WEBVTT - The Burning Mountains of Io, Part 1 0:00:03.000 --> 0:00:06.760 Welcome to Stuff to Blow Your Mind production of iHeartRadio. 0:00:12.760 --> 0:00:14.600 Hey you welcome to Stuff to Blow Your Mind. My 0:00:14.720 --> 0:00:15.520 name is Robert. 0:00:15.360 --> 0:00:18.800 Lamb and I am Joe McCormick. And today on Stuff 0:00:18.840 --> 0:00:21.239 to Blow Your Mind, we're going to begin a series 0:00:21.360 --> 0:00:25.840 on Jupiter's moon Io. Now, years ago, we did a 0:00:25.840 --> 0:00:29.440 whole series of episodes on the moons of Jupiter as 0:00:29.480 --> 0:00:33.240 a whole, focusing mainly on the four Galilean moons. We'll 0:00:33.240 --> 0:00:36.120 talk more about that in a bit. But recently I 0:00:36.240 --> 0:00:39.000 decided I wanted to come back and do a deeper 0:00:39.040 --> 0:00:44.519 revisit on Io. In particular, iobing Jupiter's innermost moon. And 0:00:44.800 --> 0:00:48.720 this was in part because I learned some new interesting 0:00:48.760 --> 0:00:51.720 things about it. But what really triggered this, this new 0:00:51.800 --> 0:00:54.800 rabbit trail of research, was that one night, I don't know, 0:00:54.840 --> 0:00:57.880 sometime in the past week, I got obsessed with new 0:00:58.200 --> 0:01:02.800 imagery generated by the NASA Juno mission in late twenty 0:01:02.800 --> 0:01:06.160 twenty three and twenty twenty four. And so, Rob, if 0:01:06.160 --> 0:01:07.920 it's all right with you, I'd like to start off 0:01:08.600 --> 0:01:10.840 with us looking at one of these images in particular, 0:01:10.920 --> 0:01:12.840 and folks at home, we will describe it for you. 0:01:13.319 --> 0:01:14.600 All right, let's do it so. 0:01:14.800 --> 0:01:19.600 This is a very crisp color image of Io's northern 0:01:19.760 --> 0:01:24.399 polar region taken by the Juno spacecraft on December thirtieth, 0:01:24.480 --> 0:01:28.600 twenty twenty three, during Juno's fifty seventh close flyby of 0:01:28.640 --> 0:01:31.880 the Moon. The image was released by NASA JPL based 0:01:31.920 --> 0:01:36.160 on data taken by the Juno spacecraft, with some additional 0:01:36.319 --> 0:01:41.400 image processing by somebody named Gerald Eichstadt. And I found 0:01:41.400 --> 0:01:46.399 this picture so weird and thrilling to the imagination. For 0:01:46.440 --> 0:01:48.200 those who can't look it up, if you can look 0:01:48.200 --> 0:01:51.000 it up, i'd recommend checking it out again. Keywords are 0:01:51.000 --> 0:01:55.200 probably Io northern Polar Region, December twenty twenty three. I'm 0:01:55.200 --> 0:01:58.000 sure that I'll pull it up. But for those who 0:01:58.000 --> 0:02:02.240 can't look it up, what we're seeing here is half 0:02:02.480 --> 0:02:07.120 of the Moon as an illuminated hemisphere, fading into darkness 0:02:07.160 --> 0:02:10.320 at the meridian. Now, there's a lot we could say 0:02:10.400 --> 0:02:13.080 about the color of Io, and we'll come back to 0:02:13.120 --> 0:02:15.480 that actually in a few minutes. But in this photo 0:02:16.320 --> 0:02:20.880 we see wide empty planes of a faded rose color, 0:02:20.960 --> 0:02:26.160 a kind of pale, rusty pink, dotted by gaping sunken 0:02:26.400 --> 0:02:31.440 craters and mountains that rise up into space. With alarming sharpness. 0:02:31.480 --> 0:02:35.079 In some cases, they're rising up like thorns, casting these 0:02:35.160 --> 0:02:39.400 long shadows on their night side slopes, And the craters 0:02:39.440 --> 0:02:42.560 are often darker than the plains around them, as if 0:02:42.560 --> 0:02:46.079 containing silent, cold seas of water. That's what I saw 0:02:46.120 --> 0:02:47.680 when I first looked at this. But of course we 0:02:47.720 --> 0:02:49.720 know it's not going to be water in those craters. 0:02:50.560 --> 0:02:53.639 What is in those craters? We'll get to that. Then 0:02:53.720 --> 0:02:57.000 in some spots we see surface features that look almost 0:02:57.040 --> 0:03:01.080 like a biological growth or infection, and a kind of 0:03:01.400 --> 0:03:06.080 mass of yellow orange slime mold shaped just like pure chaos, 0:03:06.120 --> 0:03:10.200 just reaching its fingers out across the moon looking for something. 