Montana Skies: Horsehead Nebula

If there's a break in the weather this week, take a look high up in the Southern sky and you'll find Orion the hunter shining brightly.

Two stars above represent his shoulders, two stars below represent his knees, including the very bright star Rigil.  And in the middle you'll find three bright stars in a row which are the belt of Orion.  You may also be able to see an arc of faint stars off to the right representing the shield of Orion.  To the lower left of Orion, you'll see Sirius, the brightest star anywhere in the sky, which is the eye of Canis Major, the big dog, Orion's hunting dog.  This is a beautiful piece of sky to study, either with the naked eye, or with a small telescope.  If we zoom in on the star farthest left in Orion's belt, we see this amazing sight:

Look at that!  Astronomers call this the horsehead nebula.  Why is it called the horsehead?  The answer is pretty simple:  Like many objects, it was named after the man who discovered it, the great astronomer, Sir William Horsehead.  Now, when Sir William was--  Sorry!  Sorry!  Of course the name comes from the fact that it looks like a horse's head.  What we're seeing here is actually two different nebulae.  In the background is a bunch of hydrogen gas, which has been heated up by a nearby star, so that it's glowing with this red color.  In front of this is a cloud of cool, dark gas in the horsehead shape.  The darkness comes from the dust in this cold nebula, tiny particles of carbon, silicon, and oxygen, about the size of particles in smoke. Orion is a beautiful place, so if there's a break in the weather, step outside and enjoy it, up in our beautiful Montana Skies!