That is not the inside of a light bulb, nor anything else created by humans.
Astronomy buffs stand a pretty good chance of guessing this one, I bet.
It's a major solar flarethat erupted in February, and which was recently explained in a new study. The bright release of light was part of an X-class flare — the strongest type, and in this case the strongest one in almost five years — spawned by rotating sunspots. See the full image below.
Sunspots are cool regions on the sun where magnetic activity is extreme and twisted. Rotating sunspots, the new study found, can spur a flare. "Twisting the sun's magnetic field is like twisting an elastic band," Daniel Brown at University of Central Lancashire in England. "At first you store energy in the elastic, but if you twist too much the elastic band snaps, releasing the stored energy."
The electromagnetic radiation from a solar flare — radio waves, visible light, X-rays and more — reach earth in about 8.3 minutes, covering (by definition) a distance of 8.3 light-minutes.