0:03:10.680 --> 0:03:14.640 And then surrounding these colonies of mold, and around the 0:03:14.680 --> 0:03:19.240 sharp mountains there are pale gray flats that look like 0:03:19.680 --> 0:03:23.920 borders marked in ash. I just love this photo. It 0:03:24.080 --> 0:03:28.520 makes me want to personally explore space. It's bizarre, lovely, 0:03:28.800 --> 0:03:31.200 frightening and seething with drama. 0:03:32.480 --> 0:03:37.240 Yeah, absolutely, this image. It looks like perhaps the pinkish 0:03:37.280 --> 0:03:38.880 disease scalp of a zombie. 0:03:39.520 --> 0:03:39.600 It. 0:03:39.920 --> 0:03:42.000 I also thought, well that this looks exactly like the 0:03:42.040 --> 0:03:45.040 sort of world that would be your destination in a 0:03:45.080 --> 0:03:47.680 Doom video game. Oh, you know, it just looks like 0:03:47.720 --> 0:03:50.760 a hellish planet where you're probably going to have to 0:03:50.800 --> 0:03:51.839 blast demonoids. 0:03:52.360 --> 0:03:55.400 I very much see the zombie comparison, especially like a 0:03:55.440 --> 0:03:58.960 close up on zombie skin, because when you zoom in, 0:03:59.080 --> 0:04:02.000 especially on these mountains, I see something that looks like 0:04:02.040 --> 0:04:06.840 the texture of those liquid latex makeup effects, where there's 0:04:06.920 --> 0:04:09.440 like a scab or a scar on a zombie. That's gonna, 0:04:09.680 --> 0:04:11.280 you know, if it's a full chew movie, it's gonna 0:04:11.280 --> 0:04:13.840 peel off. And sorry to get gross, but that is 0:04:13.880 --> 0:04:14.560 what it looks like. 0:04:15.160 --> 0:04:17.680 It looks infected. It looks infected. 0:04:17.920 --> 0:04:21.360 In more ways than one. But so anyway, this photo 0:04:21.440 --> 0:04:24.719 and some others got my brain racing about IO. I 0:04:24.760 --> 0:04:27.240 started reading some things about it, and I realized that 0:04:27.480 --> 0:04:29.599 there's a lot of interesting stuff about this moon that 0:04:29.640 --> 0:04:32.400 we did not get into in our larger series on 0:04:32.440 --> 0:04:35.080 the Galilean Moons years ago. So I wanted to come 0:04:35.120 --> 0:04:37.920 back and go deep on this moon. That's why we're 0:04:37.960 --> 0:04:38.599 here today. 0:04:39.080 --> 0:04:41.520 Yeah, I was looking back at our notes on the 0:04:41.640 --> 0:04:45.040 Jovian Moons series and I found that, yeah, we didn't 0:04:45.080 --> 0:04:47.520 even really get into the mythology of Io at all, 0:04:47.839 --> 0:04:50.240 Like where this name comes from? And all of that 0:04:50.279 --> 0:04:52.040 is quite fascinating as well, So that's going to be 0:04:52.080 --> 0:04:54.440 fun to explore as we proceed here. 0:04:55.200 --> 0:04:59.400 Yeah, knowing the mythology definitely does enliven and kind of 0:04:59.400 --> 0:05:02.719 throw into shadows over the geology and all of the 0:05:02.720 --> 0:05:06.719 physical facts. So I figure a good place to start 0:05:06.760 --> 0:05:09.400 is to just do a brief kind of refresher course 0:05:09.560 --> 0:05:14.400 on the Moon. So Io is the innermost of the 0:05:15.000 --> 0:05:18.360 what are known as Jupiter's Galilean moons. These are the 0:05:18.440 --> 0:05:22.920 four large moons that were discovered by the Italian astronomer 0:05:22.960 --> 0:05:28.520 and scientific pioneer Galileo Galilei in January sixteen ten using 0:05:28.600 --> 0:05:32.880 a refracting telescope with twenty times magnification power. These four 0:05:32.920 --> 0:05:36.400 moons are from innermost to outermost. So you're starting at 0:05:36.400 --> 0:05:40.000 the planet, going out, you get Io, then you get Europa, 0:05:40.240 --> 0:05:45.359 then Ganymede, than Callisto. Now these are not Jupiter's only moons. 0:05:45.400 --> 0:05:49.680 Jupiter actually has ninety five total moons according to the 0:05:49.680 --> 0:05:54.600 International Astronomical Union, and that's not even everything orbiting the planet. 0:05:54.600 --> 0:05:57.200 That's just the recognized moons. It's not including a bunch 0:05:57.240 --> 0:06:00.560 of small orbiters reaching down to the scale of human furniture. 