Episode Transcript
[00:00:00] Speaker A: Welcome to this installment of the Know the news podcast. I am your host, Chris Swindle, metro editor for the Northwest Arkansas Democrat Gazette. In this week's podcast, we speak with the University of Arkansas physics professor and a Democrat Gazette reporter who will shine a light on the expected impact of the April 8 solar eclipse in northwest Arkansas and the river valley. This is in advance of a story on the topic that we'll publish in an upcoming edition of the Northwest Arkansas Democrat Gazette.
Today on Know the news, I am joined by staff writer Stacey Ryburn, who is writing the story that will publish this weekend regarding the April 8 eclipse. We also have with us Dr. Daniel Kinnefick, a physics professor at the University of Arkansas in Fayetteville and a researcher at the Arkansas center for Space and Planetary Sciences. Thank you both for joining us today. I'd like to start with a basic science lesson. Daniel on April eigth, we'll have a solar eclipse. Can you give our listeners just a basic scientific explanation of what that is, how it occurs, and how it's different from a lunar eclipse?
[00:01:19] Speaker B: Sure. Well, about something on the order of two and a half thousand years ago, ancient greek astronomers realized for the first time that we know of that when an eclipse occurs, what's happening is that either the moon is coming between the earth and the sun and thus casting its shadow down on the surface of the earth, which is what will happen on April eigth, or alternatively, that the earth is coming between the moon and the sun and thus cutting off sunlight, which is what illuminates the moon. And so then, in that case, we have a lunar eclipse. So in a solar eclipse, two things have to happen. The first is that the moon must be around on that side of the sun, close to the sun, and that's called the new moon because, of course, at that time, the bright side of the moon lit by the sun is faced away from us. So we actually don't normally see the moon at that time.
Every new moon doesn't lead to a lunar eclipse. A solar eclipse, I'm sorry, of course, because sometimes the moon is above the sun or below the sun in the sky. The lunar orbit is actually tilted with respect to the plane of the Earth's orbit around the sun. That plane is known as the ecliptic because it's where eclipses happen. Twice a month during its orbit, the moon passes through the ecliptic at what's called a node. And when it's at a node at the new moon, a solar eclipse will take place. And when it's at a node at the full moon, we'll get a lunar eclipse. So those are the basic elements of the science. And it was worked out about 2000 plus years ago. And ever since then, scientists have been busy studying the moon's orbit to get more and more accurate in their prediction of an eclipses. So that on April the eigth, we know precisely when the eclipse is going to occur.
[00:03:00] Speaker A: And our guy who runs the podcast studio had asked the question of how od is it that the Earth and the sun, the distance between them is such that the moon lines up in the way that it does, that it kind of perfectly fits over the eclipse? I read a little bit about that online, and what I was reading was that the sun is about 400 times larger than the moon, but the moon is 400 times closer to Earth, and that's why they kind of can cover each other up like that. Is that kind of how that happens, how that works?
[00:03:40] Speaker B: That's exactly right. Yes. And it is a pretty remarkable coincidence. Obviously, the moon has no particular right to be the same size, at the same apparent size of our sky as the sun. It's just literally a coincidence of where it happens to be at this time in its evolution. It is actually getting further away from us as a result of subtle gravitational interactions with the Earth, something called tidal friction. And so eventually, but luckily, it's quite a long way into the future, it actually will get too small for total solar eclipses to happen. So it's an unusual phenomenon. There are moons in the solar system other than our own that are big enough to eclipse the sun as seen from their planets. But typically, they're much bigger in that sky than the sun. What's remarkable about our eclipse is that the sun is just obscured the body of the sun so that the solar atmosphere, the corona, which normally we can't see because it's much dimmer than the sun, is displayed as this beautiful halo around the moon. So the striking qualities of our eclipse are unique to us. It's possible, I'm told, that there are small moons, maybe, for instance, one of Neptune, that happen to be about the same apparent size as the sun. But of course, out by Neptune, the sun is pretty tiny in the sky, so it's hard to imagine that it's really quite the same kind of spectacular event.
[00:04:57] Speaker A: Sure.
Stacey told me that when he was interviewing you, you mentioned that you had seen at least one eclipse in person before.
