Cosmic Queries: Telescopes

In this Cosmic Queries episode, Neil deGrasse Tyson answers fan questions about radio and microwave telescopes, from the Hubble to the VLA to the James Webb Space Telescope.

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:01Neil deGrasse Tyson?

  Welcome to StarTalk, your place in the universe where science and pop culture collide. StarTalk begins right now.

• 0:21Neil deGrasse Tyson?

  I'm your host, Neil deGrasse Tyson, your personal astrophysicist, and this is StarTalk.

• 0:31Neil deGrasse Tyson?

  Colin Jost, Colin, welcome to StarTalk Radio.

• 0:34Speaker 01

  Oh, thank you. It's great to be here, Neil.

• 0:35Neil deGrasse Tyson?

  So, you wrote for Saturday Night Live some years ago. Do you still?

• 0:38Speaker 01

  Yeah, I've been there seven years now.

• 0:39Neil deGrasse Tyson?

  So you're still there?

• 0:40Speaker 01

  Yeah, I'm still there. I'm one of the supervising writers there now, and it's been great. Yeah, it's been a good run.

• 0:45Neil deGrasse Tyson?

  Excellent, excellent. And I did a little bit of homework on you. So you were comedian dude in college as well?

• 0:51Speaker 01

  Yeah, I worked for this magazine called The Harvard Lampoon.

• 0:54Neil deGrasse Tyson?

  This magazine called?

• 0:55Speaker 01

  This magazine called, where, you know, Conan O'Brien and people started out. And so I did that basically way more than I did any of my classes, including my astronomy class.

• 1:06Neil deGrasse Tyson?

  So you flunked out of school is what you're telling me here?

• 1:08Speaker 01

  Yeah.

• 1:09Neil deGrasse Tyson?

  All the great ones flunked out.

• 1:10Speaker 01

  I got through. I got through. I didn't mat Damon and just leave early.

• 1:14Neil deGrasse Tyson?

  Oh, gotcha, gotcha, gotcha. So, we're in the cosmic queries part, and we just came off an entire hour on telescopes. And so, we called from the internet, all ways that our listeners reach us, by telephone, by Facebook, by tweets. And so, I haven't seen any of these questions, but you've been reviewing them and just...

• 1:36Speaker 01

  Fire away.

• 1:37Neil deGrasse Tyson?

  Bring it on.

• 1:38Speaker 01

  (laughing)

• 1:39Neil deGrasse Tyson?

  I'm ready for you.

• 1:40Speaker 01

  This is great. So this is, this first one's from Facebook. It's from a guy named Dominic Irazari. And he wants to know, "Aside from the Aracibo Observatory and the VLA in New Mexico, are there any other large-scale operation radio telescopes in use today? And if so, what are we looking for, or the scientists using them, looking for, aside from SETI data?" Which I don't even know what SETI is.

• 2:01Neil deGrasse Tyson?

  Yes, you do know what SETI is.

• 2:02Speaker 01

  I should have asked that first.

• 2:03Neil deGrasse Tyson?

  Okay, so SETI, the Search for Extraterrestrial Intelligence.

• 2:05Speaker 01

  Oh, yes, okay, gotcha.

• 2:06Neil deGrasse Tyson?

  That's just the acronym.

• 2:07Speaker 01

  Of course I knew that.

• 2:08Neil deGrasse Tyson?

  Yes, of course. You would just, of course.

• 2:10Speaker 01

  I was, I was slow playing it.

• 2:11Neil deGrasse Tyson?

  So just to get people on the same page, the Aracibo Telescope is a single dish radio telescope embedded in a natural crater.

• 2:18Speaker 01

  I've been there, I've seen it, it's pretty awesome.

• 2:20Neil deGrasse Tyson?

  In the island of Puerto Rico and it's, it's, it's, it's an awesome, it's, it's otherworldly, actually. Nothing in the area looks like it and you think it just landed from space. That telescope was, had sort of a cameo appearance in the film Contact.

