WEBVTT - The James Webb Space Telescope 0:00:04.400 --> 0:00:07.800 Welcome to Tech Stuff, a production from I Heart Radio. 0:00:12.119 --> 0:00:14.800 Hey there, and welcome to tech Stuff. I'm your host, 0:00:14.960 --> 0:00:18.000 Jonathan Strickland. I'm an executive producer with iHeart Radio and 0:00:18.040 --> 0:00:21.919 I love all things tech and the long time listeners 0:00:22.000 --> 0:00:25.320 of this show know that I'm really interested in space 0:00:25.880 --> 0:00:29.560 and the technology we use to expand our understanding of 0:00:29.560 --> 0:00:33.640 the cosmos. As I record this, I am actually reading 0:00:33.720 --> 0:00:37.440 up on how the NASA Perseverance Rover has deposited the 0:00:37.720 --> 0:00:41.720 Ingenuity copter on the service of Mars, which is super exciting. 0:00:42.000 --> 0:00:44.680 But I'll have to do a follow up episode about 0:00:44.720 --> 0:00:49.440 the Perseverance and Ingenuity later on after more has actually happened. 0:00:49.760 --> 0:00:53.320 So let's get back to what I'm talking about today. Also, 0:00:53.520 --> 0:00:56.240 longtime listeners will know that I like to point out 0:00:56.400 --> 0:01:01.880 that space is always always trying to kill you, from 0:01:01.920 --> 0:01:05.120 the lack of oxygen to the proliferation of radiation that 0:01:05.160 --> 0:01:08.680 could really mess us up, to the long term effects 0:01:08.680 --> 0:01:11.720 of micro gravity. Spaces not where you want to spend 0:01:11.720 --> 0:01:15.120 any appreciable amount of time. There's just no atmosphere, you 0:01:15.160 --> 0:01:18.800 know what I'm saying. But dad jokes aside, I do 0:01:18.959 --> 0:01:22.360 really love learning about space, and moreover, learning about the 0:01:22.400 --> 0:01:25.840 tech we use to pursue that learning. To that end, 0:01:26.120 --> 0:01:28.760 I thought I would do an episode about the James 0:01:28.760 --> 0:01:32.600 Webs Space Telescope. And you know, I'm I'm really interested 0:01:32.600 --> 0:01:36.000 in this telescope because I actually have a tattoo that's 0:01:36.040 --> 0:01:41.240 part of NASA history connected to this telescope. I even 0:01:41.400 --> 0:01:44.600 got that whole thing shot on video while I was 0:01:44.640 --> 0:01:47.119 getting the tattoo. But I'll talk about that a little 0:01:47.120 --> 0:01:51.040 bit more towards the end of the episode. So let's 0:01:51.080 --> 0:01:53.680 get into this now. I'm not going to dive into 0:01:53.840 --> 0:01:57.520 all the instruments and all the technology behind the James Webb. 0:01:57.560 --> 0:01:59.840 Maybe I'll do a second episode where I go into 0:01:59.880 --> 0:02:05.080 that more detail because it is incredibly technical. Um it's 0:02:05.200 --> 0:02:08.320 it's phenomenal the technology that's going into place to make 0:02:08.360 --> 0:02:11.720 this thing work. But I really wanted to give more 0:02:11.760 --> 0:02:14.959 of a high level look at what the James Webb 0:02:15.040 --> 0:02:18.320 Space Telescope is and what it is supposed to do. 0:02:18.440 --> 0:02:23.280 So first things first, who was James Webb? Well, James E. 0:02:23.400 --> 0:02:27.559 Webb was the second person appointed as head of NASA. 0:02:27.880 --> 0:02:31.160 He served in that position from February nineteen sixty one 0:02:31.639 --> 0:02:36.520 until October nineteen That meant he led NASA during the 0:02:36.560 --> 0:02:40.280 crucial years that saw the agency launched the first American 0:02:40.320 --> 0:02:43.400 into orbit, that would be Alan Shepard in May nineteen 0:02:43.480 --> 0:02:47.160 sixty one to just before the launch of Apollo seven, 0:02:47.200 --> 0:02:50.160 which was the first Apollo mission to send an entire 0:02:50.240 --> 0:02:54.640 crew into orbit. The manned missions that NASA was pursuing 0:02:54.800 --> 0:02:59.600 understandably received a ton of attention and coverage, but Webb's 0:02:59.639 --> 0:03:04.120 goal was to balance the narrative of sending astronauts to orbit, 0:03:04.160 --> 0:03:08.520 you know, the human achievement of going into space and 0:03:08.520 --> 0:03:11.480 and later on going to the Moon. He wanted to 0:03:11.480 --> 0:03:14.160 balance that with the need to actually use those missions 0:03:14.200 --> 