Planetary Radio: Space Exploration, Astronomy and Science - Amateur Astronomers on the Lookout for Near Earth Objects

Episode Date: June 11, 2007

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Amateur astronomers keep their eyes on the prize this week on Planetary Radio. Hi everyone, welcome to Public Radio's travel show that takes you to the final frontier. I'm Matt Kaplan. James McGehee and Peter Birtwistle are just two of hundreds of the amateur and professional astronomers who are discovering and tracking near-Earth objects. NEOs are the asteroids and comets

that cross the path of the Earth, sometimes with catastrophic results. James and Peter are also past recipients of Shoemaker NEO grants from the Planetary Society. These grants have enabled them and many other astronomers Transcription by CastingWords look for the many planets now visible. He'll share that knowledge along with a new space trivia contest when we get to our regular What's Up segment. And you'll be hearing from Emily Lakdawalla about why we think there are oceans hiding under the icy surfaces of moons like Europa. Leading our space headlines this week is Space Shuttle Atlantis. It has become the first shuttle to reach the International Space Station this year.

Mission controllers are a bit concerned about a thermal protection system blanket that has come loose, but the problem is not expected to become serious. ISS astronaut Sunita Williams will be on board when Atlantis returns to Earth after 11 days. Sunita has been up there since December. NASA has also just announced that it is targeting September 10, 2008, for the fifth and final repair and maintenance mission to the Hubble Space Telescope. And it will be Atlantis, making that much-debated trip. NASA has released

about 1,200 more high-res images from the HiRISE camera on board the Mars Reconnaissance Orbiter. As Emily points out in her blog, that number isn't so extraordinary. But here's another number that is. 1.7 terabytes, yes, terabytes of data for those sharpest ever Martian snapshots, with many more to come. The story is at planetary.org. And it's Emily's turn at the mic. I'll be right back with the Shoemaker-Neo Grant awardees.

Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, Is Europa the only moon that has an ocean? The discovery that there may be an ocean underneath Europa's bright icy surface was one of the biggest surprises from the Galileo mission to Jupiter. But the same evidence that led scientists to determine that there may be an ocean at Europa also showed that there probably is a liquid ocean buried under Jupiter's other big icy moons, Ganymede and Callisto. No one has

ever actually seen liquid water on these moons. The presence of an ocean is deduced from disturbances to Jupiter's magnetic field that Galileo detected as it passed close by each moon. Scientists think that salty water is acting as a conductive fluid taking on a magnetic field induced by Jupiter's. What other places in the solar system could be hiding oceans? Stay tuned to Planetary Radio to find out. What a life James McGahey has had. He was a Special Forces Green Beret in Vietnam, who later switched from the Army to the Air Force,

flying missions during the first Gulf War. He has jumped out of airplanes more than 3,000 times, and he's a debunker of UFOs who regularly speaks on the subject. He still manages to spend many nights under the stars at the Grasslands and Sabino Canyon Observatories near his home in Tucson, Arizona. James received a Shoemaker-Neo grant from the Planetary Society back in 2002. Named after the late and beloved astronomer Gene Shoemaker, the grants enable both amateur and professional astronomers at smaller observatories to upgrade their telescopes and other systems.

Twenty-nine awards have been made, including a just-announced group of seven new recipients. They include sky watchers from Canada, China, Italy, Tahiti, and the U.S. You can read more about them and see reports from past recipients like James at planetary.org. James, thanks very much for joining us on Planetary Radio, and you'll be the first of a couple of so-called amateur astronomers that we'll be talking to today, but your record disproves that adjective, I'd say, of amateur pretty conclusively with the work that you've been doing at these two observatories that you have.

