NerdGuy Fridays #6: Orion and Not Orion

Orion

What can I say, this is just an awesome constellation. High in the sky at winter, it’s the first constellation I ever looked at with a telescope, and it never gets dull.

The mighty Greek warrior stands tall in the sky and myths surround him. Some say he holds a mighty bow before him (to the east), others say he holds a great sword raised on high above his right shoulder (to the northwest). He is ready to strike at the massive V of Taurus the Bull’s head (marked by the bright Aldebaran–not to be confused with the fictional Star Wars Alderaan). His faithful companion Canis Major (the big dog) stands close behind him ready to leap into the fray. He is marked by Sirius “The Dog Star”, the very brightest in our sky.

Most know him for the three bright stars of his belt and the scabbard that dangles below.

Orion
Orion Consteallation with connecting lines (planetarium image) (c) Neilander (cc)

With simple binoculars there are many fun things to discover. The ghostly haze at the sword belt, that even a small telescope will resolve into the “Great Nebula” is but one of these. Binarys, triple stars, red giants, even the Horsehead Nebula are all there just waiting to be discovered.

Not Orions

Back when I was running my college’s planetarium, I had a man walk up to me after a show and tell me that he had learned Orion as the “Kite.” The bright shoulders were the edges of the kite and the sword was its tail.

In my upcoming novel (Condor, a Miranda Chase thriller, March 10th, 2020), Holly Harper is remembering some of her high school days spent in the Australian Outback. There, Orion stands on his head, and so is drawn differently.

Finally, Holly looked up.

Cruising at fifty thousand feet placed ninety percent of the atmosphere below them. Over the mid-Atlantic, in the middle of the night with the dashboard dimmed down for night vision, the stars seemed to burn in the sky above.

How many nights had she lain out and watched those stars?

Except they were wrong.

The stars of home were dominated by the Southern Cross, not the Big Dipper. And Orion didn’t command the sky girded by his mighty belt and dangling scabbard. In the Southern hemisphere, Orion stood on his head and was drawn differently. Instead the belt was three brothers, and the downward-pointing scabbard was now the upward-leaping sawfish they had eaten against their laws. This had angered the Sun-woman Walu who created a waterspout and cast their canoe into the sky.

Getting away from the town lights of Tennant Creek wasn’t hard. Three thousand people in the middle of the Northern Territory desert, with the nearest roadhouses thirty klicks north or a hundred and thirty south, didn’t cast much of a glow.

As teenagers, they’d take their dirt bikes out into the Barkly Tablelands.

The Warumunga and Yapa, who made up half the town, had learned from their parents how to survive in the Outback. On school holiday, a whole group of them might go for a night and end up staying for a week. She’d learned fieldcraft out there. Holly had also lost her virginity to a lovely Yapa boy with skin the same brown-hued richness as the landscape’s crimson sand. She’d often envied him the lazy brown curls of his sun-lightened hair.

She’d also had her first puking drunk out in the Tablelands. Not one of her better moments.

Not many of the white kids went along on the jaunts.

But one other did.

Her brother had always gone out with them.

Until he hadn’t.

Holly closed her eyes but it didn’t help, she…could still see him as clear as day.

Though it was dark, she slid down her helmet’s sun visor. It blocked even the brightest stars.

She kept it down until she felt the jolt of F/A-18F Super Hornet’s wheels contacting the runway at Ramstein Air Force Base.

Betelgeuse and Rigel, two of the eleven brightest stars in the sky are his shoulder and knee. In the Australian myth, they are the prow and stern of the erring brothers’ canoe cast into the sky with them.

But Betelgeuse has a problem

It’s first problem is that it is moving very quickly away from the constellation. All of the stars are in relative motion to one another and the constellations of today will not be the constellations of a ten thousand years  ago or ten thousand to come.

Betelgeuse has another issue, it’s a red giant. What do we mean by giant?

The sun is roughly 443,690 miles in diameter = 696,347 km.

Betelgeuse is 617,000,000 km across. Now this gets awkward. Mercury, Venus, Earth, and Mars would all be orbiting will inside the star if it were to suddenly replace the sun. It is one monster ball of fire. (In fact, Mars would still be about 90,000,000 km beneath the surface–greater than the distance between Earth and Mars.

The other part of being a red giant is that it has a very fast life cycle. The sun has been around for roughly 4.7 billion years. Betelgeuse had been around for just 10 million. After orangutans, but before gorillas. Proto humans stopped being chimpanzees around 6 million years ago.

And Betelgeuse will explode as a supernova somewhere in the next 100,000 years before it collapses into a white dwarf. This process has already begun. Betelgeuse is has faded by a factor of 2.5x since October 2019. A furnace bigger than the orbit of Mars has faded in just months to significantly alter the look of Orion.

Next time you’re out on a winter (or summer south of the equator night), look up at Orion’s right shoulder, or the left corner of the kite, or the stern of the brother’s canoe. It is no longer even one of the 20 brightest stars.

Science estimates that that the explosive brightness of a supernova that will be visible during the day and cast shadows at night is still probably millennia away.

Meanwhile, one of my favorite pieces of the night sky, Mighty Orion, is changing shape and we’ll have to redraw it with new myths.