720 XTF Search Results (expand=subject;f1-subject=Supernova Remnant;f2-subject=Cassiopeia A);f1-subject%3DSupernova%20Remnant;f2-subject%3DCassiopeia%20A Results for your query: expand=subject;f1-subject=Supernova Remnant;f2-subject=Cassiopeia A Thu, 01 Jan 1970 12:00:00 GMT Sizzling Remains of a Dead Star. This new view of the historical supernova remnant Cassiopeia A was taken by NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. Blue indicates where NuSTAR has made the first resolved image ever of this source at the highest energy X-ray light, between 10 and 20 kiloelectron volts. Red and green show the lower end of NuSTAR's energy range, which overlaps with NASA's high-resolution Chandra X-ray Observatory. Thu, 01 Jan 1970 12:00:00 GMT