• 2:36Speaker 01

  Right.

• 2:36Neil deGrasse Tyson?

  That's where Jodie Foster and Matthew McConaughey establish their love interest in each other.

• 2:42Speaker 01

  Right.

• 2:42Neil deGrasse Tyson?

  As each sentence gets uttered, they get an inch closer to each other and then cut to the next scene, they're under covers together in bed. So that's what happens when you're hang out at telescope.

• 2:53Speaker 01

  Always.

• 2:54Neil deGrasse Tyson?

  Always. And the VLA, the Very Large Array Telescope, that's a set of much smaller radio telescope dishes that are, that are on tracks. And so this array can be expanded to be 14 miles across, or it can be compressed. And depending on the size, depending on the extent of these dishes on those tracks will determine what your resolution is of what it is you're looking at.

• 3:18Speaker 01

  And do those, do those combine kind of Voltron style?

• 3:21Neil deGrasse Tyson?

  They brilliantly combine in an awesome feat of hardware and software. The signals from all those dishes combine to make a single image of what you're looking at. And the farther apart they are, the more resolution you have for what it is you're looking at. You might say, well, why not always view things with a far apart configuration? The problem is it's not as sensitive when the dishes are far apart. When they're close together, you can hear, you can see dim radio signals. When they're far apart, you need a bright signal, but you can get very good detail about what's going on. So, those remain two of a few leading radio telescopes in the world. The one that's getting all the recent

• 4:02Neil deGrasse Tyson?

  attention, however, is one called ALMA, the Atacama, which, for the Atacama Desert Large Array. Okay? Did I get all my, large millimeter array? ALMA, A-L-M-A, Atacama Large Millimeter Array. So, millimeter is a wavelength of light just short of what we typically call radio waves. Millimeter light is microwaves.

• 4:28Neil deGrasse Tyson?

  And so microwaves are, if you remember what a wavelength would look like, you draw a crest in a trough, so the height of two, the distance between two consecutive crests, that's the wavelength.

• 4:39Speaker 01

  Right.

• 4:40Neil deGrasse Tyson?

  Microwaves have anywhere between a millimeter and a centimeter typically, and beyond a centimeter, you go up to meters and things, that's radio waves. That's how we've divided the kingdom there. But in fact, it transitions smoothly from one to the other. But if you Google Alma, you'll find out an extensive discussion of what it is we're targeting with this brand newly, freshly opened.

• 5:01Speaker 01

  Where is that, which desert?

• 5:03Neil deGrasse Tyson?

  That's in Chile, as the Atacama Desert. In fact, it's high altitude, and I think that the Atacama Desert has the record for the lowest rainfall of any place in the world. Like an inch a decade or so.

• 5:14Speaker 01

  I'm not gonna dispute, I'm not gonna dispute it now.

• 5:17Neil deGrasse Tyson?

  It's very low. I don't know the exact number, but it is, you don't wanna live there.

• 5:21Speaker 01

  Gotcha.

• 5:22Neil deGrasse Tyson?

  And that's important because water in the atmosphere interferes with microwaves we're trying to get from the universe. And so you wanna go to the driest possible place you can, and the Atacama Desert is just such a place. By the way, the fact that water interferes with microwaves, we exploit on the other end of this and make microwave ovens. Water as a major food additive, of course.

• 5:46Speaker 01

  Right.

• 5:47Neil deGrasse Tyson?

  So there you have something you wanna eat, you wanna heat it up, it has water in it, you put it in a microwave cavity, you beam powerful microwaves across it, that water absorbs the microwaves and it heats, and it heats the food.

• 6:00Speaker 01

  See, I never knew, I just thought it was, you know, just that spinning plate. It just moved so fast that it just started bursting into flames.

• 6:07Neil deGrasse Tyson?

