Orion the Hunter anchors winter night sky

  • Thu Jan 12th, 2012 2:15pm
  • Life

By Mike Lynch

As it does every year, the great constellation Orion the Hunter starts showing up late in the evenings in the low eastern sky about mid- to late November.

Without a doubt Orion is certainly the anchor constellation in the winter skies and arguably the best and brightest constellation in the sky. Even in heavily lit urban skies, Orion’s stars pierce through.

To some people the constellation resembles a crooked bowtie and to others an hourglass. It’s supposed to outline the torso of a giant hermit hunter, at least according to Greek mythology. The hunter is said to be holding a lion by the tail, although some imaginations see him holding up a shield or a bow.

Orion is more or less the centerpiece constellation of what some call the “Tower of Brilliance” or the “Winter Circle,” but what I like to call “Orion and his Gang.” Since November it has migrated westward from night to night, rising earlier and earlier, so now in mid-January at the start of evening Orion is already standing well above the southeastern horizon.

By 9 p.m. you can see the entire splendor of Orion and his Gang with fellow constellations like Taurus the Bull, Auriga the Charioteer, Gemini the Twins, Canis Major the Big Dog and Canis Minor the Little Dog, all of which contain brilliantly bright stars. In fact, out of the 20 brightest stars seen from in the Northwest skies through the course of the year 11 of them are concentrated in Orion’s gang.

Orion’s greatest visual assets are the three nearly identically bright stars that make up his belt: Alnitak, Alnilam and Mintak. Even though these bright stars appear close together, they’re actually hundreds of light-years apart.

Alnitak is 800 light-years away (one light-year is nearly six trillion miles). Alnilam is 1,300 light-years distant and Mintaka shines at us from 900 light-years.

There’s another coincidental line up of three dimmer stars to the lower right of Orion’s belt that depict his sword, but even with your naked eyes, you can see that the middle star in the sword is a little fuzzy. What you’re seeing is a fantastically large cosmic cloud of hydrogen called a nebula where new stars are being formed.

The great Orion Nebula, as it’s known, is more than 1,400 light-years away and more than 30 light-years across.

This colossal birthing ground of stars would be invisible if it weren’t for four very energetic stars that were born out of it and light up the nebula like a fluorescent light. The stars, arranged in the shape of a baseball diamond are known as the Trapezium and all four of its members are probably less than a million years old, mere infants.

On the upper left hand corner of Orion is without a doubt the biggest single thing you’ve ever seen, the star Betelgeuse, which is an Arabic name that debatably translates into “armpit of the great one.” Betelgeuse marks the armpit of the great hunter. Astronomers categorize it as a super red giant more than 1,000 times larger than our sun, which would give it a diameter of nearly a billion miles.

Betelgeuse is considerably younger than our sun, thought to be less than 10 million years old.

Supergiant stars like Betelgeuse are not long for this galaxy and universe since they very rapidly deplete their resources. Within a million years or possibly even a few thousand years, Betelgeuse will meet its demise. Stars the size of Betelgeuse literally blow themselves to bits in a supernova explosion.

When that happens the explosion could be nearly as bright as a full moon and stay that bright for at least a couple of weeks.

Mike Lynch is an astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and is author of the book, “Washington Starwatch,” available at bookstores. Check his website, www.lynchandthestars.com.

The Everett Astronomical Society: www.everettastro.org/.