The last figure that I had was that you've made 5,676 astrometric measurements of near-Earth asteroids. Yes, I've probably made a few more than that now, but I've made a lot of asymmetric, and, of course, every one of those observations has photometric data with it as well. Tell me, what did this grant that you received in 2002 do to help these observations? Well, before, the 62-centimeter, it's a 24-and-a-half-inch telescope was not computerized. a half-inch telescope was not computerized. And with that, we were able to computerize the telescope such that it moves with software now to specific locations. Before, I was actually having to manually move the telescope to each asteroid,

which took up a great deal of time. So by computerizing the telescope, it made the operation much more efficient and easier to do. So I take it that before that, you had a clock drive, so it would track an object once you found it, but you had to pick it out of the sky yourself. Yes, I had to actually manually, physically move the telescope. It didn't have a slewing system. It was merely on clutches. And with the grant, we computerized the telescope such that now I can sit in the control room with the computer and just move the telescope to the object that way. That's a pretty good instrument, 24 1⁄2 inch.

That's impressive, as is this facility or one of the two that you use. I read the description and saw some pictures of the Grasslands Observatory. Quite a stupendous spot you've got there to watch the sky. Right. It is a very dark sky at 5,000 feet, very well-suited to this kind of work. Really what is necessary in following up and confirming near-Earth asteroids is to be able to go very faint, very fast, and this telescope is very capable of doing that. You've done a lot of other work there as well, confirming not just near-Earth asteroids or near-Earth objects,

but a pretty fair number of comets, too. Right. Of the objects I have observed, 43 of the objects that were supposed to be near Earth asteroids turned out to be comets. So I did get independent credit for discovering those 43 comets because most of them I was the first one to see them. So you're saying there are 43 comets up there that have your name as a part of their name? No. Unfortunately, the naming convention doesn't work quite that way. What happens is when these surveys that use computerized systems and people don't ever even look at the objects, when they discover an object and then it gets put on this International Astronomical Union,

what is called the Minor Planet Center and the NEO confirmation page, once an object is put on there, then if somebody else comes along and sees the object, it is in fact not an asteroid but is a comet. fact not an asteroid, but as a comet. They get credit for having seen it as a comet, but the name goes to the computerized system or survey group that actually first found it. I see. I didn't know that. You've got something else here that intrigues me. Seven asteroid occultations successfully observed. What does that mean? Well, actually I've observed more than that, but that's just in recent years.

Asteroid occultations are very interesting in that it's one of the few ways that allows us, because asteroids are so small and so far away, it allows us to actually do a profile and actually know what the true diameter is. Asteroids occasionally pass in front of stars, and if you take the way that this is normally done, a high-speed, low-light video camera, and with very sophisticated timing on it, you can time when the asteroid passes in front of the star. That's the occultation, and the star becomes fainter, and now you have a cord across the asteroid as projected against the star. By knowing the distance to the asteroid, we can know what the diameter is.

Pretty useful for these rocks, which sometimes, by definition, get in the way of our planet, and it's nice to know how big they are. Right, because a lot of the estimates on asteroids' sizes are based on, we know how far away they are, but we're basing it on a brightness of the asteroid called the albedo, and we just are assuming what the albedo is, and asteroids have different surface brightnesses. The light is reflecting off the surface. And so if you estimate how much light is reflecting off the asteroid, too high or too low, it changes the size of the asteroid. So the only way you can really measure this very well for asteroids that are far away is to do this. The other method is to use radar off of it,

but that can only be used when asteroids are very close to the Earth. Yeah, we've actually talked about that technique on this show as well. I wonder, obviously you are someone who very much enjoys getting out and studying the sky, but do you ever reflect on this work that you're doing as you confirm the presence and the paths of these objects that are more and more being recognized as things that we ought to keep an eye on? We really do have to think about it in the sense of trying to find and then analyze the orbital characteristics of these objects

simply because they are such a danger, potential danger to the Earth if one were to hit the Earth. And that's why the work is important, and that's why I enjoy doing it. And, of course, I just love using telescopes and the night sky and enjoy the beauty of the night sky as well. I've been doing this since I've been 10 years old, and I have to say I never grow tired of it. Well, keep up the good work, James, and thank you so much for what you do on all our behalf. We'll keep watching the skies as you do. I think I started when I was 10 years old as well.

