How Do Astronomers Find Exo-Planets?

Astronomers have detected over a thousand exo-planets, recently finding three Earth-like planets in the constellation of Scorpius. And astronomers estimate there are more than 60 billion habitable planets in the Milky Way galaxy. But how do astronomers find exo-planets to begin with? Universe Today publisher Fraser Cain discusses the techniques that astronomers use to search for extrasolar planets, as well as the future missions that might be used in the hunt for other worlds.

Techniques such as monitoring a planet’s gravitational effect on a nearby pulsar or star or using gravitational microlensing — carefully measuring the brightness of one star as it passes in front of another, thereby revealing telltale planet spikes in the light signatures, or the most successful method, the transit method.