0:03:18.240 to help expand our understanding of science. He felt that 0:03:18.440 --> 0:03:21.600 he needed to make certain that there were always scientific 0:03:21.680 --> 0:03:25.720 elements to those missions in order to link the space 0:03:25.840 --> 0:03:31.880 race to gaining knowledge, to expanding our understanding of the universe. Otherwise, 0:03:32.200 --> 0:03:35.960 sending people out into space could potentially get reductive. It 0:03:36.000 --> 0:03:38.920 could end up being a political statement because really the 0:03:39.000 --> 0:03:42.320 United States was locking horns with the then Soviet Union 0:03:42.360 --> 0:03:44.600 in the space race. So he wanted to make sure 0:03:45.160 --> 0:03:48.880 that we were building a foundation to learn more, not 0:03:49.040 --> 0:03:52.400 just to you know, show off. And I don't mean 0:03:52.440 --> 0:03:55.320 to reduce the achievements of the men and women who 0:03:55.360 --> 0:03:58.720 worked in the space industry at the time. Rather, this 0:03:58.760 --> 0:04:03.600 is all about perception and the political part of trying 0:04:03.640 --> 0:04:07.760 to get space programs together. The science is pretty darn 0:04:07.800 --> 0:04:10.440 cool no matter how you look at it. Well, anyway, 0:04:10.480 --> 0:04:14.040 Web himself wasn't a scientist, but his work really helped 0:04:14.120 --> 0:04:18.159 shape NASA and allowed the organization to benefit from the 0:04:18.240 --> 0:04:21.440 support that he was able to get politically in order 0:04:21.480 --> 0:04:25.039 to conduct scientific experiments that we otherwise would not be 0:04:25.160 --> 0:04:28.160 able to do. Web was also able to form and 0:04:28.240 --> 0:04:32.000 leverage political relationships to make sure that the scientists and 0:04:32.040 --> 0:04:35.400 engineers back at NASA could realize their ambitions and goals. 0:04:35.880 --> 0:04:40.560 In fact, he was an expert at creating and maintaining 0:04:40.720 --> 0:04:45.000 those relationships like that was that was his forte and 0:04:45.400 --> 0:04:48.440 that's why NASA chose his name for the space Telescope. 0:04:48.440 --> 0:04:52.040 All right, So let's get back to that story now. Currently, 0:04:52.360 --> 0:04:55.840 the plan is to launch this spacecraft in October of 0:04:55.880 --> 0:05:00.080 this year, this year being twenty one in case you 0:05:00.120 --> 0:05:02.360 are listening to this at some point in the future 0:05:02.360 --> 0:05:04.560 and you're just going through the back catalog of tech 0:05:04.600 --> 0:05:09.080 Stuff episodes. Now, that is after several delays and hiccups 0:05:09.120 --> 0:05:13.120 that have pushed back this project that has had about 0:05:13.200 --> 0:05:15.440 a thirty year history, in fact longer if you want 0:05:15.440 --> 0:05:18.200 to be a little lucy goosey with definitions of history. 0:05:18.480 --> 0:05:21.479 And by that, I mean you could argue that the 0:05:21.680 --> 0:05:25.240 James Webb Space Telescope began its journey all the way 0:05:25.240 --> 0:05:30.839 back in September nine nine. That was before its predecessor, 0:05:30.880 --> 0:05:35.400 the Hubble Space Telescope, had even launched. The Hubble would 0:05:35.440 --> 0:05:40.240 go up in but scientists were already talking about the 0:05:40.279 --> 0:05:43.680 next step what would come after the Hubble. And this 0:05:43.760 --> 0:05:46.960 is one of the really cool things about science and technology. 0:05:47.240 --> 0:05:50.360 It's not enough to tackle really big challenges and then 0:05:50.480 --> 0:05:53.320 get them off the ground, so speak, you already need 0:05:53.400 --> 0:05:56.440 to be thinking ahead about what is going to come next, 0:05:56.920 --> 0:06:00.240 which sounds pretty exhausting to me, but really cool all 0:06:00.279 --> 0:06:03.320 the same. Also, I can kind of identify because I 0:06:03.360 --> 0:06:06.720 can't really reflect on the show I'm recording. I gotta 0:06:06.800 --> 0:06:10.800 already be thinking about the next show now. Granted that's 0:06:10.880 --> 0:06:13.839 orders of magnitude less complicated than I don't know, sending 0:06:13.880 --> 0:06:19.200 stuff into space anyway. In September, n NASA co hosted 0:06:19.240 --> 0:06:24.640 a