 Q2. Good afternoon. I'm Don Savage, Public Affairs Officer for the Office of Space Science. And welcome today to the Goddard Space Flight Center and the latest of our common update briefings here at Goddard. Today we have a major announcement to make, a major discovery by the Hubble. And our top news this morning, we will also have Dr. Renee Pronje who will tell us about how cometary debris is making the Jovi and Aurora light up. And Dr. Lucy McFadden will give us a worldwide wrap up. And Dave Levy will be here for discussions on the observing. I'd like to go ahead and introduce our panel right now. To my left, Dr. Roger Yell with the University of Arizona. He's a scientist from the University of Arizona and a member of the Hubble Space Telescope Spectroscopy team. To his left, Dr. Renee Pronje from the Institute Astrophysique spatial and Orsay France. She's a scientist from the French Institute at Orsay and a member of the HST upper atmosphere imaging team. And the center to her left, Dr. Steve Marin, our moderator for today. He's a senior staff scientist at the Goddard Space Flight Center. To his left, Dr. Lucy McFadden, University of Maryland and University of California, a visiting professor at the University of Maryland and coordinator of the Worldwide Comet Observing Campaign. And to her left, David Levy, co-discoverer of the comet and longtime comet observer. Welcome, panelists. I'd like to turn it over to you, Steve. Thank you, Don. Good morning, ladies and gentlemen. For those of you who had the advanced schedule, I'm not Eugene Shoemaker and I won't have any explosive results for you. It is a pleasure to be here again. I've lost count of all these fragments, but fragment P2 should have struck within the past hour. And as I think you all know, many of you led with it yesterday or this morning, the first of the three other big fragments, QR and S, that will be hitting Jupiter at intervals of approximately equal to its 10-hour rotation period. So they'll hit it nearly the same spot at 10-hour intervals that will start at about 332 Eastern daylight this afternoon. We'll hear a little bit more about that later. Now for this, what I personally as an astronomer think is a very exciting scientific result to emerge from Shoemaker-Levy. There's more to it than just a big show. We're fortunate to have Roger Yale of the University of Arizona tell us about this Hubble spectroscopy result. Well, good morning. And as you all know, there's two ways, two sorts of information that the Hubble Space Telescope's been gathering, which you've seen mostly as images where you see the entire planet and the impact site at a very specific color, a specific wavelength. But also with the spectrographs, we look at one spot on the planet, but look at all the colors, all the wavelengths simultaneously. And that's what we call spectroscopy. So I'm going to report on some spectroscopy results. You can see on the monitor, I believe, an image of the G impact site, and it's the spectroscopy from the G impact site. We knew that was going to be a big one, so we pointed the spectrograph there several hours after the impact. And in the next, could we have the next graphic, please? The arrow is pointing to the location of where our spectra were obtained. Spectrograph was the faint object spectrograph. That's right. I don't know how to get that on the screen. Next graphic, please. Okay, and what we're going to see in this graphic is the distribution of brightness from this spot as a function of wavelength or color. Now, different molecules, okay, there it is, and I'm going to be talking about... That's ultraviolet light. This is ultraviolet light. The wavelength is probably hard to read off that scale, off the image there, but it goes from about 150 nanometers to 3,000 nanometers. So this is light that doesn't get transmitted through the Earth's atmosphere. You need to be above the Earth's atmosphere to observe it, and that's why we use the Hubble-Finn object spectrograph to make these measurements. So what we see there is the ratio of the light from Jupiter after the impact to the light from Jupiter before the impact. And you can see that the ratio is not one, which tells us right away that something's changed. It's less than one. If it were one, it would be a straight line, right? If it were one, it would be a straight line across the top of that image. It somewhere varies from about 0.2 to, I guess, 0.7. So what that tells us is that these spots are darker in the UV after the impact than they were before, and we knew that already from the images. It's no surprise. But if you look very carefully at the distribution with light, with wavelength, you can look for molecules. Molecules will absorb at specific wavelength, specific colors that are their own signature. So one molecule will absorb at one wavelength, another molecule will absorb at another wavelength, and by analyzing this, you can identify some molecules. Yesterday, Keith Noll told you about ammonia, which happens to absorb light right around 2,000 angstroms, which is the minimum in that spectrum there. And there's ripples there. If you look carefully, you can see ripples in the spectrum, which is characteristic of ammonia. What I didn't show you yesterday were the larger ripples to the right at about 270 nanometers. They're about, I think they're fairly obvious there. It looks sort of like fish bones or something. And that was very exciting when we saw that yesterday, but we had no idea what it was. And so we spent the last 48 hours or so trying to figure out what this molecule was. And it was something of a mystery. There are a few clues that you can, that we went by in the spectrum. First of all, it's a very regular spacing of ripples in that. And that tells you that it's a simple molecule. Secondly, the ripples are close together. And that tells you that it's a heavy molecule. So armed with that, that eliminates some number of molecules in the universe. But I should have said, first of all, that we had expectations about what we were going to see. We knew what molecules to look for and where to look for them. And we didn't see those. We saw ammonia, which was expected. But this is something that was totally unexpected. So we didn't recognize it right away. We had to go off and search spectra of all the molecules that we could think of to find out what this was. And none of the simple ones matched up. So we got more and more complex, perplexed and kept looking. But as I said, we had these clues. It's heavy. And it's simple. And finally, about three o'clock in the morning, we started zeroing in on sulfur. And in fact, it's a very, those features are a very good match to the spectrum of sulfur, sulfur gas, S2, the S2 molecule. Sometimes called the dimer, the two similar molecules. So similar atoms in the same molecule. No, it's not. Can't get them all. It's a diatomic molecule. Anyway, so that's a definite detection of S2 molecule in the atmosphere of Jupiter. Now, also, there's some more structure around, in addition to ammonia at the shorter wavelengths, where that big minimum is. And by looking carefully at that, we think that there's probably some hydrogen sulfide, H2S, in the spectrum at that location. That's not as clear-cut as the S2, but nevertheless, it may be there. The spectrum is consistent with the presence of hydrogen sulfide. We haven't. It might be possible to explain it with something else also, and we're not sure of that yet. But it seems to be consistent