A remarkable new discovery suggests that volcanic sources on planets may help us spot good candidates for alien life. Astronomers from Cornell University say that exoplanets with volcanoes can be moved up on the priority list for exploration, because they would have a far greater likelihood of hosting life than a cold planet covered in icy layers.

After all, life needs warmth, and volcanoes are a good steady source of that warmth. Now, scientists can look for signs of hydrogen pouring from a volcanic source, a possible telltale sign of ideal conditions for life. Atmospheric warming might also help, so the greenhouse warming effect from hydrogen, water and carbon dioxide could expand the habitable zones around distant stars by 30 to 60 percent, according to a statement from Cornell University.

Scientists hadn’t really considered the idea of hydrogen creating a habitable climate on an exoplanet before, because an Earth-like planet can’t hold onto hydrogen for more than a few million years, but volcanoes change this equation.

“On frozen planets, any potential life would be buried under layers of ice, which would make it really hard to spot with telescopes,” said lead author Ramses Ramirez, research associate at Cornell’s Carl Sagan Institute. “But if the surface is warm enough – thanks to volcanic hydrogen and atmospheric warming – you could have life on the surface, generating a slew of detectable signatures.”

“Adding hydrogen to the air of an exoplanet is a good thing if you’re an astronomer trying to observe potential life from a telescope or a space mission. It increases your signal, making it easier to spot the makeup of the atmosphere as compared to planets without hydrogen,” said Ramirez.