Ep. 422: Geysers

So if you’ve been to Yellowstone National Park, you’ve seen one of the most amazing features of the natural world – geysers. In today’s episode, we’re going to talk about geysers on Earth, and where they might be in the solar system.
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Show Notes

  • Geysers
  • Geysers at Yellowstone
  • Old Faithful
  • Geysers in Iceland
  • Cryogeysers and Cryovolcanoes
  • Europa’s geysers
  • Enceladus’ geysers
  • Transcript

    Transcription services provided by: GMR Transcription

    Fraser Cain: Astronomy Cast Episode 422: Geysers
    Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos, where we help you understand not only what we know but how we know what we know.
    My name is Fraser Cain. I’m the publisher of Universe Today and with me is Dr. Pamela Gay, the director of CosmoQuest.
    Hey, Pamela. How are you doin’?
    Dr. Pamela Gay: I’m doing well, Fraser. How are you doing?
    Fraser Cain: Doing great. And I know we’ve been sort of saying this every week but, once again another reminder, go to astronomycast.com/events – Is that right? – Or “Live”, “Events”?
    Dr. Pamela Gay: Just go to our homepage –
    Fraser Cain: Yeah. They’ll be a link there.
    Dr. Pamela Gay: – astronomycast.com –
    Fraser Cain: And find out how you can hang out with us.
    Dr. Pamela Gay: – there’s a link that says “Trips”. The actual link is, like, stupidly long. So just go to astronomycast.com.
    Fraser Cain: Yeah. Yeah, astronomycast.com and then there’s a link to the trip. Remember, we’re going to be hanging out at the eclipse. We’ve already sold half our tickets. The rest are going – We haven’t even really cranked up the marketing efforts. The other half are going to go pretty quick. So – So, join us! And watch the eclipse. This is – This is crazy.
    I’m really looking forward to it. And also, as I mentioned in the Weekly Space Hangout, Elon Musk – please don’t break our hearts. It’s all I have to say.
    So, if you’ve been to Yellowstone National Park, you’ve seen one of the most amazing features of the natural world, a gey – yes, geysers. In today’s episode, we’re going to talk about geysers here on Earth and where they might be in the solar system. And, of course, this topic was picked also because of the amazing discoveries made on Europa and the new evidence. So we’ll be talking about that as well.
    So, let’s talk about geysers here. Have you been to Yellowstone? Have you seen geysers in your life?
    Dr. Pamela Gay: I have. Back the summer between my junior year in high school and my senior year in high school. When normal kids were going to college visits, we instead went on a tour of national parks because I already kind of knew where I wanted to go to college.
    And, among the many, many national parks we went to that summer, we went to Yellowstone and we saw Old Faithful and we saw a whole bunch of other boiling, bubbling, sulphury, gross, hot, will-kill-you things oozing up out of the ground. Because that’s what you do at Yellowstone.
    Fraser Cain: I have never – I’ve never seen a geyser in real life.
    Dr. Pamela Gay: You need to fix this. You need to take your children and fix this.
    Fraser Cain: I – Well, I’m working on my bucket list. I just saw a rocket launch. So – So cut me some slack here.
    But it’s amazing. And so, Yellowstone – Do you know how many they have? Like, they have a bunch, right? They have Old Faithful and they have others.
    Dr. Pamela Gay: It’s actually the highest concentration of geysers on the planet. There are actually very, very few places on the planet Earth that have geysers because the required conditions. There’s – It takes a lot to get a geyser.
    So the only places on the planet that we really see geysers are up in Alaska. We have them at Yellowstone. There’s a place in Chile; out in the eastern-most islandy area of Russia. Iceland – like, all of Iceland – and then out in New Zealand. All of these places have a lot of volcanic activity and they’re the only places. Just six places on the entire planet that have geysers.
    Yellowstone has the most. It has a couple dozen of them but they do come and go with time, so a geyser today – hole in the ground tomorrow.
    Fraser Cain: Right. And the – So the key with Yellowstone, of course, is that there is a supervolcano underneath which is generating all this volcanic activity. And one of the interesting side effects of having a supervolcano that could utterly devastate a goodly chunk of the continental United States is there’s some really pretty geysers.
    Dr. Pamela Gay: This is true. And Old Faithful’s the one that we know the most about. This is one that goes off roughly every 60 to 90 minutes. Due to drought conditions, it seems to be taking longer and longer to re-explode. But it only shoots stuff into the air, anywhere between 100 and 200 feet – divide by 3 to get to meters.
