Our Galaxy Has at Least 100 Billion Planets

According to a detailed statistical study based on the detection of three planets located outside our solar system, called exoplanets, our Milky Way galaxy contains a minimum of 100 billion planets. The survey results show that our galaxy contains, on average, a minimum of one planet for every star. This means that it’s likely there is a minimum of 1,500 planets within just 50 light-years of Earth. The study also concludes that there are far more Earth-sized planets than bloated Jupiter-sized worlds. A rough estimate from this survey would point to the existence of more than 10 billion terrestrial planets across our galaxy. The discovery, to be reported in the January 12 issue of Nature, was made by an international team of astronomers, including co-author Stephen Kane of NASA’s Exoplanet Science Institute at the California Institute of Technology in Pasadena, Calif.