ExploraTour: A Peek into the Lives of the Stars
Cygnus Loop - Interstellar Gas Enriched in Heavy Elements.
This is a view of the Cygnus Loop taken by the Hubble Space Telescope. It is the expanding blastwave from a supernova explosion that occurred some 15,000 years ago (about the time our early ancestors were roaming the Earth looking for food).
The beautiful colors in this image tell an interesting story. The image was created by overlaying pictures of the Cygnus Loop taken at three different wavelengths.
The blue regions are produced by doubly-ionized oxygen atoms. This means that two electrons have been stripped away from each atom. The red identifies regions containing singly-ionized sulfur atoms. Green marks regions where light is being emitted by hydrogen atoms. This is a graphic illustration of the enrichment of the interstellar medium in heavy elements by supernova explosions.