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 galaxy. The star, called V838 Monocerotis, has long since faded back to obscurity, but observations of a phenomenon called a "light echo" around the star have uncovered remarkable new features over the following years (this animation covers two years' time). The light echo is light from the earlier explosion echoing off dust surrounding the star. Light from the outburst traveled to the dust and then was reflected to Earth. Because of this indirect path, the light arrived at Earth months after light from the star that traveled directly from the star. (NASA, ESA) More (see this on Google Sky)