Mars rover spies on sun's far side to find hidden sunspots

Why should we be concerned about these sunspots? Well, the bigger they are, the more likely they are to spit out dangerous solar flares and coronal mass ejections (CMEs). These fiery outbursts can pack a punch and, if they head our way, trigger potentially hazardous geomagnetic storms on Earth.

However, the rover is on the job. Right now, Mars is conveniently positioned on the opposite side of the sun from Earth, with the rover in a direct line of sight to the sun's far side. Using its two Mastcam-Z cameras, Perseverance has become our early-warning system.

Thanks to Perseverance's view, scientists had spotted two major sunspots before they unleashed their solar fury toward Earth. One of these monsters grew to be around 10 times wider than our home planet and shot out an X-class flare, the mightiest of all solar flares. Thankfully, it missed Earth by a cosmic hair's breadth.

Are there other ways of detecting sunspots?

Now, you might wonder if there's any other way to detect these sunspots. Well, there is! Scientists use helioseismology, a technique that measures vibrations in the sun's magnetic field to create a sort of echo from the far side. However, this method can sometimes be hit or miss, especially when predicting the scale of the larger sunspots.

Also, Perseverance's images aren't the most high-resolution, but they're still quite the cosmic spectacle. They can pick up sunspots that are more than 9,300 miles (15,000 kilometers) in diameter, about 1.2 times the width of Earth. That means our rover can spot around 40 percent of all sunspots.

As Mars becomes even more aligned with the sun's hidden side, Perseverance will have an even clearer view of potential solar storms. This isn't the first time Mars has lent us a helping hand. Back in 2015, during the previous solar maximum, NASA's Curiosity rover also snapped pictures of the sun's far side.