workshop that focused pun intended on the next generations 0:06:24.720 --> 0:06:28.080 space telescope, and the other co host was the Space 0:06:28.120 --> 0:06:34.200 Telescope Science Institute or st S little c I. More 0:06:34.240 --> 0:06:37.480 than one experts in the fields of astronomy and engineering 0:06:37.960 --> 0:06:41.640 gathered to to start the process of outlining what the 0:06:41.680 --> 0:06:45.240 next generation of space telescopes should be able to do, 0:06:46.000 --> 0:06:49.040 How would we be able to make it do those things, 0:06:49.320 --> 0:06:52.000 where would we need to actually position the telescope in 0:06:52.080 --> 0:06:54.800 order to do it, and so on. Initially, the group 0:06:54.839 --> 0:06:58.560 considered the possibility of designing a near infrared telescope that 0:06:58.640 --> 0:07:02.080 would call the Moon home, or perhaps a very high 0:07:02.120 --> 0:07:04.960 Earth orbit. As it would turn out, we would go 0:07:05.040 --> 0:07:09.159 to a very specific high Earth orbit. Actually it's not 0:07:09.200 --> 0:07:12.600 really so much an Earth orbit, high solar orbit. Now, 0:07:12.640 --> 0:07:16.600 these discussions weren't resolved in a weekend or anything like that. Rather, 0:07:17.160 --> 0:07:20.160 they carried on for years as the experts debated the 0:07:20.160 --> 0:07:23.560 best course of action that would in theory, return the 0:07:23.600 --> 0:07:27.520 best results assuming mission success, of course, which is never 0:07:27.560 --> 0:07:30.320 a guarantee when we're talking about launching stuff into space. 0:07:30.360 --> 0:07:33.960 If you look at the list of attempted space missions 0:07:34.000 --> 0:07:39.400 over the course of our relatively brief space history, you 0:07:39.440 --> 0:07:42.760 know there's like a fift success rate depending on which 0:07:42.880 --> 0:07:46.080 versions you're looking at, so it is not a sure thing. 0:07:46.480 --> 0:07:50.840 A committee with formal recommendations wouldn't present their conclusions until 0:07:52.600 --> 0:07:56.280 seven years after those initial meetings, and I think that 0:07:56.840 --> 0:08:01.440 really helps illustrate that we're talking about really complicated technologies 0:08:01.480 --> 0:08:05.600 and missions here, and that that seven year span from 0:08:05.960 --> 0:08:10.160 initial ideation to recommendation is a great guide on how 0:08:10.200 --> 0:08:15.680 the project has slowly taken shape sense slowly but methodically, 0:08:16.080 --> 0:08:19.920 Like it has to be methodical because we're talking about 0:08:20.520 --> 0:08:24.360 plans where once we launch it, there's not a whole 0:08:24.400 --> 0:08:26.840 lot of opportunity to fix things if they go wrong. 0:08:27.400 --> 0:08:30.800 But in the meantime, while discussions were ongoing as to 0:08:30.880 --> 0:08:33.880 what type of telescope would follow the Hubble, we got 0:08:34.720 --> 0:08:38.080 the Hubble, while the James Web Space Telescope first began 0:08:38.160 --> 0:08:42.080 to take shape during conversations that started in nine The 0:08:42.120 --> 0:08:45.679 Hubble's conception dates all the way back to the nineties. 0:08:46.080 --> 0:08:48.200 Before we called it the Hubble, it had a different 0:08:48.480 --> 0:08:53.160 and rather mundane name. We called it the Large Space Telescope, 0:08:53.559 --> 0:08:57.959 which is descriptive at least. But why would we bother 0:08:58.080 --> 0:09:01.160 with a space telescope in the first place, Well, here 0:09:01.160 --> 0:09:04.320 on Earth We've got lots of telescopes. Some of them 0:09:04.360 --> 0:09:09.800 are purely optical telescopes using lenses. They are all about 0:09:10.120 --> 0:09:13.360 capturing and bending light so that we can actually look 0:09:13.360 --> 0:09:16.600 at stuff that's really far away. We also have some 0:09:16.760 --> 0:09:20.280 that are radio telescopes. These are giant dishes that pick 0:09:20.360 --> 0:09:24.480 up faint radio signals, which then we process and interpret 0:09:24.520 --> 0:09:27.719 to determine what might have made those radio waves way 0:09:27.760 --> 0:09:32.440 on space, stuff like stars, quasars, galaxies, that kind of thing, 0:09:32.840 --> 0:09:37.360 not necessarily, you know, aliens, not