Solar Eclipse To Take Shape In San Diego Thursday
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October 23, 2014 1:08 p.m.
Solar Eclipse To Take Shape In San Diego Thursday
Steven Snyder, Ph.D., is the executive director of the Reuben H. Fleet Science Center in Balboa Park
Related Story: Solar Eclipse Captivates San Diegans
MAUREEN CAVANAUGH: This is KPBS Midday Edition, I am Maureen Cavanaugh. There will be a change in the sunlight this afternoon, and it will not be from clouds. It partial solar eclipse begins just past 2 PM, peaks around 2:30 PM, and will end at the 4 o'clock hour. Astronomers are issuing the usual warnings about not looking directly at today's eclipse, because even now, in the high-tech space satellite world, the phenomenon of an eclipse draws people's attention and wonder. It turns out that wonder and interest in astronomical events have actually taught us a lot about our universe. I would like to introduce my guest, Doctor Stephen Snyder. Welcome back to the show. Remind us what a solar eclipse, or in this case, a partial solar eclipse, is.
STEVEN SNYDER: A solar eclipse is when the moon place itself directly between the sun and the earth in a direct line. Because of the distance that the moon is and the size of the moon, if everything lines up right, it will actually eclipse or block out the entire disk of the sun and block it. We will not see a total of clips today. We will see a partial eclipse that will cover up about 40% of the sun. You will see the moon in front of the sun if you're looking at it appropriately.
MAUREEN CAVANAUGH: How often do these happen?
STEVEN SNYDER: They would seem to be more rare, but about every eighteen months or so and eclipse happens on earth. The problem is, the earth is a big place and it usually happens where there are not a lot of people, in the middle of the ocean, the last total eclipse was off the coast of Antarctica. It is really around every 380 years for any regular spot on the earth that would actually see an eclipse.
MAUREEN CAVANAUGH: So everyone can see the sun, and the moon, why can't everybody see a solar eclipse?
STEVEN SNYDER: It is tough to picture, but the sun is much bigger than the moon. That means that the moon's shadow comes to a point and hits on the earth. A total solar eclipse is when the shadow is complete and block set off. That only goes a certain width or a certain size. That will go across the earth when the moon is actually in front of the sun. Is a path where you see the total solar eclipse. We will not see that stay, because the moon and sun are not in the right position for a total eclipse. That is a big range, but a lot of North America will be able to see this.
MAUREEN CAVANAUGH: I was thinking this is a good one for North America.
STEVEN SNYDER: It is. The great one for North America is coming up August 21, 2017. Mark your calendars. That is one that you will be looking for.
MAUREEN CAVANAUGH: What will be noticing? We will be talking about properly watching the eclipse and not just looking up with the naked eye, but when we have the rights things that we need to watch this eclipse, what will we notice? If we do not have the glasses on, what will we notice happens to the sunlight, even if we are not looking?
STEVEN SNYDER: About 40% of the sun will be covered, so you will notice some dimming. It will happen gradually. It will not suddenly turn on the dimmer switch, but it should go down a little. You will see a little decrease there, but more important, there are number of different ways you should look at it. You will see the moon move right in front of the sun. You will see the circle of the moon moving in front and block out part of the sun. That motion of the moon that you see across the surface of the sun is the motion of the earth and the spinning of the earth, and the moon revolving around the earth at the same time. You're looking at direct evidence of cosmic ballet, if you will.
MAUREEN CAVANAUGH: Why is there so much concerned about looking at the eclipse?
STEVEN SNYDER: It's one of the things where you say do not stare into the sun, it's a bad idea. During the eclipse, we all want to see it cost we all tend to stare into the sun. It's not the eclipse that does damage, per se. It's just the fact that we want to stare at the sun, which is not a good idea. You think about this when your eye detects light, it takes photons that come in, and chemical reactions happen that trigger
electrical impulses that let you see the light. But staring at the sun causes so many chemical reactions that your body cannot recover in time. It can cause serious damage. You do not want to stare at the sun at any time, particularly during an eclipse.
MAUREEN CAVANAUGH: We have a caller on the line. Bill is calling us from Fiesta Islands. You wanted to talk about an experience with the solar eclipse?
NEW SPEAKER: My favorite way to enjoy it, instead of getting a pinhole thing and all of that rigmarole, I get underneath eight deep shade tree. Even a good fluffy eucalyptus tree. I just look at the rounds, crescents everywhere, instead of a giant blob of light, it's little crescent suns of light.