    But there are others that blast steamy water significantly higher. There is one called Steamboat, which its last eruption was in July 2013, as far as I know. It seems to go off every five to ten years and when it goes off, it goes off for about ten minutes and geysers 300 feet – that’s like 100 meters – basically straight up. So –
    Fraser Cain: It takes years for it to go off?
    Dr. Pamela Gay: Yes, yes.
    Fraser Cain: Wow.
    Dr. Pamela Gay: It takes that long for it to build up the pressure, build up the pressure, build up the pressure; undergo massive phase change; explode steam into the air.
    Fraser Cain: Okay. I was going to try and show – I’m going to show off a little bit of the – of Old Faithful for the folks who are watching the livestream – which, by the way, if you want to watch us live, we do the show every Friday afternoon. So, I can play some audio. Well, it won’t help for the podcasts.
    So, that’s just amazing. Yeah, I – Bucket list: I have got to go and see a live geyser. Clearly, this is going to be on my list of things to do.
    So, what is causing the geysers of Yellowstone? And then we can sort of go to some of the other places.
    Dr. Pamela Gay: So, geysers on the planet Earth, which is actually the only place that there are true geysers in the geological definition of what a geyser is. True geysers, you have a underground cavity of some sort that has extremely hot rock beneath it. This cavity with the hot rocks beneath is filling up with water. As it fills up with water, it’s held under pressure in this cavity; filling up with water, filling up with water. That water is heating up and, as anyone who’s watched the stove knows, it takes time for water to heat up.
    So you have two things happening: Water flowing in; that water is getting heated by the hot stuff underneath. Now, because it’s all held under pressure, it is able to actually get super-heated. This means that it’s able to get well above the boiling point – well above that point where it wants to be steam – before it finally manages to break free, get so hot that it explosively goes from water to steam – all of it kind of all at once – and explodes through a fissure at the top of this cavity.
    Fraser Cain: Right. And we can get those, not only in places like Yellowstone, but we can actually get those down at the bottom of the oceans as well, right? We get these really cool underwater geysers.
    Dr. Pamela Gay: Well, with – The things that we see under water isn’t so much geysers as we do have underwater volcanoes: Underwater fissures in the Earth that allow magma to escape, lava to escape. And, in these places, water does actually get brought up to boiling but it’s the water at the bottom of the ocean. So it’s a kind of weird situation. And it’s also held under pressure, so it’s happening at different temperatures. Most of the time, you just end up with smoke and gas and stuff coming out and you end up with these underwater smokes.
    But there was recently a case of a brand new island coming into existence and almost taking out a boat in the process, where there was –
    Fraser Cain: Wow.
    Dr. Pamela Gay: – an underwater volcano and these people in a yacht, out cruising around, were like, “What is this weird stuff all over the surface of the ocean?” And they go sailing over and they’re like, “There’s pumice floating all over the ocean. What is going on?” And then they noticed the ocean is kind of bubbling. And so, they go away quickly. They back away from the pumice expanding across the sea and then, all of a sudden, – Kabluey! New island is explosively formed; lots of bubbling, boiling – new island.
    So, we do have all sorts of – The planet’s alive. The planet is alive.
    Fraser Cain: Yeah.
    Dr. Pamela Gay: But the only place where we do see this geyser experience, which is separate from volcanic stuff – the geyser is the heating of the water, the water explosively undergoing phase transition, coming out through the surface as steam, shooting into the air, emptying out the cavity, allowing the process to start over.
    Fraser Cain: Now, we don’t have any geysers here, that I know of, in Canada –
    Dr. Pamela Gay: You do not.
    Fraser Cain: – but here, on the west coast, we have a bunch of hot springs.
    Dr. Pamela Gay: Yes.
    Fraser Cain: So, is it kind of the same process but just more extreme?
    Dr. Pamela Gay: So, with hot springs, it’s not that you have this explosive phase transition going on. Springs happen everywhere. Springs are simply a place where you have water that seeps up from underground, through the surface. It’s where an aquifer, an underwater reservoir, an underground stream, lake – whatever form of underground water it is – escapes onto the surface. This is where rivers start, springs start, streams start. They’re great sources of drinking water and they come in hot and cold.
    The hot ones exist where – like you have there in Vancouver – there’s lots of local volcanism and that volcanism is heating the rocks underground and these heated rocks are then heating the water underground and then the water is coming up through the surface. So, it’s just a – It’s just a regular spring that happens to be near hot rocks.
