Sunspot AR3098, as it’s known to NASA, shot an 18-million-degree solar flare at Earth recently, but that’s not why it’s been so hot lately. Solar flares don’t actually cause heat waves, but they can affect satellites in orbit.
First of all, what even is a solar flare, and how do scientists classify them? We start with a sunspot, which is an area of the sun that’s darker and cooler than the rest of the sun. This is because the magnetic fields are so intense that heat from the interior of the sun is prevented from escaping.
When the magnetic fields suddenly move or shift, that energy is released. This results in either a solar flare, which is an explosion of radiation, or a coronal mass ejection, which is a cloud of plasma. On Earth, these flares can interact with radios, navigation systems, and sometimes even power grids.
But, not all flares are of equal intensity. Some are bigger or smaller than others. NASA has a classification system for solar flares that goes as follows. A-class, B-class, C-class, M-class, or X-class depending on strength. X-class is the strongest, and A-class is the weakest. According to a report from Newsweek, M-class or X-class flares are usually the only ones that warrant space weather alerts. So, there could be solar flares happening that we don’t even know about because they’re so weak they aren’t going to affect us on Earth.
Solar Flare Hit On September 12 Over the Pacific Ocean
This recent flare from September 12, though, was considered an M-class. According to scientist Alex Young on Twitter, “AR3098 just released an M1.7 flare at the end of the day on Sept. 12 UTC. A nice impulsive event seen in [Solar Dynamics Observatory 131] showing plasma greater than 10 million Kelvin [10 million Celsius]. Hot hot!”
Apparently, the flare hit over the Pacific Ocean. This coincided with a 2-minute radio burst reported by NOAA’s Space Weather Prediction Center. While the flare was on the high side of the spectrum, it was a relatively weak M-class flare. M denotes the flare’s general strength, and the number next to it indicates how strong that is. 1 is the lowest and 9 is the highest. This flare sits around 1.7 in strength.
Solar flares can also cause auroras, but also affect satellite communication and orbit speed by pummeling them with radiation. In turn, long-term solar flares can actually affect the Earth’s climate. According to three Greek scientists, the March 2012 heat wave could possibly have been caused by prolonged exposure to solar flares. They wrote, in part, that the change in climate was related to “Sun-generated special space plasma structures triggering large magnetic storms.”
Though Earth was a little hotter during that time, there wasn’t much in terms of radiation. Martin Mlynczak, associate principal investigator on the Sounding of the Atmosphere using Broadband Emission Radiometry instrument from NASA, said at the time, “The extra energy from this storm is on the order of 100,000 times less than the energy we normally get at the Earth’s surface. It’s so small that you wouldn’t even notice it.”