MAUREEN CAVANAUGH: I appreciate it, thank you for calling in. How would that work again, Stephen?
STEVEN SNYDER: He's describing effects similar to a pinhole camera. One of the ways to view the eclipse is to take a card, put a pinhole in it, stand with your back to the sun and let the sun shine through. The pinhole is like a lens that allows you to see the sun safely. If you're looking through the sunlight through the leaves of the tree, You have the effect of tiny little pinholes, and you can see crescent shadows all over the ground. A can be beautiful if you get the right tree in the right time and everything works out. It can be really beautiful.
MAUREEN CAVANAUGH: I think it is good to remember when we see these events, we are not the first generation to do that. We have had ancient cultures fascinated by these events. I'm interested in what humans have learned about the universe because of watching eclipses.
STEVEN SNYDER: Clips is are one of so many things that hold our attention in the sky, eclipses are extraordinarily dramatic. Mansion watching the sun go out, that has to be extremely scary. It comes right back, but that fascinates people. For years and years and centuries, people have been actively looking at its. It goes back to one of the first recordings of the eclipse, before the common era. People have always been fascinated watching. It's one of the things we can understand about how all those bodies in space move together. More recently, one of the things we have learned is that it is one of the best ways for scientists to study the corona, the upper atmosphere of the sun. Normally that is too bright for us to see, but during the solar eclipse, the body of the sun is left out and you are able to look at the atmosphere of the sun, which is a beautiful thing. Again, this is one of the best ways to possibly study it.
MAUREEN CAVANAUGH: I'm wondering if when astronomers, back in the 1600s, again studying the universe, did eclipses give them any hint as to how the planets and the solar system actually worked?
STEVEN SNYDER: It's really only about the earth, moon and sun. In that sense, as long as you have the moon going around the earth and the sun in relationship to it, you can explain the eclipse without having to have a Copernican view of the universe. You can have the earth as the center of the moon, you have a lot of ways to view its. In early days it may not have helped as much as looking at Jupiter, seeing the moons move around it. There are certainly a lot of things they learned about the timing of the sun itself, there is more to it than just this disc. There has been a huge amount of study of the sun, the moon, and in fact now using eclipses is a way to correct timing and correct our clocks. When we pricked the eclipse, is that when it really happens? The planets obey their own clocks. They make their own time. Our clocks are mechanical. This is a way for us to reset our alarms, if you will.
MAUREEN CAVANAUGH: Besides being a fascinating show, are there any effects that the eclipses have on the earth?
STEVEN SNYDER: Other than getting people excited, that is probably the biggest thing. To some extent, when you are blocking part of the sun, you get temperature changes potentially. Not as much heat reaches the earth, but the big effects, the big important effects of that right now are the abilities to study the heavens and get people excited about science and astronomy.
MAUREEN CAVANAUGH: Another thing that people may notice watching the eclipse today is a huge sunspot. Ellis about that.
STEVEN SNYDER: I haven't really looked at it, but I wanted to make sure I had all my equipment ready, and there you could see with the right equipment if you have solar viewing glasses, you can look directly at the sun and see the sunspot, it is that big. Is a huge area of magnetic activity on the surface of the sun. What it does is in that area where the magnetic activity is so strong, the surface of the sun is actually cooler by about 1000? of the surrounding area around it. So it looks dark. If you took that dark spot and took away from the sun, it would be brighter than the moon. But relative to the brightness of the sun, you see this spot and it is huge. It would easily swallow the earth, and it is much bigger and the entire Earth. It is very magnetically active, it is spewing out flares and discharges into space. This is a two for, a gorgeous sunspot and a gorgeous eclipse here.
MAUREEN CAVANAUGH: There is a lot of attention paid to celestial events in the last few months with super moons, blood moons, has the Science Center been fielding a lot of calls about these events?
STEVEN SNYDER: While a lot of people do not like the blood Moon title, I just think it is good PR. I think the moon has got a great PR agent. I'm not sure who they are working with, but these titles seem to attract attention. Have a lot of questions and a lot of interest in it. That is fantastic. One of the great things about being in San Diego, one of the great things about our climate, is pretty much at any nights you can tip your head back and look up and see the sky. That is not something that you get everywhere. In fact, as a kid, the first time in eclipse was going to happen where I was, it was raining. Chances are it was going to be raining cost you cannot see it. Here, we can see it all the time. Anytime we can tip our heads back and enjoy the wonder of the universe, that is a good thing.