with hydrogen sulfide. Hey, thank you, Roger. S2 was found in Comet IRS or Racky Alcock. Yes, that's true. It's been seen in one comet before. Sulfur is seen in most comets, I believe, although not in the S2 molecule. And we're going to have to do some work to try to determine whether this sulfur. There's, of course, sulfur also in the atmosphere at Jupiter. And it's not obvious just from this result at this point, whether the sulfur is from the comet or from the atmosphere. Okay, and of course, as everyone knows, Hubble doesn't just take spectra. It also takes images. And one of the areas of the study of the comet that I think we have not heard about in these briefings thus far, because we haven't had a lot of news in that area, has to do with the effects involving the magnetic field of Jupiter and the interaction with the comet. And Dr. René Prangé from the Institut d'Astrophysique, Spatial and Orsay, who can pronounce all those words much better than I, is involved in the Hubble imaging team working on these problems and tell us what you've been learning. Okay. It's all right, but one of our major interests in the observation on top of studying the upper atmosphere of Jupiter was to understand the physics at work in the magnetosphere. And since the magnetosphere is not a trivial object, I will just briefly put it into context before I discuss the observations. Jupiter, like the Earth, is a very strong magnet, and the magnetic field lines delineate, cause a cavity in the surface, where a lot of plasma, which plasma in our dracon is a tenuous ionized gas of electrons and ions are confined. This cavity is very extended. It's a million of kilometers in diameter. It's five times the sun. And the tail extends still farther at times it goes up or down, as you would like, to Saturn, which is five astronomical units. So the magnetosphere of any magnetist planet is a huge natural laboratory for plasma physics, and that's why we're interested in that. And like the atmosphere that you have seen a lot in the last few days, the magnetosphere of Jupiter is not visible, practically invisible at all wavelengths, except in the decimetric radio wavelength, which has been used to discover the magnetic field of Jupiter. So we can only study the magnetosphere by deep space mission in-situ measurements, or by monitoring remotely the oral emissions, and that's why we are interested in that. The aurorae that again are alike the aurorae on Earth, which also become polar lights, they are at the end of the chain of processes in the magnetosphere. It's at the place where energetic particles, so electrons and ions, finally fall and we say precipitate on the top of the upper atmosphere, and the energy of the collision of these particles on the constituent species of the atmosphere makes the atmosphere shine, either in the UV or in the infrared, not in the visible spectrum. And you can see on this picture which is on top, which is in an image of the Weave Peak II camera, about around below 2,000 angstrom in the far ultraviolet, so it's not visible just by naked eyes. On both sides, the polar region north and south, you can see these light kinds of ovals with spots, which are the footprint of magnetic field lines that go far away in the magnetosphere of Jupiter, and where the particles which are along these magnetic field lines, they fall down and they impact the atmosphere, they make it shine. For us, it's a signature what happens in the magnetosphere. We have been using two cameras, we have been using the Weave Peak II, which is the American camera, and we have been also using the faint of break camera, which is the European camera on both HST. This is an image which has been taken on July 13th before the impact, two days before the first impact, and already one week after the first dust being, sufficient dust was inside the magnetosphere that could expect some effect from the dust with the plasma in the magnetosphere. There had been a lot of prediction of what could happen in the magnetosphere. Some effects could come from the dust in the leading edge, some could come from the comet itself interfering with the plasma in the magnetosphere, and we could expect to see some effect even before, like precursors of the impact. In this image, you can see also the north pole, the south pole. We cannot see the whole... Can we have that graphic, Mac, please? So we cannot have the whole planet because the field of view of the faint of break camera is much smaller than the field of view of the weak peak, too. But the interest of the faint of break camera is that you can get... You have a very, very good spatial resolution. You can get very faint details, so they are very complementary. And on this graphic, you can see what... We are somewhat frustrated because we didn't see anything spectacular before the impact. We already had images of the aurora that looked like that, except that the north aurora consistently looked somewhat fainter, maybe at times much fainter than usual. And it looked fainter than the south aurora, which is a nice necklace on the lower panel. We got the same kind of result with IUE. We have been monitoring the aurora with IUE for several weeks already, and we found that the north aurora was weaker. We cannot tell why, we cannot understand that. We expected if any fainting, we expected it in the south because the dust could be inhibiting the processes that would give rise to the aurora. We get it fainting in the north. Maybe it's dust coincidence, but we have to... But maybe it's greater. Couldn't it be brighter in the south and it's being enhanced by the dust from the comet fragments? Oh, it's clearly fainter in the north. We have a lot of trouble getting the north. Okay. Normally you can see a novel which is around... We have a thought in the middle. This is very, very obvious in older data. And you find this both with the Hubble telescope and with the International Ultraviolet Explorer. Right, with both. So we can tell for sure it's an effect of the comet. It may be an effect, a general global effect of the dust in the magnetosphere. Then we got this nice image on July... Today's a good one, July 18. Yes. We've picked two that I hope we'll get here on the screen. Next graphic, please. And you can compare this image to the one we got before. You can see the aurora on top, the north. It's still fainter. You can see the left edge. You can see the aurora in the south. And below the north aurora, you have two bright spots, which are very low for us. It's very low latitude. It's totally unusual. It was not unexpected. I can tell they're having predictions that maybe the comet plasma could be ionized. This could ride of current and enhance the... create new... Okay, so the two bright spots you're talking about are the upper left and the... The upper left, just at the footprints of this new magnetic field line, which has been drawn now. And this is quite new. We never saw that. We never saw any aurora below, which is the one you have seen on the previous two graphics. So to make sure I understand what you're proposing, you think that material from the south pole, where the fragments are impacting, might be drawn through the magnetic field lines up to the north pole? That's what I'm thinking. There have been... Well, if you look back to the prediction that has been made, it's clear that we expected some effect of the ionized plasma in the material in the comet to interact with the plasma in the magnetosphere. But we didn't