~~Supernova Remnant Cassiopeia A (NASA, Chandra) ~ for the first time, a multiwavelength three-dimensional (3-D) reconstruction of a supernova remnant has been created. This stunning visualization of Cassiopeia A (Cas A), the result of an explosion approximately 330 years ago by NASA's Marshall Space Flight Center~~
NGC 6745 used to be a typical spiral galaxy. But that was hundreds of millions of years ago. Since then it has been interacting with a nearby smaller galaxy (a portion of which is seen in the lower right of this image), contorting its appearance. NGC 6745 spans about 80 thousand light years and is about 200 million light years away from Earth toward the constellation Lyra.
The first astronomical object cataloged by Charles Messier, M1 is perhaps better known as the Crab Nebula. It's a supernova remnant; its massive explosion visible to skygazers in the year 1054. At its center is a rapidly rotating pulsar - a neutron star - located about 6,500 light-years from Earth in the constellation Taurus.
NGC 206 is a vast stellar association of young blue stars spanning 4,000 light years at the southwestern side of the Andromeda Galaxy, M31. M31 is only about 2.5 million light-years from Earth and is on a direct course to merge with the Milky Way in the distant future.
Clearly visible in the night skies of the southern hemisphere is the Large Magellanic Cloud. It is the largest satellite dwarf irregular galaxy of our own Milky Way, about 160,000 light-years from Earth and itself spanning 15,000 light-years. It is home to some of the largest star-forming regions in the Local Group of galaxies. The largest such region (left of center) in this image is 30 Doradus - the Tarantula Nebula.
A region of glowing gas in the Sagittarius arm of the Milky Way galaxy, NGC 3576 is located about 9,000 light years from Earth. Such nebulas present a tableau of the drama of the evolution of massive stars, from the formation in vast dark clouds, their relatively brief (a few million years) lives, and the eventual destruction in supernova explosions. The diffuse X-ray data detected by Chandra (blue) are likely due to the winds from young, massive stars that are blowing throughout the nebula.