On Friday morning (May 29), our star fired off its strongest flare since October 2017, an eruption spotted by NASA's sun-watching Solar Dynamics Observatory (SDO).

Solar flares are bursts of radiation that originate from sunspots, temporary dark and relatively cool patches on the solar surface that boast very strong magnetic fields.

(And it wasn't aimed at Earth, so there's no chance of supercharged auroras from a potential associated coronal mass ejection of solar plasma.) But the outburst could still be a sign that the sun is ramping up to a more active phase of its 11-year activity cycle, NASA officials said.

If that's the case, the most recent such cycle, known as Solar Cycle 24, may already have come to an end!

"However, it takes at least six months of solar observations and sunspot-counting after a minimum to know when it's occurred," NASA officials wrote today in an update announcing SDO's flare detection. .

"That means solar minimum is an instance only recognizable in hindsight: It could take six to 12 months after the fact to confirm when minimum has actually passed.".

More observations should tell us if we're already in Solar Cycle 25.