know what we should do. And in any case, we expected to get something in the south, not in the north. And we worked out a lot to get the possibility to have closed field lines because the magnetosphere at times the field lines that open to the solar wind. So in that case, something would happen in the south, do not have any counter part in the part in the other hemisphere. So we worked the geometry so that we can get a closed field line with a footprint print in the north, visible also from earth. So the north and south are connected by the magnetic field? In that case, they're connected. And on top of that, the footprint of the north is in front of... Because the field line is distorted in the meridian plane. So you can see the footprint in the south, it's just right at the limb. But you can see it's already 30 or 40 degrees on the limb from the limb on the north. If you imagine kind of a bar magnet inside Jupiter that is responsible for magnetic field in that model, then the bar is off-center and tilted. And that's why it can be in the back. These lines can be in the back on the south and in front on the north. So we are lucky when not only lucky, we worked it out. And we get this bright spot in the north, but we have nothing in the center, and we didn't get anything except maybe you can see something very, very faint and diffuse at the footprint of the larger in the south of the larger field line. We cannot tell, well, that's probably not precipitation of particles. We do not know what it is. It may be related. But this on the north pole, it's necessarily energetic particles. So something happened. Some material from the coma, from the comet itself, was liberated in the south pole, accelerated by some way along these magnetic field lines, and fell into the northern hemisphere, like an iron gun, in fact. Now, Renee, would these be visible in visible light where our eyes are sensitive? It's far ultraviolet. The oral emission, I mean, the emission collisionally excited in the atmosphere on Jupiter, they cannot be seen in the visible only in the ultraviolet from the, it depends on the composition of the atmosphere. On earth it's visible. On Jupiter, it's mainly from hydrogen or for hydrocarbon. And it's either ultraviolet or infrared. Unfortunately, you can see them in the visible. So that's a major, I think it's a major discovery. We have to understand what happens. We have two options so far. Maybe there are other options open, but we thought of two. Either the material was liberated after impact, and we got it along the field lines, and we see in the north, and that's why we do not see anything in the south, or another possibility which was predicted, in fact. And I think I should send an email to Dr. Wing Yip. We have sent the, published a paper very short ago, telling that within one Jovian radius, we have the conditions so that the coma entering before impact could create a current along the field lines, which would give the condition for such an effect to appear. So you have to do more than just throw stuff up from the impact. You have to have an electrical or magnetic process that accelerates these electrified particles and drives them up the magnetic field line. You have to get like an electric circuit, and then you have to have like kilovolts of potential drops to accelerate the particle to a thousand of volts to accelerate the particle. So it's not an easy process, and we have to work on that. And it's a lot of modeling probably, and we learn a lot about the plasma physics in general and Jupiter in particular. Great. Thank you, Dr. Pranje. I think these are two really fascinating findings from the Hubble Telescope, and we had an assist from the IUE. I'm sure we'd be hearing more about IUE as the week goes on. Now I have to tear myself away from this orbiting observatory. We used to say there were hundreds of telescopes looking at Jupiter this week. Now from the reports coming in that amateur astronomers and the public are streaming into observatory science museums. I think Lucy McFadden told me this morning hundreds of people are coming to the University of Maryland observatory over here near Adelphi. There probably are thousands of telescopes looking. They won't all see Aurora that you have to look in ultraviolet light. But what are the telescopes on the ground finding Lucy McFadden? Well, actually, Steve, with that introduction, I think I'm going to let David Levy talk about the hundreds of telescopes that are being pointed toward Jupiter and let him talk about what the amateurs are seeing and the role they can play in the science. And then I'll come back and fill in on ground-based. This is almost a contest as to which is which is the best surprise, which is the biggest surprise of this whole magnificent week. And I can say that the fact that these dark spots are visible for virtually everybody to see is the biggest surprise, but it sure is one of the biggest. Nobody expected this. We have some very large spots on Jupiter. They seem to be the brightest ones at the latest that I heard still is the one from the impact of Fragment G. And it seems to me that no matter what part of the world you're on and no matter what area you're watching, by now there are enough of these spots that no matter where you are, when Jupiter is in the sky after dark, you will probably be seeing some spots. You didn't mean brightest, most prominent. It's actually dark for... I meant darkest, yes. When I say brightest, I mean darkest. Thank you, too. His comedy can play that anyway. No, one report that I got from a professional astronomer who actually began as an amateur and still has his original telescope is from Clark Chapman of the Planetary Science Institute. He said that the spot from Fragment G in his years of observing Jupiter is the most obvious feature ever to appear on this planet. And he is challenged over the over the internet. Anyone to argue that and so far nobody has. He sent me to the telescope last night and it was pretty spectacular. So I looked directly through the eyepiece and there it was. So I encourage everybody including all the crew and everyone doing the support work for all this event. Lucy, I forgot to say that we have and you're going to tell us about this. We have more than just telescopes on the ground and telescopes in space. We have something kind of partway up, isn't that right? Yeah, but let's let David finish with his points. Yeah, I think it's hard to tell at the moment just why these spots are so prominent. One of the theories to explain them has to do with that these are comet dust or a form of soot that is from the comet. There are other theories, but this is one of them. It's very important to emphasize that if if you are an amateur astronomer, if you have any experience at all looking at Jupiter, any experience, these spots should be extremely easy for you to see. If, however, you have never looked at Jupiter before, my recommendation is that you go to one of the many star parties that are being organized by planetariums and amateur astronomy clubs all over the world right now and get someone to point the spots out to you. They're very easy to see, but if you haven't had, if you've never looked at Jupiter before, it helps if you get someone to point them out. This is an extraordinary thing. These spots are major, major effects from the collision. They're visible to anybody. The philosophical question is that if the comet had never been found, right now people would be seeing