Planetary Radio: Space Exploration, Astronomy and Science - Astronomer Heidi Hammel on the New Jupiter Impact

Episode Date: August 10, 2009

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Heidi Hamel with the story behind the new Jupiter impact, 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 of the Planetary Society. Something sure slammed into Jupiter about three weeks ago, exactly 15 years after a comet smacked the king of local planets. Astronomer Heidi Hamel studied that earlier bombardment, and she's all over this one, as you'll hear. Our other big news, Emily is back. Ms. Laktawalla is ready to pick up where

she left off, answering your questions about the cosmos in her Q&A segment, which will be followed by my weekly visit with Bruce Betts to learn what's up in the night sky. It's a jam-packed edition of Plan Rad, so let's get underway by turning to the science and planetary guy for his commentary about gas stations in space. I'll be right back with Heidi Hamel. Hey, hey, Bill Nye the Planetary Guy here, Vice President of the Planetary Society. And this week, along with all the talk about retiring the space shuttle and the new administrator, Charles Bolden, people are finally talking about what to do next.

What's the next cool thing? And I wrote a blog for the Planetary Society website, in case you didn't read it, which I know is possible. I talked about this idea of having refueling stations way up, way out, way beyond low Earth orbit, in and around what are called Lagrange points. And these Lagrange points, it turns out, are places where the gravity of the moon and the gravity of the earth and the gravity of the sun are just about almost exactly in balance. And sure enough, there's little clouds of dust in these places where interstellar dust just finds a nice happy home with no gravity to nudge it one way or the other. So what we would

do is we would send spaceships full of fuel up to those Lagrange points and park them. And then the next spaceship would go up and it could refuel. It wouldn't have to be as big a rocket. And sure enough, at the same time, these engineers have come out of the NASA woodwork with this idea to build the Jupiter. This is the space shuttle boosters. And you'd make a new nose cone and that would make a new rocket out of existing space shuttle stuff. Very cool idea. Nobody's sure. People argue about whether or not it's the right thing, but whatever it is,

new Administrator Bolden, you should look into this, and you should look into these high, high Lagrange point orbits because we may be able to use this kind of orbital mechanic to get rockets up to go to asteroids. See, there's an asteroid with our name on it somewhere out there. It's going to come by and hit the Earth. So the more we can understand those things, the better chances we have are deflecting it safely. Maybe one day we'd find a way to mine them, bring a whole 15 tons of platinum in one big pure swoop down to Earth without trauma. It could be a fantastic thing. And using the same Lagrangian technology,

maybe we'd go on to Mars. Somebody to think about. Well, thanks for listening and looking up. I got to fly. Bill Nye, the Planetary Guy. The first report came on July 19 from Anthony Wesley, an amateur astronomer in New South Wales, Australia. What was that black spot that had suddenly appeared on Jupiter? Word soon reached Heidi Hamel, a senior research scientist with the Space Science Institute. We've talked with Heidi about Uranus and Neptune, but she also led much of the research on the last big Jupiter impact. That was 15 years ago, when fragments of comet Shoemaker-Levy 9 slammed the planet. Now she's one of many astronomers who have turned some of Earth's most powerful telescopes toward this new interplanetary collision.

Even the newly refurbished Hubble Space Telescope was rushed into service. We have a link to the spectacular image it caught on July 23rd. I caught Heidi by phone just a few days ago at her Connecticut home. Heidi, I want to welcome you back to Planetary Radio. How did you first hear about this new impact on the planet Jupiter? Well, you know, I was up in the middle of the night, should have been sleeping, but, you know, there I was at 1 or 2 in the morning, and I was reading email, because what else is there to do at 1 or 2 in the morning? And I saw this report fly by about this possible impact,

and there was a picture, and I looked at it and thought, well, that's a dark spot all right, but so what? These things aren't supposed to happen this regularly. It was supposed to be another 500 years, not 15. But I also saw that Glenn Orton's name was mentioned, and I knew he had been working at the IRTF, so I sent him an email and said, Glenn, tell me about this. Like, is this for real?

