Stargazing at Northwestern
With the final landing of space shuttle Atlantis earlier this month, the thirty-year US space program came to an end. But just because these shuttles are now headed for museums rather than space doesn’t mean we no longer need—or want—to explore the final frontier.
Amateur enthusiasts can begin their exploration right in Evanston’s own backyard. Northwestern University is home to the historic Dearborn Observatory, where members of the community can gaze at the depths of our universe every Friday night.
Science in Society spoke with Michael Smutko, distinguished senior lecturer at Northwestern University, astronomer at the Adler Planetarium, and manager of operations at Dearborn. We asked him about visiting the observatory, his own work, and why astronomy research is still so important to all of our lives.
What can someone expect from a visit to the Dearborn Observatory?
Most people who use the telescope here at Northwestern have never looked through [one] before. So it’s a really great opportunity to show that these things are really there, and you can see them with your own eyes.
The people who host the Friday night sessions are trained not only to run the telescope, but to explain what you’re are looking at, and why it’s interesting. [For example], what the cloud bands on Jupiter mean, or how far away [a certain] star cluster is and why it’s interesting to astronomy.
Was the Dearborn telescope ever used for research?
It was, absolutely. In fact, the Dearborn telescope was the largest refracting telescope in the world for six years (from 1862 to 1868). A refracting telescope is a telescope that uses lenses to gather its light instead of mirrors. It’s what you’d think of as the traditional telescope, like Galileo’s telescope, only a much bigger version.
We still have the original 1862 lenses—we use them all the time. They were made by a very famous optician, Alvan Clark, and his sons. Clark is to telescopes and lenses the way Stradivarius is to violins and stringed instruments. [Clark’s] instruments are very rare—they are collector’s items, and they’re in museums around the world. We are very privileged to have his optics here today.
Northwestern wasn’t the original destination for these lenses. How did we come to acquire them?
In 1861, the biggest telescope in the world was a fifteen-inch-diameter telescope at Harvard University. There was also one in Russia that was fifteen inches. The University of Mississippi wanted a telescope that would beat the one at Harvard, so they commissioned Clark to make an eighteen-and-a-half-inch set of lenses.
When it was finished (in 1861-62), it was the beginning of the Civil War, and there was no way that a lens made in Boston was going to be sent to Mississippi. So the deal fell through. Eventually the lens came to the University of Chicago—not the current University of Chicago, but the original, which later went bankrupt. The ownership of the lens then fell into question for a few years. It ended up at Northwestern, where it’s been ever since. It’s a little intimidating sometimes, that we have this piece of history sitting right here.
Do you utilize the telescope in Northwestern astronomy classes?
We do. During all of the 100-level astronomy classes—the science distribution classes—we have the students come to the observatory at least once during the quarter. They all get to experience what it’s like to look through a telescope firsthand instead of just seeing pictures in textbooks and online.
We also have a more advanced class for our majors and for graduate students where they use our telescope to make actual scientific observations. It’s a fantastic tool for that, because the techniques students learn on our telescope are the exact same techniques used at any of the major observatories around the world. So when they graduate from here and go on to a career in astronomy, they’re ready to go.
What do you love about teaching astronomy?
I think astronomy is such an inherently interesting topic for so many people. So many kids, after they want to be a cowboy, want to be an astronaut.
To me, teaching astronomy is almost like cheating. I think the material is so interesting on its own that all I have to do is introduce it and then get out of the way. That’s when I know I’ve been successful: when the students leap into it on their own, without me having to prompt them.
In addition to your work at Northwestern, you are also an astronomer at the Adler Planetarium. Tell me about your research there.
My current research focuses on how stars form in the Milky Way Galaxy. In particular, [I study] high mass stars—at least ten or twenty times the mass of our Sun. Those turn out to be some of the most interesting stars, because they’re extremely luminous, but they also end in these fiery, supernova explosions that generate many of the chemical elements that make up the Earth.
So they’re important stars, but not much is actually known about how they form. Part of the reason is that they’re fairly rare. For maybe every thousand or even ten thousand stars like our Sun, only one of these high mass stars will form.
All stars form in dark, dense, cold gas clouds. The reason they have to be dark and cold is [because] that allows them to collapse under their own gravity. If [the gas was] too hot, the pressure would keep it stable and prevent it from collapsing. [When] they can’t resist their own gravity they get crushed down in the center to make stars.
Stars typically don’t form on their own; they typically form in clusters. So you might get a hundred or a thousand or more stars all forming from the same original cloud. One of our questions is: why would you get a thousand small stars, as opposed to a few very large stars?
