December 10: Winter Constellations

The other night I helped lead a wonderful evening nature program for elementary school aged kids at the Tualatin Hills Nature Park. We did a craft, 
ate pizza, walked in the woods at night and listed to a story by candlelight. Talk about exposing kids to the PB and J of nature! My favorite part of the evening, though, was conversations I had with one of the older girls in attendance. She was a 7th grader and very into stars and astronomy. Together we looked up at the abnormally clear Portland night and pointed out constellations to each other. She found the big dipper and I showed her Cassiopeia. She asked me about Orion, if it was visible tonight. When we walked in the woods it was not visible but as we came out heading back to the interpretive center she spotted him. With a gasp she grabbed my arm and pointed. "Look! There it is!" We both stood and looked together at his belt, at the giant red star in the constellation and even tried to spot his dog, Sirius, close to the horizon. Talk about the PB and J of science! We were both, literally, in awe.

Winter can be such a fantastic time for stargazing because it is dark for so darn long each day. In Western Oregon the almost ever present cloud cover can get in the way, but there are many nights when you can go outside and see a few bright stars. Most people can find the Big Dipper, usually about midway between the horizon and the zenith in the northern sky this time of year. These seven bright stars never go below the horizon in Oregon, and are visible all year round. The Big dipper is a great constellation to start out with both because it is so visible and also because it helps you find so many other constellations like the Little Dipper with Polaris, the north star, and all the other cirucumpolar constellations (like Draco, my favorite constellation!). 

My little friend's favorite constellation, Orion the hunter, is another one you should look for on clear winter nights. It is visible in the eastern sky in the early evening hours in December and is recognizable most easily by the three stars in a line that make up his belt. Orion is an amazing constellation for the budding astronomer to get to know because there are so many fun astronomical phenomenon to discover in this one constellation. Many of the stars in this constellation are actually double stars or star clusters. The star we call Meissa, Orion's head,  is actually a cluster and the right-most star in the belt is a double star easily seen in binoculars. The middle star in the belt is actually a nebula, a cloud where stars are being born. It helps to have a telescope to see the Orion Nebula, but you can observe the redness of one of the stars in Orion even with your bare eyes on some nights. Betelguese, the right shoulder of the hunter, is a red giant and one of the largest stars known in our visible universe. It is 600 times wider than our sun, but the surface temperature is only 6,000 degrees F compared with 10,000 degrees for our sun's surface. It is a star in its twilight years as it reaches the end of it's hydrogen fuel. Soon it will collapse soon and explode into a supernova which will be visible by daylight. Unfortunatley, soon in astronomical terms means anytime in the next million years - and since it's 430 light years away, even if it exploded today none of us alive would see the supernova. Like the Big Dipper, Orion is helpful for finding other constellations. 

The two stars of his shoulder point to Procyon, or Canis Major, and his belt points downwards to Sirius, Canis Major, his two hunting dogs. 

Like my friend at the Nature Park and I,  you too can be in awe of the night sky. Many of these stars can be seen even from the suburban areas of a city like Portland, and if you find your way out into darker skies you will see so many more. A pair of binoculars will help you see some of the cool stuff in Orion, but you don't need them to enjoy the constellations. If you are a science buff there is so much to learn about the different sizes of stars and types of nebulae but if literature is more your style then you are in luck, too. Our modern constellations are mostly named after ancient mythologies and the stories are as thrilling as any modern block buster (saving a princess from a sea serpent? Giant scorpions and heroes fighting for eternity? Tracking a bear for a whole season and the underground railroad? Does it get any more thrilling?) All you need is a dark sky and the clouds go go away for a few hours, which happens occasionally even here in Portland, Oregon.

When was the last time you went stargazing? What is your favorite constellation? Can you point out Orion or at least the big dipper? What winter PB and J of Science are you celebrating this week?

The images in this post are holiday cards created with images from the Hubble telescope. Learn more about what amazing things Hubble is observing and download the cards for free by checking out Hubblesite.org.