VIDEO SPECIAL: 1,800 Exoplanets Have Been Discovered
By Space Coast Daily // August 20, 2014
Over 1,800 exoplanets have been discovered
ABOVE VIDEO: Astronomers are not only discovering planets around distant suns, they are also starting to measure those worlds with astonishing precision. The diameter of a super-Earth named Kepler 93B is now known to within an accuracy of 148 miles.
An exoplanet or extrasolar planet is a planet that does not orbit Earth’s Sun and instead orbits a different star, stellar remnant, or brown dwarf.
More than 1,800 exoplanets have been discovered (1,815 planets in 1,130 planetary systems including 466 multiple planetary systems as of August 14, 2014).
There are also free floating planets, not orbiting any star, which tend to be considered separately, especially if they are free floating gas giants, in which case they are often counted, like WISE 0855–0714, as low-mass brown dwarfs.
The Kepler mission space telescope has also detected a few thousand candidate planets, of which about 11 percent may be false positives. There is at least one planet on average per star.
Around 1 in 5 Sun-like stars have an “Earth-sized” planet in the habitable zone, with the nearest expected to be within 12 light-years distance from Earth.
Assuming 200 billion stars in the Milky Way, that would be 11 billion potentially habitable Earths, rising to 40 billion if red dwarf stars are included. The free-floating planets in the Milky Way possibly number in the trillions.
On February 26, 2014, NASA announced the discovery of 715 newly verified exoplanets around 305 stars by the Kepler Space Telescope. These exoplanets were checked using a statistical technique called “verification by multiplicity”.
Prior to these results, most confirmed planets were gas giants comparable in size to Jupiter or larger as they are more easily detected, but the Kepler planets are mostly between the size of Neptune and the size of Earth.