Making Friends with the Night Sky: Seeing stars that aren’t really there!

The red supergiant Antares

The red supergiant Antares in the constellation Scorpius.

Maui astronomer Harriet Witt describes one of the brightest stars in the constellation Scorpius, a distant red supergiant that may no longer exist.

Listen here [4:22m]:

Download here [4 Mb]:

What’s the facts:

In the center of the constellation Scorpius lies the bright red star Antares, the 16th brightest star in the night sky.  Antares is what is known as a red supergiant – its surface is cool and hugely extended, 800 times larger than the Sun. Indeed, if Antares were in the Solar System, it would engulf Mercury, Venus, Earth and Mars.  Stars become red supergiants at the end of their lifetimes, when they have exhausted most of their hydrogen fuel, and they on their way to a spectacular stellar death in the form of a supernova.  The red supergiant stage of a star’s lifetime is relatively short – a few hundred thousand to a million years.  In contrast, the light we see from this star was emitted 600 years ago, since it takes light 600 years to travel the 600 light-years of distance between us and Antares.  So it is possible that Antares is no longer there.  Ponder that while you’re enjoying your view of Scorpius tonight!

Original air date 30 June 2009.


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