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uh, yeah. Conversation from the University of Florida. A discussion of social, political, scientific and religious issues of the day. Your host is Michael V. Gannon, professor of history and ethics and associate dean of the College of liberal Arts and Sciences at the University of Florida. Yeah, mhm.

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Hello and welcome to another conversation. My guest this time is Jack Horkheimer, who is director of Space Transit Planetarium in Miami. And as many of you know, the host of the PBS program Star Hustler Jack. Welcome to conversations. Good evening. My pleasure. You've been seen by millions of Americans not on only on your own program, but on others.

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Besides, it's a a real treat to have you here to talk about, Oh, the heavens in general and perhaps Halley's Comet in particular. Well, it's always my pleasure to talk about the stars, and because my show is so so short, I frequently welcome a time to be a little bit lengthier about the things that our dearest to my heart, the stars and the planets and anything up there at the night sky.

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Well, if the stars and the heavens are dearest to you, Florida is closest among all of the states in the union to Halley's Comet for viewing. Isn't that absolutely. We're going to have a really exceptional view here in Florida in March and April. As a matter of fact, anything that we've seen prior to this and not a lot of people have seen Halley's Comet with the naked eye.

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But anything prior to this is really just a little tiny bit of a tease. It's not even an appetizer. The real show comes for Floridians in the middle of April, when I guarantee we are going to have people from all over the world coming down to our shores and our beautiful land and enjoying a comet site that will be comparable, believe it or not, to the kind of sites that people will be seeing who spent all that money to go to South America and Australia.

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As a matter of fact, we will see Halley's comet as bright and as big from right here all throughout Florida than anyone will in South America, Australia wherever. It's just that we won't see it high up overhead, we will have it a little bit lower to the horizon and that, and not for as many hours per night.

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But there'll be several nights during April roughly, oh, the seventh through the for the 20th, when we will see Halley's comet for several hours a night. Now, because the comet will be closer to the horizon, one would have to go into an area that's very dark away from street lights and so forth.

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Absolutely, that is that that is a prerequisite with all comments, but especially in the 20th century. In our day of high tech are lighting put so much glow into the sky that it really causes any astronomical objects to be quite diminished. The stars are not seen, uh, even among some rural areas in the United States the way they were seen years ago.

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Remember when I was a kid up in Wisconsin? Uh, came from a small town of 1300 people, a little town called Randolph, and I could go out on any clear night and right from from my back yard, see the Milky Way. A lot of kids grow up all across America today and have never actually seen the Milky Way.

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It's something they've seen in the planetarium or in their school books, but they really have never experienced it for themselves in Florida, because we have such a beautiful weather and we have such clear, transparent skies. We have much more of an opportunity to have that kind of link with the with the cosmos than other people.

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And in Florida, there's so much open space away from lighting artificial lighting where one could get a view of the sky and one very important thing. When I used to watch Orion, the hunter, back when I was a child in Wisconsin, it was frequently 20 degrees below zero.

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Here in Florida, you have to put out a light jacket and go out to see the stars. So we've got it. We really got a kind of, uh, kind of a semi ideal world for amateur stargazing. So you became a stargazer while still a boy. How did you become a professional stargazer?

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Oh, I kind of fell into that. As a matter of fact, Vince got Benelli here with the Florida State Museum. Vince Campanelli was the director of the Miami Museum of Science and Space Transit Planetarium, and I was a regular visitor to the observatory and planetarium, which had just been built and a couple of friends of evinces in himself asked me because they had heard that I was a writer by trade.

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Asked me if I would write some shows or to help them with the planet. Came in this in the scripting and, uh, one thing led after another. I eventually became the director of the planetarium, and, uh, it was kind of serendipitous. My hobby, my avocation turned up becoming my vocation, which is the last thing I ever expected to do in the world.

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Well, that's a wonderful thing to have happened to anybody. To have a hobby become means of earning one's livelihood. I've never had much knowledge or experience where the stars and planets are concerned, but I did have one extraordinary experience. Once, in the mid 19 sixties, I was crossing the Pacific on the S s lure line, which was a very famous cruise ship of the time, and I counted myself very lucky.

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One night when the captain came on the inter communication system, it was about 11 30 at night and said all those passengers who are still awake and who would like to see an extraordinary display of fireworks in the sky. Come on, Deck. I'll turn out all the deck lights.