Are you still jumping out of airplanes, too? No, I haven't jumped in a few years, but I've been thinking about maybe making some jumps. Well, good luck with that, too, and make sure it's a soft landing. Thanks very much for joining us. You're welcome. James McGaha is a 2002 recipient of a Shoemaker-Neo grant. We'll be right back after this break with one of his colleagues, someone from across the pond. That'll be when Planetary Radio continues in a minute.

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The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. We leap now from the American Southwest to about 60 miles west of London, England. That's where 2005 Shoemaker-Neo grant recipient Peter Birtwistle spends night after night scanning the skies in his Great Shepherd Observatory. Like James McGehee, Peter has made and recorded thousands of observations of near-Earth objects. We caught him just after returning home from his day job and just before another night of watching the skies.

Peter, thanks very much for joining us on Planetary Radio. And, of course, we want to talk about what your 2005 Shoemaker-Neo grant has been able to do for your observations. But first of all, tell us a little bit about Great Shepherd Observatory there in Berkshire, England. Okay. Well, I started out back in 2002 with the intention of doing work on near-Earth objects started off with a 12-inch telescope and did a lot of observing in the next three years. And then in 2005, at the same time as the Team Maker grant came through, replaced the 12-inch telescope with a 16-inch.

So 16-inch and the Benefit to Grant have been carrying on since then. So a 16-inch, I assume, with my small amount of astronomical expertise, probably gave you about twice as much light gathering as a 12-inch? Yeah, just about, yeah, a bit less than that. And quite a big difference, you know, it's a 12-inch to a 16-inch did make a great deal of difference. But the ones I used to actually upgrade the the camera the CCD camera that I was using and previously it had a long download time so you take an image and it

took up to 50 seconds to get that image back onto the computer so the grant has allowed me to get that change to a USB connection which means that the images are down in a second or two. Wow. And I now get the same difference I got with upgrading from 12 to 16-inch. I'm getting that same sort of differential between the old camera and the new, so it's like two steps up in one go. Wow. And from what I've read, you are able to track very faint objects, magnitude 21? Yeah. I mean, it's not straightforward.

You do have to follow these things for a fair amount of time to build up the light to get that faint. But yeah, it's perseverance. And getting down to that sort of magnitude with the equipment I've got, just one image, one measurable image, will probably take anywhere between half an hour and three quarters of an hour. And to actually send the results in, you've got to do that three times. So, you know, it takes up a bit of a chunk of the evening to just record one object.

I read on our website that you've got over 7,400 astrometric positions that are now on file. You've got over 7,400 astrometric positions that are now on file. Yeah, I mean, numerically, you know, a lot of work that's been done over those last five years. But the way things are going, the discoveries that are being reported are getting fainter. All the bright ones, to a great extent, have been already discovered. So new ones are getting fainter and so as things go on through the months and years um you need to get down to those faint magnets still stay in touch with the discoveries that are happening so i'm taking more images of fewer objects nowadays so you know trying to get down fainter, but that takes a lot more time during the

night, so I'd expect that the rate of reporting positions will probably go down over the next few years. Yeah, inevitably, and that just means that you and your colleagues around the world who are searching for these objects are doing a good job. You're finding the low-hanging fruit, as we would say. What does it mean when I read that you have made 60 first confirmations of near-Earth objects? Well, the hard work's being done by the surveys, the NASA-funded surveys, to actually discover these things. to actually discover these things.

But once they're discovered, they're put on the web to try and get people to follow them up, to keep them under observation so that they don't get lost. A confirming observation is where the discoverers have found it and have reported their positions. And it may be 12 hours, maybe 24 hours later or whatever before anybody picks it up. And fairly crucial that if they're not picked up soon, then they quite often get lost, especially if they're fast-moving.