necessarily like artificially created 0:09:37.720 --> 0:09:42.040 radio signals. Typically we're talking about actual celestial bodies that 0:09:42.160 --> 0:09:46.400 generate radio waves. But these types of telescopes have a barrier, 0:09:46.679 --> 0:09:50.400 and that barrier is Earth's atmosphere. While we depend upon 0:09:50.520 --> 0:09:52.960 that atmosphere because you know, without it we would die, 0:09:53.400 --> 0:09:57.440 the atmosphere also absorbs, reflects and otherwise blocks some stuff 0:09:57.440 --> 0:10:01.240 from getting through. This isn't all bad, mind you. Our 0:10:01.240 --> 0:10:04.040 atmosphere is part of the protective layer we have that 0:10:04.160 --> 0:10:07.679 keeps us from being bombarded with cosmic radiation. But it 0:10:07.720 --> 0:10:11.199 does mean that if you're making observations of deep space 0:10:11.440 --> 0:10:14.199 and you're fighting against those layers of atmosphere in order 0:10:14.240 --> 0:10:16.520 to do it, and you're going to run up against 0:10:16.600 --> 0:10:19.720 some fundamental limitations of how sharp an image you can produce. 0:10:20.480 --> 0:10:22.640 I mean, it's all these things just happen, right. We 0:10:22.800 --> 0:10:25.360 we've it's like having a foggy lens. You you're not 0:10:25.440 --> 0:10:27.959 able to see as far away. You're not able to 0:10:28.000 --> 0:10:31.520 see as clearly because we've got this atmosphere that's blurring 0:10:31.600 --> 0:10:34.400 the image. Putting a telescope out into space gets around 0:10:34.440 --> 0:10:37.319 that problem, right, I mean, the telescope can be outside 0:10:37.400 --> 0:10:40.440 the atmosphere and we get a clear view of the 0:10:40.480 --> 0:10:44.200 depths of space. A space telescope with the proper sensors 0:10:44.240 --> 0:10:48.520 can examine wavelengths of the electro magnetic spectrum that wouldn't 0:10:48.559 --> 0:10:51.600 be able to penetrate the air's atmosphere very effectively. I 0:10:51.600 --> 0:10:54.680 should also mention that the Hubble was not the first 0:10:54.800 --> 0:10:58.240 space telescope, but it did mark the most ambitious space 0:10:58.240 --> 0:11:02.440 telescope project at that time and for many decades. While 0:11:02.440 --> 0:11:05.960 the paper in nineteen six was the first to propose 0:11:06.000 --> 0:11:09.439 putting a telescope in orbit, years before anyone had managed 0:11:09.440 --> 0:11:13.000 to even launch the simplest of satellites, the first working 0:11:13.040 --> 0:11:16.520 group to concentrate on this challenge didn't really happen until 0:11:16.600 --> 0:11:20.480 nineteen seventy four. The US Congress approved the project in 0:11:20.559 --> 0:11:23.719 nineteen seventy seven, and the following year engineers began to 0:11:23.760 --> 0:11:27.320 build the primary mirror for the telescope. The purpose of 0:11:27.360 --> 0:11:31.400 the telescope's mirror is to focus incoming light from far 0:11:31.640 --> 0:11:36.520 distant astronomical objects onto really a secondary mirror which then 0:11:36.559 --> 0:11:39.960 reflects that light into sensors. And now it's time to 0:11:40.080 --> 0:11:43.040 learn about optics. And I'm not using optics in that 0:11:43.160 --> 0:11:46.240 corporate speak way of this is gonna look bad for us, 0:11:46.240 --> 0:11:48.280 and our shareholders are going to be angry. I'm using 0:11:48.320 --> 0:11:51.679 optics the proper way. Gosh darn ittt, I hate corporate speak, 0:11:52.040 --> 0:11:56.200 all right. So, a refracting telescope is one that uses 0:11:56.320 --> 0:11:59.760 lenses made out of curved glass to collect and focus 0:11:59.800 --> 0:12:01.920 LIE eight so that we can get a good look 0:12:01.920 --> 0:12:06.800 at distant objects. A simple refracting telescope would have two lenses. 