The radial velocity method is a technique used in astronomy to detect exoplanets, or planets outside our solar system. It measures the changes in the wavelengths of light emitted by a star as it moves in response to the gravitational pull of an orbiting planet. When a planet orbits a star, it causes the star to wobble slightly, leading to shifts in the light spectrum due to the Doppler effect. By observing these shifts, scientists can determine the star's velocity toward or away from Earth. This information helps estimate the planet's mass and orbit, providing valuable insights into the characteristics of exoplanets and their potential for supporting life.