BBC Focus Magazine

[Shadowwolf]

This image, taken by the NASA/ESA Hubble Space Telescope, shows a detailed view of the spiral arms on one side of the galaxy Messier 99. Messier 99 is a so-called grand design spiral, with long, large and clearly defined spiral arms — giving it a structure somewhat similar to the Milky Way.

Lying around 50 million light-years away, Messier 99 is one of over a thousand galaxies that make up the Virgo Cluster, the closest cluster of galaxies to us. Messier 99 itself is relatively bright and large, meaning it was one of the first galaxies to be discovered, way back in the 18th century. This earned it a place in Charles Messier’s famous catalog of astronomical objects.

In recent years, a number of unexplained phenomena in Messier 99 have been studied by astronomers. Among these is the nature of one of the brighter stars visible in this image.

http://www.nasa.gov/mission_pages/hubble/science/m99-spark.html

[King Random]

supernova?

[Shadowwolf]

Not bright enough for that and too bright to be a nova.

They think it might be because the star dined on nearby planet. Or perhaps someone used a Genesis device, it's a long way away and we're unlikely to ever be certain without observing a few more similar events we can see a little better.