An Exoplanet is a planet that is outside of our own Solar System.
The first Exoplanets to be discovered were in orbit around a Pulsar in 1992. Since then, hundreds more Exoplanets have been discovered. (4284 Exoplanets as of 20th of September 2020)
This number changes regularly as new Exoplanets are being discovered all the time, this is a field that is at the forefront of modern scientific research.
Why search for Exoplanets?
The search for exoplanets is tied up with one of the biggest questions for Humanity -
Are we alone in the Universe?
In the effort to answer this question, scientists have searched our Solar System for signs of habitable places, and as technology improves, this search has been widened to include other star systems.
The video below gives a brief introduction into the methods of detecting Exoplanets.
There are several methods that can be used to detect Exoplanets, some are much more successful than others. The graph below shows the number of Exoplanets detected by each method (up to September 2014):-
Direct Imaging Micro-lensing Transit Radial Velocity Timing