Ruth Murray-Clay

A planet's orbit is its path around its star. If the path is perfectly circular, the planet always stays at the same distance from the star. But many planets have slightly stretched paths, like a running track in a stadium. Astronomers studied hundreds of giant planets around other stars and found a curious pattern.

A planet hugging its star is like an ice cube forgotten on a scorching skillet. The ice melts and evaporates, except instead of water, it's hydrogen and helium from the planet's upper layers.