  Or people, I think three out of five people surveyed still say, they use the word nuke, they nuke it, yeah, they think it's something nuclear. And it's so not nuclear, it's ordinary microwaves. And, well, that's why the holes, if you look at the screen, by the way, microwaves pass through glass, and all microwave ovens have a glass door, so what prevents them from coming out? Look on the other side of the glass door, you'll see a mesh, a screen mesh.

• 6:31Speaker 01

  So that prevents it?

• 6:32Neil deGrasse Tyson?

  Check the size of those holes, alright? If they are larger than, you know, if...

• 6:39Neil deGrasse Tyson?

  You don't want the hole to be larger than the size of the wavelength of the microwave. Otherwise it'll pass right on through.

• 6:46Speaker 01

  But now, so there's no way of getting, if it's, they can't sneak in somehow, huh? If they hit at the right moment.

• 6:52Neil deGrasse Tyson?

  No, any more than visible light can sneak through the wall of a room.

• 6:56Speaker 01

  Right.

• 6:56Neil deGrasse Tyson?

  Uh, it's just not transparent to microwaves. A dish, a mesh that you could otherwise see through using visible light with much smaller wavelength.

• 7:05Speaker 01

  Wow.

• 7:06Neil deGrasse Tyson?

  Microwaves can't make it through.

• 7:08Speaker 01

  That's great.

• 7:08Neil deGrasse Tyson?

  Yeah, so we've got smart people figuring smart engineers.

• 7:13Neil deGrasse Tyson?

  You're listening to StarTalk. Stay tuned for another segment.

• 7:30Neil deGrasse Tyson?

  Welcome back to StarTalk. Here's more of this week's episode.

• 7:37Neil deGrasse Tyson?

  Well, so we're in the, we're in the cosmic queries part of our telescope show. And we left off talking about microwaves and how they don't come out of your microwave oven. Cause you ask, where in the universe might you find microwaves? And in fact, they're everywhere, coming to us from the depths of space. But they also come from regions of the galaxy where stars are being born. So they help us map gas clouds, sort of the birth sack of stellar nurseries. And so, microwaves are-

• 8:04Speaker 01

  Are they almost like in the way there's a big bang, the big bang, they start over again in different areas?

• 8:10Neil deGrasse Tyson?

  Yeah, so the big bang births all the matter and energy in the universe. But now what are you gonna, now what do you show for me lately? So the matter and energy, we have gas clouds that condense and form galaxies and condense and form stars and planets and people. Right? So in there, different bands of light, including microwaves, probe different parts of the universe. And for the longest while, we thought it was just visible light, you know, red, orange, yellow, green, blue, violet. And then we realized, oh, there's ultraviolet and X-rays and gamma rays and and radio waves. The universe is trying to talk to us in more ways than our eyes can see. Thus, the birth of these, this whole suite of telescopes. And so you asked, where do you, where are you going to get microwaves? So I was talking about Alma, the Atacama Large Microwave Array.

• 8:54Neil deGrasse Tyson?

  Uh, in everyday life, microwaves are what is used for your cellphone communication. Most communications are there are microwaves, exactly. And the walkie talkies are all microwaves. If you, if you had sensitivity to microwaves with your eyes, you can tune it, let's say. If you tune them to microwaves and look around, first you'd be able to see through walls. Because why else would your cellphone work inside of a room? Unless the microwaves can see through the walls.

• 9:21Speaker 01

  Getting through.

• 9:21Neil deGrasse Tyson?

  Can get through, exactly. So the most.

• 9:23Speaker 01

  So is that where X-ray, you know, there's X-ray vision, but should we be working on microwave?

• 9:27Neil deGrasse Tyson?

  Microwave vision is just as good as X-ray. In fact, it's better. It's better.

• 9:31Speaker 01

  We gotta talk after this.

• 9:32Neil deGrasse Tyson?

  We'll talk.

• 9:33Speaker 01

  Yeah, some prototypes gone.

• 9:35Neil deGrasse Tyson?