So it's that first confirmation is when you found it after the discoverers reported it. You know, you mentioned fast-moving, and that's in one of the write-ups that you submitted to our website last March, that I guess you've changed your software so that you're able to track objects that are shooting across the sky pretty fast. And I guess you need to know whether they are NEOs or just artificial satellites. Yeah, well, the very fastest NEO objects, you know, they're moving at the same sort of rates as slow artificial satellites, and so there is a bit of a crossover there, and you quite often see fast-moving objects in the field of view. And so certainly over the last couple of years,

we've changed things so that it's easier to just keep following very fast-moving objects if they cross my field of view. You know, every time I've done that so far, it's worked out to be an artificial satellite. You never know one day. Well, keep it up. We are just about out of time. I hope that you will keep that lovely, very snowy picture of your observatory on your website, so that when we provide the link to the Great Shefford Observatory website, which you maintain, people will be able to get a taste of that.

It's quite an idyllic spot that you're in. Yeah, we're away from many of the sort of big towns and cities around here, so it's a fairly rural location, but nowhere in the south of England is dark really anymore, but it's as good as you can get in this sort of area. Well, I hope I can drop in some evening. You're very welcome. Thank you so much. I wish we had more time to talk, but I know that you will keep up your work,

and perhaps there will be another opportunity to hear about these objects that you and your colleagues around the world, including many Shoemaker-Neo grant recipients and including the ones just named in the last few weeks, will be able to keep identifying these rocks and other objects and make sure that we stay out of their way. Peter Burtwistle operates the Great Shufford Observatory in Berkshire, England, not too far from London, but far enough out to be in a beautiful rural spot there. And it would be fun to drop in sometime. We'll be dropping in on Bruce Betts for this week's edition of What's Up. Of course, that'll be right after our return visit by Emily.

I'm Emily Lakdawalla, back with Q&A. Europa is not the only place in the solar system that could have a massive underground ocean. Its neighbors at Jupiter, Callisto and Ganymede, probably do as well. And if these three worlds have oceans, then it seems likely that other moons of similar size and composition probably do too. These include Saturn's moons Titan and Rhea, Uranus's moons Titania and Oberon, and Neptune's moon Triton. It's even possible that some of the largest Kuiper Belt objects, including Pluto, Eris, and Sedna,

have liquid water oceans buried 100 kilometers or more beneath their surfaces. However, there's no solid proof yet that these underground oceans exist. All of these possibles are based upon mathematical models, not direct evidence. In fact, it's not even a sure thing that Europa has an ocean. What tests can scientists do to figure out if an ocean is actually there? The best test will be to measure very carefully how the shape of Europa changes as Jupiter's tidal forces sweep across its surface. Tides will flex Europa's surface much more if there's an ocean underneath

than if it's solid ice all the way down. It's going to take another dedicated mission to the moons of Jupiter to find out the answer to this question. Got a question about the universe? Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Bruce Betts is here. It is time for What's Up.

Just like we said a minute or so ago, it's time for us to check on the night sky and hear about the latest trivia contest and maybe some other good stuff. And let's say welcome. Welcome, one and all. Welcome to the night sky. This evening, if you go outside, you can see the night sky. Please look up at the night sky. But I'm busy tonight.

Can I go out tomorrow during the day? No, that will be the day sky. Tomorrow night, you can see the night sky again, but the following night, it's been canceled. Due to lack of interest? Certainly hope not. If so, we're in big trouble. It'll be back. But seriously, folks, cool planets up there.

Venus and Saturn coming, snuggling soon. Get ready for the planetary snuggle fest. You've been teasing us with this. I am, and it's getting closer. It's still a little far off, but depending on when people listen to it, I want to make sure they know June 30th and July 1st, both evenings, look for Venus. Can't miss it. Hugely bright, as it is all the rest of the time right now. So June 30th and July 1st, both evenings, look for Venus. Can't miss it.

Hugely bright, as it is all the rest of the time right now, off there in the west after sunset. And Saturn will be less than one degree away. So not quite a snuggle, but at least a gentle hello. Darn close. Yeah. We also have Jupiter up at the same time. It's up by sunset, basically, and setting before dawn. And you can still catch Mars in the pre-dawn sky as well. It's exciting, don't you think?

I do. I think I saw, I'm pretty sure I saw Jupiter a couple of nights ago. Well, be sure, man. Stare. All right. I don't say this for my health. It's such a hassle to get the telescope out, but I'll do it for you. Stan, stare. All right. I don't say this for my health. It's such a hassle to get the telescope out, but I'll do it for you.