    Fraser Cain: So, Yellowstone is the one place we talked about. Where else can we see them? Iceland?
    Dr. Pamela Gay: Iceland is kind of covered in geysers. It’s – This is what happens when you have a new section of land being kind of formed all the time.
    We also have these out in the southern area of Alaska, where there’s, again, lots of active volcanoes. Then, if you go all the way east in Russia – out to the part of Russia that’s just north of Japan – there’s a lot of active volcanoes there and also geysers. Then, in Chile where there’s active volcanoes, there’s a small a small area of Chile where there is also geysers. And then, northern New Zealand has geysers. Again, all of these are tectonically, volcanically active parts of the planet.
    Fraser Cain: So – So we’ve talked about what the geysers are on Earth. Now, let’s take this concept and start to explore the solar system with it.
    So, where else do we find geysers, in the loosest sense of the term, around the solar system?
    Dr. Pamela Gay: So, here’s the thing. We misuse the word geyser all the time. It’s just sort of like you might grab a tissue that is made by a company that isn’t Kleenex and you still call it a Kleenex because it is a rectangle of flimsy stuff that you can use when you have a cold or to clean your glasses. But it’s not a Kleenex.
    So, when we see stuff spewing out of the surface of a rocky body – and that stuff happens to be water in nature – we call it a geyser, even if it might not actually be a geyser.
    And we see not-geyser places, where volatiles like water are getting shot out the surface of the world, kind of all over the outer solar system.
    So Triton, we noticed with the Voyager missions; Enceladus. We were able to see these around Saturn. Then Europa was the big discovery this week but all of these things aren’t geysers. They – They’re sometimes called cryogeysers, which is a little bit closer to the truth. Cryovolcanoes is the more – if you start digging through what astro – not astrophysicists – if you start digging through what geophysicists –
    Fraser Cain: Right.
    Dr. Pamela Gay: – and planetary scientists want them to be called, those are better terms.
    Fraser Cain: They’re like cryovolcanic plumes.
    Dr. Pamela Gay: Yes. Yes, they are.
    Fraser Cain: Right. And so, in this case, because they’re not getting heat up by rock – Is that sort of –
    Dr. Pamela Gay: Well, it’s actually that lack of phase change that’s going on.
    So, for instance, when we look at Enceladus or Europa, where we have, we think, subsurface liquid water and sub-water tidal heating of some sort – so, hot rocks – we don’t have a phase change to steam. What we have is a cavity that is getting filled with melted water and that melted water does get pressurized and then goes up through the vent in the ice, whether it be a crack or whatever, and escapes as vapor but not as steam.
    Fraser Cain: Well, so, let’s talk about what’s going on, then, with Enceladus and Europa. I – Let’s start with Enceladus, just because I feel like the evidence is a lot clearer and we’ve definitely seen this, thanks to Cassini flying around and around and through the plume.
    So, what’s happening over on Enceladus?
    Dr. Pamela Gay: So, what I love is you’re asking me something that the general answer is: Don’t totally know but it’s awesome.
    Fraser Cain: Yeah.
    Dr. Pamela Gay: Sometimes that’s the answer you get in science.
    So, what we see is this icy moon has dark, stripey bands that we have actually named well. They have the awesome name of “tiger stripes” and this may be, like, one of the very first times I’ve said something was named well in astronomy and space science.
    Fraser Cain: As opposed to “black holes”, “big bang” –
    Dr. Pamela Gay: Yeah.
    Fraser Cain: It’s the worst names, yeah.
    Dr. Pamela Gay: Yeah. So the Cassini mission, which is slowly working out through the last parts of its orbits, early on, revealed that there are four dark tiger stripes. And these appear to be some sort of a linear depression. So, it’s not just a color difference, there’s actual, like, topography associated with these darker stripes. They’re about 2 to 4 kilometers wide, about a half a kilometer deep. So, these are big structures.
    And there’s evidence that these plumes of vapor of volatiles that we see exploding away, being released with violence away from the surface of Enceladus, are coming out through these tiger stripes.
    Fraser Cain: Right. And, you know, not truly geysers but cryovolcanic plumes. You know, one of the really exciting things – we’ll talk about this with Europa as well – is that, you know, with the discovery of these, you know – that these objects probably have some kind of ice shell with some kind of liquid ocean underneath – you know, then you’re like, “Well, we want to explore those oceans. We want to see if there’s life there.” Because where do we find life on Earth? We find – You know, wherever we found water on Earth, we find life.
    And so the analogy is like, “Well, we should totally go send a submarine down into these worlds and find out if there’s any life down there.”