one spot after another appearing on Jupiter. They'd be wiping off their lenses. What's going on? That's right. They'd wonder what's going on. Probably the visual observers would have been spotting them first. If there had just been one spot, if the G impact sighted in the only one, someone might have said maybe there was an impact, but these spots are now forming all over that area of Jupiter and they would say maybe it was an impact and they'd say no, how could you possibly get so many impacts in the course of a week and nobody would have figured it out. I guess it's entirely possible that a comet we hadn't discovered yet could hit Jupiter and make a spot that large. Yes. I think we're lucky that these guys were watching and found it. So this is the time to get out and if there's ever been a time to get out with a small telescope and look at Jupiter ever since Galileo first observed Jupiter through a telescope in 1610, this is the time to do it. This is just a marvelous time to be looking at Jupiter. Can I just mention that there are interesting, you probably talked about this earlier in the week, but there's interesting strings of craters on some of the satellites of Jupiter which have been theorized to be due to a similar process, the breakup of a comet falling upon one of the satellites and it may have occurred to someone that that was similar to. So that the multiply split comet may not be such a rare phenomenon. It might have occurred and that's a good point. That could have happened any time in the past four and a half billion years. There's even one of these crater chains on the moon on top of the crater Davey. There's a series of these craters. And that's getting pretty close. Yes, but these did not hit Jupiter all at once. Those crater chains hit Callisto or the moon all at once, all within a few seconds of each other. These are things hitting over the period of a week and to make that intuitive leap to get the the only way this could have not happened is that a comet past near Jupiter earlier, at some earlier time, broke apart, completed another orbit and then hit. And if someone had come up with a theory like that, he or she would have been laughed off the stage. It would be a spring of implausible events, all of which however we're seeing occur now. Yes, I think we need to get on to Lucy's Report Leave Room for Questions while we have the satellite. Okay, we have some some some more images from ground-based observatories around the world. The first one coming up is from Lick Observatory from the 120-inch telescope there. It is an image taken with speckle inner ferrometry, I'm sorry, speckle imaging, which is a process that astronomers and members of the Department of Defense have both been developing over the years. And with speckle imaging they have the they use computer, let's see, they use complex computer algorithms to clean up the noise and improve the spatial resolution of the image. And as you can see from looking at this, the parallel cloud structure is is quite prominent and it's very well, yes better defined than in most of the ground-based images. Not quite as as clear as as the Hubble, so it's not as good as getting above the Earth's atmosphere. That's the adaptive optics project led by Dr. Claire Maxx and Lawrence Livermore National Laboratory. Thank you, Steve. Then next we have some more observations from the Keck Observatory where NASA and the NSF have been have contributed to building the instruments that from which we're taking these measurements and we have a mosaic. Now these are seven images, not ignore the time difference. Each image is a different wavelength and in the upper left corner we started a wavelength of 1.2 microns and we go across the dark one, the third one on the right, is at 2.3 microns and we continue to go to longer wavelengths and the final one on the bottom where Jupiter is the darkest is at 4.2 microns I believe. Now the importance of this, all the features appear as bright spots so they're still radiating thermal heat, they're they're just radiating the heat from the impact sites. The advantage of using different wavelengths is as the wavelengths get longer the wavelengths penetrate deeper into the atmosphere. So this is like a stratogram, we're looking at the layers through Jupiter's atmosphere. So I guess besides the fireball that came up that Jean Schumacher has been talking about from the simulations, you still have some hot material down under that's glowing after days and after the event. Right, and this is important, once we can interpret these and coordinate, correlate the information from the different wavelengths, we hope to be able to determine how deep the projectile went into the atmosphere. I don't have any numbers and we haven't really understood that yet, I can only present it in a generic case. We have a report from the Kuiper Airborne Observatory which is a C-141 cargo aircraft. It's a really spectacular aircraft, it's been compartmentalized, they blocked off one part of it where they placed the telescope. There's a 36 inch telescope in this compartment which is pressurized and they cut a hole in the side of the cargo plane and they point the telescope out the hole in the plane. Now this plane flies at 41,000 feet and there are astronomers on board and everyone who's flown on it reports an exciting adventure. At 41,000 feet they have oxygen within reach in case the interlock between the telescope and the observers breaks, they have 15 seconds to get their oxygen masks on. The advantage of this telescope is that they can fly anywhere around the world and they can fly anywhere around the world they get up above the atmosphere and we will have a report from Gordon Boryaker from Goddard Space Flight Center who's reporting some of his results. We have two channels, one is a temperature channel and one is a search for water. The temperature channel was truly dramatic and we have very good coverage of both the G and the K fragments. After having looked at the G fragment then we decided to set up the investigation a little differently. For the K fragment we concentrated almost exclusively on the temperature. We wanted to make sure that we pin that down very precisely and we have even better data for the K fragment. The going from the pre-crash signal level to the peak of the fireball went up by a factor of 25 so it was absolutely stunning and you know since we have some spatial resolution you can see all of all of Jupiter at once and then in the the limb of Jupiter where the fireball was it's like seeing a supernova go off or a star go off. The main reason for using the Kuiper airborne observatory is that you're flying above 99.9% of the water vapor in the Earth's atmosphere and you're above just 80% of the total atmosphere. Our key thermometer is the methane molecule which is present in the Earth's atmosphere by flying at 41,000 feet. This opens up a window where we can measure very strong methane features on Jupiter that are not measurable from ground-based telescopes. Now what's important here is that they have they're penetrating deeper into the atmosphere at 10 microns and they are measuring emission lines from methane so they're getting they're getting heated methane they're heating there's evidence of heating of the methane clouds in Jupiter. That's the methane gas in the stratosphere you're observing. Okay so it's the high the stratosphere the high levels higher levels of the atmosphere okay and they're floating in our stratosphere