As the first successful technique used to detect exoplanets orbiting distant stars, the radial velocity method aims to detect a periodic Doppler shift in a stellar spectrum due to the star's motion ...

Scientists have discovered more than 4,000 alien planets since spotting the first ones orbiting a star beyond our sun back in 1992. Here's a brief rundown of the main techniques they use to find these ...

Doppler radar uses the Doppler effect to measure the radial velocity of targets in the antenna's directional beam. The Doppler effect shifts the received frequency up or down based on the radial ...

The search for Earth-like planets outside our Solar System is bedevilled by the lack of an adequate frequency standard for calibrating starlight. Tweaking existing laser 'frequency combs' could be a ...