Venus Transit

Venus Transit

June 5 – 6, 2012

Photo Credit: NASA

Composite image of Mercury transit across the Sun, as seen by NASA's Solar Dynamics Oberservatory on Nov. 11, 2019. CREDIT: NASA's Goddard Space Flight Center

Mercury Transit

November 11, 2019

Photo Credit: NASA’s Goddard Space Flight Center

TRANSITS OUTSIDE OUR SOLAR SYSTEM

Outside our solar system, transits are used to search for planets (exoplanets).

Most known exoplanets have been discovered using the transit method. A transit occurs when a planet passes between a star and its observer. Transits reveal an exoplanet not because we directly see it from many light-years away, but because the planet passing in front of its star ever so slightly dims its light. This dimming can be seen in light curves – graphs showing light received over a period of time. When the exoplanet passes in front of the star, the light curve will show a dip in brightness.
The Webb Telescope is using this technique to search for planets.