And I got an email back from him saying, yeah, looks hot, looks like an impact. And so, you know, we were all, I was still pretty skeptical of the whole thing, but I sent an email to the director of Space Telescope Science Institute, Matt Mountain, saying, well, Matt, I just thought I'd let you know that there's been this report of an impact on Jupiter, and it looks like it might be real, and if that's the case, then I think we ought to try to get a glance at it. Then I went back to bed, because I figured I might as well get some sleep, because if it turned out to be real, I figured there'd be very little sleep for a long time afterwards,

which turned out to be correct. Were you surprised that the first sighting of this small black dot was by an Australian amateur with a 14-inch home-built reflector? I was not at all surprised that this discovery was made by an amateur astronomer. The amateur astronomers play an absolutely critical role in studying skies for these transient phenomena. Professional astronomers who are using the big telescopes have extremely limited time. And our proposals to use those big telescopes are very focused.

So we say we're going to say we want to look at Jupiter. You know, we know nine months ahead of time pretty much exactly what we want to look at. And we typically only have a few hours to do that. typically only have a few hours to do that. And just by chance, I was planning on leaving sort of two days after this impact to go to Hawaii to use the Keck telescope to work with my colleague Imke de Potter to look at Jupiter. That's what we had been scheduled to look at months and months ahead of time. That was terrific because, you know, we already knew that we'd be looking at Jupiter. But it did make for some challenging work before I left, because, you know, once we discovered that this thing absolutely was real, you know, and we went through a lot of discussion about it, all the different lines of evidence. In fact, our first proposal to Space Telescope had sort of a

list of evidence that suggested this was a real event, because we weren't sure. But once it became clear it was real, you know, I basically had about 24 hours before I had to get on an airplane to go out to Hawaii to use telescopes. So it was a pretty crazy time. We were told we basically had until 4 o'clock in the afternoon to get that proposal into Space Telescope, and we did. I had a great team of people helping me, I have to say.

This is not something that I did alone. We had a team of people ranging from Spain to Hawaii and everywhere in between that were all sending email around, pulling it all together. Now, we should say that what is likely to become the signature image from the Hubble Space Telescope of this impact from the Wide Field Camera 3, third generation. It credits NASA, ESA, the European Space Agency, and the Jupiter impact team, but you're the only person down here by name. That's just because I was the person who put the proposal in, and I insisted on, they actually

just had my name there, and I said, no, no, no, this is a team effort, you know. I think they ought to have had that team, you know, the wide-field camera team. They ought to have the people at Space Telescope team. It was a huge, huge effort to get the image. It was a very, very challenging observation. Normally they are not taking any science data at this time. Normally, they are working hard to do the orbital verification to check out every aspect of the equipment on that telescope, making sure it's all functioning

perfectly and doing all the calibration work. And, you know, it was a huge imposition for us to come along and say, excuse me, can we take some science data? The fact that they were able to accommodate that is a credit to the flexibility of that team that's working at Space Telescope and at Goddard and at NASA headquarters, all the people who had to weigh in. That's just what I was going to ask you about next. Did you meet much resistance from the folks at the Space Telescope Institute, or did they just jump on this like you wanted to?

Well, they did jump on it, and they were extremely supportive. But, you know, we're working within a very strict system of rules for very good reasons. And normally this kind of thing just wouldn't happen. I mean, there is a press conference planned for September where the first images are scheduled to be released. And this was such an anomalous event that it required working around these rules a little bit. Now, I was largely shielded from all of that because I was thousands of miles away on Mauna Kea, but I could tell from the tenor of the emails that I was getting that it was a very difficult process

to try to flex the rules enough to allow us to release that image. And I'm very grateful that they did because I think it was to Hubble's benefit. It really showed Hubble is in the game, and we are able to do this terrific science, and isn't it fantastic? So I am glad that they were able to do it, and I'm also glad that I was thousands of miles away during the process. We'll hear more in a minute from astronomer Heidi Hamel about the new impact on Jupiter. This is Planetary Radio.

Hey, Bill Nye the Science Guy here. I hope you're enjoying Planetary Radio. We put a lot of work into this show and all our other great Planetary Society projects. I've been a member since the disco era. Now I'm the Society's Vice President. And you may well ask, why do we go to all this trouble? Simple. We believe in the PB&J, the passion, beauty, and joy of space exploration. You probably do too, or you wouldn't be listening. Of course, you can do more than just listen. You can become part of the action, helping us fly solar sails, discover new planets,

and search for extraterrestrial intelligence and life elsewhere in the universe. Here's how to find out more. You can learn more about the Planetary Society at our website, planetary.org slash radio, or by calling 1-800-9-WORLDS. Planetary Radio listeners who aren't yet members can join and receive a Planetary Radio t-shirt. Members receive the internationally acclaimed Planetary Report magazine. That's planetary.org slash radio. The Planetary Society, exploring new worlds. Welcome back to Planetary Radio. I'm Matt Kaplan. Many astronomers around the world have turned their attention and their telescopes to mighty Jupiter in the last three weeks. Space Science

