The Sun wakes up

The Sun unleashed a strong solar flare last week for the first time since 2017, potentially signaling that our nearest star's activity is ramping up after a long period of quiescence.

Why it matters: Strong solar flares can harm satellites and people in space, while the most extreme flares could take down Earth's electrical grids.

• Tracking the Sun's 11-year solar cycle can help scientists learn more about why it behaves the way it does and possibly predict the star's activity.

Details: NASA probes in space caught sight of the M-class flare on May 29 as it shot out from a family of sunspots — dark, transient regions on the Sun — that should be rotating into view shortly.

• The flare was relatively weak and therefore didn't trigger an alert from the Space Weather Prediction Center. Future flares from this family of sunspots, however, could be stronger.

What's next: Scientists will closely watch the Sun's activity in the coming weeks to see if the star is, in fact, coming out of its slumber and entering into a new period of activity.

• The Sun's period of least activity — known as "solar minimum" — can only be seen in hindsight, after many months have passed.
• "The sunspots may well be harbingers of the Sun's solar cycle ramping up and becoming more active," NASA said in a statement. "Or, they may not. It will be a few more months before we know for sure."

Go deeper: We're about to learn a lot more about the Sun