The Crab Nebula is the remnant of a supernova that appeared in 1054. "Historical records, including Chinese accounts, describe an unusually bright star appearing in the sky," said the KU researcher.

Over 2 decades of Chandra X-ray Observatory views of the Crab Nebula and Cassiopeia A have been time-lapsed. The Chandra team explains here. Credit: NASA/CXC/A. Hobart Mitt Romney’s Complicated ...