Institute senior researchist Heidi Hamel has already told us how that investigation has taken shape. Let's switch gears and talk about this impact. First of all, can you compare it to what's come to be known as SL9, Shoemaker-Levy 9? Almost incredibly, this was discovered, or I guess the impact actually happened, 15 years to the day after SL9? Yeah, that's right. I mean, SL9 was a big event. It was a week-long event because the comet that hit Jupiter had been shattered into, you know, two dozen pieces. And it took a week for those pieces to go in. And this event happened on the 15th anniversary right of the

middle of that week. Kind of freaky. You know, I thought of Gene Shoemaker, and I thought, you know, his spirit is up there chuckling. You know, maybe even nudged at this thing. That had happened on the 15th anniversary. You know, he would have been delighted with how these events transpired. And, you know, I just, you know, sort of sent a little mental thank you to him.

Yeah, but how crazy is that exactly 15 years later? Of course we compare it to Shoemaker-Levy 9 because that's the only thing we have to compare it to. But, you know, in many respects it's a fair comparison because we don't know what the thing was that hit, but certainly the characteristics of the impact site are very reminiscent of sort of the medium-sized impacts that occurred on Shoemaker-Levy 9. Well, that doesn't mean it was exactly a medium-sized object because we don't know the velocity exactly, but, you know, more or less, you know what the terminal impact velocity is going to be. You can make some estimates. And we'll go and we'll explore, when I say we, I mean the scientific community,

we'll explore the range of possibilities. You know, could it have been a smaller thing going faster, big thing going slower? Given those constraints, could it have made an impact site like we saw? You know, that'll all come out in due course. At this point in time, we're still really very busy capturing the data. The impact site is still visible, but the winds are shearing it quite rapidly now. And so it's becoming more and more difficult to see. Not much time left at optical and ultraviolet and near-infrared wavelengths. If it's anything like Shoemaker-Levy 9, there will be other tracers at other wavelengths of light that we'll be able to track for some period of time, but right now we're just scrambling to get that last bit of data.

I heard someone say that this impact site, it could be compared roughly to the size of the Pacific Ocean. Yeah, yeah. The initial impact site was the big black clouds that were left there after this explosion. Now the winds have been shearing it, so the black material is dispersing over a wider area than that, which is to be expected. Why is this black? Do we know enough about the mechanics of something like this and Jupiter's many layers to say, you know, why isn't this a red spot or, for that matter, a white spot? Well, you know, it actually, it's black.

Depending on what wavelength you look at, it's black. But if you look at other wavelengths of light, it looks brighter than its surroundings. It really just has to do with which particular wavelength of light you look at. When we say black, we mean it's black at the visible wavelengths of light. If we were on a spacecraft or looking through a 14-inch telescope, it looks black compared to the surroundings. Now, I don't think it's too hard to understand why it's black. I mean, basically what happened there was a massive explosion in the atmosphere. This material of Jupiter, I mean, this is what we said for

Shoemaker-Levy 9, and it's true for this 2009 impact as well, it basically heated the Jovian atmosphere in the impact site itself to extremely hot temperatures. In Shoemaker-Levy 9, we actually saw impacts, and so we had ways of extracting temperatures from certain molecules, and those temperatures got up to tens of thousands of degrees, if not higher. And so you're basically burning up Jupiter's atmosphere. And when you burn up stuff, you get soot, and soot is black. So, I mean, it's kind of not too hard to figure that part out. Exactly what this stuff is, we don't know that yet. I know that some spectroscopy has been done, which is sort of our tool for figuring out composition. I haven't heard any answers yet. I know in the cases of Shoemaker-Levy 9, we saw sulfur and we saw, you know, carbon and that kind of stuff. How much will what we've learned

from Shoemaker-Levy 9 help us to understand what happened with this impact and how important is this second opportunity to collect data? Well, Shoemaker-Levy 9 is tremendously important for helping us understand this, because with Shoemaker-Levy 9, we had this range of sizes of impacts and ranges of explosions, and we could watch sort of the different ways in which the atmosphere responded to the different energy inputs. Here, we've got a single event. We don't have that diversity. So we'll be looking already this morning.