0:06:01.800 --> 0:06:06.200 We've talked on the show before about how the observation 0:06:06.520 --> 0:06:11.279 of the Galilean moons was not just an important thing 0:06:11.360 --> 0:06:13.560 in the history of astronomy, not just like, oh, we 0:06:13.680 --> 0:06:16.560 learned about some new things out in the sky in 0:06:16.600 --> 0:06:19.080 the Solar System, but it was an important moment in 0:06:19.120 --> 0:06:22.799 the history of science because it was one of many 0:06:23.320 --> 0:06:28.120 pieces of evidence that Galileo marshaled against the geocentric model 0:06:28.200 --> 0:06:33.200 of the cosmos. Because, to simplify the argument, if it 0:06:33.240 --> 0:06:37.360 can be shown that objects orbit another planet like Jupiter, 0:06:37.760 --> 0:06:40.760 why then should we assume that everything in the universe 0:06:41.000 --> 0:06:44.360 orbits the Earth. Maybe instead, the Earth and the planets 0:06:44.360 --> 0:06:47.800 all orbit the Sun, and moons orbit the planets, and 0:06:48.000 --> 0:06:51.880 orbital pathways are a result of some deeper general principle 0:06:51.920 --> 0:06:56.000 other than everything goes around the Earth. Now, technically, when 0:06:56.120 --> 0:06:59.800 Galileo first spied the moons of Jupiter through his telescope, 0:07:00.640 --> 0:07:03.480 at the very beginning, he thought that they were fixed stars. 0:07:03.480 --> 0:07:04.080 He thought he was. 0:07:04.000 --> 0:07:07.640 Looking at stars beyond Jupiter and marked their place. But 0:07:07.680 --> 0:07:09.840 then he looked at Jupiter again later and the stars 0:07:09.840 --> 0:07:12.240 were in a different arrangement, so he realized, like, oh, 0:07:12.280 --> 0:07:14.680 those are not stars, those are something else in the foreground. 0:07:14.680 --> 0:07:18.320 They're going around the planet. And when he first saw them, 0:07:18.360 --> 0:07:21.800 he thought he saw three, not four, because he was 0:07:21.880 --> 0:07:26.240 not able to distinguish Io and Europa. Europa being the 0:07:26.280 --> 0:07:29.160 second innermost of the large moons, he was not able 0:07:29.200 --> 0:07:31.520 to distinguish them as separate points of light. It was 0:07:31.560 --> 0:07:34.040 only in later observations he realized that there were four 0:07:34.120 --> 0:07:38.160 of them. Now, in terms of mass and volume, Io 0:07:38.400 --> 0:07:42.760 is the third largest of Jupiter's moons, after Ganymede and Callisto, 0:07:43.360 --> 0:07:47.720 and it is just slightly larger in diameter than Earth's Moon. 0:07:48.240 --> 0:07:51.440 As the nearest of the Galilean moons to Jupiter, its 0:07:51.480 --> 0:07:54.640 average orbital distance from the planet is four hundred and 0:07:54.640 --> 0:07:57.760 twenty two thousand kilometers or two hundred and sixty two 0:07:57.840 --> 0:08:02.400 thousand miles. Now, the fact that you might know which 0:08:02.480 --> 0:08:05.040 really sets Io apart and is probably going to be 0:08:05.080 --> 0:08:08.920 one of our main focuses in this series, is that 0:08:09.040 --> 0:08:14.400 Io is the most volcanically active object in our solar system, 0:08:14.800 --> 0:08:19.200 with hundreds of active volcanoes at any given time. I 0:08:19.240 --> 0:08:22.800 think there are more than one hundred and fifty active 0:08:22.880 --> 0:08:27.120 volcanoes that have been directly observed, and scientists have estimated 0:08:27.280 --> 0:08:29.480 based on what we have observed, that there are probably 0:08:29.560 --> 0:08:42.760 like four hundred or so in total on the surface. Now, 0:08:42.840 --> 0:08:45.400 just earlier today, I was actually reading the story of 0:08:45.480 --> 0:08:49.760 how the existence of those volcanoes on Io was first confirmed. 