The sky this week: the rise of Orion
We’re heading into the winter months, which can only mean one thing: the mighty Orion is back.
The sun might be setting at 5:15 p.m. these days, but on the bright side, or in this case dark, it gives more time for stargazing! The highlight of every astronomer’s winter months moves from the summer Milky Way to the night sky’s second most recognizable constellation: Orion.
The full constellation of Orion is quite large but the most recognized part consists of 4 main stars that make up its body, 3 stars that make up its belt, and a few more dimming stars that make up the sword. Orion currently begins to rise around 8 p.m. and is high in the sky at midnight and especially before dawn. The first star to break the horizon is Bellatrix followed by Betelgeuse, Rigel and finally the darker Saiph. The stars that make up the belt are known as Mintaka, Alnilam, and Alnitak.
The constellation has been observed and recorded for tens of thousands of years. The earliest known representations of it are found in prehistoric cave drawings in Germany, estimated to be 28-32,000 years old. Since then it has been part of the tradition of almost all cultures and many myths and superstitions can be attributed to it. It is the only constellation to be found in the Bible and is mentioned 3 times; twice to Job and once to Amos.
The name Orion comes from Greek mythology (a common theme among heavenly bodies). Orion is the son of Poseidon and was a great hunter.
The constellation is aptly named because it contains some of the most fascinating objects in the winter sky. Betelgeuse is a very studied red giant. Over the next 100,000 years or so, it is expected to grow into a supernova and become bright enough to be seen during the day, after which it will darken so that it can never be seen with the naked eye again. leaving the constellation very different. Currently, Betelgeuse ranges between the 10th and 23rd brightest star in the sky, as it undergoes a bright / dim process every 425 days. Rigel is the brightest star in the constellation and the 6th brightest in the night sky. It appears white to the naked eye. Bellatrix and Saiph are the two remaining corners of the armor and both appear in blue.
Orion also contains several bright nebulae, including M42 (aka the Orion Nebula) which is the only nebula easily visible to the naked eye. The nebula is incredibly easy to find with small telescopes or powerful binoculars. Across these, it appears as a bright green cloud with 3 bright stars in the middle, known as the trapezoid. It is located in the sword of Orion and is not the only nebula in this region.
Right next to it is the “Running Man” nebula, which is not as easily seen with telescopes but can still be seen in dark skies. It is a bright nebula but not as bright as the Orion Nebula it is next to. In the photos, he looks like a running man, hence his name.
Orion has been around for tens of thousands of years and will likely last for tens of thousands more. All of Orion’s stars are quite distant from many other constellations, which means that over time they will appear to move less. The constellation as we know it will outlive most others because their stars are closer and therefore move faster (but still VERY slow) relative to Earth. The only fly in the ointment will be the stars that become nova, like Betelgeuse. Even still, it will probably be a long time.
So go out this week and take a look at the mighty hunter. If you have binoculars or a small telescope be sure to check out the Light Nebula as well, I can assure you they are definitely worth a look.
As always, look at the sky!