Email was flowing. Do you have those remap scans of the blah, blah impact site, MSL9? Oh, well, I've been looking. I can't find it. Oh, I have it. You know, everyone is digging back in their data to dredge out. You know, I have on my to-do list, get out the paper we wrote and review. What did we see and what did we say?

Yeah, it's going to be incredibly important to tie these things together. Now, the big looming question, of course, is why did this happen so soon? We really didn't expect one of these to happen this quickly. That is going to be the question of the hour that, you know, we're really going to have to set our minds to it. And like, it could just be chance. You know, statistics works that way. It could just be chance, or maybe it's not chance. Maybe these things do happen much more frequently. I have a suspicion that a lot of amateur astronomers are going to be looking at Jupiter very carefully now in the hopes of capturing their own impact. Maybe it happens a lot more frequently, and we've missed it. What a nice lead-in to my last question with about a minute left to go here.

Turning from near-Jupiter objects to near-Earth objects, any object lessons for us to learn back on this blue-green planet? Let's not get complacent. That's my takeaway lesson. I mean, we got a wake-up call with Shoemaker-Levy 9 that collisions are a real-time thing. And we've just gotten a second wake-up call here that not only are they a real-time happening thing, but they're happening maybe a little faster than we had anticipated. Now, Jupiter is the barn door out there, easy to hit. We are not a barn door, all right? So I'm not, I still have auto insurance

and fire insurance, and I have not taken out any impact insurance. So I'm not, I still have auto insurance and fire insurance, and I have not taken out any impact insurance. So I'm not worried. But, you know, knowing that there are things that we can do to characterize the population of the small bodies in our solar system, it seems to me it's a wise thing to invest some time and money into really understanding what's floating around there in the near-Earth orbit. Well, I hope all the amateur astronomers out there are listening up, and it would be very nice to give one of them credit when one of these rocks heads our way. Heidi, I know you've got a lot going on today. Thank you very much for taking a few minutes to talk with us as the data is still gathered about this impact,

and I guess we should watch for that. You said there might be a press conference or something published? Well, there's a press conference about the Hubble Space Telescope and the new cameras coming up in September, so keep an eye out for that. We'll do that. And please keep your eyes on the skies. It sure makes for wonderful observation, doesn't it? Yeah, thanks. Great talking with you.

You too. Heidi Hamel is with the Space Science Institute, where she is a senior research scientist. She was a 2002 recipient of the Carl Sagan Medal and is a member of the Planetary Society's Board of Directors. She also took the number one spot when Scientific American decided to pick Hubble's top ten. And you know what that was about? Her observations of Shoemaker-Levy 9 15 years ago. We'll be right back with this week's edition of What's Up and Bruce Betts, but that's after the return of Emily Lakdawalla.

Hi, I'm Emily Lakdawalla with questions and answers. A listener asked, I've heard Jupiter called a failed star because it's made mostly of hydrogen. What is it made of other than hydrogen? Like all the planets, Jupiter condensed from the same nebula of gas and dust that the Sun did, so it started out with a complement of chemical elements similar to the Sun, mostly hydrogen, some helium, and trace amounts of everything else. Unlike the other planets, though, Jupiter is massive enough that it's been able to hang on to the lion's share of the atoms it began with. As a result, it's the planet that has the most

Sun-like composition. It's 75% hydrogen and 24% helium. The remaining 1% is dominated by relatively light elements like carbon and nitrogen. We can only see the uppermost levels of Jupiter's atmosphere, where the pressures and temperatures are similar to those in Earth's atmosphere, so Jupiter's clouds are actually made of materials that are pretty familiar. Some of the clouds are made of water ice, just like on Earth. At slightly higher altitudes than the water ice clouds, Jupiter's atmosphere gets cold enough that ammonium hydrosulfide and ammonia can condense, so Jupiter's clouds may have different compositions at different altitudes.

Also, just as on Earth, there are very minor amounts of more complex compounds like acetylene, ethane, propane, and other hydrocarbons. Although these make up a tiny fraction of Jupiter's clouds, it's those hydrogen and nitrogen compounds that are responsible for their glorious colors. Deep within Jupiter, conditions become much less familiar. Tune in next week to find out more. Got a question about the universe?

Send it to us at planetaryradio at planetary.org. And now here's Matt with more Planetary Radio. Time for What's Up with Bruce Betts, the Director of Projects for the Planetary Society. We get to do it in person back in Studio A here at Society Headquarters, which, of course, is the carriage house out back. Welcome back. Thank you. So tell us, what's in the night sky? Too late for the Perseids?