0:08:50.320 --> 0:08:53.360 And this actually brings us back to the question of 0:08:53.520 --> 0:08:56.120 the color, the color of the surface of the Moon, 0:08:56.360 --> 0:08:59.520 which I brought up earlier, and where I was reading 0:08:59.559 --> 0:09:03.319 about this was in Carl Sagan's book Cosmos, first published 0:09:03.320 --> 0:09:05.559 in nineteen eighty, sort of as a companion to the 0:09:06.640 --> 0:09:10.480 documentary series he did. Sagan was writing about Io in 0:09:10.559 --> 0:09:14.600 that saying that the following was his favorite of what 0:09:14.640 --> 0:09:18.920 he called the traveler's tales that were returned by the 0:09:19.000 --> 0:09:19.920 voyager probe. 0:09:20.440 --> 0:09:21.520 Are you going to do the voice? 0:09:22.120 --> 0:09:24.040 I appreciate you putting me on the spot, but no, 0:09:24.160 --> 0:09:25.200 I can't do the voice. 0:09:25.240 --> 0:09:25.320 No. 0:09:25.720 --> 0:09:28.280 Anytime I read Sagan, though, I hear it in his voice. 0:09:28.360 --> 0:09:29.720 Oh good, I know exactly what. 0:09:29.800 --> 0:09:29.959 Yeah. 0:09:30.000 --> 0:09:33.160 I hear it in the voice too. Yeah, but I can't. Okay, 0:09:33.200 --> 0:09:36.120 So here it is in my voice, his words, my voice, 0:09:36.800 --> 0:09:40.880 Sagan writes, quote, before voyager we were aware of something 0:09:40.960 --> 0:09:45.199 strange about Io. We could resolve few features on its surface, 0:09:45.280 --> 0:09:50.040 but we knew it was red, extremely read redder than Mars, 0:09:50.200 --> 0:09:54.000 perhaps the reddest object in the Solar System. Over a 0:09:54.040 --> 0:09:57.040 period of years, something seemed to be changing on it 0:09:57.360 --> 0:10:01.200 in infrared light and perhaps in its radar reflection properties. 0:10:01.640 --> 0:10:05.199 We also know that partially surrounding Jupiter in the orbital 0:10:05.240 --> 0:10:09.440 position of Io was a great doughnut shaped tube of 0:10:09.600 --> 0:10:16.080 atoms sulfur and sodium and potassium material somehow lost from Io. 0:10:17.720 --> 0:10:20.720 Oh wow, what a mystery. Okay, so you know, we've 0:10:20.720 --> 0:10:23.840 never gotten close enough to see what's happening on the surface, 0:10:23.880 --> 0:10:26.400 but for some reason, it looks super red, redder than 0:10:26.440 --> 0:10:29.240 anything else we can see around, and it's leaving this 0:10:29.480 --> 0:10:32.920 trail of atoms in space, like it's just spitting out 0:10:32.960 --> 0:10:36.520 atoms into orbit around Jupiter. And then the mystery only 0:10:36.520 --> 0:10:40.160 gets weirder once the voyager probe actually approaches the Moon 0:10:40.280 --> 0:10:43.280 and sends back images in nineteen seventy nine. What they 0:10:43.320 --> 0:10:47.240 see is very strange. First of all, the surface is 0:10:47.640 --> 0:10:51.200 multi colored, as we brought up earlier. If you see 0:10:51.920 --> 0:10:55.120 what they call true color photos of Io, they are 0:10:55.160 --> 0:10:59.440 often overwhelmingly yellow, like a I don't know, a canary 0:10:59.559 --> 0:11:01.480 or a ban and I kind of yellow except I 0:11:01.480 --> 0:11:04.280 don't know, maybe a little paler and more sickly, some 0:11:04.400 --> 0:11:10.800 kind of vomitous duckling yellow with these blotches of red, pink, gray, 0:11:11.040 --> 0:11:14.560 and green. I feel like this has too normative of 0:11:14.559 --> 0:11:17.320 a connotation, but it really does always kind of remind 0:11:17.360 --> 0:11:20.800 me of sickness in some way, not trying to say 0:11:20.840 --> 0:11:23.640 io is a bad place. So one of the happier 0:11:23.679 --> 0:11:27.840 comparisons that astronomers sometimes make about the different coloration patterns 0:11:27.880 --> 0:11:30.520 is they call it a pizza planet. They're like, it's 0:11:30.520 --> 0:11:33.480 got like cheese and pepperonis and olives and all that. 0:11:33.640 --> 0:11:35.600 Well that's a way to make it attractive, I guess. 0:11:35.600 --> 0:11:37.600 But yeah, it does look like some sort of a 0:11:37.640 --> 0:11:39.720 strange like nergal world. 