  And so, uh, so, um, so microwaves, if you tune into that and went by those cellphone towers, they'd be ablaze with light. They'd be the brightest things on the horizon. You wouldn't even see the streetlights. You'd be seeing the microwave towers. And you see people walking on the phone as they go down the street. The whole, the, the phone would be a glow.

• 9:55Speaker 01

  Now, is there, is there danger to that? Do we know?

• 9:58Neil deGrasse Tyson?

  There are people who would claim there is, but there's no reliable evidence to say, to say so.

• 10:02Speaker 01

  Are you concerned at all or not?

• 10:03Neil deGrasse Tyson?

  No, not in the least.

• 10:04Speaker 01

  Oh, great.

• 10:05Neil deGrasse Tyson?

  Yeah.

• 10:05Speaker 01

  Good. I'm, I'm, I'm.

• 10:06Neil deGrasse Tyson?

  In fact, I sleep with all my cellphones, you know, all around me.

• 10:09Speaker 01

  I know, I know. I end up doing, and not by choice always.

• 10:13Speaker 01

  I've been on a couple of conversations with people who would have thought they were going to continue, but then I was asleep.

• 10:20Neil deGrasse Tyson?

  What'd you, what'd you?

• 10:24Neil deGrasse Tyson?

  Yeah, what did that night cost on your, on your credit card?

• 10:26Speaker 01

  Yeah, or in my personal account life, yeah.

• 10:29Neil deGrasse Tyson?

  So what other, you got other questions that came in?

• 10:31Speaker 01

  Yes. Here's one from Facebook. It's from, uh, Tim Giren Jr. And if you were on, it says, if you were on a livable planet near Deneb. I don't know.

• 10:41Neil deGrasse Tyson?

  Deneb is one of the stars that trace the constellation Cygnus the Swan.

• 10:46Speaker 01

  Oh, okay, there you go. If you were on a livable planet near Deneb with a telescope looking toward Earth, would our sun be in a constellation? Can we, with our computer technology, visualize what the night sky would look like from that planet?

• 11:00Neil deGrasse Tyson?

  Totally. Oh, my gosh. Yeah, we've got three-dimensional coordinates of all the stars in the neighborhood out to, you know, several thousand light-years. And so, oh, yeah. You can transpose what the night sky would look like on any of the... By the way, it wouldn't have to be a livable planet.

• 11:17Speaker 01

  Right, it could be from any...

• 11:18Neil deGrasse Tyson?

  Just from any point in space. You could... like, apparently he wants to move.

• 11:22Speaker 01

  Yeah, I guess. But he wants to know the view first.

• 11:25Neil deGrasse Tyson?

  The view. Was he creating a real estate brochure?

• 11:28Speaker 01

  Exactly, yeah. He's not looking at ones that don't have photos.

• 11:31Neil deGrasse Tyson?

  So, the nighttime view. So, I don't have off the top of my head what this part of the night sky would look like. But what matters is not what the constellation looks like, because they never really look like what they're supposed to, anyway. There's like three out of the 88 that sort of resemble what they're purported to be.

• 11:52Speaker 01

  To be, yeah, exactly.

• 11:53Neil deGrasse Tyson?

  For example, do you know the constellation Apus? A.P.U.S. You ever hear of it?

• 11:56Speaker 01

  No, no, I don't know.

• 11:56Neil deGrasse Tyson?

  It's a bird of paradise. It's got four stars in it. It's like, somebody is smoking something to call these five stars a bird of paradise. I'm not going there. So, you know what we did when we rebuilt the Hayden Planetarium? I had a, in a fit of, of... I don't know, of, in a fit of irresponsibility, I thought to myself, you know what I want to do? I want to sneak into the star ball and update all the constellations to stuff that matters to us today. You know, put in this guy, the Prius, you know? The cellphone, the laptop.

• 12:31Speaker 01

  It's like two dots are a Prius.

