Taking Time for Astronomy: Why Do It?

Because It Takes You Places You’ll Never Go

Star-forming region NGC 3582

T. A. Rector (U. Alaska), T. Abbott, NOAO, AURA, NSF

Courtesy Astronomy Picture of the Day

A few weeks ago I was flying to a meeting across the country. I always bring along some reading material, since it doesn’t take me more than 10 minutes to get through the airline magazine. I sat there reading a copy of Physics Today,. After I put it down to rest my eyes a bit, the person sitting next to me looked it over and smiled. “I always hated physics,” was the comment. I patted the magazine and said, “I flunked it once. But I went back and took it again because physics describes how things work. And that fascinates me.”

We kept talking for a while, and eventually my seatmate asked what I do for a living. I never quite know what to say because I’ve done a great many things. I’m a writer, for sure. But, to get here, I had to go a lot of other places. I’ve been in astronomy research, worked at a newspaper (where I agitated to write more stuff about astronomy), edited a magazine (about astronomy), written books (about astronomy), write scripts (about astronomy) and… well, you get the picture. So, I said that I write about astronomy. That led to another question, “Why do that? Are you into it?”

Now, these questions aren’t asked maliciously–the person really does want to know. So, we got into a discussion about astronomy, how I first got started, and how I work to spread the word about astronomy these days. And, I got in a few points about how astronomy is a great science for everybody to appreciate. My seatmate mentioned going out stargazing with family members as a child. And talked a little about going to the planetarium for school visits. And then said, “What I like about astronomy are the pictures. I don’t always understand them, but I like them.”

I asked why, and after pondering a while, my airplane friend said, “Because they take me places I could never go.”

The Dance of the Galaxies

Hubble Sees It

Hubble Space Telescope has been peering out at galaxies (and all kinds of other objects in the cosmos) since 1990. Over the years it has captured many views of galaxies interacting. By interacting, I mean that they come together, they collide, they mingle stars and clouds of gas and dust, and then in the aftermath, new stars are formed. The view from a distance is breathtaking. Like this one. The combined galaxy interaction is named NGC 5331, and they lie about 450 million light-years away from us in the direction of the constellation Virgo.

The collision of a pair (or more) of galaxies begins long before they look like they’re actually touching. The gravitational influence of both galaxies begins to pull shreds of galaxy parts (gas, dust, stars). It also starts to distort the shape of the galaxies doing the interacting. If you look closely at this pair you’ll see some part of the lower galaxy is being pulled toward the “upper” galaxy. There are also little blue clouds out to either side of the galaxy. Most likely those are star-forming regions, so-called “starburst” knots that are ignited during galaxy interactions. (There are also other galaxies in the picture — see if you can spot them all.)  As things proceed, you start to see definite “shredding” effects as the shockwaves of collision distort the galaxies.

To celebrate the 18th anniversary of Hubble’s launch (gad, has it been 18 years already?), the Space Telescope Science Institute and the Hubble ESA folks have released an image collection of 59 galaxy interactions. Here’s another one — the interacting galaxy pair that makes up Arp 148. This one shows the pair well after the collision (interaction) began. The blue “ring-shaped” object is a collection of matter ejected by the shockwave generated during the collision. It’s blue because the shock also touched off a burst of star formation. Those are hot, young blue stars there, just beginning their lives in the chaos of a galaxy collision.

You can see the other 57 galaxy interactions here. Be prepared for quite a fascinating tour! It’s amazing what can happen when some of the biggest structures in the universe do a little cosmic dance with each other!