0:11:39.840 --> 0:11:44.920 So yeah, yeah. Also, scientists looking at the images of 0:11:44.920 --> 0:11:50.560 iosurface realized it was missing something impact craters due to 0:11:50.840 --> 0:11:55.240 its position near the asteroid belt. Sagan writes that this 0:11:55.320 --> 0:11:59.800 object really would have to have undergone repeated impacts from space, 0:12:00.080 --> 0:12:03.960 should be hammered by asteroids, by things coming down on 0:12:04.040 --> 0:12:06.680 it and leaving pocks in its surface that we would 0:12:06.720 --> 0:12:09.160 be able to see, you know, just like look at 0:12:09.160 --> 0:12:11.840 the Moon. It should maybe look something like that, but 0:12:12.000 --> 0:12:16.000 instead its surface showed little to no sign of impacts, 0:12:16.040 --> 0:12:20.880 as if something was rapidly erasing the evidence of collisions. Now, 0:12:21.040 --> 0:12:25.240 whatever was doing that erasing could not be atmospheric in nature, 0:12:25.600 --> 0:12:28.800 because Io has almost no atmosphere. It does have an atmosphere, 0:12:28.800 --> 0:12:33.600 but it's incredibly thin, made primarily of sulfur dioxide. If 0:12:33.600 --> 0:12:36.640 those surface features are being erased, they couldn't be erased 0:12:36.679 --> 0:12:40.600 by erosion of running water because the conditions on the 0:12:40.640 --> 0:12:44.600 surface of Io would not permit liquid water. So it 0:12:44.760 --> 0:12:50.920 had been theorized by some astrophysicists. Segan names an astrophysicist 0:12:51.000 --> 0:12:57.000 named Stanton Peel that Io might have erupting volcanoes due 0:12:57.080 --> 0:13:00.840 to tidal heating of its interior. So this is a 0:13:00.920 --> 0:13:03.640 frictional heating of the inside of the planet caused by 0:13:03.679 --> 0:13:06.480 gravitational forces. We'll explain more about this as we go 0:13:06.520 --> 0:13:11.000 on in the series. But that could lead to volcanic eruptions, 0:13:11.240 --> 0:13:14.280 which could do the job of repaving the surface if 0:13:14.320 --> 0:13:17.840 these volcanoes existed. But up until this point in nineteen 0:13:17.920 --> 0:13:20.120 seventy nine, there was no way to know if any 0:13:20.120 --> 0:13:22.080 of that was true. It was just an idea. That's 0:13:22.160 --> 0:13:25.040 one thing that could be going on. Here then Sagan 0:13:25.120 --> 0:13:29.240 tells of the discovery. He writes, quote Linda Moribto, a 0:13:29.320 --> 0:13:33.640 member of the Voyager navigation team responsible for keeping Voyager 0:13:33.720 --> 0:13:38.320 precisely on its trajectory, was routinely ordering a computer to 0:13:38.480 --> 0:13:41.640 enhance an image of the edge of Io to bring 0:13:41.679 --> 0:13:45.800 out the stars behind it. To her astonishment, she saw 0:13:45.840 --> 0:13:49.240 a bright plume standing off in the darkness from the 0:13:49.280 --> 0:13:53.000 satellite's surface, and soon determined that the plume was in 0:13:53.120 --> 0:13:57.560 exactly the position of one of the suspected volcanoes. Voyager 0:13:57.600 --> 0:14:00.880 had discovered, the first active volcano being on the Earth. 0:14:01.320 --> 0:14:04.480 We now know of nine large volcanoes spewing out gas 0:14:04.480 --> 0:14:07.120 and debris. Remember this was in nineteen eighty when this 0:14:07.120 --> 0:14:11.240 book was written. Nine large volcanoes spewing out gas and debris, 0:14:11.280 --> 0:14:15.840 and hundreds, perhaps thousands of extinct volcanoes on Io. The 0:14:15.920 --> 0:14:20.000 debris rolling and flowing down the sides of the volcanic mountains, 0:14:20.320 --> 0:14:24.160 arching in great jets over the polychrome landscape is more 0:14:24.200 --> 0:14:27.120 than enough to cover the impact craters. We are looking 0:14:27.200 --> 0:14:31.800 at a fresh planetary landscape, a surface newly hatched. How 0:14:31.880 --> 0:14:35.680 Galileo and Huygens would have marveled now I love that 0:14:35.800 --> 0:14:38.600 story for multiple reasons, one of which is the idea 0:14:38.680 --> 0:14:42.720 that the plume from the volcano was spotted not by 0:14:42.760 --> 0:14:47.200 somebody who was intentionally hunting four volcanoes, but in the 0:14:47.280 --> 0:14:52.000 process of trying to better resolve navigation navigationally relevant data. 0:14:53.160 --> 0:14:56.360 But I also love how it paints this picture of 0:14:56.600 --> 0:15:00.120 Io as a place of a freshness of chain. 