Numerous rocky, Earth-like worlds have been discovered by transit surveys such as the Kepler mission. For those familiar with the transit of Venus last year, exoplanet transits are the same idea – an exoplanet crosses the face of its parent star as perceived by observers on Earth. By comparing the amount of starlight the transiting planet blocks and the total starlight emitted by the host star, astronomers can determine the radius of a transiting planet.
Recent surveys have hinted at the existence of exoplanets with rocky surfaces, making them similar to our own “terrestrial” planets Mercury, Venus, Earth and Mars. However, a number of the exoplanets thought to have rocky surfaces appear to not have any significant atmospheres. One such exoplanet is Corot-7b, which orbits very close to its parent star. Exoplanet 55 Cancri e, estimated to have roughly twice Earth’s radius and roughly eight times Earth’s mass, also may be a rocky planet, and perhaps even made of diamond.
Read my full article on how researchers hope to better understand the surfaces of distant planets at: http://www.astrobio.net/exclusive/5493/investigating-exoplanet-surfaces
Using publicly available data from NASA’s Kepler space telescope, astronomers at the Harvard-Smithsonian Center for Astrophysics estimate that six percent of red dwarf stars in the galaxy have Earth-size planets in the “habitable zone,” the range of distances from a star where the surface temperature of an orbiting planet might be suitable for liquid water.
The majority of the sun’s closest stellar neighbors are red dwarfs. Researchers now believe that an Earth-size planet with a moderate temperature may be just 13 light-years away. “We don’t know if life could exist on a planet orbiting a red dwarf, but the findings pique my curiosity and leave me wondering if the cosmic cradles of life are more diverse than we humans have imagined,” said Natalie Batalha, Kepler mission scientist at NASA’s Ames Research Center in Moffett Field, Calif.
Rogue planets – also known as free floating planets – are pretty intriguing. They are not orbiting a star but instead are wandering through the galaxy, having been either forcibly ejected from a solar system or having formed very early on in the Universe. While only a handful of these planets have been actually found, astronomers estimate these vagrant worlds could vastly outnumber stars. In fact, it’s been suggested there could be 100,000 times more rogue planets than stars in our Milky Way galaxy alone!
Check out the full article, courtesy of Universe Today at: http://www.universetoday.com/98478/new-rogue-planet-found-closest-to-our-solar-system/