as they do it. That's right stratosphere to stratosphere. Okay now I think out of time let's see well the next images are from the from the IRTF at Monacaia and those show these are at four different wavelengths we have in the four different wavelengths at the upper left is the temperature in the upper atmosphere the one on the right is ammonia in the region of ammonia band the one on the lower left is the region of methane and the lower right is another ammonia region. Let's go on to the next one we can take questions about that later. We've reported have a report from Galileo that the photo polarimeter radiometer has has detected the impact of fragment fragment G I believe and they radio they sent back some preliminary observations these are not images so I do not have a visual for that but Galileo we have data back from Galileo and remember Galileo is getting the direct eye straight line shot of these collisions and the profile the change in time of the intensity measured by the photo polarimeter will show us how the flash intensifies and the rate at which the flash decays. Then our last images are okay thank you then our last images are from a McDonald observatory and we have a report from Anita Cochran there. We were able to get on in with both of the telescopes and start imaging so we didn't actually catch the flash available we were able to start looking at the morphology of the L site very very quickly. The conditions turned spectacular very soon on we had excellent excellent transparency almost all night and extremely stable atmospheric conditions so we have some really really pretty images that we've gotten out with both an IR camera on the 2.7 meter telescope and a CCD camera on the 0.8 meter telescope. We've mostly been running around like giddy little kids because it's very exciting to watch this we've all had to take our turns looking through the eyepiece because you can see the structure of the spots in the eyepiece in good conditions and things are just changing and it's so much fun to watch Jupiter change below our eyes. Image number two is a methane image taking the CCD camera and in this image we see a number of the spots but one of the striking features of this image is that the H spot is just rotating into onto the limb and we've caught it in this image at a point where we see it detached from the planet. A hydrogen molecular band that is again observed with the IR camera on the 2.7 meter in this we have four spots and the great red spot in the middle of the planet we sent this in the conventional orientation we find amusing to turn this and some of the other images upside down and look at it you'll see why when you see the image. That sums it up. Thank you very much Lucene if I can just sum up all the news we've heard today or not all but the high spots we have the detection of the diatomic sulfur molecule S2 from the Hubble Space Telescope with the faint object spectrograph Roger Yell told us about that we have these wonderful auroral glows at the foot points of magnetic field lines in the North Polar Cap of Jupiter at a lower or more southern more southerly northern latitude than aurora has been observed before that was done in ultraviolet light as explained to us by Rene Pranget with the wide field and planetary camera too and they know it wasn't there before because few days prior they looked with the faint object camera also in the ultraviolet. David Levy told us the G impact site is so extraordinarily prominent wonders if maybe that's comet dust that's making it dark and visible light. The Keck Telescope we saw the hot impact spot still glowing in the infrared there's still some heat there after some days after the first impacts. The first report back from the Galileo space probe you're wondering why we told you you won't see anything for weeks from Galileo that's images these photopolymeter measurements the much lower data rate you get it back pretty rapidly. Galileo at a distance of about a hundred and fifty million miles looking in the ninety four hundred and fifty nanometer ninety four hundred and fifty angstrom or nine forty five nanometers sees the H spot. The Kuiper airborne observatory the audio report from Gordon Yoraker told us about the heating of the methane gas in the stratosphere and then Anita Neil Cochran at the McDonald Observatory for Davis Texas looking in the molecular hydrogen or H2 band you see some glowing features and spots you turn it upside down and Jupiter doesn't seem so unhappy. Thank you Steve we're going to turn to question and answers here at Goddard and I understand we have a lot of questions from our center so I hope we have enough time on the satellite we'll start here. Please state your name and affiliation. Bill Horwood CVS and I'm maybe asking you if you'd maybe be more elementary in terms of the significance of the sulfur observation. If you knew the sulfur is in the atmosphere anyway and you don't know where this sulfur comes from I'm confused as to the significance of that and also I was reading a message on the internet yesterday from some other University of Arizona researchers who were claiming that they had done some studies or observations that indicated they were actually seeing cometary material and I'm wondering if these two things are linking up somehow or they're totally separate issues. Okay first of all we believe that there's sulfur in the atmosphere of Jupiter although we hadn't detected it yet just because the solar system has sulfur in it and Jupiter should not be an exception however that sulfur is deep in the atmosphere it's in the form of hydrogen sulfide we believe H2S and as you go higher in Jupiter's atmosphere it gets colder just like it does in the Earth's atmosphere you form clouds and the hydrogen sulfide should disappear into clouds at a fairly deep level in Jupiter's atmosphere. So just as an example potentially we could convince ourselves that this material was coming from Jupiter not from the comet that would tell us something about the depth to which the cometary fragments penetrated. I think maybe you're referring to the second part of your question I think perhaps you're referring to an article that was in the New York Times this morning I understood on the internet that the material was cometary. Well I didn't see it but what jumps out at us from looking at this at least from the HST data is that the molecules we've seen so far ammonia and sulfur molecules are things that are in the clouds of Jupiter. There's also an ammonia cloud in Jupiter. The visible clouds on Jupiter that we have understood that those are ammonia. That's right. And there's an ammonia hydro sulfide cloud which is at a deeper level below one bar. There are other molecules associated with comets, oxygen. You might expect the oxygen molecules for example. We don't see any of those. What we see so far is things from Jupiter and well you know this is going to be a long story but I don't understand that internet message. I'm still awfully ignorant of chemistry. What is so exciting about finding this sulfur is why would the man in the street want to jump up and down about this? Well as I just said it might tell you something about the impact itself. The particular molecule to be perfectly honest I don't know a lot about it because I didn't expect to see it. So it's a surprise. It'll be interesting to watch how this develops in time. One of the reasons this is interesting. I study atmospheres rather than comets although I think comets