MAUREEN CAVANAUGH: Are there any particularly good places to see these events in San Diego County?
STEVEN SNYDER: For events like this, as long as you are in a good viewing position of the sun, you're okay. But others, meteor showers, because we have nice weather and climate, it is a good place for viewing anytime you can move away from the city lights and get darker, head out east, and you can see many more stars. In fact, you do not have to go far before you see the Milky Way. Again, it is a great thing about being where we are.
MAUREEN CAVANAUGH: You are a a physicist by training, how did you become interested in astronomy?
STEVEN SNYDER: How can you not? It is so cool. I was probably a science week from an early age. I will admit that. At some point, my parents got me a telescope as a gift for Christmas or something. I must have been nine or ten. I took it outside and put it on top of my dad's car, crawled up on the car and I was looking around trying to see the moon. I had a telescope, might as well use it. I came across a is the oblong dot. I was thinking I discovered a comet. I told my dad how do you call NASA? His response was to go outside and draw its. So I wrapped a pad of paper and a book that I had, and when I got back outside, the telescope moved and I tried to find it again, I found it and thought I'd better make sure I focused. Suddenly the dot is getting smaller and smaller and clearer. And all of a sudden, it is not a comet. It is a little round disc with a tiny red band running through it. It's not a comet. It's Jupiter! I discovered Jupiter! It was incredible. There's Jupiter, I was looking at it with my own eyes. I could see the four moons lined up like little diamonds. These are the things that Galileo saw that changed our perception of the universe. It was an incredible experience.
MAUREEN CAVANAUGH: And an unforgettable one?
STEVEN SNYDER: Absolutely.
MAUREEN CAVANAUGH: Tell us about the astronomical event you are looking forward to.
STEVEN SNYDER: August 21, 2017, a total solar eclipse will be viewable in North America and the United States. This will run from the northwestern states through the center of the country, all the way to the middle United States. It will go right across North America, a very rare thing. We can all get to its. But it will only be partial in San Diego. I will tell you and I want my kids now, We are going to pack up the car and moved that path where we will see the total solar eclipse and they will love it. Whether they like it or not, they will love it.
MAUREEN CAVANAUGH: And this is sort of a preview.
STEVEN SNYDER: Exactly, it's a warm-up act for the big one.
MAUREEN CAVANAUGH: I want to go through the ways to look at the success, because I think it is really important. I think people know not to look directly at it, but it is really so tempting to do so. You talked about the pinhole projector, what are some of the other ways? I heard about picking a loop with your fingers, how do you do that?
STEVEN SNYDER: The whole idea of making a loop with your fingers or tree, or using a colander, anything that creates a tiny hole. You can use that to make a pinhole projector. You want to create a space with the sun to your back, shine it through small holes and have it protect onto the surface. It is even better if that surface is in the shade, so you have better contrast. It is the same idea. Each of those holes act as a tiny lens and give you a tiny picture of the eclipse.
MAUREEN CAVANAUGH: A lot of people like to wear those eclipse glasses, where do you get those?
STEVEN SNYDER: We have them at the fleet, and we will have an event outside in front of us by the fountain in Balboa Park. Come on down. We will have our astronomer, glasses, and pinhole devices. The glasses are great, because you put them on and they are filtered and designed to protect your eyes, and you can really see. It gives a great, great view. The other way to do it, arc welders have filters. They are looking at something that shoots off a lot of UV. Number thirteen or fourteen welder glasses, that's another way to look at it. If you have a solar filter from a telescope, that is another way. Don't point it at the sun without a filter. That will do significant damage to your eyes. But if you know how to do it safely, this is a pretty cool and amazing thing to see.
MAUREEN CAVANAUGH: And you're having an event at Balboa Park at 2:15?
STEVEN SNYDER: That's right. It will start here in San Diego, at about 3:30 it will reach a peak at 4:45, it's a two hour window to look at the eclipse and the sunspot. It's an amazing thing. This is a great opportunity.
MAUREEN CAVANAUGH: Get out your colanders now! Thank you so much.
STEVEN SNYDER: Thank you.