NASA's three Great Observatories, the Hubble Space Telescope, the Spitzer Space Telescope, and the Chandra X-ray Observatory, joined forces to probe the expanding remains of a supernova, called Kepler's supernova remnant, first seen 400 years ago by sky watchers, including astronomer Johannes Kepler. The combined image unveils a bubble-shaped shroud of gas and dust that is 14 light-years wide and is expanding at 4 million miles per hour.
PHOTO: NASA/ESA/Johns Hopkins University
