Distant galaxies have subtle beauty
Amateur stargazers often train their telescopes at faint fuzzy patches. They respond to the sight of a few precious photons with a delight not shared perhaps by the public at large.
At our public programs at Perkins, some respond to the faint galaxies with comments like, “Is it that smudge? Right. Can we look at the moon now?”
Professional astronomers sometimes don’t appreciate the sheer beauty of all things faint and small either. When offered view of a galaxy in an amateur telescope, a pro of my acquaintance responded, “Tom, if I want to look at a galaxy, I’ll get a book and look at a picture of a galaxy.” Sigh.
Amateur stargazing is often a delicate balance between aesthetics and knowledge. To appreciate a distant galaxy, you have to appreciate its subtle beauty and know enough about it to respond emotionally and intellectually to its great size and distance.
That’s the way it is with the galaxies called M81 and M82. These distant denizens of our universe are bright enough to be seen easily in a small amateur telescope. They fit nicely in the same field of view and differ enough in size and shape to provide a lovely visual contrast — if you can see them at all.
You are looking at the collected light of hundreds of billions of stars.
Yes, they’re faint, but they’re also 102 million trillion and 42 million trillion miles away, respectively. If that fact doesn’t make your brain melt with mind-numbing wonder, then nothing will.
To show you what I mean, you’ll have to stop reading and run out and buy a $500 telescope. I’ll wait. Dum de dum … .
Okay, take the ’scope outside. Look to the northeast for the Big Dipper. Point the ’scope at the faint star up and to the left of the bowl of the Dipper. Slowly, move your telescope back toward the bowl and you will be rewarded with the view of not one but two smudges in the same field of view.
Yow! The larger, oval-shaped galaxy is M81. Galaxies are egg– or disk-shaped collections of hundreds of billions of stars. M81 is disk shaped, a “spiral” galaxy very similar to our own Milky Way in structure, age, and number of stars. From a bright central hub, thin arcs of countless stars curve outward like the vanes of a child’s pinwheel.
M81 is seen from above, or “face-on” as astronomers like to say. Its bright central hub is what you see. A very large telescope or a long-exposure photograph is required to see its spiral arms.
M82 is also disk shaped, but we see it from its edge and not from above. It looks like a thin sliver of light, and contrasts well with the fatter M81. If you look carefully, you’ll see that M82 is divided across its thin cross-section by a dark line, an unusual band of dust that obscures the combined light of the stars behind it.
Something weird is going on in M82, but astronomers aren’t quite sure what. Some speculate that 18.5 million years ago, a massive explosion in the galaxy expelled dusty material from deep in its core.
The dark lane you see is one of many filaments left over from that great galactic cataclysm.
Or we could just be seeing dust and gas that has not resolved into stars yet or the effects of a supermassive black hole at the center of the galaxy. Or we could be seeing a normal stage in galactic evolution.
Or something else. It is so hard to fathom the workings of something so very far from our reach, let alone our grasp.
Now I know that some of you don’t have the cash or inclination to go out and buy a $500 telescope. Stop by one of our public programs at Perkins some clear night, and we’ll be glad to show you just how beauty and knowledge are so inextricably intertwined.
Tom Burns is the director of Perkins Observatory. He can be reached at firstname.lastname@example.org.