0:12:07.120 --> 0:12:09.320 You've got one which is the at the large end 0:12:09.320 --> 0:12:12.040 of the telescope. This is the end that's pointing up 0:12:12.080 --> 0:12:15.920 towards the sky. That lens gathers light and it bends 0:12:15.960 --> 0:12:20.880 that light, the incoming light, into a pathway that converges 0:12:20.960 --> 0:12:24.920 on a point that's inside the telescope, and rather than 0:12:24.960 --> 0:12:27.840 the light just traveling straight down the tube of the telescope, 0:12:27.880 --> 0:12:30.480 if there were no lens there would just go straight instead, 0:12:30.520 --> 0:12:34.920 it all gets focused onto that single focal point. At 0:12:34.960 --> 0:12:37.840 the other end of the telescope is a eye piece, 0:12:37.880 --> 0:12:41.080 a second piece of curved glass much smaller in size, 0:12:41.280 --> 0:12:43.920 and it acts like a magnifying lens with a focal 0:12:43.960 --> 0:12:47.800 point that hits that same spot inside the telescope. This 0:12:47.920 --> 0:12:51.800 lens effectively unbends the light so that we can see 0:12:51.800 --> 0:12:55.320 a representation of what is out there in space as 0:12:55.320 --> 0:12:58.000 if that stuff were much much closer to us. For 0:12:58.040 --> 0:13:00.480 this to work, the lenses have to be very smooth, 0:13:00.559 --> 0:13:03.160 they have to be curved precisely, and they have to 0:13:03.160 --> 0:13:06.280 be the right distance apart from one another, otherwise the 0:13:06.360 --> 0:13:10.240 image won't be clear. Focusing a telescope is a matter 0:13:10.400 --> 0:13:13.800 of making very fine adjustments in the distance between the 0:13:13.840 --> 0:13:16.720 eye piece and the other lens so that those focal 0:13:16.760 --> 0:13:20.960 points line up properly. And lenses work okay, but they 0:13:20.960 --> 0:13:24.680 have some pretty major drawbacks. One is that they get 0:13:24.840 --> 0:13:28.000 pretty heavy, especially the bigger they are. It's hard to 0:13:28.080 --> 0:13:31.600 make thin curved glass that can serve as a lens, 0:13:31.640 --> 0:13:35.120 and so as lenses get larger, they get thicker, and 0:13:35.160 --> 0:13:38.240 they get heavier and heavy is not a great feature 0:13:38.320 --> 0:13:41.200 when you're talking about shooting stuff up into space where 0:13:41.200 --> 0:13:45.200 every pound or kilogram really counts. You also can't, you know, 0:13:45.400 --> 0:13:48.760 collapse it. You can't make it go into a smaller 0:13:48.800 --> 0:13:51.880 form without crushing the glass and turning it into silica. 0:13:51.960 --> 0:13:55.800 So that's not not a great great solution. However, we 0:13:56.000 --> 0:14:01.480 can make really thin mirrors curve to mirrors, and mirrors 0:14:01.679 --> 0:14:05.480 bend light as well, though now you're talking about reflecting 0:14:05.600 --> 0:14:10.480 light rather than refracting light. So a typical reflecting telescope 0:14:10.840 --> 0:14:13.640 looks kind of like a cylindrical drum that has an 0:14:13.640 --> 0:14:15.880 eye piece near the top end of it, and at 0:14:15.880 --> 0:14:18.440 the base of the cylinder is a curved mirror that 0:14:18.480 --> 0:14:21.840 collects light that's coming into the telescope. It reflects that 0:14:21.920 --> 0:14:25.600 light up to a smaller mirror closer to the top 0:14:25.640 --> 0:14:29.120 of the telescope, and the smaller mirror is angled to 0:14:29.240 --> 0:14:32.360 reflect that light toward an eyepiece which you look into 0:14:32.920 --> 0:14:35.640 um and that may still have a magnifying lens part 0:14:35.680 --> 0:14:38.920 attached to it. This approach does mean, however, that that 0:14:39.000 --> 0:14:42.520 secondary mirror can block a little bit of the incoming light, 0:14:43.080 --> 0:14:46.480 so the image can be a little dim Depending upon 0:14:47.440 --> 0:14:53.080 the design of the reflecting telescope, mirrors can weigh way 0:14:53.200 --> 0:14:57.120 less than lenses. You just need a very reflective surface, 0:14:57.240 --> 0:15:00.400 and so they are ideal for the purpose says of 0:15:00.400 --> 0:15:04.800 a space telescope. Using curved mirrors around a detector allows 0:15:04.840 --> 0:15:08.960 the telescope to collect and then direct light that can 0:15:09.000 --> 0:15:12.120 then be captured by whatever that detector is, which is 0:15:12.240 --> 0:15:15.760 effectively acting like the eye piece lens. It's it's typically 0:15:15.760 --> 0:15:19.320 like a camera or some other sensor. The Hubble's primary 0:15:19.360 --> 0:15:23.520 mirror measured two point four meters across or seven point 0:15:23.680 --> 0:15:27.520 nine feet. The company making the mirror was the Perkin 0:15:27.640 --> 0:15:31.880 Elmer Corporation, and it took years to make this mirror. 