'It's Alive': Sunspot Explodes Creating Huge Solar Flare, Radio Blackouts

The Sun spat out a large solar flare from a sunspot early on Monday, leading to temporary radio blackouts in the Pacific Ocean.

Sunspot AR3141 exploded with an M5-class solar flare, which is fairly powerful, at 00:11 UTC (around 7 p.m. ET on Sunday).

"IT'S ALIVE! The Sun is up from its nap! An M5.2 flare came from AR3141 at the beginning of Nov. 7 at 00:11 UTC. Bring it on AR3141!! The radio blackout was over the Pacific," wrote the The Sun Today: Solar Facts and Space Weather Facebook page in a post.

Solar flares are emissions of high-energy electromagnetic radiation, usually X-rays, from the Sun's surface, often from more active sunspot regions.

"[M5-class flares are] pretty severe. It's a bit like the 'Gale force' scale for earth winds. An M-class flare is 10 times as intense as the next scale down (C-class)," Huw Morgan, head of solar system physics at Aberystwyth University in the United Kingdom, told Newsweek.

Solar flares are sorted into five categories: X-class flares, M-class, C-class, B-class and A-class. A-, B- and C-class flares are generally small and don't have any effect on the Earth, while M-class flares may lead to radio blackouts and minor geomagnetic storms.

X-class flares are huge, however, and can trigger planet-wide radio blackouts. Within each category, flares are rated by power, increasing by a factor of ten: an M5 storm is 10 times more powerful than an M4 storm, which is 10 times more powerful than an M3.

"However, it's not just the intensity; it's also the location of the flare on the Sun, as seen from Earth. So if you have a flare occurring at the right place on the Sun, it can have a more severe effect on Earth," Morgan said.

The November 7 flare's radiation ionized gas atoms in the Earth's atmosphere, leading to the radio blackout in some areas of the Pacific, including parts of Australia and New Zealand.

The intense radiation from the flare causes the ionization of layers in Earth's atmosphere, leading to X-rays knocking electrons out of the atoms in the atmosphere.

"The most striking feature of solar flares is that they produce intense bursts of X-rays and extreme ultraviolet (EUV) light that can then reach Earth at the speed of light. The EUV is absorbed high (100 to 300 km) in Earth's atmosphere, enhancing the ionosphere and sometimes also the electric currents that flow in the ionosphere," Mike Hapgood, a space weather scientist at Rutherford Appleton Laboratory Space, told Newsweek.

This ionization causes radio waves that interact with electrons to lose energy.

"But the X-rays can penetrate more deeply down to 60-90 km altitude where they produce an extra ionospheric layer that absorbs rather than reflects short-wave (aka high-frequency, 3-30 MHz) radio waves. It's that absorption that causes the HF (high frequency) radio blackout, blocking HF radio reflections from higher layers that are used for some long-distance radio communications, e.g. by aircraft on routes over the oceans, also military comms," Hapgood said.

"The blackout is limited to the dayside of the Earth and worst where the Sun is overhead. It typically lasts a few tens of minutes, so can be worked around on, say, long flights. Aircraft don't use HF for take-off and landing—they would use short-range VHF radio (30-300 MHz) not affected by flares."

While this may sound like a big threat to civilization in a world that relies so heavily on electromagnetic communication, the likelihood of a solar flare knocking out radio transmissions across the globe is minuscule.

"The damage that solar storms (CMEs, Flares, etc) cause depends on their strength, direction, polarity, etc," Rami Qahwaji, a visual computing professor at the University of Bradford, told Newsweek.

"A number of conditions need to be satisfied for the maximum damage to occur. It happened in the past (The Carrington Event 1859), but back then we didn't have critical digital infrastructure, similar to what we have today. But an event similar to the Carrington event happening today could result in between $0.6 and $2.6 trillion in damages to the U.S. alone, according to NASA spaceflight."