0:15:01.400 --> 0:15:01.600 Rob. 0:15:01.640 --> 0:15:03.360 I think we've talked about this on the show before 0:15:03.400 --> 0:15:06.960 that often when we think of anything beyond Earth, things 0:15:07.000 --> 0:15:13.320 in space, we tend to think of a kind of inert, changeless, 0:15:14.520 --> 0:15:20.480 frozen or dead landscape, places where nothing all that interesting 0:15:20.560 --> 0:15:24.080 ever really happens. Like what is interesting about the places 0:15:24.120 --> 0:15:27.560 beyond Earth is kind of a I don't know, features 0:15:27.600 --> 0:15:30.240 of permanent interest, just the way things are and have 0:15:30.320 --> 0:15:33.040 always been and will always be. Obviously, we know that's 0:15:33.080 --> 0:15:35.320 not true, and if you like fast forward the tape 0:15:35.360 --> 0:15:39.240 of geologic time and cosmic time, things change a lot. 0:15:39.320 --> 0:15:42.360 But just thinking about other planets and moons seems like 0:15:42.400 --> 0:15:45.600 not a lot is happening there, and that is absolutely 0:15:45.640 --> 0:15:48.520 not the case on the surface of Io. You know 0:15:48.800 --> 0:15:51.960 he's talking Segan here is talking about Io as a 0:15:52.040 --> 0:15:56.080 place where the surface changes on a timescale of months. 0:15:57.080 --> 0:15:58.600 It is a dynamic world. 0:15:59.200 --> 0:16:01.280 And so this leads to another thing he gets into 0:16:01.320 --> 0:16:05.200 about the chemistry of Io and its volcanic activity, and 0:16:05.240 --> 0:16:09.000 how this actually relates to the strange patterns of what 0:16:09.080 --> 0:16:12.080 he called the polychrome surface, the different coloration patterns we 0:16:12.080 --> 0:16:15.280 see on the surface. Sagan writes that this is actually 0:16:15.320 --> 0:16:18.000 what we would expect to see from the release of 0:16:18.080 --> 0:16:23.080 molten sulfur and the interactions of sulfur compounds from Io's 0:16:23.160 --> 0:16:25.680 volcanoes and on the surface of the moon. So you 0:16:25.760 --> 0:16:30.040 get like these black coloration at the hottest places where 0:16:30.040 --> 0:16:32.480 the sulfur is just coming out, and maybe near the 0:16:32.480 --> 0:16:35.040 top of the volcano or the mouth of the volcano, 0:16:35.680 --> 0:16:38.640 and then nearby where there would be flows of what's 0:16:38.640 --> 0:16:41.080 coming out of the volcanoes, you get something more like 0:16:41.200 --> 0:16:44.600 red and orange. And then beyond that you get these 0:16:44.680 --> 0:16:47.680 big empty planes that are just kind of like yellow, 0:16:47.880 --> 0:16:51.560 yellowish sulfur. Now, on the subject of what is coming 0:16:51.600 --> 0:16:53.760 out of the mouth of the volcanoes, or what might 0:16:53.760 --> 0:16:57.240 be forming sort of lakes or rivers of flows beyond 0:16:57.680 --> 0:17:02.160 beyond a volcano on Io, it's worth noting that materials 0:17:02.200 --> 0:17:06.359 ejected from volcanoes tend to be very hot. That's true, 0:17:06.359 --> 0:17:09.440 whether we're talking about Earth or Io. They can form 0:17:09.560 --> 0:17:13.679 these searing lava flows. But a crazy fact that I 0:17:13.760 --> 0:17:18.680 came across is that apparently lava flows on Io are 0:17:18.960 --> 0:17:23.520 even hotter than lava flows on Earth. You know, I 0:17:23.600 --> 0:17:26.080 might have just assumed that la lava is going to 0:17:26.119 --> 0:17:28.199 be roughly the same temperature wherever it is. You know, 0:17:28.240 --> 0:17:30.719 once it sort of reaches the surface, it's you know, 0:17:30.800 --> 0:17:33.240 it's probably cooling off. I don't know, I don't know 0:17:33.280 --> 0:17:35.720 why I would have thought that, but that's clearly wrong. 0:17:36.359 --> 0:17:39.680 So I was reading about this in an August first, 0:17:39.720 --> 0:17:43.000 two thousand and one press release from NASA JPL that 0:17:43.200 --> 0:17:48.439 included an interview with a JPL volcanologist named doctor Rosalie Lopez, 0:17:48.960 --> 0:17:52.119 and she says a number of really interesting things in 0:17:52.160 --> 0:17:56.040 this little interview. One of them comes back to that 0:17:57.000 --> 0:18:00.080 sort of designation that people have of Io as the 0:18:00.080 --> 0:18:04.440 most volcanic body in the Solar System. She stresses that 0:18:04.480 --> 0:18:09.439 this is not because Io has the most volcanoes, as in, like, 0:18:09.480 --> 0:18:12.080 you count up all the volcanoes and it has the most. 0:18:12.600 --> 0:18:15.520 Because I actually checked, this Earth has more volcanoes total. 