A Solar Flare on July 12, 2012
This close-up image of the Sun was taken on July 12 at 12:56 pm, during a powerful X1.4-class solar flare.
A solar flare is a flash of high-energy light. It is created when magnetic fields on the surface of the Sun slam together, releasing vast amounts of energy. The ultraviolet and X-ray light created by a flare does not penetrate the Earth's atmosphere.
However, the light of a flare heats up the clouds of gas (called plages) nearby, making the plages glow brilliantly for just a few minutes. This is how a visitor using a hydrogen-alpha telescope at the Public Observatory can safely observe a flare.
The July 12 flare happened in the massive sunspot group AR 1520, visible as a cluster of dark spots. The plages are the bright areas around the sunspots.
While a flare poses no direct threat to life on Earth, it can increase radiation for astronauts. When the light of the flare is absorbed by the atmosphere, the outer layers of the atmosphere heat and puff up, disrupting radio communications and GPS signals.
Just a few days later, on July 23, 2012, a pair of coronal mass ejections (CMEs) were flung away from the same sunspot group, AR 1520. By then, the sunspot group was on the far side of the Sun, and the fast-moving clouds of gas missed the Earth. Scientists analyzed the events closely, however. Nineteen months later, in early 2014, scientists concluded that those CMEs were very powerful and fast-moving, a superstorm. This superstorm might have been even stronger than the "Carrington event" of 1859, which induced strong currents in telegraph lines and caused bright aurorae to be seen as far south as Cuba. Had the July 2012 superstorm hit the Earth, modern electrical grids may have been damaged, causing widespread blackouts.
Telescope: Lunt 100mm
Camera: Lumenera SkyNYX 2-2M
Image Number: WEB12540-2012
Credit: Image by Geneviève de Messières, Smithsonian Public Observatory Project
For print or commercial use please see our permissions page.