Nearly 4000 exoplanets
Explanation:
Nearly 4000 exoplanets have been confirmed by NASA till date.
An exoplanet is planet outside of the solar system. Such planets do not have the sun as their star.
They are made up of other star systems in our galaxies.
There are about 4,173 confirmed exoplanets in 3,096 systems, with 678 systems having more than one planet.
Some of these planets have been proposed to be earth-like and support life too sparking the controversial claim about alien life.
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Nitrogen, carbon dioxide, oxygen, and argon