0:18:16.040 --> 0:18:19.800 Earth has more than Io does, but Earth is also larger. 0:18:19.840 --> 0:18:24.000 Of course, the reason that scientists call Io the most 0:18:24.080 --> 0:18:27.760 volcanic body in the Solar System is that its volcanoes 0:18:27.840 --> 0:18:31.680 put out the most total heat. So it's the most 0:18:31.840 --> 0:18:36.119 volcanic because it's a question of total energy released. Io 0:18:36.320 --> 0:18:39.439 is only about one third the size of Earth, but 0:18:39.520 --> 0:18:42.520 it puts out like double the heat of Earth from 0:18:42.520 --> 0:18:48.560 its volcanoes. And Lopez notes that one single volcano on Io, 0:18:48.640 --> 0:18:52.840 known as Loki, is more powerful than every volcano on 0:18:52.960 --> 0:18:57.920 Earth put together. Now, another interesting part in this exchange 0:18:57.920 --> 0:19:00.960 is that the interviewer asks Lopez whether the volcanoes on 0:19:01.040 --> 0:19:03.840 Io would be similar to volcanoes on Earth. How would 0:19:03.840 --> 0:19:07.800 they be similar? How would they be different? And Lopez says, quote, 0:19:07.840 --> 0:19:10.760 the types of eruptions we've observed on Io are similar 0:19:10.800 --> 0:19:14.840 to types of eruptions on Earth. Lava flows, calderas, fire 0:19:14.960 --> 0:19:18.639 fountains like in Hawaii. But there are some very different aspects. 0:19:19.000 --> 0:19:22.680 One is that lava on Io is much hotter than 0:19:22.760 --> 0:19:27.080 any lava that flows on Earth today. Billions of years ago, 0:19:27.359 --> 0:19:31.960 Earth had lava that hot. Another difference is that the calderas, 0:19:32.040 --> 0:19:35.919 the volcanic craters on Io are much larger, than on Earth. 0:19:36.480 --> 0:19:40.040 Lava flows are much larger too, and then she cites 0:19:40.080 --> 0:19:44.720 a volcano on Io named Amirani that has a lava 0:19:44.760 --> 0:19:48.399 flow going three hundred kilometers long or about one hundred 0:19:48.400 --> 0:19:51.639 and ninety miles. She of course notes that that's longer 0:19:51.680 --> 0:19:54.640 than any known lava flow on Earth, but I looked 0:19:54.720 --> 0:19:57.399 up something to try to find a comparison. Three hundred 0:19:57.440 --> 0:20:00.359 kilometers is roughly the distance from New York to Providence, 0:20:00.440 --> 0:20:04.440 Rhode Island, So just imagine an active lava flow that long. 0:20:05.160 --> 0:20:08.000 And then finally, in this answer, she notes that io 0:20:08.560 --> 0:20:11.880 eruptions on Io produce like one hundred times as much 0:20:11.920 --> 0:20:15.600 molten lava per year as eruptions on Earth. And that's 0:20:15.760 --> 0:20:18.400 counting up all of the erupting volcanoes on Earth, even 0:20:18.440 --> 0:20:21.640 the ones under the sea. So that's all amazing. I'm 0:20:21.720 --> 0:20:25.199 especially fascinated by the idea that Earth used to have 0:20:25.320 --> 0:20:28.320 hotter lava, Like we're kind of in decline and our 0:20:28.359 --> 0:20:31.000 planets just like we can't put out lava like we 0:20:31.119 --> 0:20:35.200 used to. But if you take all that together, think 0:20:35.200 --> 0:20:38.920 about like the massive number of erupting volcanoes on Io, 0:20:39.160 --> 0:20:42.520 how much heat they put out, and just like what 0:20:42.720 --> 0:20:46.680 a in some ways boiling world. This is that might 0:20:46.840 --> 0:20:50.840 paint a picture of a hothouse, a sort of planetary 0:20:50.960 --> 0:20:54.800 hell world like Venus, but actually that would not be 0:20:54.960 --> 0:20:57.119 accurate if you're trying to imagine what it's like on 0:20:57.200 --> 0:21:01.480 the surface of Io. Because the apage surface temperature of 0:21:01.560 --> 0:21:07.040 Io is extremely cold. Io has a very thin atmosphere, 0:21:07.200 --> 0:21:12.480 extremely thin