are interesting too. But the best way to learn about something not just atmospheres to poke it and see what happens. So we just gave Jupiter's atmosphere a giant poke and we're going to see how it develops in time and that's going to tell us something about how atmospheres behave. It's going to add to our knowledge base of atmospheres and that's going to be useful for our society. It'll help us understand the Earth's atmosphere ultimately. I have a question to Dr. You told us about the change of aurora of Jupiter and we have some example that the same thing happened to Earth in the past and what is the meaning of your discovery from Jupiter to us like knowing about the aurora of Earth and knowing about the meaning of the weather of Earth and what if something happened like Jupiter to Earth what is the meaning for our life I mean like a short wave transmission of something. Well I think what we see is the effect of the comet the gas or the or both maybe the dust in the comet which has been ionized or the other option the gas which has been ejected in after the fire ball and it was very very hot hot enough to be ionized. So these are the two options. In the case we get some ions and electrons which are free in free space and we know from the fight that they have been able to go along the field lines and to excite to glow the aurora on the other side we know that they have been put at very high energy. The kind of thing we can learn from that is the processes in the further processes in the comet which how they can ionize how they can be accelerated and then how these particles are accelerated in the magnetosphere itself. This is a problem which is of high interest for plasma physics and on earth there are numbers of satellites which have electron guns, ion guns which artificially accelerate ions and electrons to thousands of volts and see what happens at the footprint on earth. Of course there were one or more experiments I don't remember when but the first one was authorized by President Kennedy that to explode a nuclear weapon up in the magnetosphere and see the effect of the precipitating particles as a famous was debated whether it would be safe or not and finally Kennedy called Van Allen he said it's his belts and that's all right. I think the other part of your question was what would be the effect on the earth well of course there might be geomagnetic storm or something like that but comet hits the earth then the the effects of magnetosphere will be of secondary interest to many of us or I guess it will be a terrible effect because storms it would affect communication ionosphere but magnet even great very strong magnetic storms from the effect of the solar wind they do not affect life just communications and broadcasting. Paul Hoverston USA today back on the sulfur question for a moment Dr. Yell if it turns out that the sulfur is from the comet and not the atmosphere what would be the significance of that? Well it would tell you that there was sulfur in this comet and eventually you might be able to figure out something about the abundance of sulfur in the comet and the reason we study the abundances of comets is is so we can understand comets one of the building blocks of the solar system or remnant of the building block of the solar system so you might be able to say eventually something about the composition of the early solar system. I should also point out that when you do observe comets sulfur other molecules and comets you're seeing gas around the around the main body and most of the masses in the main body and it's always difficult to try to infer something about the bulk composition from what you see in the in the coma because there's chemistry that goes on it alters things and stuff like that so what we just did is we just pulverized the comet and find out what was inside it perhaps and it's a different way to look at things. Miles? I have Miles O'Brien with CNN. I'd appreciate from anybody here sort of a little more of a layman's term explanation of what's going on in the magnetosphere of Jupiter here. I'm not sure that I'm real clear on what's going on. I think what we were what Dr. Pranget was talking about was that these are of course observations we've only just seen the last day or two but the preliminary impression is that we have this big impact the big splash and the fireball on the southern part of Jupiter and that this send up some plasma like the fireball that you saw some of this material gets electrified loses the atoms or molecules lose electrons and then these They become charged. Right. You have charged particles now and I think the electrons in particular probably you're talking about they get accelerated by some forces that have to be worked out that but we know things like this happen on the earth in other situations they get accelerated they travel to the other side of the globe of Jupiter and cause an aurora there at a place we've never seen before because it's further south whatever makes the aurora on Jupiter ordinarily doesn't bring it down that far south it's like normally we see nice aurora in Canada and New England and so on it's a rare time when you see a Mexico city or the does does happen after a big flare the the the charged particles that constrain to move along these field lines magnetic lines of magnetic field that you can see in the image so they want to escape the atmosphere but they they can't they have to move along these field lines and end up getting turned around and you know come back on the other side of the planet so if you were on Jupiter right now you'd see northern lights like you've never seen them before you'd be glad you were seeing northern lights you weren't down south any evidence that you've seen over the last 24 hours which has is settling one way or another whether this is a comet or an asteroid once and for all oh no that that's a very important question but it's going to be very difficult to get an answer to that so i'm i'm afraid i just have to say flat out there's no evidence that will help us determine whether it's a comet or an asteroid well there may be evidence we just haven't had enough time to think about it exactly would like to go to some of the centers for questions now is we're going to run out of time on the satellite which is first one up please okay well we're holding on that is there one more here first Matt Crenson the Dallas morning news for Dr. Yell uh i don't want all the great details but in general how can you tell whether the sulfur came from Jupiter or from the comet and what are the chances that you'll be able to do that i don't know how good the chances are but to finally get the answer we're going to have to correlate lots of different pieces of information left uh you know what we've seen so far as far as chemistry goes through the molecules that are easiest to detect with more work and with all the other observations being made we're undoubtedly here about a lot more molecules look at the whole suite of molecules that will help you try to infer something about the temperatures and the fireball and that will tell you about the chemistry in the atmosphere that'll help you understand what's going on and i'm trying to correlate all this i have hopes that we'll be able to say something about how much of the um what we see is due to the comet and how much of what we see is is from Jupiter itself so i'm optimistic but it's hard to put a number on the chances we'll be coming back to questions here pardon