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Did you know? Orion

This month . . . . Orion

Named after the mythological Greek hunter, the constellation Orion is one of the most famous, and recognisable, constellations in the night sky.

Orion is a hunter with a shield in his hand, a belt and sword around his waist, surrounded by his hunting dogs Canis Major and Canis Minor and fighting the bull represented by the constellation Taurus. The object of his affections are the Pleiades, the seven daughters of the giant Atlas. They begged Zeus to save them from Orion’s pursuit, so he placed them in the night sky with the giant hunter chasing them from east to west, without ever being able to catch them. The image below is from Johannes Hevelius, Prodromus Astronomia, volume III: Firmamentum Sobiescianum, sive Uranographia, table QQ: Orion, 1690.

The equator of the sky passes close to the upper star of his belt, so that half of Orion is in the Northern hemisphere, and the other half is in the Southern hemisphere. From our perspective in the southern hemisphere Orion is standing on his head, upside down and flipped right to left compared to the Northern hemisphere.

The books of Job and Amos in the Bible mention the constellation Orion three times, referring to it as “Kesil” which according to scholars is literally – fool.

Below Orion’s belt is a curved line of three stars which represent the giant’s sword. The middle star is not a star but the Orion Nebula (M42) a huge cloud of dust and gas almost 25 light years across inside which new stars are being formed.

All of the seven main stars in Orion, with the exception of the red super giant Betelgeuse, are young blue supergiants. The stars are gradually moving apart, but they are located at such a great distance from us that the constellation will remain recognizable a long time after most of the other constellations.

One event which could cause a dramatic change in appearance would be Betelgeuse going supernova, which is predicted to happen sometime in the ”astronomical near future”.


Footnote: At present something strange is happening with Betelgeuse. It started dimming dramatically in 2019 and during January and February 2020 reached a record low of around 40 per cent of its usual brightness, enough to be noticeable with the naked eye. This dimming led to speculation that a supernova could be imminent. However, recent observations suggest that Betelgeuse wasn't fluctuating internally but shot out a huge cloud of dust, which obscured its light for a while. The image left is by Anirban Nandi and available form Creative Commons.

Stay tuned on this one !!

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