LOOKING to the west just after sunset at the moment you can be forgiven for being a little bit confused.
About a third of the way up from the horizon will be what looks like two versions of the planet Mars. Both points of light appear reddish and both are about the same brightness.
One is of course Mars, the slightly higher one, while the lower one is Antares, one of the truly remarkable stars in the sky.
The brightest star in the constellation Scorpius, Antares gets its name from looking similar to the planet Mars.
Whenever Mars passes close to the star like it is at the moment, it’s easy to see that they are very close in brightness and colour. The Greek name for Mars is Ares and because of its similarity to the planet, the star was consequently called Anti-Ares, or Antares, which literally means “a rival of Ares”.
Antares, like Mars, has a distinct reddish hue and because of this it represents the heart of the scorpion. It is one of only four stars in the night sky that visibly appear reddish.
Unlike Mars however, the red colour comes not from being rusty, but from its temperature. As a star reaches the end of its life it expands. As it expands it cools down and this means it becomes a red colour.
The statistics of Antares are truly spectacular, the most impressive of which is its size.
It is the second largest star visible to the unaided eye. If you were to replace the sun with Antares, it would engulf the entire inner solar system out to past the asteroid belt. That makes it over one billion kilometres across or almost 800 times the diameter of the sun.
It is also 10,000 times brighter than the sun, but due to its distance of 600 light years it only appears as the 15th brightest star in the sky.
Keeping track of Antares over the next couple of weeks will show that Mars slowly leaves it behind, but interestingly it is slowly joined by yet another planet, Mercury.
Mercury is the bright point of light located below Antares. Incidentally if you ever wanted to see Mercury now is the time to do it as it appears as far from the sun as it ever gets for the year and consequently is at its easiest to find.