A sunspot 7 times the size of Earth could spark aurora as far south as Michigan, New York, and Pennsylvania this Friday

• A stunning aurora may be visible farther south than usual this Friday, lighting up the northern US.
• That's thanks to an overactive, giant spot seven times the size of Earth that's erupting on the sun.
• Northern border states from Washington to Michigan are most likely to see the aurora Friday night.

The Northern Lights are forecast to reach farther south than usual this Friday, dazzling the northern US.

Typically, the best time to see aurora is between 10:00 p.m. and 2:00 a.m. local time, because this is when it will be the most active, according to the National Oceanic Atmospheric Administration.

We mainly owe this spectacle to a giant, hyperactive sunspot called AR3664 that's seven times the size of Earth and has been producing powerful eruptions, called coronal mass ejections, for the last several days.

Powerful eruptions like these can hurl high-energy solar particles toward Earth that interact with our atmosphere to create aurora borealis, a dazzling display of colorful lights.

Typically aurora are contained in the uppermost region of the northern hemisphere. But when Earth receives a more powerful blow of these high-energy particles, it can cause aurora over a larger portion of the planet.

Over the last several days, AR3664 has grown in size, becoming one of the biggest and most active sunspots for this solar cycle (which began in 2019), Space.com reported.

And in the last 24 hours, AR3664 spit out four coronal mass ejections that are now hurtling toward Earth at roughly 560 miles per second, Matt Owens, a professor of space physics at the University of Reading, told Business Insider.

Due to the relatively strong magnetic field of these oncoming coronal mass ejections, Friday's aurora is forecast to make a rare appearance, stretching all the way down to Montana, North Dakota, Minnesota, Wisconsin, and Michigan.

Even states including Maryland, New York, and Pennsylvania, could catch a glimpse of the aurora low on the horizon, Andrew Gerrard, director of the Center for Solar-Terrestrial Research at the New Jersey Institute of Technology, told BI.

"That's the most extreme estimate," Gerrard said. The reality is that we just won't know how bright, active, and wide-reaching the aurora will be until the coronal mass ejections reach Earth's atmosphere. Even experts' estimates of when they'll arrive offers only a rough ballpark.

"Our timing estimates may be way off," Owens said.

While the aurora are beautiful, coronal mass ejections bring some risks with them, too. When they interact with Earth's magnetic field, they can cause radio blackouts and power grid outages. But both Owens and Gerrard expect these approaching ejections won't cause any trouble on Friday.

"With the eruptions from this group, I think we're going to see some really good aurora. I wouldn't expect too many really bad effects," Owens said.

To watch the aurora on Friday, head to the NOAA's space weather website for the latest forecast to see if they'll be visible where you are.

Then, just step outside once it's totally dark and look up. If you're lucky, you may get to see this spectacular sight.