The space mission to buy us vital extra hours before a solar storm strikes

The Carrington Event is probably the most famous occurrence in the history of space weather. A massive solar storm that hit Earth in 1859, it produced so much geomagnetic activity that the Northern Lights were seen as far south as Cuba. Telegraph operators reported sparks flying from their equipment. This doesn’t sound too bad, but if it happened today, it could debilitate power in urban centers, cut off GPS, and put satellite communications at risk.

Storms like this may happen only once every 100 or 200 years, but if one is coming, we will need to know.

Space weather analysis looks for warnings of such catastrophic events (and smaller, more frequent solar flares) by observing the sun’s solar wind, coronal mass ejections (when the sun throws out plasma from its corona, disturbing magnetic fields), and other phenomena. The forecasts can predict when auroras will light up the sky, but more important, they can warn of an impending catastrophic event.

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Right now, though, we get only a few hours to a few days of warning. The main reason is that we don’t have a good view of the entire sun, and so we can’t see when something dangerous is forming around its back side. A planned mission from the European Space Agency could change that by giving us a peek around the side—adding a vital resource to the arsenal of solar forecasters. Scientists are in a race against time to get the Lagrange mission launched before our other methods of spotting dangerous sun weather are no longer operational.

Diagram of Lagrange points between the Earth and the sun.


Until now, most space weather missions have been either Earth-orbiting or located at Lagrange point L1, which sits between Earth and the sun. Lagrange points are locations in space where an object will maintain the same position relative to two bodies that are in orbit around each other. For example, an object at the L1 point appears to stay right in front of Earth, affording an uninterrupted view of the sun at all…