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We have a phenomenal display of shooting stars. Was it in August? Do you remember? I don't remember, Jack. I forgotten now, but a number of us, uh and I was still still awake. We went up on deck and lay down on the deck with all the lights out and the sky was ablaze with shooting stars.

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Now what? I know it. Just what was I seeing? You were seeing an exceptional meteor shower in 1960. It was called the Leonid shower. And it was one of those rare instances with not just, uh, tens of Meteors are seen per hour or hundreds, but thousands of Meteors are seen prior that that was remember that in the sixties, it's funny You should mention the Lurling because I was on the Lurling back in the back in the fifties.

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And I also saw a meteor shower while I was on board one of the boats going to the island. Uh, boy, those were beautiful ships. Then I'll tell us they were What you were seeing was what we call I call a comet. I called meteor showers.

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Comic junk shows they're kind of the the real. All they are is they were watching cosmic junk slamming into the earth. You see, as a comet pays its visits to the sun, and right now, as we speak, Halley's comet is behind the son. He's invisible from view, and the sun is making it grow a very long tail on a much larger head right now.

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Well, every time a comet pays a visit to the sun, it sheds a lot of its material. As a matter of fact, every time Halley's visits the sun, it loses about a meteor. Excuse me about a meter of its material. Now the interesting thing about comets is this.

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If we can follow one on its tricks around the source, it's right behind it in its orbit. Kind of. It'll be kind of like it would be kind of like driving a convertible down a gravel road following right on the tail of a garbage truck with a lid down.

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Because comets are like garbage trucks, they on a bumpy road litter. They constantly litter their orbital path with tons of little tiny pieces. Debris, everything from little oh, size is the head of a pin to items about the size of a fingernail or or a P.

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Now, when our Earth crosses the orbit of certain comments that have left a lot of debris in their trail, including Halley's, when we cross these trails, we slam right into this debris and this debris slams against the atmosphere of the Earth. And great fiction is created because of the speed of the particles.

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And instead of seeing these particles burn up, what we actually see is this. These particles are so hot that it heats up the gases in the earth's atmosphere around the particle and that the gases glow and what we call them. What I, uh I called him when I was a kid.

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My grandmother called them shooting stars are my Irish grandmother used to say there's another soul on its way to heaven. I I used to question that because it's not good theology. Well, I used to question because one day I said to my grandmother, but I thought that heaven was the other direction.

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Yeah, these are all coming down. You had to raise a practical point, didn't you? But that's what that's so that's what I was saying. Now you mentioned that as Halley's comet continues on its elliptical path around the sun, it loses. It continues to lose a certain amount of this substance.

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Well, if Halley's comet has been going around in Iran for Lo these millions of years, why isn't it down to nothing? Well, we think that Halley's comet, uh, is a relative newcomer to the system, the scientific guesstimates. And that's all we can really give our that.

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Halley's comet may have been around anywhere between 3 to 204,000 years ago. Nobody really, really agrees. Now Halley's comet, the nucleus of it and is roughly 3.5 to 5 miles wide. We believe the majority of comments, we believe are roughly in that area, so it's good for several thousands more trips.

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Unless, of course, uh, it gets deflected in its path by what we call internal gassing mechanisms that would distort it. Or when it would come close to, say, Saturn or Jupiter. The Halley's comet could eventually be be, uh, caught up by the gravity of the giant planets and flung either completely out of the solar system forever, or it could be flung into a different orbit.

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We know that Halley's comet is a captured comment. It was captured by Jupiter a long, long time ago and put into this once every 76 years orbit. As a matter of fact, the reason that Halley's comet isn't precisely on a 76 year track sometimes it's 75 74 years, sometimes 78 years is because of the irregularity of the comet, and it rolls and tumbles that comes near the sun.

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The closer it gets to the sun, the more gas jets are produced off the nucleus, which caused the that this nucleus to deviate in its orbit slightly so we might reach a point. And we assume most likely this would happen that if it doesn't last long enough to wear itself up by repeated trips to the sun, that it could either get slung out of the solar system or slung into an entirely different orbit.

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And the interesting thing is, it's really fascinating is that if we start studying comments, especially in the last century, the last century, for some reason was a very, very good century for comments. We find that many comments break up as they passed too close to the sun.

