As we gaze into the night sky it is not hard to notice the numerous stars that stretch across the beautiful landscape. We know that there are at least 100 billion stars in the Milky Way, but a recent study at the California Institute of Technology (Caltech) has estimated that there are at least 100 billion planets in our galaxy as well.
The Caltech team studied planets orbiting a star in our galaxy called Kepler-32. The star is an M dwarf, and the majority of stars in the Milky Way are classified as M dwarfs. NASA’s Kepler space telescope discovered five planets roughly the size of the Earth orbiting Kepler-32. These planets are similar to planets that orbit other M-dwarfs, and making them great models in studying the formation of planets.
The planets orbit the star in a rare, edge-on orientation, meaning the starlight of Kepler-32 is blocked once a planet moves across it. This allowed the scientists to determine the planets’ sizes and orbital periods.
Although it is not known how the Kepler-32 system was formed, there is evidence that suggests the planets first formed further away from the star than their current locations and over time moved closer to the star.
Though the researcher’s estimation of 100 billion planets include planets that are in close orbit to M-dwarfs, this does not include planets further out in orbit or orbiting other stars. In light of this, the actual number of planets could be much greater.
Source: Science Daily
