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From the Magazine: Night Sky

Professor of Physics and Astronomy Bryan Penprase spoke recently with Pomona College Magazine Executive Editor Mark Wood about his new book, The Power of Stars: How Celestial Observations Have Shaped Civilization.

This book is as much about human culture as it is about astronomy. As a scientist, what motivated you to write such an interdisciplinary, multicultural book?

Everyone in this country of ours is a mix of places and cultures. Part of what motivated me into archaeoastronomy was feeling that deep ancestral connection to the sky that’s reflected in star tales and creation stories and recognizing that ancient people had a sort of cultural continuity that we don’t have.

I was also curious because that sort of thing is so absent from our training in astronomy. You can get Ph.D.’s in astronomy going outside and not even being able to recognize where Orion is. They know all the technical names for the different H2 regions in Orion but they don’t know which group of stars up there is Orion, let alone the lore that’s associated with it.

So what opened your eyes to that broader appreciation of the wonders of the night sky? 

One night in grad school, there was a star party, and we were up on the roof looking at the beautiful Wisconsin sky, a beautiful dark night. Being a grad student, I was usually staggering out of the lab at about midnight, and every night I would look up and see shifts in the sky. I was just starting to come to the point where ancient people were, where every night they would be doing that same thing and noticing the changes, the seasonal variations. This all kind of came together that night. One of the older grad students who knew some of the star lore started pointing out all the constellations, and I was just amazed. I realized that, wow, that’s a part of astronomy that really connects with people and yet isn’t part of the standard curricula. There’s this whole other humanistic and cultural side that’s completely off the books. So that’s when it all started--the archaeoastronomy thing.

I know this book grew out of your class in archaeoastronomy, but how did the class itself get started?

Actually, it happened while I was interviewing here. They asked me, if I could teach one course here, what would it be? And I kind of looked around and said,"Well, I’d probably teach a course on the history of astronomy around the world,and I’d call it Multicultural Cosmology.” And then they signed me up for a freshman seminar the next year.

Now I’ve been here about 17 years, and I’ve taught that class probably a dozen times--three times as freshman seminars, and the regular class eight or nine times.

How have students responded to the class?

It seems to resonate with them. Teaching is a two-way thing. You can plan a curriculum, but then as the students react or don’t react, it gets modified, so it’s been iterated over the years. What the students seem to like most is the parts that tie in to their own culture. You come with little tales from an aunt or a grandma, some vague sense of how your people saw the world, but you haven’t had a chance to broaden it out, so being able to see a full treatment of how the Mayan would chart out the skies, for example, how they would write down their discoveries and keep track of the cycles of the universe, I think that really helps people who otherwise wouldn’t have a real connection with that culture.

And the other part I think they like--which I’m happy to see--is just being aware of the sky, the same way I was made aware that night in grad school. I ask them to go out every day and look at the same place in the sky and write little diagrams of where the sun is, how the moon is moving against the stars, what constellations are up.

Going into writing the book, I took all those notes and threw them into the different chapters, adding some new research from things that I found. So now the book will go back into the classroom, and we’ll see what the students like and don’t like. So it’s definitely an iterative, interactive process.

Do you think of this book as an archaeoastronomy textbook first and a broader-interest book second or the other way around?

Being a fan of Carl Sagan, I always knew I’d like to write something that the public would like, so that was always an essential thing, to make sure it would be enjoyable, but I also wanted a textbook for my class, so it’s organized like my class. For instance, chapter one is about our experience of the sky and star knowledge--pretty much the first thing I do with the students.

What are your own favorite parts of the book?

One thing that fascinates me is the way our modern civilization is still doing a lot of the same things ancient societies did, just with different tools and at a different scale. You can see aligned pyramids and ziggurats and Native American kivas all pointing toward solstice directions or being aligned with pure north, but it kind of surprised me, going around and looking at our modern society and seeing how so many cities are snapped onto a cardinal direction grid, or maybe by coincidence are aligned with solstice directions, which future civilizations might look back on and say, “Aha, they’re aligning their street grid.”

Timekeeping too--ancient people would push the limits of their science and technology to get to the most detailed calendar with all kinds of motions of planets, eclipses and so on. The Mayan did that. The Chinese. The Babylonian. We do it, too. We have our Naval Observatory marking down the nearest millionth of seconds. Our timekeeping is so good that we had to decide whether we wanted to continue to be aligned with the stars or align our civilization to the motion of atoms. And we decided to keep the atomic clocks and just add leap-seconds to align atomic time with the poor old Earth’s wobbling and spinning.

Do you see the field of astronomy today as a continuation of these past cosmologies or a clean break with the past?

It’s a bit of both. The same motivation is there, the same instincts, the same human mind. We’re no smarter or less smart than people three thousand, five thousand years ago, but we have this advantage of technology, and so using that allows us to break away from these other traditions and fill in the gaps in our knowledge with this flood of data that we get from these amazing telescopes. So it’s both.

But in the introduction to your book, you note rather pointedly that we, too, will be ancients someday.

I like to inject a little bit of humility. Every culture in their time thought of themselves as the greatest thing ever, but you can look back and realize they missed the boat in a lot of areas. We probably have a lot of gaps in our understanding, too. Our knowledge is really impressive, and our telescopes are amazing, and we’ve got this detailed theory of how the universe all fits together, so we’ve definitely broken away from ancient cultures in that regard, but at the same time, there’s this absence of any effort to summarize: Well, so what does it all mean? How do we fit into this picture? Science, wisely, has partitioned that off as not part of their domain, but that’s what the ancient cultures were all about, and in a way we’ve lost that. So we’re both more and less than ancient cultures.

This article originally appeared in the spring/summer 2011 issue of Pomona College Magazine [pdf] .