How do scientists discover exoplanets?

Until recently it was almost impossible to discover exoplanets but the latest improvement in technology is the main reason why currently there are about 400 discovered exoplanets, and few thousands more are expected to be discovered in years to come.

Exoplanets are the best proof to the theory that our Milky Way galaxy is probably home to a millions different solar systems, and perhaps on some of these planets there is life. Now that would be a real discovery.

When searching for exoplanets astromonomers combine different factors such as their understanding of physics and sophisticated instrumentation and data analysis which helps them to detect signals that indicate the presence of certain exoplanet.

Almost 20 years have passed since the time first exoplanet was discovered back in 1991. The first method of discovering exoplanets included usage of radial velocity measurements, namely the detecting and measuring of the gravitational tug that expolanets exert on their parent stars, which causes the stars to wobble.

Some other methods were also used in discovering new planets, such as transit observation (measuring the dimming of a star's brightness as a planet passes in front of it) or nulling interferometry (where light waves received by several telescopes are combined to give a proportionately higher-resolution image).

Today astronomers pin much hope to the Gemini Plant Imager, which should enable more superior sensitive searches for fainter planets in closer orbits, and some astronomers are even hopeful that this new method has the best chance in discovering the new Earth.

The more planets scientists detect the better chance there is that one of this planets could actually hold life.