Depends on when you're listening to our fabulous show. If you pick it up right after it hits the web, then no, not too late. The peak is August 12th, but it's going to continue to have increased meteors for a few days after that. I think I mentioned I'm going to be up in central California. I've just got to get above the fog bank, and I'm going to try and catch it. Somebody said that evening of the 12th, like from 9 to 11, because then the moon comes out. That is true. No, the best viewing is traditionally after midnight, but in this case, the moon rises later in the evening and then starts to wash out the meteors, so it's actually optimum. This year, early on, in fact, may actually

have increased meteor activity this year. Oh, really? Good. So there are thoughts that this may be a really good year? Yeah, but the Perseids are pretty consistent, so they're always solid. They'll be there for us. They will. I forced you into that. What what else you want to tell us nothing there's no the solar system is out to lunch this week it's on august vacation everything's disappeared no that's not true in the uh in the pre-dawn is still where you got things going on with extremely bright venus over there in the east. And up above it is dimmer, redder Mars. And in the evening, Jupiter, quite lovely. Not pretty much after sunset over in the east

and high up by the middle of the night, looking faboo. Okay. This week in space history, 2005, Mars Reconnaissance Orbiter launched. Yeah. Beautiful pictures. Lots of wonderful data. Mm-hmm. Cool.

All right, let us go on to Random Space Fact. I'm kind of shocked. I didn't realize. I had no idea that was coming. Oh. Hey, the sun, if you're at Saturn, which I know sometimes you are, the Sun is about 1% as bright as it is from here on Earth. Wow. Still really darn bright, but only about 1%.

So imagine what it is from Pluto. I mean, at Pluto, is it really hard to tell it from another star? No. It would still be the brightest thing, right? It's still by far the brightest thing. It's much, much, much dimmer than it is as we see it, but it's still clearly the bright, happy home. Fascinating and factual. Why, yes, it was.

Let us go on to the trivia contest. We asked you, the Galilean satellites of Jupiter, what has the highest surface gravity? If you're on the surface, what has the highest gravity? How'd we do, Matt? Well, we pointed out that you might have been a little tricky with this. And indeed you were, because it's not the moon with the highest mass or the greatest diameter, right? It turns out. Very right. So which one is it? Io. Io, because you're smaller, but you also have a higher average density with Io. It's rockier. And that's exactly what we heard from almost all the listeners.

Our winner, Sonja Vining. Sonja Vining of Plymouth, Michigan. First-time winner who's picked up not a Planetary Radio t-shirt this time, but the tile, that Ulysses tile. It's a rare item. This is definitely a collectible. And a rewards card from Oceanside Photo and Telescope. So congratulations, Sonia. Thanks for listening.

By the way, we did hear from a number of people that the surface gravity is 0.183 G, which is almost a fifth of Earth gravity. And there were any number of people who talked about that's a good thing because they probably spend most of their time jumping up in the air going, ow, ow, ow. Due to the volcanism? Yeah. I think there's going to be some alternative lifestyle group, you know, age of Aquarius group that's going to be like walking on hot coals. It'll be walking on Io someday.

Mark my words. Might as well be walking on Io. Anywho, let us go on to the next trivia question, which I'll phrase in the form of a statement just to confuse matters. But you do not have to answer in the form of a statement just to confuse matters but you do not have to answer in the form of a question name all the telescopes and by this I mean optical telescopes in the world that have single, not segmented

mirrors larger than 8 meters mirrors larger than 8 meters, all of them but they need to be one giant piece, not a bunch of segments big piece of whatever it's made of. Right. Okay.

Bigger than eight meters. Go to planetary.org slash radio and find out how to enter. You've got until the 17th of August at 2 p.m. Pacific time to get us that answer. Can I mention just something about the current contest, which it's too late to enter? We're getting really entertaining stuff. There are a lot of Marvin the Martian fans out there. As well there should be. Except for his desire to destroy Earth periodically.

Yes. Okay, but that'll be next week that we talk a little bit about our favorite Martian. Okay, we're done. All right, everybody go out there, look up at the night sky, and think about obelisks. Thank you, and good night. Obelisks, mandals, they all came from aliens. He's Bruce Betts, the Director of Projects for the Planetary Society,

and he joins us every week here for What's Up. Planetary Radio is produced by the Planetary Society in Pasadena, California. Have a great week. Thank you.