In the midst of searching for another Earth-like planet using NASA's Kepler spacecraft, astronomers are at least finding Earth-sized planets orbiting distant stars. According to research presented at the 221st meeting of the American Astronomical Society, the Milky Way is claimed to have no less than 17 billion planets that are roughly the size of earth.
A new analysis of the data shows that about 17% of stars have an Earth-sized planet in an orbit closer than Mercury -- that's about one in every six star systems. Since the Milky Way has about 100 billion stars, that means there are at least 17 billion Earth-sized orbs out there floating around. However, not all of them are necessarily Earth-like.
It's important to note that this number only includes those planets which are in close proximity to their respective stars which is a distance that places them outside the solar system's habitable zone, or orbits that are about 85 days or less. Right now, it's very difficult to detect small planets further out because of the limitation of current telescopic technologies.
During the investigation, the astronomers surveyed about 2,400 candidate planets spotted by the Kepler satellite over the first 16 months of its operation. Fressin's figures took into account an obvious effect: the only planets that can be detected are the ones that pass along the same plane as the Earth, which required the astronomers to do some guessing.
A challenge for the astronomers will be to detect Earth-sized and Earth-like planets that sit farther out in space. However, because they orbit less frequently, they are less susceptible to detection by astronomers and scientists. However, it's a problem that will likely be solved by due diligence and large amounts of patience.