How Do We Know There Are Exoplanets?
How do we count planets we never seen around stars we never see? There are five common techniques used to detect exoplanets: the Doppler technique, direct imaging, light curves, transit timing variations, and microlensing. Between 1993 and 2013, humanity went from acknowledging the existence of exoplanets to knowing there may be billions in our galaxy alone.
from Piled Higher and Deeper (PHD Comics)
Key Facts In This Video
The way we discovered the first planets outside our solar system was with the Doppler Technique. (0:25)
Actually trying to see a planet would be like standing on Hawaii and looking at flame flickering near a lighthouse in California. (2:26)
Every 30 minutes, Kepler takes a measurement of the brightnesses of 160,000 stars. (3:41)