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As a matter of fact, in 1910, when Comet Halley was closer to the sun, some astronomers figured that it might break up. Then we don't know no. Right now we're we're really at a loss to see what? How is this doing on the other side of the sun?

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Because we can't see it and communicate with it. For all we know, Halley's comet is well and good and growing an enormously long tail. Or it could have split into 12 parts or three parts or four parts like Common West in 1976. That comment went around the sun when it appeared in the morning sky.

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When it reappeared, we saw it in a period of 3 to 4 days. We actually saw the nucleus of that comment breakup into four different pieces with four different tales, and one of the pieces entirely disappeared. So we may have a case of this happening. We never know.

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It's not likely for Halley's comment, but it is. It's very, very possible. Did you say that the body of the comet is no larger than 3 to 5 miles absolutely. How can we possibly see such a small objects so many miles away from us? You know, I'm very glad you asked that question, because this is a really fascinating part about comments is that almost all comments are just lumps of frozen material for 99% of their entire lifetimes.

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So what we call a comet is much different than what a comment really is. Most the time. We should have two names for comments, we should say, like a comet at rest and a comet when it's active, because for the most of its journey, Comet Halley is just that cold lump 3.5 miles wide.

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Only when it gets in around the path between Jupiter and Saturn do we start seeing some outgassing. What happens is when a comment comes close towards the sun. The sun's heat, the pressure of sunlight, which is considerable, and the solar wind exert activity on this nucleus and caused these gases to go directly from a solid state to a gaseous state called sublimation little different than evaporation.

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And these gases very fine particles. So fine, as a matter of fact, that you get one little gas particle for about every cubic mile. These gas particles spread out around the nucleus of the comet informed that comet's coma, its head and the solar wind pushes the major tail back behind it so that the comet's tail is always pointed away from the sun.

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For instance, now when we see Comet Halley coming back around the last of February, better yet, the first week of March, when Comet Halley comes back around its tail will be going ahead of its nucleus will be going back out that way. Kind of like kind of like the headlight on automobile.

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The headlight always goes ahead of the car, And that's the same thing. The tale of how his common always faces away from the sun. Well, when common, Halle develops its best tail, depending on how close it it comes to the sun, that tail well, that tail can grow to a length of 100 million miles.

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Now that's longer than the distance from the earth to the sun and that little 3.5 mile wide nucleus. It can have a gas envelope around it. It can expand to over 300 to 500,000 miles wide incredible. It's just unbelievable. A comet is. I know that many people may be lessons.

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Will have heard this, but it bears repeating. A comet is the biggest nothing that can be something in the universe. You could take all of how his comic tale and stuff all of its material inside a briefcase so far as it's solid mass is concerned with the solid match.

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The you know, the tail. Yes, the solid mass. These particles the particles people have asked. Well, how small are those little particles in the tail? And I think the most beautiful description I ever read was sometimes years ago. Astronomer said that when you look uh into a beam of sunlight streaming through a window pane in your house, sometimes you can see little motes of dust dancing in the in the Sunbeam, those motes of dust are much, much larger than the particles and Halley's Comet tail, and there's about one every cubic mile.

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That's incredible. But Jack, what causes these little particles to admit so much light? Are they reflecting? Well, they are excited. There is some light generated within the comet tail itself. It's It's kind of like a neon neon light. The gases molecules are excited material, but most of the comments light 90% of it is all reflected sunlight, just like our earth light is reflected sunlight just like our moon.

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You know, that's what interesting point comics are like. The planets planets never emit their own light. They only reflect light from the sun, like the moons of the our moon and the moons of the other planets. And comments also, uh, shine principally by reflecting sunlight only stars as far as we know and the universe only stars are capable of really generating their own major light source.

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One description of Halley's comet I've heard from astronomers is Dirty Snowball. Oh yes, that's Fred Whipple's, uh, contribution major contribution to the to the field of astronomy Fred Whipple, who's probably one of the century's greatest astronomers. He came up with the theory that the only way that comments could act the way they do, the way they change their orbit, the way they the way they shine with so little known material, was that they had to be chunks of frozen gases, uh, irregular chunks that had out gassings as they come closer to the sun, and we think pretty much that when the five spacecraft that are right on the way for a rendezvous in about three weeks time in the middle of March.

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We think that when these five spacecraft send back pictures and also other other data that we will find pretty much that Fred Whipple was right. We we don't have the opportunity, which we almost have. We don't have the opportunity of an exciting spacecraft mission we had planned one years ago.

