September 2007 - V838 Monocerotis light echo
The unusual variable star V838 Monocerotis underwent an outburst early in 2002, during which it temporarily increased in brightness to become 600,000 times more luminous than our Sun. Light from this sudden eruption is illuminating the interstellar dust surrounding the star, producing the most spectacular "light echo" in the history of astronomy.
Credit:NASA, ESA, and H. Bond (STScI)