There have been 95 exoplanets discovered in 2010. You'll need to be more specific on the question.
We won't know that until we are sure that we have discovered all of them.
The first confirmed exoplanet is called 51 Pegasi b. It was discovered on October 6th 1995 by Michel Mayor and Didier Queloz. Note: 51 Pegasi or 51 Pegasi a is the parent star.
which exoplanet is 'THE exoplanet'?
The average size of an exoplanet is generally larger than Earth but smaller than gas giants like Jupiter. Most exoplanets discovered so far have a size between that of Earth and Neptune.
The darkest exoplanet is "TRES-2B".
No. An exoplanet is a planet outside of our Solar System.
51 Pegasi itself isn't an exoplanet, it's a Sun-like Star. But it does have an Exoplanet orbiting it, 51 Pegasi b (informally named Bellerophon.).
they were discovered in 2010
No. A moon is not a planet. An exoplanet is aplanet that orbits a star other than the sun.
Both exoplanet and extrasolar planet are planets that are outside the solar sysytem.
Yes. While we know relatively little about the atmospheres of individual expolanets, there is no reason an exoplanet couldn't have an exosphere.
The theory was published in a famous book entitled (in Latin): 'De revolutionibus orbium coelestium', which means, 'On the revolutions of the orbs of the heavens'.