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 tlburns@owu.edu.

Posted by Staff Reports on Mar 12 2013. You can follow any responses to this entry through the RSS Feed. Comments can be made below.