To [investigate] this, I use an infrared telescope in New Mexico. The reason we use infrared light for this is because those dense, dark clouds where the stars are forming completely block visible light. We can only see the edges of the cloud. But to do this work, we need to be able to peer down deep inside.
What have you found so far?
We’ve actually found some examples of high mass stars in the very early stages of formation. We just submitted a paper to an astrophysical journal last week on the discovery of a new example. So that’s kind of exciting. We’re hoping to find out if there is an inherently different mechanism that causes [these stars] to be high mass stars, or if [a high mass star is] just a low mass star that ate too much—consumed a larger than average portion of its cloud. It’s sort of a nature versus nurture question: is there something special about the cloud, gas, or dust that forms a big star, or is it just one of those things—every now and then you’ll just happen to get a big star?
With our sample size of one right now, it’s a little hard to draw a conclusion. But we’re looking for others. We’ve studied about twenty or so prospective candidates. We’re in the process of looking at the data and seeing what it tells us.
You’ve also worked on improving the resolution of ground-based telescopes. Would you tell me more about that?
My PhD thesis was on an area of astronomical instrumentation called “adaptive optics.” What adaptive optics does is try to remove the twinkling from stars. Twinkling, as romantic as it sounds, is the bane of ground-based astronomers.
Starlight [travels] for thousands, millions or even billions of years completely undistorted, [but] that last fraction of a second when it passes through the Earth’s atmosphere it gets blurred out. It’s a little like looking at your feet in a swimming pool. Your feet are perfectly fine and in focus, but the water ripples and distorts them.
(Pulling out an instrument.) Each of these little pistons here are ceramics, and when you put a voltage on them they grow. They shrink or they enlarge depending on how much and in what direction the volts are. This thin piece of glass is flexible, so as these pistons get bigger or smaller, they bend the shape of the mirror. The trick of adaptive optics is to bend this mirror in exactly the opposite way that the Earth’s atmosphere is distorting the starlight.
It’s just like when you go to the eye doctor and you get a prescription, the lenses match the distortion in your eyes—they compensate. So it’s a bit like putting glasses on a telescope. What makes it challenging is that the atmosphere changes so quickly, so the prescription has to change a hundred times, maybe a thousand times a second.
A variation of this technology is used in pretty much every major optical and infrared observatory around the world. You can actually get, with an adaptive optics system, images that are sharper than you get from the Hubble Space Telescope, and for a lot less money.
Is there now a focus on ground-based, rather than space-based, telescopes?
There is still a need to send things into space. There are certain wavelengths of light that don’t penetrate the Earth’s atmosphere—some infrared light, ultraviolet light, and x-ray light. To study the universe in any of these wavelengths, you have to get above the Earth’s atmosphere.
Just last week, funding for the second version of the Hubble Space Telescope was yanked by Congress. It’s called the James Webb Space Telescope, and its future is very uncertain at the moment. It would have a mirror that is much larger than the current version of Hubble, and it would be more sensitive in infrared wavelengths than Hubble is now. So it would, for example, allow us to peer at these high mass stars that are forming throughout the Milky Way. It would allow us to look at very young, almost primordial galaxies at the edge of our universe, and do all kinds of amazing things. But it’s a little scary right now in that it might not happen.
Honestly, Hubble has probably [allowed] more discoveries about our galaxy and other distant galaxies than any other single telescope has done. It has been an amazing asset to astronomers, and it will be a very sad day when Hubble stops working.
Why is maintaining funding for this kind of research so important?
It’s hard to come up with a bullet-point list of the benefits that basic science will provide in future, because we don’t know. All we can say is what it has done in the past: things like electronics, computers, digital cameras, global positioning systems (GPS), and revolutions in medicine. All this has come from asking basic, simple questions about how the universe works. How is it put together? What happens when this metal mixes with that metal and then you heat it up? Sometimes nothing. That’s the way science works. If nothing happens, then you try something else.
There are people who have spent their careers [on research] and have just never had that magic moment. That’s also the way science works. But fortunately, many others have made amazing discoveries that have revolutionized our lives. And there’s no reason to think there is an end to that. We can only assume that the universe still has many mysteries left for us to unravel.
To me, that’s the importance of basic science. You don’t discover these things unless you try. One thing we can guarantee is that if you cut money for fundamental research, we won’t discover anything else. If we stop looking, then we’re done. And that’s a very sad day.
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