That was a total eclipse. And I've heard so many people talk about seeing a total solar eclipse, and they describe it as being a very powerful moment, to the point that some people start planning vacations so they can travel somewhere, they'll be able to see another one as soon as possible. And I'm curious what your experience was like seeing a total solar eclipse. If it was just a moment of purely scientific curiosity or if there was something more to that moment that affected you on a different, maybe deeper level.
[00:05:35] Speaker B: Certainly I was very interested scientifically. I have been interested in eclipses because of their role in the history of science, because I'm a physicist and a historian of science for many years now. So, of course it was very exciting on that level to see the eclipse, but it was also a very remarkable experience, I think, something definitely worth having. It's probably fair to say that I haven't started traveling the world to see eclipses, but I don't know that I really have the money to see all of them. There are quite a few of them. It's just that because they're so localized, it's rare for them to be near enough to go see easily. So the previous eclipse that I saw was the 2017 one, which I saw in Missouri. I had tried once previously and been clouded out, though actually, even through cloud, it's still a very interesting experience.
I'm very much looking forward to this one, and I'm certainly hoping to get clear views. I did find it a really remarkable experience, and I do remember, in fact, the last time that we went as a family, and my daughter, who was then a teenager, you know, why are we bothering to travel? Can't we just see it on YouTube? And even she admitted that it actually was worth going to. It's quite a remarkable experience to experience in the flesh.
[00:06:46] Speaker A: Some of our listeners won't actually be in the path of totality. If you're not in the path of totality and you can't make it to a spot where you will be, what can you expect to see?
[00:06:59] Speaker B: Well, I think it will be still a very interesting experience. There is a pretty dramatic difference between partial eclipses and total eclipses. When it comes to the sun. A partial eclipse of the sun, if it exposes any reasonable remnant of the sun, is still going to have. You're still going to have daylight. The sun is so bright that even a relatively small proportion of it is still plenty to illuminate our sky. However, even here in Fayetteville, where I am, which is, in Arkansas terms, about as far as you can get from the region of totality will be still very close to 99% total. And although I've never experienced 99% totality. My understanding is that there will, in that case, be an actual noticeable dimming of the sky and sun, whereas with many partial solar eclipses, many people wander around without realizing it's happening. So I think it will still be pretty dramatic, although I am planning to go to the zone of totality myself. One thing to note, of course, is that when a bit of the sun is still visible, that does make it dangerous to look at the sun. It would be good to use clips, glasses, or to do some kind of projection. And one thing that people might look out for is to look under a tree where you see dappling of light. Those little circles of light are caused by diffraction of the sunlight through little gaps between the leaves, and they're circular because the sun is circular. And if you look at them during the eclipse, there'll be little projections of the crescent sun during the eclipse. And I always think that that's worth looking at. Even during a partial eclipse, I think it's still a very interesting phenomenon.
[00:08:37] Speaker A: I did that in 2017, and in addition to that, I remember doing the camera obscura trick where you're supposed to stick a hole in a sheet of paper and it gives you that glow. And I thought that was very interesting because I didn't have eclipse glasses. So for anyone out there who doesn't have eclipse glasses or any way to protect their eyes, there are other ways to observe it. Are there any other types of scientific activities that you think people should consider doing while the eclipse is going on?
[00:09:11] Speaker B: Well, here, I'll give my wife's advice. She's, as we like to say, the real astronomer in the family. My main interest is in black holes and things like that that you can actually see, so you don't need a telescope. But she always likes to say, I don't want to do an experiment during the eclipse. I want to actually see it and experience it. So, of course, yes, there are many remarkable scientific activities that are done during eclipses, and for many people, they want to photograph it, if that's what they're into.
But there is a lot to be said. It only lasts for a couple of minutes. There is a lot to be said for just being in the moment. And I think that's what my wife and I hope to do. Certainly, I can tell you, having studied the history of many eclipse expeditions where people were going to do important, very important scientific experiments, those scientists confess that they hardly even saw the eclipse because they were so busy doing the experiment. So there is something to be said for taking a moment to look around and see what's going on as the eclipse happens, the people around you, how they're reacting. Sometimes people like to talk about what the animals and the birds are doing and just to see, maybe even to look around the sky a little bit. If you're in the region of totality, you will actually be able to see stars during the daytime, which is one of the reasons that the eclipse is interesting, actually, for science.
