Exoplanets are planets that do not revolve around our sun. Hence, by very definition, these are planetry bodies that exist outside our solar system ( which consists of planets and other celestial bodies revolving around the sun). Exoplanets are celestial bodies of planetry dimensions and rotate around other stars. They can be extremely light (a few times the weight of moon) or very massive (a few times the mass of Jupiter). They can also be very close to their star or can be very distant to be at edge of that star's gravitational pull. For the general public, exoplanets offer the chance of extraterrestrial life. For scientists, they offer the chance to study planet formation, development, atmosphere (if any), water presence, etc.