0:15:32.320 --> 0:15:34.760 The cameras aboard the Hubble would be able to take 0:15:34.880 --> 0:15:38.400 images in the visible, infrared, and ultra violet bands of light, 0:15:38.480 --> 0:15:43.080 but primarily was focused on again pun intended the visible spectrum. 0:15:43.600 --> 0:15:47.320 In n three, the Large Space Telescope officially became the 0:15:47.400 --> 0:15:51.640 Hubble Space Telescope, honoring Edwin Hubble, this astronomer who had 0:15:51.680 --> 0:15:55.000 passed away in nineteen fifty three had proven that what 0:15:55.040 --> 0:15:57.920 we once believed to be merely clouds of gas and 0:15:58.000 --> 0:16:02.120 dust out there in space were in fact other galaxies, 0:16:02.440 --> 0:16:05.280 and that they were moving away from our galaxy. So 0:16:05.560 --> 0:16:09.360 naming the telescope after him was a fitting tribute. Work 0:16:09.640 --> 0:16:13.280 continued on the Hubble tragedy would delay the planned launch 0:16:13.400 --> 0:16:18.480 of the space Telescope WIN. On January ninety six, the 0:16:18.600 --> 0:16:22.280 Space Shuttle Challenger broke apart a little more than a 0:16:22.320 --> 0:16:26.320 minute after it had launched, losing all hands aboard. NASA 0:16:26.360 --> 0:16:29.160 suspended the Space Shuttle program for more than a year 0:16:29.360 --> 0:16:32.320 in order to investigate the cause of the disaster and 0:16:32.320 --> 0:16:35.200 to take measures to prevent it from happening again. And 0:16:35.280 --> 0:16:39.440 since the Hubble was to be lifted into space inside 0:16:39.440 --> 0:16:42.280 a Space Shuttle, ad meant that its own launch would 0:16:42.320 --> 0:16:45.640 have to be pushed back. Hubble would launch in nineteen, 0:16:46.320 --> 0:16:49.720 as I mentioned earlier, a year after scientists were already 0:16:49.760 --> 0:16:54.400 talking about the next space telescope. A few months after deployment, 0:16:54.760 --> 0:16:59.440 scientists discovered that the Hubble's mirror had a slight imperfection 0:16:59.600 --> 0:17:02.760 in the heurvature. And by slight, i'm talking about an 0:17:02.840 --> 0:17:06.639 error that measured just to microns, and a micron is 0:17:06.760 --> 0:17:11.480 point zero zero one millimeters, So we're talking about an 0:17:11.560 --> 0:17:15.080 error that would be imperceptible to humans without the aid 0:17:15.080 --> 0:17:18.480 of special instruments to measure it. When we come back, 0:17:18.880 --> 0:17:21.800 I'll talk briefly about the mission that's set out to 0:17:21.920 --> 0:17:24.040 adjust for this error, and then we'll move on to 0:17:24.160 --> 0:17:27.800 the James Web Space Telescope. But first, let's take a 0:17:27.880 --> 0:17:38.680 quick break. All right, let's get back to that mistake 0:17:39.160 --> 0:17:43.840 in the Hubble. So that tiny mirror curvature error meant 0:17:43.880 --> 0:17:46.399 that the Hubble was unable to achieve the level of 0:17:46.520 --> 0:17:50.600 focus that scientists were hoping for. It could still take pictures, 0:17:51.160 --> 0:17:53.439 it's just they weren't quite as sharp as they were 0:17:53.440 --> 0:17:55.680 supposed to be. So it worked just not as well 0:17:55.720 --> 0:17:59.679 as anticipated. The scientists and engineers who designed the Hubble 0:18:00.040 --> 0:18:02.680 had always intended it to be a technology that could 0:18:02.800 --> 0:18:06.879 be upgraded by sending astronauts up there to make adjustments. 0:18:06.880 --> 0:18:10.680 I mean, the Hubble was and still is in Earth orbit. 0:18:11.040 --> 0:18:15.480 It's it was accessible for Space Shuttle missions, so that 0:18:15.600 --> 0:18:17.320 was always part of the plan, and so some of 0:18:17.359 --> 0:18:22.479 the early work in that regard of upgrades really revolved 0:18:22.480 --> 0:18:25.679 around finding ways to work around this tiny error in 0:18:25.720 --> 0:18:29.960 the mirror's curvature. The first mission to really address this 0:18:30.040 --> 0:18:35.600 happened in late nine when astronauts installed two new instruments 0:18:35.640 --> 0:18:41.080 that can actually accept light from this imperfect mirror, and 0:18:41.119 --> 0:18:46.080 the kind of a post processing approach correct for that error. So, 