Here’s Your July Assignment

Take a hike. No, really. Go out for a hike somewhere and closely examine the rocks and soil you encounter. If you live near mountains, look at them and imagine them as they were when they were young. Then, think about where all this stuff came from. If you go back to almost first principles, you find out that what you’re seeing and hiking on is the leftovers of star formation. That’s because sometimes planets are what’s left after a star forms. And, in the case of our four inner planets, the leftovers became worlds we know and love.

The elements in those rocks, the ones that make up the plants and animals you see on yourhike, and you yourself, are all part of stuff that was a star–ashes that were recycled into the Sun and somehow made it into the soup of stuff that created Earth. Quite a cool thing to think about when you’re out hiking.

Recently, I looked up at the sky from my aunt’s house (she lives in a rural area) and gasped at the beauty of the sky. You’d think I’d be used to it by now, but there’s something about a sky full of stars that still grabs my attention. And that’s good. I’d hate to get jaded!

I remember one time I was observing on Mauna Kea on the Big Island of Hawai’i, and decided to take a break. I stepped out onto the outside catwalk of the telescope we were using and looked up. It was a sea of stars. The sky itself was so black it really did look like velvet. And, for the only time in my life, I actually felt as if I was going to fall up into the sky. It was uncanny and sent shivers down my spine. I’ve never forgotten that experience. I wish everybody could have it.

Galactic Cannibalism Rules

We live in a galaxy that used to be several other galaxies that consumed each other to become the Milky Way. In fact, it’s still eating up a dwarf galaxy or two. It turns out that many larger galaxies grew to their current configurations by snacking on each other, amassing size and bulk. If we could watch it happen “in real time” the process of two galaxies out for a munch would look like an animation created by the American Museum of Natural History in New York City. (Check it out!)

These collisions don’t happen overnight, even by cosmic standards. The process begins well before the galaxies even touch each other. This is because the gravitational influences of each galaxy (and associated dark matter components) reach out far beyond the “lit” component (stars, etc.) Those influences start stripping away materials as the galaxies approach, and continue to do so throughout the collision and for a long time afterward.

The whole process can take many hundreds of millions of years, and as I pointed out above, it’s still happening as the Milky Way gobbles up the Sagittarius dwarf galaxy, for example. And, you can look out in the universe and see lots of other places where galaxy cannibalism and merging is taking place.

This Hubble Space Telescope image shows a collision in progress called The Antennae. It shows quite well one aspect of galaxy cannabalism–starbursts. All that colliding material spurs a lot of formation of hot, blue, massive stars — which show up as blue streamers and hotspots.

The Milky Way may be headed for another collision, this time with the Andromeda Galaxy, which lies some 2.5 million light-years away. If it happens, it could really change the appearance of our skies in five billion years’ time. It’s a matter of some conjecture as what effect this will have on planets and life in the galaxy, but by the time this happens, Earth and the Sun will have been long gone. Even a close approach, however, will affect the shapes of both galaxies forever.

What Does It Mean

For a good many years I’ve been a writer. One of my mainstays is planetarium shows (or, if you like, in today’s new digital world, I write for fulldome video). Last week I attended the once-every-two-years meeting of the International Planetarium Society, held this year in Chicago, Illinois. We had around 600 attendees from around the world, and it was a very busy and rewarding meeting.

That’s the Adler over to the left. It actually has two domed theaters and one “flat screen” theater, and we had several sessions there throughout the week, seeing each other’s shows (I had one in the mix) as well as Adler’s panoply of presentations.

During the meeting, we discussed what we are, as planetarians. The word “planetarian” wasn’t in the dictionary for a long time; it now is online. It is defined in the Random House Unabridged dictionary as:

All of us fit under the second category, so that’s kind of a gimme. Those of us who work at planetariums or with planetariums (or planetaria, if you like) fit under categories 1 and 3, interchangeably.

But, there should be a fourth description that tells what we actually DO in those domed theaters. There are many tasks that we accomplish, but they are mostly all related to telling good stories in the dome about astronomy and space science. So, for example, I write scripts and produce shows that accomplish that goal, and together Mark and I have created many shows that planetarium theaters use.

There are others who build equipment for the theaters, install it, test it, and then go out and sell it to theaters. They’re also planetarians. There are those who use the domed theaters as classrooms, or visualization labs to test new visual ideas. All are equally valid members of the society of planetarians.

I think that the fourth definition is dimensionless in that it really is expandable and includes people who work at traditional planetariums as well as at the new digital fulldome theaters. We all work in the same kind of domed space, telling stories of the cosmos.

Are Stars Scary?

Let’s take a break from black holes and come home to Earth for a bit. A while back I was in line at a store and was talking to the person ahead of me about what I do. (I was wearing a Hubble Space Telescope t-shirt, which tipped her off, I suppose, that I might be one of THOSE people…)

She asked me if there was anything in the sky that could scare kids. She wanted to take her 8-year-old son to the Museum of Science to look through a telescope, but didn’t want him to get scared. I asked her if he was easily scared and she said that he wasn’t. So I asked what she was worried about. She finally admitted that she thought he might learn something that would scare him, like the fact that our Sun might go supernova.

Now that’s an interesting concept-the possibility of our Sun blowing up as a frightening thing to an eight-year-old child. Most kids I know of that age are really INTO making explosive noises, and their cartoons are chock-full of such stuff. So, there had to be something more to this concern. In the course of our conversation, it became pretty clear that she didn’t want her child to be frightened by science and she was worried that astronomy might have too much violence for a young child.

Just to allay any concerned folks who may be reading this, the Sun isn’t going to go supernova. Its death is going to be more gentle, as star death goes, and it isn’t going to happen for five billion years or so. So, there’s not much to worry about in the near term, and certainly not for an eight-year-old.

I think what intrigued me about this mom’s concern was that her son would get scared of something like this simply by looking through a telescope at other stars. I did mention to her that looking at stars is normally something very enjoyable and thought-provoking. And, I did point out that looking at the Sun was NOT a good idea and I wouldn’t recommend it. I told her that the folks at the museum usually look at planets, especially since those are easy to find in light-polluted skies.

She decided that would be cool, so I guess one of these nights, her son will get to see some celestial delights through a big telescope. I can just about guarantee that he won’t be scared. But he might come home and want a telescope…