In January 2002, a dull star in an obscure constellation suddenly became 600,000 times more luminous than our Sun, temporarily making it the brightest star in our Milky Way galaxy. The mysterious star, called V838 Monocerotis, has long since faded back to obscurity. But observations by NASA’s Hubble Space Telescope of a phenomenon called a “light echo” around the star have uncovered remarkable new features. […]

Light echo it is light from a stellar explosion echoing off dust surrounding the star. V838 Monocerotis produced enough energy in a brief flash to illuminate surrounding dust, like a spelunker taking a flash picture of the walls of an undiscovered cavern. The star presumably ejected the illuminated dust shells in previous outbursts. Light from the latest outburst travels to the dust and then is reflected to Earth. Because of this indirect path, the light arrives at Earth months after light from the star that traveled directly toward Earth. […]

This sequence of pictures from the NASA Hubble Space Telescope’s Advanced Camera for Surveys dramatically demonstrates the reverberation of light through space caused by an unusual stellar outburst in January 2002. A burst of light from the bizarre star is spreading into space and reflecting off of surrounding shells of dust to reveal a spectacular, multicolored bull’s eye. (via Hubble)