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The United States uh, NASA. I'm talking about Jet Propulsion Labs. We had planned to send a spaceship out to meet Hallie's on the way in and ride sidesaddle all the way in around behind the sun and then and watch it as it grows. And then have the spacecraft actually try to land on the nucleus and take a core sample, which we have the technology to do incident.

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That technology is not too exotic for our for the state of technology at this time. Well, money constrictions force us not to do that. The Europeans and the Japanese jumped into that right and and they are not able to do quite the things that we have the capabilities of although their their experiments are performing would be very, quite quite profound.

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Even so, 200 of our top scientists are working with all these missions. As a matter of fact, I read recently that one astronomer was particularly perturbed because we have had to give the Russians their information in order to use gravity. Assists from Venus they do not have.

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Supposedly, they do not have enough knowledge to use gravity. Assist the way we did with our recent encounter last month with Uranus, right? We know how to do that very well. And, uh, a couple of astronomers have been quite upset that we have so just be given away a one of the tricks that, well, we discovered and learned it.

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But there is one American designed experiment I understand that's flying on the Soviet probe, right? And a lot of a lot of American input into the into the other other probes to which is it's kind of a universal space effort. Uh, it's going to be quite exciting to see how close Fred Whipple is on the mark.

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I personally think he's going to be right on the money. Jack has a comet ever collided with the planet Earth? Yes. Yes, indeed. As a matter of fact, there was a lot of talk and still is a lot of talk about, uh, an asteroid or a comet Haven't even hit down here in Central Florida.

00:20:08.760 - 00:20:36.560

Many, many a long, long time ago. And back in 19 8 in Siberia, a great event occurred. They call the Tunguska incident. Tunguska, Siberia. From the there was a great explosion, Uh, occurred in the morning. I forget the date Exactly. In 19 oh eight. And people 40 to 60 miles away from the center of the explosion were blown off their porches.

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Trees were burned from mile after mile after mile trees fanned out in kind of a radio pattern, as if, like something had created a great force and spread out in all directions equidistant from this great forest. No meteorites were ever found, and I've ever back in the seventies there are a lot of bizarre theories about the Tunguska incident.

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The one which was really, really right off the wall was kind of wonderful. Was aliens tested atom bombs, atomic bombs at the turn of the century in Siberia. That was one another one was that we got hit by a mini black hole, which is really fantastic, the one that I really like.

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What I like is the head of a comet. Because since the head of a comet is icy material, this thing could have completely shattered and Mel to destroy itself before it ever hit the ground. We could find no evidence of any extraterrestrial material. So it seems like we were hit by a comet then.

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And of course, a very current very big current popular theory is that 65 million years ago, when the dinosaurs were, you know, ruling the planet, that we got hit either by a swarm of comments or or a large comet or an asteroid, and that this punch such a hole in the atmosphere punch such and made such a great explosion that enough dust was thrown around the Earth, the earth's upper atmosphere to blanket the earth and dust.

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For a long time, the sunlight was occult ID from the Earth and the necessary plant life in the food chains, uh, did not flourish, and thus the dinosaurs died. And we feel that some people feel that this has happened on many occasions because there are several kinds of animal species extinctions throughout geologic time.

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The only one we seem to hear about all the time is the dinosaurs, and there is nothing to say that this will not happen again. As a matter of fact, I saw a picture that's still kind of stands up my mind. It was just in a in a casual public astronomer, a popular public, a popular astronomy journal called Sky and Telescope.

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Some years ago, some automatic cameras out and I believe in Utah had picked up a fireball, and it was bright enough to be seen in bright daylight and attract this fireball. I've actually seen the movie film of this, and they estimated this fireball to have been several meters in diameter.

00:23:05.810 - 00:23:43.970

If that had collided with the Earth, that would have produced a blast equal to at least a couple atomic bombs. There's no reason to believe we won't be hit in the future if we look at all the results from our spacecraft and Voyager last January, which is three weeks ago, Voyager I took pictures of the moons of the arenas, and those moons are pockmarked with the Meteors, and we take a look at our moon, the surface of Mars, mercury we see and and and through radar images of Venus, we see volcanic craters everywhere, volcanic craters and also other cratering impact cratering from meteoroids or comments.

