Astronomy
Spectroscopic Techniques for Measuring Stellar Radial Velocities
Quick fact
The radial velocity method has discovered thousands of exoplanets, including the first exoplanet orbiting a sun-like star, 51 Pegasi b in 1995.
Why this is interesting
A star that looks perfectly still in the night sky may actually be drifting towards or away from us. How can we possibly detect such motion from light-years away?