Astronomers know that space entities can unleash flares, but they haven't been watching them long enough to know the maximum possible intensity. Consider this, on Earth we have super-volcanoes, and we have tsunamis - but they don't happen every decade or even every century...so being zapped from outer space is quite a possibility, based on what has not been observed yet
The Galaxy Evolution Explorer (GALEX) satellite inadvertently picked up an assortment of astronomical goodies in our solar neighborhood while surveying distant galaxies in ultraviolet light. The satellite's large field of view, 1.5° of sky, catches many nearby objects that unexpectedly flare and glow in this high-energy part of the spectrum.... including an exciting flare in a red-dwarf star whose brightness increased more than 10,000 times!
"We can create a movie of how a star brightens with time," says Welsh. And that's just what GALEX did. On April 20, 2004, the 13th-magnitude star, GJ 3685A, situated 45 light-years away in the constellation Virgo, erupted in a massive UV flash — brightening by 12 magnitudes in ultraviolet light. The movie, edited from about 20 minutes of data, shows that the red dwarf ignited not once, but twice. Through the events the star gave off more than one million times the energy of a typical solar flare. This flare was an extremely energetic case; most red dwarfs caught by GALEX have an average UV brightening of about 5 magnitudes.