    But Enceladus, and now Europa, have been spewing this material off into space, that we can literally just fly a nose through and find out – you know, taste – or a tongue – taste the chemicals. Taste the organic material. Taste the soup.
    Dr. Pamela Gay: I think rather than taste, it’s better to say, “We’re going to do mass spectroscopy on these suckers.”
    Fraser Cain: Or, taste; spacecraft’s version of tasting. But, yes, I agree with you.
    So, we’ve talked about – We’ve talked about Enceladus, so let’s talk about Europa. And first, let’s kind of roll this out a little bit and – because, you know, the big announcement this week – but there was actually some previous announcements and some theories and some hints and speculations.
    So, give us a bit of a history on this discovery.
    Dr. Pamela Gay: So, one of the things that I start out describing was with – One of the things I started off describing was with water geysers here on Earth. You have a cavity that fills up with water, ends up under a lot of pressure, kablueys out through the top. And this is a regular process sometimes, where, like, Old Faithful – every 60 to 90 minutes. But then, Steamboat, we’re looking at every many years. And so this is one of those processes that can take a long time.
    Now, with Europa, Hubble Space Telescope had taken a good look at it several years ago and had seen hints that there was something off to the side, reflecting light. It had been captured in infrared and there was this, “Is that geysers? Are we seeing –” Yes, I know “geysers” is the wrong word. I’m the one that said that earlier. There was this, “Is this a plume?”
    And we wanted to believe it was a plume. We want Europa to have liquid near the surface. And we kept looking and kept looking and there’s all sorts of stories with headlines like, “Europa’s Plumes Disappear”, “Europa’s Plumes Unconfirmed”. Were we seeing things?
    And scientists are diligent. We are capable of just sitting there, waiting for the pot to boil, waiting for the pot to boil, waiting for the pot to boil. And we don’t know how many times it boiled when we left the room and then someone came along and added cold water.
    But, eventually, Hubble looked back again and, once again, was able to catch these plumes in the moment, going off, using Hubble Space Telescope.
    Fraser Cain: Right. And so, I guess the key here is that it was caught – That it’s not constantly going off. Like Old Faithful, there is a – some time in between and then the event – the geyser goes off but, in this case, the cryo volcanic plume goes off and it happened to be seen by Hubble.
    Dr. Pamela Gay: And what’s amazing is looking at Europa, you again see these cracks in the surface. You again see these different colors and different parts. There is a chemistry to these worlds that is getting revealed in what’s allowed to escape through the surface. And it seems to be that this is a fairly common phenomena.
    Back when Voyager flew past Neptune and captured images of Triton, we got these beautiful images that seemed to demonstrate plumes that had settled back over 150 kilometers to the surface of this icy world orbiting Neptune. So here, we’ve got plumes off of the moons of Saturn, of Jupiter, of Neptune. This is a common phenomena that we’re still struggling to understand.
    We don’t have the ability to do all of the testing we can do down here on Earth, where we can actually start to, like, map out these chambers and follow the entire process and – We can’t do that, yet, on these distant icy moons but –
    Fraser Cain: But it’s possible that, you know – that these kinds of under-ice oceans exist across all of the icy bodies across the entire solar system; not just Europa, not just Enceladus – the ones that are even having these gravitational interactions. It’s possible they’re on Pluto, Charon, Eris –
    Dr. Pamela Gay: And this is where we get –
    Fraser Cain: Sedna –
    Dr. Pamela Gay: This is where we get confused. Because we can understand how Europa’s getting heating. It’s tidally locked with several of the other moons. It’s getting regularly distorted. We can see the reflections of differences in rotation between the surface and subsurface in the cracks. We understand Europa getting internally heated through tidal forces.
    We can get it – how that would happen – with Enceladus. But, when you start looking at Pluto –
    Fraser Cain: Mm-hmm.
    Dr. Pamela Gay: Pluto’s a tiny world. It just doesn’t have the levels of getting squished and released, squished and released, that we thought were needed. But, you know, the universe likes to prove us wrong –
    Fraser Cain: Right.
    Dr. Pamela Gay: – by being far more interesting than our human minds could imagine.
    And so now, we’re trying to understand how it is that we appear to have a young, active surface on Pluto. And we don’t know yet what all we’re going to discover as we continue to dig through these brand new images that are still coming down from New Horizons.
