Wednesday, 22-Nov-2017 20:00:23 GMT
Cass A is a supernova remnant in our own Galaxy. This is the remnant of a star which exploded in ???? Since then, the material thrown off in the explosion has been expanding and interacting with the surrounding gas. It is this interaction which produces the fine structure seen in the shell.
Taken with the Chandra satellite at a very specific wavelength to show the location of gas clouds containing the element silicon.
Image credit: Chandra