NASA - National Aeronautics and Space Administration

Stephen Kane gained his love for astronomy when his sixth-grade class visited a planetarium. Image Credit: NASA

On April 25, 2012, NASA research scientist Stephen Kane answered questions from students about a study he co-authored showing the Milky Way has a minimum of 100 billion planets.

Our Milky Way galaxy contains a minimum of 100 billion planets, according to a detailed statistical study based on the detection of three planets located outside our solar system. These planets are called exoplanets.

This discovery was made by an international team of astronomers, including today’s video chat expert, Stephen Kane of NASA's Exoplanet Science Institute at the California Institute of Technology in Pasadena, Calif.

The survey results show that the Milky Way contains, on average, a minimum of one planet for every star. This means that it's likely a minimum of 1,500 planets are within just 50 light-years of Earth.

The study is based on observations taken over six years using a technique called microlensing to survey the galaxy for planets. In this technique, one star acts like a magnifying lens to brighten the light from a background star. If planets are orbiting the foreground star, the background star's light will further brighten, revealing the presence of a planet that is otherwise too faint to be seen.

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.

Stephen Kane was born in Goulburn, Australia. He gained his love for astronomy when his sixth-grade class visited a planetarium. Thereafter, he made it his goal to become an astrophysicist one day. Kane is currently a research scientist at NASA’s Exoplanet Science Institute in Pasadena, Calif.


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