    Fraser Cain: Yeah, it was great. When we talked to some of the scientists in advance about what they were expecting to see in New Horizons, nobody expected to see what they saw on the surface of Pluto. They were not expecting to see this young surface. They would have expected something that was ancient; icy, but not necessarily with these, like, mountains of water, ice and the – but also, the fresh, clean parts of the surface as well. This was a total surprise.
    And so, I guess, you know – Are, like, the cryovolcanists and the geyserologists the new cool kids, with all of this stuff being discovered?
    Dr. Pamela Gay: Well, I think this is actually more along the lines of the planetary science equivalent of trying to understand magnetic fields. It’s one of those complex modeling problems of: How do you guess at what’s happening at what level and what is driving what? And you have to make estimates of the amount of radioactive material that’s providing heating, and all these other different things, to try and model the – well, it starts to become hydraulics.
    Fraser Cain: Mm-hmm.
    Dr. Pamela Gay: And so, here we have the hydraulics of icy moons is that new magnetic field’s scary question of, “Well, how does magnetic fields affect that?” Well, how does hydraulics affect icy moons?
    Fraser Cain: So, let’s talk a bit about what this means for the search for life. You know, if you talked to scientists 20 years ago and said, “Where should we be looking for life?” most of them would have said, “Mars.”
    Dr. Pamela Gay: Yeah.
    Fraser Cain: And you talk to them now and they will all tell you –
    Dr. Pamela Gay: Europa.
    Fraser Cain: Europa.
    So, you know, what do these geysers – You know, if they have – You know, if we can confirm these geysers, find their locations, figure out what’s causing them, what does this tell us about the potential for life on Europa?
    Dr. Pamela Gay: It tells us that there is a thermal gradient on Europa and it’s a thermal gradient that’s that third thing that’s required for life. You have to have nutrients, you have to have a solvent and you have to have a thermal gradient. And we know the solvent is there because – water. We don’t know yet if there’s nutrients but, you know, we keep finding organic molecules pretty much everywhere we look in our universe: Nebulas, other worlds. They’re just about everywhere.
    So, now it’s the, “Let’s go flip this rock over and look to see what bugs live underneath it.” Except it’s actually more like, “Let’s go dig down through five kilometers of ice and see what’s beneath it.” And, there could be bugs. There could be jellyfish. There could be protozoa. There could be single-celled things that don’t even have –
    Fraser Cain: Space whales.
    Dr. Pamela Gay: – nuclei or mitochondria. There could be space whales but that one, I doubt.
    Fraser Cain: Come on, space whales.
    Dr. Pamela Gay: Well, I think space whales would require an atmosphere –
    Fraser Cain: Mm.
    Dr. Pamela Gay: – so maybe space sharks.
    Fraser Cain: Mm-hmm.
    Dr. Pamela Gay: Whatever it is has to live fully submerged.
    Fraser Cain: Yeah.
    Dr. Pamela Gay: But now, we have this great unknown. We know that the thermal vents in the bottom of the Earth’s oceans are rich with life. And so, I mean, it could be Enceladus, Europa, Mars, all completely dead, dead, dead – nothing alive there – but it could be that we’re going to find some alien version of what we found down in the Marianas Trench, here on Earth. A completely new ecology that, when you and I were kids, we were told totally could not exist because there’s no sunlight. Now we know – our books were wrong.
    Fraser Cain: So –
    Dr. Pamela Gay: And this is why we do science.
    Fraser Cain: I don’t normally mash the chat with the live show – with the episode – because the people who are listening can’t actually see the chat that happens during our live show. By the way, if you’re listening to this, we do this live and you can come and watch us and hang out with us. But TacTang just gave the name for what these must be called: Crysers. So –
    Dr. Pamela Gay: I appreciate that, yes.
    Fraser Cain: Yeah. So, Tac, that’s fantastic. I am going to make sure that all of our writers on Universe Today start using that term now. We’re going to make that stick. So – Crysers.
    Dr. Pamela Gay: That is –
    Fraser Cain: That’s a – That’s perfect.
    Dr. Pamela Gay: – far better than cryogeysers –
    Fraser Cain: Yeah, cryo – yeah, exactly.
    Dr. Pamela Gay: – which is the – I like “crysers”.
    Fraser Cain: So, let’s – Before we sort of wrap this up, let’s talk about missions to Europa that can help us get to the bottom of this. So, boy, sure would be handy if there was a mission arrive – that had recently arrived at Jupiter with the capability of viewing Europa a little better. Does this exist?
    Dr. Pamela Gay: Well, so we have the Juno mission. Juno wasn’t exactly designed to explore Europa. In fact, it was kind of designed to stay the expletive away from Europa because we don’t want to pollute Europa with our Earth germs.