excuse me we'll be coming back to questions here in a moment but let's have one from jpl uh please state your name and affiliation this is Robert Lee House from the Los Angeles Times two uh related questions one i guess i'm surprised to be hearing at this stage of the game that we're not sure this is a comet uh can you tell us why there's a any question at this stage why this might be a comet or an asteroid and then secondly is it uh disconcerting to you folks that you're not seeing uh evidence of water yet okay i'll i'll field that one if if gene we're gene shoemaker we're here he would say oh it's definitely a comet um and the probability of it being a comet and gene can argue persuasively that it's probably a comet um dynamically it is possible um to to give a gravitational push to an object anywhere in the solar system and so dynamically it's also possible to to exert a gravitational force on an object in the outer region of the asteroid belt and perturb it so that it goes into orbit around jupiter as this as this object did and we call it a comet because it was discovered as a diffuse object um which is the uh discriminating characteristic of a comet observationally now it's a very important question to determine whether this was a comet or an asteroid because the comets are remnants of the original solar system they've been kept in cold storage for four and a half billion years and we can get a better handle on the starting material of the solar system if we're studying a comet if we're studying an asteroid the asteroids have been in the inner solar system they've been subjected to higher temperatures they've been subjected to greater uh frequency of collisions and so the the material is altered and we just need to know what we're looking at presumably the reason you might even though it's diffuse you might think it could be an asteroid is we know it's something that was fragmented by the right and we don't know what could be dust from this fragmentation and not an atmosphere like the comet has of of evaporator sublime gases and the other question was about water are we surprised that we haven't seen water well yes or no yes and no I appreciate the difficulty in analyzing the data from the kuiper airborne observatory and and I continue to think of scenarios which would exist where water is there but we don't see it and it may not be stable in jupiter's atmosphere for long enough to get a detectable signal with the instrumentation or it could be some chemical thing so we have a lot to think about and we also have to wait patiently and get some results back let let the the scientists analyze their data instead of showing us their raw images that have spectacular signatures on them just a quick follow can you tell us what fragment we were looking at in the irtf images you always catch me on these questions on which what image was it um oh actually that was the a site remember a long time ago so this is they were observing a to watch for its evolution it's it's very we're going to become interested in how these things evolve with time so that was the site of the first impact there are so many of these sites now that we've already seen reports where uh as swiftly pointed out by their colleagues astronomers are saying this site looked like thus and so and someone else says no at that time you look you were seeing a different site there's so many of them now you you need a program when you go to the telescope to tell the spots on jupiter okay uh we have some questions now from the kennedy space center in florida please state your name and affiliation hi jim banki of florida today a question maybe for uh dave levy or or lucy uh you said earlier in the week that you thought these spots would last for weeks if not months is there any evidence from the ground-based observatories and telescopes that any of the earlier spots are fading away we're going to ask lucy mcfan to answer that because dave levy was called away he is in great demand um there is evidence of fading of some of the spots changes in the brightness of some of the spots um none of them have disappeared remember some of the impacts didn't leave a scar uh fragment b did not make a significant uh feature um there's some change galio people told us that besides spotting h they looked for an impact site from b and did not see it with that photo polarimeter in the second question uh maybe a little trivial for you folks but uh in the forest of jupiter did uh the comet make a sound when it uh when it hits uh in i know there's no one there to hear it but uh did it make a sound what would be the sound of a comet hitting jupiter very loud it made a very big sound um one of the things we'll be looking at for seismic waves which are uh a wave um that sounds they're a wave um i don't think there's any conclusions on that yet but it certainly did make a big noise not just a sound but it's a sonic boom that's going on there oh thank you um undoubtedly yes this is philochina earth news for roger how certain are you that this is also have you eliminated all the other possible molecules um is there any possibility that this might be from the isle of course or from the magnetosphere some kind of ionized sulfur how sure are you that it's sulfur it's sulfur oh we're we're absolutely sure it's sulfur we um you saw that it had this this very interesting structure where the it were wiggles up and down and there's about 30 of those wiggles and they all line up with 30 lines expected from sulfur and then the distribution of intensities is also understandable in terms of sulfur so i think there's no doubt now i also reported uh a more tentative uh detection of h2s and i want to be careful with that the the spectrum is consistent with with hydrogen sulfide but it might be possible to explain that feature with with some combination of other molecules will have to be more careful and wait and see on that but for the for the s2 there's just no doubt couldn't be anything else the other part of phil chen's question was could this sulfur be oh the volcanoes on eo that's very hard for me to imagine i think i'd have to say no okay and will you be making this data available on the internet and using heidi hammers analogy yeah how bad is the traffic jam on information super highway um traffic's very heavy on the information super highway um i have reports that the uh computer up at space science telescope institute is jammed standstill just like los angeles um our computer at university of maryland which is available for professional astronomers and the observers um has been running at 50 to 70 capacity um and we have anywhere from one to two dozen people on at any one time and we cannot compute we can't keep track of how many people log on and and the same at Hubble space telescope they had to move their program that counts how many people are logging on to another machine because the machine couldn't handle the incoming traffic so uh it's it's busy it's the way it's supposed to be i guess we'll go to headquarters now for some questions please state your name and affiliation i'm not sure if we're having a technical difficulty headquarters are you there okay we're going to have time for one more question here and i've been assured the panelists will stay around for questions later on this is mark corrode the houston chronicle could you talk a little bit about q r and s and even the uh the last fragments and how they're going to how they compare in size brightness or whatever with