HEIDELBERG, Germany — Astronomers consider the Crab nebula one of the steadiest sources of high-energy radiation in the universe. Radiation from the supernova remnant is believed to be so constant that astronomers use it as a standard candle with which to measure the energetic radiation of other astronomical sources.
Note: To comment, Science News subscribing members must now establish a separate login relationship with Disqus. Click the Disqus icon below, enter your e-mail and click “forgot password” to reset your password. You may also log into Disqus using Facebook, Twitter or Google.