We all tend to think of the naked-eye night sky as unchanging, aside from the rare visit of a large comet and the steady passage of the planets. In act many stars are 'variable' but it can take some effort to detect the changes.

Recently, however, there has been a dramatic change which is easy to see.

If you are familiar with the constellation Orion, pop out on one of the clear nights expected this weekend and look for the yellowish star at top left (bottom right Aussies!)

This is Betelgeuse and we are used to it being one of the brightest stars in the sky but it has rapidly faded.

Between October 31st and December 31st it went from 10th brightest to 21st brightest, and it has continued to fade since this article was written:

http://www.skyandtelescope.com/observing/fainting-betelgeuse/

It's not unprecedented, but it's about a century since it was last this faint.

Betelguese is expected to go supernova some time in the next one or two hundred thousand years but there's only an outside chance it could go pop soon (or has gone and the flash hasn't reached us!)

If it does go it could be as bright as the moon for an extended period, but no danger to life on Earth.

Neil