When a massive star exhausts its nuclear fuel it explodes . This stellar detonation, a supernova , propels vast amounts of starstuff outwards, initially at millions of miles per hour. For another 100,000 years or so the expanding supernova remnant gradually slows as it sweeps up material and ultimately merges with the gas and dust of interstellar space. Short lived by cosmic standards, these stellar debris clouds are relatively rare and valuable objects for astronomers exploring the life cycles of stars . This image in the light of excited Hydrogen atoms along with images at X-Ray, radio and other optical wavelengths , suggests that the bubbles are indeed two separate regions of hot gas surrounded by cooler dense shells begining to interact as they expand and make contact.
Specific rights apply .