those that have hit before um the q r and s impacts will occur within about 10 hours of each other which means they will land on jupiter at the same location um let's see dav jude at university of hawaii has done some recent astrometry he had a an instrument which allowed which blocked out the light from jupiter and allowed him to look at the fragments as they were approaching jupiter very close and um with his measurements of the positions of the fragments he enabled paul chotis and don yoman's at jet propulsion lab to update the impact times and those impact times have moved forward about 15 minutes um so they but the spacing between them i believe is still the same so we're we're interested in watching what's going to happen when these sites land on top of each other and and um it's going to make it harder for us to disentangle the information but we may learn something from it as well q should be big right i think that's part of the question yeah q should be big p's p should be big too they're they all they're all big let's try headquarters again uh go ahead please uh yeah this is ron kellan from sciences for dr proje can you tell me how many kilometers uh this this new footprint is below the the existing one is a way to understand why this commentary debris just getting on to the north pole why it wouldn't just brighten the existing footprint why wouldn't he create a new one and again how many kilometers beneath is it well the size in terms of kilometers it's it's rather narrow in terms of latitude it may be like it's less than a thousand kilometers in latitude in longitude it's elongated and i would say probably like a few thousand kilometers maybe 10 000 kilometers but out of that we cannot tell whether it's spot which has been moving on on top of the planet because the the exposures have been four five six six minutes long during that time a fixed spot in the magnetosphere rotates in the in front of the of the telescope by about four degrees i guess i'm not sure but that's your of the order the spot itself will measure the trace which is about 15 degrees so in fact it's longer than that either this is remaining light and it has been created locally by the by the comet but the comet in the last two hours the comet is going from the the dusk side to the noon at noon and then to the morning side very very fast so if you have emission which is blowing blowing from for say 10 minutes you will see it like a track on the on the observations so we cannot tell so far how how large is the spot if it's a temporal effect of if it is a special effect and the other answer the other part of Ron Cowan's question why doesn't it just shine in the normal or rural place is that it's not like all the bees go to the same nest to get honey but the the magnetic line from the normal northern or rural zone doesn't come to the place where the comet hit the normal the normal aura comes from apparently the last observation we got with the with the Hubble last year suggests very very strongly in the comparison with Ulysses we did comparison with Hubble and Ulysses this year and it's it's very strongly suggest that the normal or observable we see it's related to currents which flow right at the limit between what we call the polar cap and the closed field line inside the magnetosphere the closed field line they rotate to the planet in 10 hours the open field lines as we say in our dragon the one which are pushed away in detail by the solar pressure solar wind pressure and which are open to the solar wind normally they do not rotate with the with the the planet itself this creates a condition for strong currents and there we see a sheet of precipitation this is very very high latitude it is connected at something like 60 60 planetary radius the the the glow we have seen this transient glow is on field lines which go like two or three rg at maximum at the equator from the from the center of the planet very very closed field line in what we call the inner magnetosphere in the inner magnetosphere normally we do not have plasma to get this uh this effect and it was also connected to the past of the of the comet itself I think we have one more from headquarters please watch the U.S. report I guess I'm wondering if you see any uh widening yet at the thin dark ring from can you hear me no please repeat I'm wondering if you see any widening yet at the thin dark ring from from from fragment G the one surrounding the dark watch that's that's for me sure it's a Hubble question oh I don't I don't think we're we have any more results on that at this time okay that's all the questions we have time for today we'll rerun the video and uh feed that on this the satellite and uh that's end of the press conference thank you and start imaging uh so we didn't actually catch the flash available we were able to start looking at the morphology of the L site very very quickly uh the conditions turned spectacular very soon on we had excellent excellent transparency almost all night uh and extremely stable atmospheric conditions so we have some really really pretty images that we've gotten out with both an IR camera on the 2.7 meter telescope and a uh ccd camera on the 0.8 meter telescope we've mostly been running around like giddy little kids because it's very exciting to watch this we've we've all had to take our turns looking through the eyepiece because you can see the structure of the spots in the eyepiece in good conditions and things are just changing and it's so much fun to watch um Jupiter change below our eyes image number two is a methane image taking the ccd camera and in this image we see a number of the spots but one of the striking features of this image is that the h spot is just rotating into onto the limb and we've caught it in this image at a point where we see it detached from the planet a hydrogen molecular band uh that is again observed with the IR camera on the 2.7 meter in this we have four spots and the great red spot in the middle of the planet uh we sent this in the conventional orientation we find amusing to turn this and some of the other images upside down and look at it you'll see why when you see the image we have two two channels one is a temperature channel and one is a search for water the temperature channel was truly dramatic and we have very good coverage of both the g and the k fragments after having looked at the g fragments then we decided to to set up the investigation a little differently uh for the k fragment we concentrated almost exclusively on the temperature we wanted to make sure that we pin that down very precisely and we have even even better data for the k fragment the the uh going from the pre-crash signal level to the peak of the fireball went up by a factor 25 so it was absolutely stunning and you know since we have some spatial resolution um you can see all of all of Jupiter at once and then in the the limb of Jupiter where the fireball was it's like seeing a super nova go off or a star go off the main reason for using the Kuiper airborne observatory is that um you're flying above 99.9 percent of the water vapor in the earth's atmosphere and you're above just 80 percent of the total atmosphere um our key thermometer is the methane molecule which is present in the earth's atmosphere by flying at 41 thousand feet this opens up a window where we can measure very strong methane features on jupiter that are not measurable from ground-based telescopes 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