00:23:44.740 - 00:24:08.600

We know that Earth was struck probably just as often as these other bodies in the solar system. The only reason we don't show as many we call Astro blames blemishes, uh is the Astro wounds, the star wounds, which are really meteor blooms and comet wounds. The reason we don't see much of this is because of our incredible weather system around our planet Earth.

00:24:08.610 - 00:24:31.940

Our earth is constantly changing its face in time. And of course, when we're talking about astronomy, we measure time and immensely long concepts. It's almost impossible for people to kind of think about how long is foreign in a half billion years. Emotionally, it's difficult to conceive even light years.

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It's hard to comprehend very, very hard, and as a matter of fact, the spacecraft wedge or two will be rendezvous ng with Neptune in 89 1989 and I remember when I was out of JPL, two propulsion labs in Pasadena for the Voyager fly by a Jupiter and Saturn.

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And I remember back then I saw a computer generated footage of the plan encounter with Uranus and I thought to myself, Gee, that's a long way away 1986 I wonder if I'll be around to see it, and that's when Halley's comet is coming to, and now I just marvel at the fact that we are actually doing it.

00:25:16.050 - 00:25:47.710

We are bringing answers in for the first time we are participating, you and I, and everybody out there who pays taxes was American taxpayer. We are participating in probably the greatest age discovery this planet will ever see. There has to be, they say, a once a first time for a planet to become cosmically awake and aware that their environment is simply a part of a much larger environment, and we actually go to explore other environments.

00:25:48.140 - 00:26:04.960

And this is really what you and I are living in right now. What we people in the last half of the 20th century are living in a time that will become legend. More legendary than the Colombian. Yes, that's right. The Voyager two will go down with the Santa Maria.

00:26:05.540 - 00:26:32.920

Probably exactly and long forgotten. Probably when that's forgotten this we remembered. What we are living today is the stuff of which legends are made thousands of years from now. They will remember a golden age mm on Earth. Because we are. We have witnessed and are witnessing a planet that has going from pre tech to high tech in lifetime, the lifetime of the average individual.

00:26:32.930 - 00:26:51.330

Yes, it's just phenomenal when you think of George Burns. He's not his birthday. A few weeks ago, I thought, Now that he's 90 years old, he really saw it go from low tech tie deck. He certainly did. He saw more progress than 90 years than the world had experienced in 1500 years before him.

00:26:51.330 - 00:27:10.450

I said, I reflect on the fact that I was born here. I am giving it all away. The year Lindbergh flew the Atlantic that was 1944. Washington. Of course it was. Thank you, Jack. Yes, you're quite right. And here we are, on the verge of celebrating the 5/100 anniversary of the Colombian voyage of Discovery in 14 92.

00:27:10.460 - 00:27:34.260

Fantastic. Just a comparative. Few years away from that But we are in the middle of an even more exciting age of discovery, aren't we? It is so unusual. It's such an outrageous age discovery that we are living in such incredible time. The media barrage knowledge explosion So much is being discovered in all the sciences every single day.

00:27:34.270 - 00:27:54.320

They're not even specialists in their field can any longer specialized in a broad area, you have to be a specialist within a specialized field in order to keep track of all the all the data that is being added to our knowledge banks. We are. We are exploding with knowledge acquisition at this time in this planet's life.

00:27:54.320 - 00:28:11.790

It's really phenomenal, Jack, I'll be watching with great interest your programs on PBS Star Hustler. This has been a fascinating conversation. I couldn't have gotten anyone more excited about the comment. As I can tell you are, anybody who wears a comet for a stipend has got to be committed.

00:28:11.800 - 00:28:29.690

Well, you know, you and your guests are going to see how these comment beautifully in April. So just hang in there and you will see it, I guarantee, Or my name isn't star hustler. All right, Thank you. Jack Horkheimer, who is director of the Miami Space Transit Planetarium and the host of the PPS program Star Hustler.

00:28:30.030 - 00:30:17.450

Thank you, My viewers, for being with us on conversation. Yeah. Thanks. Yeah. Mhm. Yeah. Hi. I'm Jack Horkheimer, PBS television star Hustler. And when I'm in Gainesville, I watch conversation and hi, I'm Mike Cannon in Gainesville. I watched Star Hustler with Jack Horkheimer. Jack is going to be on conversation and tell me and you everything we always wanted to know about Halley's comet.

00:30:18.440 - 00:30:30.770

Mhm, mhm.