0:18:46.119 --> 0:18:49.200 in other words, they didn't fix the mirror because that 0:18:49.240 --> 0:18:51.680 would have been incredibly difficult. I'm not even sure how 0:18:51.720 --> 0:18:55.800 they would have managed it. So instead they installed sensors 0:18:55.880 --> 0:19:00.240 or cameras with systems that could correct for that imperfect action, 0:19:00.320 --> 0:19:04.080 which was a pretty neat approach. The Hubble played a 0:19:04.119 --> 0:19:08.520 central role in expanding our understanding of the universe. Scientists 0:19:08.600 --> 0:19:11.680 used it to study questions about the age and evolution 0:19:11.760 --> 0:19:15.880 of the universe itself. Hubble observations led to the confirmation 0:19:15.920 --> 0:19:19.480 that supermassive black holes do in fact exist at the 0:19:19.520 --> 0:19:23.560 centers of galaxies. Using the Hubble, scientists were able to 0:19:23.560 --> 0:19:26.960 figure out how far away other galaxies were from our own. 0:19:27.600 --> 0:19:31.000 The Hubble captured images of weird stars, some of them 0:19:31.080 --> 0:19:34.720 much more active and unstable than our own son. We 0:19:34.760 --> 0:19:38.240 should be thankful for that, because our son mostly behaves itself. 0:19:38.880 --> 0:19:41.840 The Hubble looked at how pieces of a comet crashed 0:19:41.840 --> 0:19:46.280 into Jupiter, leaving behind large marks on the planet's surface. 0:19:46.840 --> 0:19:49.960 Scientists used the Hubble to study various moons in our 0:19:49.960 --> 0:19:53.520 Solar System, leading to the discovery that Jupiter's moon Europa 0:19:53.800 --> 0:19:57.320 has oxygen in its atmosphere. The Hubble caught images of 0:19:57.440 --> 0:20:01.199 proto stars and wide angled views of the universe that 0:20:01.280 --> 0:20:05.560 showed more than fift nd galaxies out there, all before 0:20:05.800 --> 0:20:10.360 the formal recommendation to NASA and the European Space Agency 0:20:10.680 --> 0:20:13.560 that they get to work on the next space telescope. 0:20:14.080 --> 0:20:16.480 But let's move on. Even though we could talk a 0:20:16.520 --> 0:20:18.639 lot more about the Hubble, the Hubble is still in 0:20:18.720 --> 0:20:22.480 operation today, even though the last servicing mission was way 0:20:22.480 --> 0:20:26.119 back in two thousand nine. The James Webb Space Telescope 0:20:26.520 --> 0:20:28.960 won't be able to get that kind of upkeep, and 0:20:29.000 --> 0:20:32.560 that's because it's going to occupy an orbit far away 0:20:32.560 --> 0:20:35.400 from Earth, far too far away for us to access 0:20:35.480 --> 0:20:39.360 easily for stuff like maintenance, and that means we need 0:20:39.400 --> 0:20:43.040 to make sure everything is right before we deploy it. 0:20:43.720 --> 0:20:47.120 Construction on the James Webb Space Telescope began in two 0:20:47.160 --> 0:20:50.600 thousand four, and it took seven years to make all 0:20:50.640 --> 0:20:55.760 the mirror segments. They're eighteen in total. Their hexagonal mirror 0:20:55.800 --> 0:20:59.919 panels that fit together and collectively they serve as the 0:21:00.080 --> 0:21:03.960 primary mirror for the telescope. So the James Web Space 0:21:04.000 --> 0:21:07.560 Telescope is going to orbit the second lagrange point a 0:21:07.680 --> 0:21:10.800 K A L two. But those are just words, right, 0:21:10.840 --> 0:21:13.760 I mean, what does that actually mean? Well, getting stuff 0:21:13.920 --> 0:21:17.480 into space is hard, but getting stuff to stay where 0:21:17.520 --> 0:21:19.480 you need it to once you get it out in 0:21:19.600 --> 0:21:23.920 space is also hard. You can include stuff like thrusters 0:21:23.920 --> 0:21:27.400 to help a spacecraft maintain its relative position to some 0:21:27.520 --> 0:21:32.240 other point of reference, but thrusters require energy to operate, 0:21:32.440 --> 0:21:34.800 so you can use fuel that fuels heavy has a 0:21:34.800 --> 0:21:38.439 limited resource. There's no refueling stations out there, so you 0:21:38.480 --> 0:21:40.920 can't top off the fuel tank once it runs low. 0:21:41.640 --> 0:21:44.679 So you could potentially use like an ion drive and 0:21:44.760 --> 0:21:47.800 power it some other way, such as with a radioactive 0:21:47.920 --> 