Spitzer Space Telescope / Images
"This stunning false-color picture shows off the many sides of the supernova remnant Cassiopeia A. It is made up of images taken by three of NASA's Great Observatories, using three different wavebands of light. Infrared data from the Spitzer Space Telescope are colored red; visible data from the Hubble Space Telescope are yellow; and X-ray data from the Chandra X-ray Observatory are green and blue...."
Downloads are available in 450x360, 900x720, and 3000x2400 pixel resolution.
The descriptions give the distance to this explosion remnant as 10,000 and 11,000 light years. As I recall, the exact distance is still a bit iffy.
The picture is quite impressive. Although a human eye would never see Cassiopeia A that way, it's a good way to 'see' the structure of the nebula.
One reason that I'm interested in astronomy is that it helps me get a sense of perspective. Cassiopeia A is a good example of this.
- A massive star collapsed and exploded, a bit before people worked out how to make a living by putting seeds in the ground and waiting for a harvest.
- Light from that explosion was about half-way here when city-states were growing, and writing was on the cutting edge of information technology.
- Photons from the Cassiopeia A supernova reached Earth as England was working its way through the Restoration, the Whigs were an up-and-coming party, and the first university museum was opening in Oxford: the Ashmolean.