This week, NASA astronomers spotted a gaping, black region on the sun. The so-called “coronal hole” looks as if someone blew a hole right through our star, and its appearance spurred NOAA to issue an alert for geomagnetic storms.
The “hole” isn’t really a hole, but rather is a large region much cooler than the rest of the Sun, causing it to appear black. As explained by NOAA in its alert on Wednesday, the dynamics of the coronal hole were expected to speed up the solar winds, and so the agency warned of minor-to-moderate geomagnetic storms as a result, falling under the classifications G1 and G2 (on a scale that goes all the way up to G5).
This coronal hole is simply massive. According to Insider, it’s the size of 20-30 Earths. “The current coronal hole, the big one right now, is about 300,000 to 400,000 kilometers across,” Alex Young from NASA Goddard’s Heliophysics Science Division told the outlet. “That is about 20-30 Earths lined up back-to-back.”
Importantly, there’s nothing to worry about when it comes to a coronal hole appearing in the Sun. It’s stunning to look at, and thankfully, that’s all that most of us will get from it.
Other activity on the Sun isn’t so benign, however. On Friday, Earth was hit with a surprise “severe” G4 geomagnetic storm due to a coronal mass ejection—when the Sun yeets some of its magnetic field and plasma into the solar system. The storm was expected to affect spacecraft operations and possibly lead to “widespread” voltage control problems with planetside power grids.
The Sun undergoes 11-year cycles of activity, and is currently in its active phase. Last month, scientists observed something we’ve never seen before: a piece of the sun’s plasma tore off and started swirling like a massive polar vortex. Like the coronal hole, this event posed no risk, and was merely an opportunity to learn more about the star that has nurtured life on our planet.