The Sun Just Produced an Explosion So Big It Will Be Studied 'for Years'

An enormous explosion erupted from behind the sun on Monday, and scientists think its source could be rotating toward the Earth in the coming days.

On September 5, NASA's STEREO-A spacecraft recorded a significant coronal mass ejection (CME)—an eruption of plasma and magnetic activity from the sun's atmosphere—that occurred on the far side of the sun.

Since the CME did not occur in the direction of Earth, scientists spotted it by its "halo," a giant shockwave that could be seen from Earth's position on the other side of the sun.

September 5 CME
The halo of the huge coronal mass ejection on September 5, as seen by NASA's STEREO-A spacecraft. The CME occurred on the far side of the sun. NASA/STEREO Ahead COR2

CMEs occur all the time, some facing toward Earth and some facing away from it. But George Ho, a space physicist at Johns Hopkins University's Applied Physics Lab (APL) who works with the European Space Agency's Solar Orbiter satellite, told solar activity news website Spaceweather.com that the September 5 explosion was so big that "science papers will be studying this for years to come."

"I can safely say the Sept. 5th event is one of the largest (if not THE largest) Solar Energetic Particle (SEP) storms that we have seen so far since Solar Orbiter launched in 2020," he said.

"If this shock/CME/particle [eruption] was Earth-directing, we could have some pretty significant geo-storms impacting high-latitude, and put all of our near-Earth satellite's operation at risk," Ho told Newsweek. "And the sun is only gearing up for more activities to come in the solar maximum!"

Solar activity is increasing as part of the sun's roughly 11-year natural cycle, and activity is expected to peak in the summer of 2025. However, scientists have noticed that the activity in the current stage of the sun's cycle is much higher than predicted.

"When the sun changes, it also changes the environment around it," Nour Raouafi, Parker Solar Probe project scientist at the APL, said in a NASA press release on August 31. "The activity at this time is way higher than we expected."

It's thought the September 5 CME headed in the direction of Venus, with the nearby Solar Orbiter satellite detecting a wave of energetic particles passing by.

CMEs are good to keep track of since they can cause disruption here on Earth. When these solar eruptions interfere with Earth's magnetic field, radio communication can be interrupted and power grids can be affected. They can also spark auroras, the colorful lights in the night sky.

Solar material
A stock illustration shows material erupting from a star. Solar explosions like flares and coronal mass ejections regularly occur on the sun, with some stronger than others. LV4260/Getty

Most CMEs are not strong enough to cause any disruption that the public will notice, but particularly strong CMEs are possible.

While the September 5 CME is not expected to cause any problems on Earth, it's possible that its suspected source—a huge sunspot known as AR3088, might.

Sunspots are areas of the sun that have particularly active magnetic fields. These magnetic fields are so strong they can prevent some heat from the sun's interior from reaching the surface, making sunspots appear as dark patches.

When the tangled magnetic field lines on sunspots suddenly shift or realign, a CME or solar flare is the result.

AR3088 is currently on the side of the sun that we cannot see, but it's expected to rotate into Earth's view in just over a week. Sunspots come and go, so it remains to be seen whether AR3088 will remain as it is, weaken or disappear before it comes back into view.

Update, 9/12/22, 11:34 a.m. ET: This article has been updated to include an additional comment from George Ho.