This color "picture" of globular star cluster M55 may not look like any star cluster you've ever seen. Still, it shows a most fundamental view for students of stellar astronomy. In the picture...

A new star, likely the brightest supernova in recorded human history, appeared in planet Earth's sky about 1,000 years ago today, in 1006 AD. The expanding debris cloud from the stellar explosion is still visible to modern astronomers, but what did the supernova look like in 1006?

A new star, likely the brightest supernova in recorded human history, appeared in planet Earth's sky in the year 1006 AD. The expanding debris cloud from the stellar explosion is still visible to modern astronomers, but what did the supernova look like in 1006?