• 12:32Neil deGrasse Tyson?

  Yeah, I know, I mean, he's just... why not?

• 12:35Speaker 01

  Or just make them box line.

• 12:38Neil deGrasse Tyson?

  Actually, there are, there's a constellation called Triangulum, which is just a triangle. We got you already.

• 12:43Speaker 01

  They got real there, yeah.

• 12:44Neil deGrasse Tyson?

  They got so real as to be boring, right? So, what's fun about the constellations of the ancients is that they're embedded within their, their mythologies and their, what mattered in their everyday lives. So, so it's a window to the past, and back then, very few people were literate. So, it was, it was a way, it was kind of the library books of the day. You'd go out with people, they'd say, "Oh, there's Perseus, and he saved Andromeda," and Androm-- you know, all the stories, it's, it's quite a bit of storytelling. So, I'm thinking today, it's time to update the constellations.

• 13:15Speaker 01

  Yeah.

• 13:16Neil deGrasse Tyson?

  I think of, have the ice cream cone, there's some that have V shapes, and I like ice cream, and if Konus Major, Konus Minor, you know, we could do that.

• 13:23Speaker 01

  Like a one scoop, two scoop?

• 13:25Neil deGrasse Tyson?

  Exactly, a two scoop constellation, yeah. So, who knows what they'll look like, but they'd be subject, not so much to what they literally look like, but what the cultural imperative is for those who are--

• 13:36Speaker 01

  It's like, yeah, it's like cloud gazing, where you're just, it's reflecting your own personality as much as--

• 13:40Neil deGrasse Tyson?

  It's very Rorschach, yes.

• 13:42Speaker 01

  This next question, I'm very curious about too, it comes from Facebook, from Brandon Fitzpatrick, and he asks, "Can amateur astronomers buy time on space telescopes? Who decides how the Hubble gets used and by whom? What about terrestrial observatories? Can you go and buy time, or rent time?"

• 14:00Neil deGrasse Tyson?

  Yeah, excellent question, and the big ones, no. The big ones are all for professional use, and even so, they're quite expensive. I mean, they're, they're tens of thousands of dollars a night--

• 14:09Speaker 01

  Even for, for universities to rent--

• 14:12Neil deGrasse Tyson?

  Yeah, yeah, universities that own them, you're paying for the physical plant, the maintenance, there are engineers there at all times, there's the food services. You're living nocturnally on the mountaintop, and there's an entire support structure. Somebody built the road to get to the mountaintop, so it costs money. And so, even if they could afford it, they would not, it's not available to them. Unless, they applied competitively for time. And there's something called the TAC, the Telescope Allocation Committee. Every telescope has it. And usually quarterly or semi-annually, you apply for time. "I want to use that telescope with this filter and that detector to observe this object for that long." For this reason.

• 14:54Speaker 01

  Huh.

• 14:55Neil deGrasse Tyson?

  That's all in your proposal. And so all the proposals get put on a table and the telescope allocation committee reviews them, figures out how much total time is requested. Can it be wedged into the total time available? If not, they come at you and say, we're going to cut you in half. We're not going to give you time at all. We're, we like this one better than that one. We think this will be more fertile as a research path. And so this gets done in every time period. Some people get telescope time and others don't.

• 15:24Speaker 01

  And is it a little bit bidding too? Like money or is it?

• 15:27Neil deGrasse Tyson?

  No, no, no, no, no.

• 15:28Speaker 01

  It's all based on the scientific.

• 15:29Neil deGrasse Tyson?

  It's always scientific.

• 15:30Speaker 01

  So you can't be like, I want to check out this girl. I, she.

• 15:33Neil deGrasse Tyson?

  You know, that would not work.

• 15:34Speaker 01

  That's less, less convincing.

• 15:36Neil deGrasse Tyson?

  And as far as I know, no one has bought their way onto it. Because plus, if you buy because your, your research isn't good, we know it. We'll know you're, you're not, you can't hide if you're not good.