If it's the brightest star-like object. Okay, in the east. In the east. Okay. All right, all right. In the evening. Tonight for sure. That's Jupiter.

All right. Jupiter. Big Jupiter. All right, let's move on. Please. on please this week in this week in space history 1963 valentina tereshkova becomes the first woman in space the only woman to have ever flown alone in space oh yeah i never thought of it that way that's what we're here for 1967 so that's some kind of an anniversary, 40 years since Mariner 5 was launched. It went off to Venus. And, in fact, let's talk a little more about Mariner 5 right now in Random Space Fact!

Super bright. Thank you. Mariner 5 was a refurbished backup. It was a refurbished hard drive. No, it was a refurbished backup. It was a refurbished hard drive. No, it was a refurbished backup spacecraft. Is that right? It was a backup spacecraft. Get this for Mariner 4 that went to Mars.

It was designed as a Mars spacecraft. Oh, shades of the Express series from those crazy Europeans. How interesting. There you go. Yes, and this is not a TV show. Of course, referring to Mars Express and Venus Express for those playing the home game. Yes, it was converted from a Mars mission to a Venus mission and was successful. Went off and did good stuff 40 years ago.

They just tore off some of the solar panels and sent it in the opposite direction. Three words, black duct tape. All right. Let us move on to the trivia contest. We asked you, oh, yes, we are playing Where in the Solar System? We asked you where in the solar system are Don Quixote and Dulcinea. How'd we do? A lot of people found this. Everybody found it, actually, and we had a lot of responses.

But the winning one, Anna Miskovic. You know what? We tell people, please tell us how to pronounce your last name, and then I ignore it. Okay. So I guess you don't have to go to that time. No, let me see if I can get it right. All right.

Anna Miskovic. Miskovic. That's got to be closer. She's from Serbia, Belgrade, Serbia. Oh, neat neat and so thank you Anna for entering and uh you get your reward this week because you're the randomly selected winner uh because you said asteroid arrows it is indeed asteroid arrows all of those uh creator features named after famous lovers albeit sometimes star-crossed lovers so to speak get it

star-crossed I do it's all space Get it? Star-crossed? I do. It's a little space reference. And as somebody said, actually as several people said, how perfect for an asteroid named Eros. Exactly. I don't think it was coincidental. Oh. Ah. They're so clever.

I know. Let's go on to the next trivia contest, and you too can win a Glorious Planetary Radio t-shirt if you get this right right and are randomly selected as our winner. Tell us, for what or for whom does the bell toll? No. No. For what or for whom? I'm sorry.

Did you have an answer? I was going to say it tolls for thee. Oh, well, then let me think of another one. For what or for whom was the mineral armicalite named? Say that a couple more times, please. Yeah, I'll try it with different pronunciations, and we'll put the spelling on the website if people need it. Armicalite. Armicalite. Armicalite. There are geologists out there beating their heads against the wall right now.

You were going to say something about geologists. I know that because I know you, but sorry. No, I was going to admit, hey, I've got a degree with the name geology somewhere in there. Oh, you do? Among the others? Yeah. The little-known miner to a PhD miner. But they did not go over obscure mineral pronunciation.

All right. So who's it named after? I can't tell you. No, I'm just repeating that's a movie. Got it. Yes, yes. Go to planetary.org slash radio. Find out how to enter and tell us who our mall collide is named after.

And you've got until, let me think now real hard. You've got until June 18, Monday, June 18 at 2 p.m. Pacific time to get us that answer. Alright, everybody, go out there, look up at the night sky, and think about the glory of cheese balls. Thank you, and good night. I love cheese balls. Is it the kind with the nuts on the outside,

the walnuts, or whatever those are? Yeah. What I would do for a cheese ball right now. Well, hey, you're in luck! I'm going to settle for Bruce Fetz, the director of projects for the Planetary Society, who joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week, everyone. Thank you.