|The supernova remnant G1.9+0.3, located about 28,000 light years from Earth. This composite image shows a combination of data from Chandra and the digitized sky survey. Credit: X-ray (NASA/CXC/NCSU/K.Borkowski et al.); Optical (DSS)|
|The remains of SN 1006, as seen with Chandra. Credit: NASA/CXC/Middlebury College/F.Winkler|
|Kepler's supernova remnant, seen with Chandra. Credit: X-ray: NASA/CXC/NCSU/M.Burkey et al; Optical: DSS|
There are many differences between these two types. One important difference is that a massive star self-destructs, but a white dwarf has to interact with another star to push it over a weight limit and explode, granting independence to about 6 million trillion trillion pounds of material. Without this interaction its mass would be locked up as it gradually cools down over countless billions of years.
When a core-collapse supernova occurs some material is locked up inside a newly-formed neutron star or a black hole. In Cassiopeia A the neutron star is clearly visible at the center of the supernova remnant.
|The Cassiopeia A supernova remnant, seen with Chandra and HST. Credit: X-ray: NASA/CXC/UNAM/Ioffe/D.Page,P.Shternin et al; Optical: NASA/STScI; Illustration: NASA/CXC/M.Weiss|
Clearly our view of these cosmic fireworks is incomplete, but Chandra has only been observing since 1999.
The antithesis of cosmic independence occurs when a black hole forms, as may have occurred after the supernova that formed W49B. Here it's the lack of evidence for a compact central object that helps make the case for a black hole, along with other features.
|The supernova remnant W49B, as seen with Chandra, the NSFs Very Large Array and Caltech's Palomar Observatory. Credit: X-ray: NASA/CXC/MIT/L.Lopez et al.; Infrared: Palomar; Radio: NSF/NRAO/VLA|
Finally, here's a completely different type of cosmic fireworks in the form of planetary nebulas.
|Four planetary nebulas seen with Chandra and HST. Credit: X-ray: NASA/CXC/RIT/J.Kastner et al.; Optical: NASA/STScI|
These objects are not as spectacular as supernovas in terms of the light and energy they produce, but they're just as beautiful. Because the Sun will evolve into a red giant and planetary nebula in about 5 billion years, Earth will inevitably become part of the show. Maybe by then humans will have travelled well away from the solar system so they can enjoy the stellar fireworks from a safe distance.