[00:10:27] Speaker A: We're going to take a quick break and then come right back. Stay with us.
[00:10:32] Speaker C: If you're enjoying this podcast, consider a newspaper subscription to the northwest Arkansas Democrat Gazette or the River Valley Democrat Gazette. We have a special offer for our podcast listeners, so visit nwanline.com nwapodcast to get started. You can also click the subscribe button on our websites, nwanline.com and rivervalleddemocratgazette.com. Or call us at 479-684-5509 and be sure to say that you're a podcast listener. Now back to the show.
[00:11:03] Speaker A: Daniel, you wrote a book called no shadow of a doubt, the 1919 eclipse that confirmed Einstein's theory of relativity. I'm adding that to my reading list because from the title, it sounds like something I'd really enjoy.
And obviously you can't give us the whole book right now, but I was wondering if you could give us maybe a quick synopsis of how they were able to use the eclipse to provide evidence of relativity, because that's just so interesting.
[00:11:29] Speaker B: Yes, I'd be happy to. And thank you for taking an interest in the book. Yes. So Einstein, as a lot of people know, developed theory of relativity early in the 20th century, and he began with his theory of special relativity. And people are familiar with a famous equation from that theory equals Mc squared, which says that if something has energy, e, it also has mass, m. And that was, in certain respects, a new idea. Many people at that time, many physicists at that time thought of light as being different from ordinary matter. It was radiation, it was ethereal, and therefore it wasn't affected. So they thought by gravity. Einstein said, no, it clearly has energy. By my equation, it has mass, and if it has mass, I think it must have weight and it must be affected by gravity. And therefore light should fall close to a gravitational mass. And the thing is, of course, that light travels so quickly, we don't have a time to see it fall as it flashes by. But the sun is the biggest thing in the solar system. It does have strong gravity, much stronger than the earth, right. And Einstein realized that it might be possible to notice that stars close to the sun would be shifted just a teeny bit from their usual position, because that is to say, their usual position when the sun wasn't near to them. Because of this effect of gravity on light. Of course, you can't see stars close to the sun except during a total solar eclipse. And so starting from about 1913, Einstein started trying to interest astronomers in going to an eclipse to check if there were very, very tiny shifts in the positions of stars. Very difficult experiment to do. Scientists began trying to do it. They encountered all sorts of difficulties. World War I got in the way. Finally, in 1919, just after the war, two teams of astronomers from english observatories traveled to Africa and South America to test Einstein's theory. And they ended up confirming Einstein's prediction. And it made Einstein world famous almost literally overnight. It's the reason why we know who he is today. E equal Mc squared was of interest to physicists, but not to most people. It was really the eclipse test of his theory of gravity and the vindication, of course, admittedly, of the equal Mc squared, because everybody realized, oh, he was right, light has weight. It really called the public imagination, and it was a remarkable story. It was a very difficult experiment under very difficult conditions, and I certainly enjoyed doing the research that led to me writing books.
[00:13:57] Speaker A: That's really fascinating. And I'm curious if you have any other, maybe more recent examples of scientists using eclipses to advance scientific knowledge.
[00:14:09] Speaker B: There are a number of examples. Starting from the early 19th century, scientists found that they were able to predict the location and the timing of eclipses sufficiently accurately, and travel had improved to the point where it was easier, that it was worth their while to travel to eclipses. And they began to discover all sorts of interesting things about the sun that they didn't know. They studied the corona, the solar atmosphere. They were able to start doing spectroscopy in the late 19th century to find out what the sun is made of, which, of course, previously nobody had the slightest idea, in fact, that the element helium was first noticed. Or at least the spectral lines of helium were first detected during a solar eclipse in the late 19th century. So there were a number of remarkable discoveries. And at some level, 1919 was just about the peak of the scientific excitement surrounding eclipses. Scientists, of course, are ingenious people. As time went on, the discoveries they were making at the eclipses allowed them to figure out ways to continue to do their scientific study of the sun and other phenomena without the eclipse. So although there is still quite a lot of science done at eclipses, and I personally know people who'll be doing experiments here in the forthcoming eclipse in April. Nevertheless, it's probably fair to say that as time has gone by, the experimental significance of the eclipses has declined somewhat from the peak of about a century.
