What is an extrasolar planet?
Q: What is an extrasolar planet?
A: An extrasolar planet, also known as an exoplanet, is a natural planet in a planetary system outside our own solar system.
Q: What is an exomoon?
A: An exomoon is a natural satellite orbiting an exoplanet.
Q: How many terrestrial planets are estimated to exist in the Milky Way?
A: Estimates of the number of terrestrial planets in the Milky Way range from at least 17 billion to at least 144 billion.
Q: How many Earth-size planets have been found by Kepler space observatory?
A: The Kepler space observatory has found 461 Earth-size planets.
Q: Is there an "Earth 2.0"?
A: One of the four Earth-size planets discovered by Kepler, dubbed Kepler-69c, is about as close as current data allows to finding an "Earth 2.0". It is 1.5 times the size of Earth and orbits around a star like our Sun.
Q: Are all extrasolar planets similar to those in our Solar System?
A: No, most extrasolar planets are quite different from those in our Solar System; for example, some are called "hot Jupiters".