• 15:47Speaker 01

  Right.

• 15:48Neil deGrasse Tyson?

  Right? And so this is the self, the, the self-checking that goes on in science as an enterprise. Right? You can't, there's a limit to how long you can try to pull the wool over someone's eyes because you're incompetent.

• 16:01Speaker 01

  Because it's ultimately still science.

• 16:03Neil deGrasse Tyson?

  Well, still, we will so reveal this fact. Uh, it, it, it cannot hide. So, uh, the Hubble, what we talk about is what is the award rate of your applied time? Uh, depending on how competitive one cycle is versus another, uh, as many as two thirds of all proposals won't get awarded time.

• 16:23Speaker 01

  Wow.

• 16:23Neil deGrasse Tyson?

  And so then you try again and try to come up with a better idea. And that's how that goes. Now, there are other telescopes that are not on the frontier, but still exist and still have time available to them. And most of the big observatories have some telescopes where they give access to amateur astronomers. And so what you do is call the main office of the various observatories.

• 16:45Neil deGrasse Tyson?

  You're listening to StarTalk Radio. Stay tuned. More up next.

• 17:03Neil deGrasse Tyson?

  Welcome back. Here's more of StarTalk.

• 17:08Neil deGrasse Tyson?

  So, we are in the Cosmic Queries part of StarTalk Radio for the show on telescopes. And Colin, you're just pulling these off the internet, off of Twitter. I haven't seen any of these questions in advance. What do you have for me?

• 17:20Speaker 01

  Yeah, we were just talking about the Hubble telescope, and Brandon Fitzpatrick continues. He had another question about the Hubble, which is, "Is it possible to build a telescope on Earth that's just as good as the Hubble?" So, in what ways do telescope operators account for atmospheric distortion? And he wants to know, "When is that going to be retired, and are there going to be plans for replacing it?"

• 17:41Neil deGrasse Tyson?

  Yeah, first of all, that's an awesome question, but there are several parts of that. Let me back up for a minute. It turns out, data from the Hubble telescope, once it's obtained by the people who request it, they get to study it and analyze it in all the ways they had intended. Then the data gets posted, and it essentially becomes public at that point. So, while you can't typically apply as an amateur to command the Hubble telescope, you can actually apply to mine the pre-existing data. Maybe there's a question you could ask of those data that the original people had not considered for them.

• 18:19Speaker 01

  Wow.

• 18:20Neil deGrasse Tyson?

  Exactly. And in fact, we had big plans that fell a little short, but we had big plans of creating something called the International Virtual Observatory, where all the data from all the telescopes would be in one place, and you'd say, "Observe this part of the sky in these wavelength bands." And you'd go into the data, and you'd send a worm through, and it'd find all the images taken in all the various wavelength bands you cared about, and would find them in the repositories of data that hadn't been looked at for years, possibly. And it'd bring it back to you, and you would have the chance to discover something that no one even thought to ask.

• 18:54Speaker 01

  Wow.

• 18:55Neil deGrasse Tyson?

  And so, it's called data mining. That's what it's called, as a procedure. Now, in terms of Hubble, we have telescopes far more powerful than Hubble. Hubble is only 94 inches in diameter. Only it's big. It's 94 inches in diameter. The Keck Telescope, there's a pair of them in Hawaii, those are 10 meters across. What's that in inches? That would be...

• 19:19Speaker 01

  Yes. I'm bad at this.

• 19:20Neil deGrasse Tyson?

  400 inches.

• 19:22Speaker 01

  80 million.

• 19:23Neil deGrasse Tyson?

  80 million. Four hundred inches versus ninety, ninety-four inches. So the Keck telescope can see much, much dimmer things in the universe. The bigger your telescope is, the dimmer you can observe.

• 19:35Speaker 01

  Right.

• 19:35Neil deGrasse Tyson?

