, is smaller than sun and will have a longer lifespan (about 30 billion years). If the star has passed its initial solar-wind emitting stage, the planet could be habitable.
Discovery date: 23/07/2015
Distance from Earth: 1400 light years
This planet, despite being so far away (it would take 26 million years to reach it, at the very least) lies in a quite similar position its own system like Earth in our own. Citing similar characteristics, it is sometimes called as Coruscant (a planet in Star Wars universe) by NASA. Current research suggests that if it does have any oceans, it could hold on to them for 500 million more years as its star is quite similar to ours.
Discovery date: 17/12/2015
Distance from Earth: 13.8 light years
This planet lies quite close to its star, in the inner edge of habitable range. The closeness makes its one side locked towards the star and one side away. Also, life sustaining conditions could be present on this planet on the terminal line, which separates the bright side from the dark side. It, like other, would need thick atmosphere however.
Discovery date: 12/05/2016
Distance from Earth: 770 light years
This planet is quite habitable if given the right atmosphere. The planet is larger than Earth, and has one side locked towards its star and the other submerged in darkness. Certain areas could have liquid water, but it will need a thick atmosphere if some form of life is to be present on the planet.
Discovery date: 06/2014
Distance from Earth: 12.8 light years
Not much is known about this one as its discovery has not been confirmed by all, pointing out the fact that it may well be something else other than a planet. If it is indeed a planet though, it could be the second nearest habitable planet after the recently discovered Proxima Centauri b. This planet is bigger than Earth and has temperature too cold to support liquid water and sustenance could only be possible after a temperature rise.
Discovery date: 18/04/2013
Distance from Earth: 1200 light years
This planet, being 1200 light years away, cannot be studied through telescopes. However, some studies have indicated that this planet, and some others like this, could have large areas covered with water given the right circumstances, especially since the planet is quite old (3-11 billion years old). In current conditions though, it most probably has a negligible atmosphere and could even be covered entirely with ice.
Discovery date: 17/04/2014
Distance from Earth: 558 light years
Being this far away, it was very difficult to make any observation about its atmosphere or other characteristics. This planet is slightly bigger than Earth as well as closer to its star. It is thought that this planet could have a rocky structure and colder surface temperature compared to Earth in absence of atmosphere.
Title image: Spaceflightinsider