Are There Worlds Like Ours Out There?
For centuries man has wondered if there are other worlds like our Earth somewhere in the Universe. Now this question has been answered. Yes, says NASA (National Aeronautics and Space Administration) which recently made its finding of Kepler 22b public.
What Is Kepler-22b?
Kepler-22b is one of the many extrasolar planets or exoplanets so called because they lie beyond our solar system. It lies about 600 light years away from the Earth orbiting around its parent sun, G-type star Kepler-22, in 290 days. First discovered in 2009 by NASA's Kepler Space Telescope,it has been confirmed to be the a planet most like our Earth so far by NASA on December 5, 2011.
Search for another earth-like world goes long back in the history of science. With millions and millions of stars in the Universe, it could be safely assumed that there was a strong possibility that there may exist a star-planet system closely resembling our Earth and the Sun. Now with the aid of Kepler Space Telescope the NASA has found hundreds of such candidate planets which could satisfy such conditions. Out of such probable candidates, Kepler 22b has been confirmed to be the most earth-like planet discovered so far.
Why Kepler-22b Is Considered an Earth-like Planet?
- Right Distance
Kepler-22b lies in the middle of the habitable zone of its sun where water could possibly exist to sustain life.
The habitable zone is that space around a star where the possibility of life could exist. If a planet is too far from its sun, it would be too cold: if too near, it would be too hot – both these conditions preclude the possibility of conditions which could sustain life.
But the right distance from its host star is not the only condition for a planet to be considered to be an earth-like body. It should be of the right size and right temperature and this is what Kepler-22b seems to be having.
- Right Temperature and Size
Kepler -22b is 2.4 times the size of our Earth which puts it into the class of “super-Earths” and is 15% nearer to its sun than our Earth is to the Sun. Its sun or host star is slightly smaller than our Sun in mass and radius with the result that it gives out 25% less light than our Sun. So it is presumed that its near-surface temperature should be about 72 degrees Fahrenheit (22 Celsius) which would be conducive to support life.
Is Kepler-22b Really Another Earth?
If by another earth, you mean a planet which is inhabited by human-like or other forms of life, the answer is nobody can say for sure.
The right disCredit: By NASA/Ames/JPL-Caltech[see page for license], via Wikimedia Commonstance, temperature and size are characteristics that make Kepler -22b to be one of the likeliest planets to harbor life where water is expected to exist which is necessary for sustaining life. But scientists are not sure that water is actually there on Kepler -22b. In fact they don’t know if Kepler 22-b is made mostly of rock, gas or liquid.
So what can be said about Kepler-22b at the most is that it is confirmed to be an Earth-like planet until we know more about it. And Kepler-22b is not the only such planet. Astronomers have also identified other such planets many of which could be confirmed to be Earth-like in the near future after research.Credit: By NASA/Ames/JPL-Caltech[see page for license], via Wikimedia Commons