[00:15:38] Speaker A: Well, Stacey, we've talked about the science of an eclipse and ideas for viewing one.
Can you let our listeners know a little more about what types of topics your story this weekend are going to cover, maybe in terms of preparations being made in the area or the expected impact to the.
[00:15:59] Speaker D: Sure. You know, I think this is really interesting because I was looking through our archives to see what we'd written about the clips up to this point. I saw a story from our colleague Monica brick from two years ago talking about Fort Smith preparing for the eclipse. At the time, they were saying that they were expecting like 50,000 people and essentially like a football game all over the state, no matter where you are kind of thing.
I'll be talking about just the anticipated insurgence of people that we're expecting to have here in northwest Arkansas. The interesting thing about Fayetteville is that we're not in the path of totality, but we're pretty dang close, and it's still going to be pretty cool to see.
But from what the tourism director here in Fayetteville is telling me is that the hotels are completely booked for that weekend, but on the day of, not so much. The idea is that it seems like a lot of people are going to get a room for the weekend, hang out in Fayetteville, see the sights and the sounds, and then go travel to wherever they're going to go during the eclipse and then come back.
So even though we're not in the past, so to speak, we're still getting some of that residual benefit of this thing being so close to us. And it's Fayetteville, so there's always stuff going on. There's a big track event going on that weekend. There's a mountain biking.
You know, if you're in Fayetteville, it's going to be a lot going on here. But in terms of seeing the know, if you get a good spot where there's not a tree obscuring your view, you should be. Should be. All right.
According to my little NASA map that I've got pulled up here, it looks like in Fayetteville the peak time will be at 01:51 p.m. On April eigth. And I hate to burst everybody's bubble, but there's a little storm icon next to the Fayetteville name here, so we'll have to see how the weather shakes out, but it should be something that you'll definitely remember. And I was here for the 2017 one and that was pretty cool and this is going to be better than that, so should be pretty exciting. Hopefully we don't all stare directly into it because that would be unwise. Eye doctors will be making a killing around here.
[00:18:27] Speaker A: If not, I think based on what you've said, that a good piece of advice for everyone would be to anywhere you've got to go in the region that day, leave early, because I have a feeling traffic may be slightly affected.
[00:18:41] Speaker D: Especially on your highways and whatnot. If people are coming from here and going to Jasper, Marshall or wherever they might be going in the past there, that you might want to just keep your road trip plans held off for a day. If that's not what you're going to be, it's going to be interesting for sure.
[00:18:59] Speaker A: Well, I'd like to thank you both for joining me and sharing your expertise on this topic. I appreciate it a lot.
In other news coming soon, Thomas Ascente will write about Bentonville's Quilt of Parks project, which should be entering its next phase soon. Tracy Neal is writing about prosecutors and law enforcement who say they are starting to see instances of child sexual abuse material created using artificial intelligence. Doug Thompson will report from a meeting of the Democratic State Committee in Fayetteville, the first time the committee has met anywhere in northwest Arkansas in eight years. Campbell Roper tells us about downtown Rogers'efforts to promote itself as a dog friendly city. Al Gaspany gives readers the details on a new bachelor's degree program focused on artificial intelligence. Becca Martin Brown previews the community school of the Arts production of Something Rotten, and she speaks with the artistic director of a dance company that is bringing a performance to the Walton Arts center and who was once also the zombie choreographer on the AMC hit series the Walking Dead. Monica Hooper previews the next season of shows at the Walton Arts center and interviews Chris Stone, Kingfish Ingram, who will be performing March 14 at Temple Live in Fort Smith. Samantha Laciro tells us about work on a $27 million residence hall at the University of the Ozarks in Clarksville. Monica Brick writes about the city of Fort Smith's plans to continue leasing office space for various departments. All of this and more will be available to our subscribers on our tablet and smartphone apps and at our websites nwanline.com and rivervallidemocratgazette.com I really appreciate you listening to this point and want to thank you for your support of local journalism. Know the news is a weekly podcast brought to you by the newsrooms of the Northwest Arkansas Democrat Gazette and the River Valley Democrat Gazette. Again, I'm Chris Swindle, your host for this week. Have a great weekend, and until next Friday, so long.