  The advantage of Hubble being above the atmosphere is that the atmosphere renders the sharpness of images fuzzy.

• 19:42Speaker 01

  Yeah.

• 19:42Neil deGrasse Tyson?

  And so you go above this fuzz layer and then you see the universe as the universe intended to be viewed.

• 19:47Speaker 01

  Right.

• 19:48Neil deGrasse Tyson?

  Over the years, however, we've invoked special technology borrowed from the military that allows us to compensate for the fuzzying effects of the atmosphere. And it's called adaptive optics.

• 20:00Speaker 01

  Whoa.

• 20:01Neil deGrasse Tyson?

  It will deform the shape of the mirror in real time with what it reads is going on in the turbulent layers of the atmosphere and exactly compensate for it in a remarkable feat of engineering and software. So that you can get very close to the sharpness of the images that Hubble.

• 20:22Speaker 01

  Like a contact lens or something.

• 20:23Neil deGrasse Tyson?

  Yeah, oh yeah, right.

• 20:24Speaker 01

  Constantly updating.

• 20:25Neil deGrasse Tyson?

  Constantly updating. It's an awesome bit of hardware that we now have called adaptive optics.

• 20:30Speaker 01

  And so now is that making telescopes like the ones in Hawaii getting, you know, to that level?

• 20:35Neil deGrasse Tyson?

  It has greatly, uh, improved the usability of telescopes or, or, or given them a new lease on life. There are objects that were just too fuzzy to do any work with them. Even though you were, your telescope was big enough to detect them, you were detecting just something that was fuzzy. Now we can detect them and we have sufficient detail.

• 20:53Speaker 01

  So you know more about it.

• 20:54Neil deGrasse Tyson?

  Exactly.

• 20:55Speaker 01

  Huh, interesting. Um, this next question, uh, is from, uh, DeRay Pringle, Mr. Pringle, who had a great one.

• 21:02Neil deGrasse Tyson?

  The same guy from?

• 21:03Speaker 01

  Same, same, but he's, he's multi, he's got a lot of topics on his mind.

• 21:07Neil deGrasse Tyson?

  Is he related?

• 21:08Speaker 01

  I don't know. Well, we'll see. Um, he asks, do you think the James Webb telescope will end up getting cut due to budget shortfalls?

• 21:17Neil deGrasse Tyson?

  Yeah, not if I have anything to do with it. That's, I'm kicking some congressional butt.

• 21:22Speaker 01

  Let's hope then this is the real Pringle. This is the Pringle family and they're, he's, he's willing to chip in. Can I use that joke?

• 21:30Neil deGrasse Tyson?

  Chip in, very good. Very good.

• 21:32Speaker 01

  Thank you. Professional. Thank you.

• 21:37Neil deGrasse Tyson?

  Keep your distance from my professional glow. So, the question surely arose because the budget, there were cost overruns on the James Webb Telescope, I mean by a factor of four even, and there was great worry that Congress would just get fed up with this and cut the budget. And my response here is, the James Webb Telescope, which is gonna, it's gonna, it's not gonna just go in orbit around the earth, it's gonna go a million miles on the other side of the moon, and we're gonna park it there, far away from earth, far away from any contamination, and it's gonna observe galaxies being born in the early universe. It's a telescope unlike any other and required extraordinary engineering innovations to make it happen. And I say, if you're gonna have a cost overrun on anything, let it not be the highway system

• 22:21Neil deGrasse Tyson?

  you're building, or anything else you've done a million times before, why, why be surprised that if you encounter a cost overrun on something you have never even attempted- Right. -that's going to advance human understanding of the universe? Right.

• 22:37Neil deGrasse Tyson?

  You're listening to StarTalk. Stay tuned for another segment.

• 22:53Neil deGrasse Tyson?

  Welcome back to StarTalk. Here's more of this week's episode.

• 23:00Neil deGrasse Tyson?

  So, you got questions? More on telescopes?

