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 ...

ABSTRACT Published images of the Crab Nebula have been scanned and measured to derive proper motions, the age of the nebula, and its point of origin. Astrometric reductions provided rms errors ranging ...

This week’s naked-eye object is the Beehive Cluster in Cancer the Crab. Because this cluster is bright — magnitude 3.1 — it has acquired ... the Orion Nebula is M42; and M51 is the Whirlpool ...

Staelin, D. H., and Reifenstein, E. C., IAU Circ. No. 2110 (1968). Lovelace, R. B. E., Sutton, J. M., and Craft, H. D., IAU Circ. No. 2113 (1968).

36,356 people played the daily Crossword recently. Can you solve it faster than others?36,356 people played the daily Crossword recently. Can you solve it faster than others?