    Fraser Cain: Also, attempt no landing there.
    Dr. Pamela Gay: Right, exactly. Exactly. 2001 Space Odyssey got that one completely right.
    So we do have a spacecraft out there. Its mission is not, not, not – can’t say this enough – its mission is not to explore Europa. Its job is to explore the gravitational field, the magnetic field, the magnetosphere, the poles – all of the cool parts of Jupiter that we want to know more about. So it’s there to look at Jupiter, thus the name Juno.
    So, hey, Congress – I’m looking at you. Hey, European Union, I’m also looking at you. Can we have money for science? Can you, like, give us a spacecraft, please? There’s lots of us that would want your spacecraft money.
    Fraser Cain: But haven’t – I mean, isn’t there a mission to Europa in the works?
    Dr. Pamela Gay: There is a mission in planning phase. It is not going to be one to land and explore, it is one to orbit. So, yeah. There is a clipper in the plans. They have announced all of the instruments for it. This is in the process of being built.
    We do have some serious technological hurdles to figure out before we can go land. Like: How do we do this without killing everything there with, like, the single-celled version of small pox?
    Fraser Cain: Yep.
    Dr. Pamela Gay: But –
    Fraser Cain: That was a very dark analogy but, yes, we understand.
    Dr. Pamela Gay: Yeah. So, we also – when they awarded all the instruments for the clipper that we’re sending to Europa, we didn’t know yet about these plumes. And so I’m sure there’s instruments that people would love to get the chance to go back and do a little bit of re-engineering on, which will take a little bit of money – to just take advantage of all of these new results we have from Hubble.
    Fraser Cain: It should be called “Cryser” and then have some kind of acronym that, you know, Cryovolcanic – I don’t know. There’s the rest of the acronym.
    But anyway, yeah – absolutely.
    So the point is that very fortunately, with these kinds of discoveries, Europa has become really the center of attention for both NASA and EASA and I think that we should see a lot more close-up pictures and information on Europa shortly. And we’ll get to the bottom of this and try and see how many there are, where they happen.
    I mean, we really need a spacecraft like Dawn, that’s going to go into orbit around Europa, stay there and study it to the Nth degree at super-high resolution. Like, we just – I’m bored of these same Europa pictures that we keep having to look at. I need new ones.
    Dr. Pamela Gay: They’re kind of stunning. So, yeah. I get that –
    Fraser Cain: Boring.
    Dr. Pamela Gay: – you’re bored with it.
    Fraser Cain: Bored.
    Come on. Like, the new pictures of Pluto – that was the greatest thing ever. And now – And now I got Pluto pictures for years. So, I need –
    Dr. Pamela Gay: So, we will at least have a mass spectrometer. The currently-planned spacecraft has a plasma instrument for magnetic sounding; it has a magnetometer, which is named “Icemag” because, of course it is, which is going to do internal characterization of Europa. We have a mapping, imaging spectrometer, which basically means you look at the surface with the kinds of cameras to let you go, “And there is CO2 here and there is H2O there.”
    Then there’s, of course, an imager, so we will get those shiny, pretty images that you want. There’s a radar. There’s a thermal-emission imaging system, which is a fancy way of saying we’re going to be able to tell what the temperature variations are across the surface. There’s an ultraviolent spectrograph, to just give us more information beyond what our eyes could see. And we are even going to be catching dust, to do a surface dust mass analyzer.
    So, it’s a complicated mission. It’s going to do 45 fly-bys of Europa at altitude varying from 1,700 miles to 16 miles and will not crash into the surface. But we have a few years to go.
    Fraser Cain: That sounds exciting.
    Alright. Well, thank you very much, Pamela. We’ll talk to you next week.
    Dr. Pamela Gay: My pleasure.
    Female Speaker: Thank you for listening to Astronomy Cast, a non-profit resource provided by Astrosphere New Media Association, Fraser Cain and Dr. Pamela Gay. You can find show notes and transcripts for every episode at astronomycast.com. You can email us at info@astronomycast.com. Tweet us @astronomycast. Like us on Facebook or circle us on Google Plus.
    We record our show live on YouTube every Friday at 1:30 p.m. Pacific, 4:30 p.m. Eastern or 2030 GMT. If you missed the live event, you can always catch up over on cosmoquest.org or on our YouTube page. Our music is provided by Travis Serl, and the show was edited by Susie Murph.
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    Duration: 33 minutes

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