0:21:51.399 decay or something. But it would be way easier if 0:21:51.440 --> 0:21:54.320 you could just PLoP something onto a specific point in 0:21:54.359 --> 0:21:56.680 space and it would just kind of stay there. And 0:21:56.760 --> 0:22:00.200 by specific point, I mean relative to something else. It's 0:22:00.200 --> 0:22:05.200 not just occupy a a a point in space and 0:22:05.480 --> 0:22:07.359 that's where it stays. As the rest of the Solar 0:22:07.359 --> 0:22:11.480 system continues to move away from it. So a smarty 0:22:11.560 --> 0:22:16.520 pants mathematician named Joseph Louis Lagrange began to think about 0:22:16.640 --> 0:22:19.000 orbital paths and whether or not it might be possible 0:22:19.040 --> 0:22:22.720 to find points in which three different bodies could orbit 0:22:22.760 --> 0:22:25.719 each other but stay in the same positions relative to 0:22:25.760 --> 0:22:29.760 one another. So, in other words, unlike say Earthen Mars, 0:22:29.880 --> 0:22:31.960 let's use that as an example, We've got the Sun, 0:22:32.520 --> 0:22:37.399 We've got Earth, We've got Mars. Three bodies. Earthen Mars 0:22:37.440 --> 0:22:40.480 both orbit the Sun, but they both do so at 0:22:40.520 --> 0:22:44.320 different rates. So sometimes Earthen Mars are on the same 0:22:44.400 --> 0:22:47.239 side of the Sun, like they're both on. Let's if 0:22:47.240 --> 0:22:50.560 we're looking top down, let's imagine that both the Earth 0:22:50.640 --> 0:22:52.840 and Mars are on the right side of the Sun. 0:22:53.000 --> 0:22:56.440 Mars is a little further out from Earth. Other times though, 0:22:56.600 --> 0:22:59.520 during those orbits, you get them on opposite sides of 0:22:59.560 --> 0:23:01.560 the Sun. Maybe the Earth's on the right side but 0:23:01.640 --> 0:23:04.080 Mars is on the left side. The Sun's in between them, 0:23:04.119 --> 0:23:06.359 so they are not in the same position relative to 0:23:06.359 --> 0:23:09.159 each other throughout their orbits. In fact, it takes about 0:23:09.200 --> 0:23:12.240 two years for the two planets to get close to 0:23:12.280 --> 0:23:15.960 each other. That's why any planned missions to Mars that 0:23:16.040 --> 0:23:20.960 involves sending people up there usually also involved camping out 0:23:21.000 --> 0:23:24.320 on the planet for you know, a couple of years 0:23:24.480 --> 0:23:28.240 in order to be able to return. However, a stable 0:23:28.400 --> 0:23:31.359 orbit would mean that the three bodies would remain in 0:23:31.359 --> 0:23:34.600 their same relative positions. So if Earth is one of 0:23:34.640 --> 0:23:37.560 the three and the Sun is another, the third body 0:23:37.760 --> 0:23:40.800 would remain in the same relative position in its orbital path. 0:23:41.000 --> 0:23:43.639 So this would be like if the Earth and Mars 0:23:44.080 --> 0:23:47.920 were always lined up in their respective orbits around the Sun. 0:23:48.080 --> 0:23:52.239 So Mars would always be behind Earth further out, and 0:23:52.359 --> 0:23:54.320 that would mean Mars would have to be traveling faster 0:23:54.440 --> 0:23:58.680 through space to keep pace right, because it's traveling greater distance. 0:23:58.720 --> 0:24:02.320 It's a it's orbit is arger, it's traveling further. It 0:24:02.320 --> 0:24:04.600 would have to go faster in order to maintain the 0:24:04.640 --> 0:24:08.800 same position relative to the Earth. That's not happening. However, 0:24:09.359 --> 0:24:14.800 through mathematics, Lagrange identified five points where this sort of 0:24:14.920 --> 0:24:18.120 orbit would be possible. So there are five points we've 0:24:18.160 --> 0:24:21.720 identified where something in that position would pretty much stay 0:24:21.760 --> 0:24:24.720 there relative to the Earth and the Sun. And that's 0:24:24.720 --> 0:24:29.200 because these bodies would be exerting roughly equal gravitational forces 0:24:29.320 --> 0:24:33.360 on that third body out in space, and the same 0:24:33.400 --> 0:24:35.840 amount of force as that third body was experiencing in 0:24:35.880 --> 0:24:38.960 the form of centripetal force. That's a lot of words. 0:24:39.080 --> 0:24:41.239 I know it sounds confusing, but imagine you've got a 0:24:41.240 --> 0:24:44.159