A satellite peering at Earth from a vantage point almost 1.5 million kilometres away can track volcanic eruptions more accurately than spacecraft orbiting much closer to the planet’s surface. This could allow scientists to pinpoint remote eruptions faster than ever.

The distant view is provided by a NASA camera aboard the Deep Space Climate Observatory (DSCOVR) spacecraft, which was launched in 2015. It takes pictures of the entire sunlit side of Earth as often as about every hour.

A team led by Simon Carn at Michigan Technological University in Houghton used the camera to catalogue volcanic plumes from 16 eruptions between 2015 and 2018. During an eruption in the Galapagos Islands, DSCOVR’s camera took at least eight exposures in about eight hours, allowing the scientists to precisely check their models’ predictions of the plumes’ spread.

DSCOVR can measure both ash plumes, which threaten aviation safety, and sulfur dioxide plumes, which affect atmospheric chemistry and climate. Having this information within hours of an eruption will help scientists to predict the impact of such events.