You might have heard that Earth recently gained an extra moon. Apparently, though, this isn’t enough disruption for our solar system for some scientists’ tastes. Now they want to get rid of the sun as well. More specifically, a group of researchers at the European Space Agency are planning to launch a pair of satellites into orbit around Earth, with the aim of creating a solar eclipse on command.

Why would anyone want to trigger an artificial solar eclipse? To slow down global warming? To protect us from apocalyptic solar storms? As a backlash against solar power? To force us to use fossil fuels, like Mr Burns in that one episode of The Simpsons? We’ve tried to answer all of these important questions, and more, below.

THE MISSION IS SET TO LAUNCH BEFORE THE END OF 2024

You might think that blocking out the sun sounds like a distant sci-fi dream (or nightmare) but the two satellites that will undertake the mission are scheduled to be launched before the year is out, maybe even as soon as the next few weeks. Together, they’re known as Proba-3, and can fly in sync – to the tune of a single millimetre – thanks to lasers and light sensors that communicate their exact location. For the mission, they’ll orbit Earth at a distance of 144 metres apart, functioning as a single observatory.

WHAT WILL PROBA-3 ACTUALLY DO?

During their precise orbit, one of the Proba-3 spacecraft will block the view of the sun as seen from the other craft using a disc or “occulter”. Essentially, this will create an eclipse that can last several hours, during which the second craft can take measurements and take a look at the sun’s corona (the bit that bleeds around the edge of an object during an eclipse) in unprecedented detail.

BUT WHY?

On a basic level, the mission’s goal is to better understand the study of the sun. This is an increasingly important research topic due to the growth of technologies that could be disrupted by erratic solar activity, including power grids, computer chips, and satellite-dependent tech like the internet and GPS. 

This year alone, we’ve seen some explosive solar activity that caused beautiful auroras across the globe (you probably saw pictures on X or Instagram, if you didn’t witness them yourself). It also caused some power problems in places like Sweden and South Africa, and experts are even less sure about what long-term effects can come from solar storms interacting with the atmosphere.

SO HOW WILL BLOCKING OUT THE SUN HELP?

Proba-3’s artificial eclipse will teach us more about the sun in a few ways. For one, it will make the corona much easier to see by shielding the majority of the sun’s glare. On an even more practical level, it will mean that scientists can observe the sun for hours at a time, instead of chasing a rare natural eclipse across the globe, only to witness it for a few minutes (or miss it completely, if it happens to be cloudy that day). The increased data will shed light on things like the fluctuating temperatures within the sun, which will help figure out how it ‘works’ and potentially help safeguard against solar threats in the future.

SO WE WON’T ACTUALLY SEE THE SUN DISAPPEAR?

Sadly, no. For now, the eclipses will stay in space. Proba-3 could be groundbreaking in a different sense, though. As a first-of-its-kind probe that flies in tight formation, it has the potential to revolutionise robot spaceflight methods, paving the way for future cosmic missions aimed at understanding the likes of black holes, dark matter, and distant exoplanets with the potential to hold alien life.

In the meantime, you can revisit some of the best scientific breakthroughs we’ve made with another pioneering piece of space tech, the James Webb Telescope, here.