sulfur dioxide atmosphere, too thin to trap heat effectively, 0:21:12.600 --> 0:21:14.920 and that's you know, one reason Venus is so hot. 0:21:15.000 --> 0:21:17.399 It's it's because it's got a very thick atmosphere that 0:21:17.520 --> 0:21:21.879 traps heat within the atmosphere. Io does not have that. 0:21:22.359 --> 0:21:26.359 So while it's got these super you know, extremely hot 0:21:26.440 --> 0:21:29.280 hot spots where the volcanoes are erupting or the lava 0:21:29.320 --> 0:21:31.200 flows are taking place. You might have a lake of 0:21:31.320 --> 0:21:35.080 lava that's you know, going to be incredibly hot. Most 0:21:35.320 --> 0:21:38.159 of the Moon is very cold, with an average surface 0:21:38.200 --> 0:21:41.320 temperature of negative one hundred and thirty degrees celsius or 0:21:41.359 --> 0:21:44.840 negative two two fahrenheit, So astronomers sometimes call it a 0:21:45.000 --> 0:21:47.680 like a world of fire and ice. It's a place 0:21:47.680 --> 0:21:52.119 where you have these these gigantic, massive erupting volcanoes and 0:21:52.560 --> 0:21:56.200 giant long lava flows, you know, going New York to Providence, 0:21:56.280 --> 0:21:59.000 Rhode Island. But at the same time you'll have these 0:21:59.000 --> 0:22:03.440 almost whimsic frisky ice world conditions. For example, I mentioned 0:22:03.480 --> 0:22:06.359 the fact that Io has this very thin atmosphere of 0:22:06.600 --> 0:22:11.120 mostly sulfur dioxide. Some of that sulfur dioxide comes directly 0:22:11.240 --> 0:22:15.320 from volcanic eruptions venting screaming hot sulfur from below, but 0:22:15.560 --> 0:22:20.400 the other half comes from the gradual evaporation or technically 0:22:20.640 --> 0:22:25.960 sublimation of vast fields of sulfurous ice already on the 0:22:26.040 --> 0:22:29.240 planet's surface. So there's a pattern that goes like this. 0:22:29.680 --> 0:22:34.439 The volcanoes erupt and they shoot sulfur dioxide into the atmosphere. 0:22:35.000 --> 0:22:38.639 It floats around. Then, once every forty two hours or so, 0:22:39.400 --> 0:22:44.119 Io passes briefly into Jupiter's shadow, so it becomes eclipsed 0:22:44.200 --> 0:22:47.520 and all sunlight is blocked, and this causes the surface 0:22:47.560 --> 0:22:50.680 temperature to drop even further. It causes the Moon to 0:22:50.880 --> 0:22:54.679 temporarily go into a deep cold cold enough to actually 0:22:54.800 --> 0:22:58.960 cause the lower SO two atmosphere level to freeze and 0:22:59.119 --> 0:23:02.600 fall to the surface. Then, when I emerges from its 0:23:02.640 --> 0:23:06.520 eclipse and comes back into the sunlight, the frozen planes 0:23:06.560 --> 0:23:10.200 of sulfur snow start to warm up and sublimate into 0:23:10.440 --> 0:23:13.720 gas once again, which becomes part of the tenuous atmosphere. 0:23:14.480 --> 0:23:16.120 So there's a lot more we'll have to get into 0:23:16.760 --> 0:23:19.560 about the Moon, but just starting with this portrait, this 0:23:19.640 --> 0:23:22.160 sketch here, I really would make the case for Io 0:23:22.280 --> 0:23:25.520 as one of the most interesting places in the Solar System, 0:23:25.720 --> 0:23:29.560 you know, beyond Earth, of one of the most challenging 0:23:30.080 --> 0:23:34.800 and strange and dramatic and fascinating places in all of space. 0:23:35.480 --> 0:23:38.960 Absolutely. Yeah, the closer you look at it than the 0:23:39.080 --> 0:23:40.840 more amazing details there are. 0:23:41.840 --> 0:23:44.160 Now, speaking of dramatic landscapes, I did want to mention 0:23:44.359 --> 0:23:46.840 one more of the images that really got me interested 0:23:46.920 --> 0:23:50.200 in doing the series of episodes. This one actually is 0:23:50.840 --> 0:23:54.920 less a I think, less directly a photograph and more 0:23:55.000 --> 0:23:57.879 kind of an image generated based on It was like 0:23:57.920 --> 0:24:01.280 a three D image that's like an artist concept based 0:24:01.440 --> 0:24:05.560 on data from Juno's Junokam instrument. So it's not just 0:24:05.680 --> 0:24:07.520 made up like it is based on data they took 0:24:07.560 --> 0:24:09.520