Fireworks in the Sky

Glowing gaseous streamers of red, white, and blue - as well as green and pink - illuminate the heavens like Fourth of July fireworks. The colorful streamers that float across the sky in this photo taken by the NASA/ESA Hubble Space Telescope were created by the universe's biggest firecracker, the titanic supernova explosion of a massive star.

The light from the exploding star reached Earth 320 years ago. The dead star's shredded remains are called Cassiopeia A, or 'Cas A' for short. Cas A is the youngest known supernova remnant in our Milky Way Galaxy and resides 10, 000 light-years away in the constellation Cassiopeia, so the star actually blew up 10, 000 years before the light reached Earth in the late 1600s.