• 23:02Speaker 01

  Yes. I had a question too, because, you know, obviously curiosity's now on Mars.

• 23:06Neil deGrasse Tyson?

  Curiosity, the rover, yes.

• 23:08Speaker 01

  That's the rover, yes. And I'm wondering what, is there any sort of opportunity there to establish, to build either a telescope, or is there any sort of telescoping technology they're sending over with that? Does that aid us in any way?

• 23:21Neil deGrasse Tyson?

  No, not really.

• 23:22Speaker 01

  From that vantage point?

• 23:23Neil deGrasse Tyson?

  Yeah, no. I mean, Mars is a little farther out, away from the sun-

• 23:26Speaker 01

  Right.

• 23:27Neil deGrasse Tyson?

  -but it's not so much closer to the rest of the universe that that gives us any kind of telescopic advantage. It's, so, no. And, plus, you might ask, would we use a telescope to see our way just on Mars? That's not necessary. When you have a rover, you can just-

• 23:44Neil deGrasse Tyson?

  Maybe the robot got lazy one day, "Hey, I'm just pulling out the telescopes on this one."

• 23:49Speaker 01

  I think I'm just gonna sit here.

• 23:50Neil deGrasse Tyson?

  Just gonna sit. No, get off your duff.

• 23:51Speaker 01

  I did travel all the way here from Earth. Give me a second.

• 23:55Neil deGrasse Tyson?

  Give me a second. So, yeah, we just send it there and it's got tools to actually dig into the rocks and analyze the chemical composition of them. So, that's something a telescope can't do. So, yeah, when you're there, tell...

• 24:09Speaker 01

  Maybe just do it in person.

• 24:10Neil deGrasse Tyson?

  Forget tell... Yeah, just, just, just, yeah, do it in person with your own damn rock.

• 24:13Speaker 01

  Yeah.

• 24:14Neil deGrasse Tyson?

  And so, yeah, yeah, so...

• 24:16Speaker 01

  Why watch pornography when you could have a girlfriend, right? I mean, that's basically...

• 24:19Neil deGrasse Tyson?

  Oh, that would be the corollary to that theorem. Yes.

• 24:23Speaker 01

  I'm trying to take it, put it in real layman's terms.

• 24:25Neil deGrasse Tyson?

  Exactly.

• 24:26Speaker 01

  Um, alright, so this, this next question is, uh, it comes from Google Plus, from Paul Stewart, and he's wondering, "We keep, uh, producing larger and larger telescopes. Is there any limit on how large they can be?"

• 24:37Neil deGrasse Tyson?

  No, in fact, we are, we are taking it to, we are, we, that's what we're doing. So, so, check out...

• 24:45Speaker 01

  Well said.

• 24:46Neil deGrasse Tyson?

  Hear what we're about to do. We're about to say, "Okay, the bigger the telescope, the more light it can collect." Alright, that's, it's like a bucket and you're trying to collect rain. The person with the bigger bucket collects more rain than the person with the little bucket. Because we're passive receivers of light that comes from the universe. We can't hurry the light along. We can't go grab it before it gets here. We sit here and wait for it to reach us. Big telescopes gather more light and see dimmer things. Not only that, the wider the telescope, the more precise, uh, the sharper the resolution will be for what it is it's observing.

• 25:21Speaker 01

  Hmm, why is that? Is it just...

• 25:23Neil deGrasse Tyson?

  Oh, because you have...

• 25:24Speaker 01

  Because you're getting more information?

• 25:24Neil deGrasse Tyson?

  You have a much, uh, your angle of the, the, so, the way it works is, the, the wider your, the diameter of your detector. So, by the way, it doesn't have to be one solid detector, such as the VLA. You can be spread out. Then you have to be clever about how you combine them.

• 25:43Speaker 01

  Yeah.

• 25:43Neil deGrasse Tyson?

  So, the wider is that field of view, the... The smaller is the, the angle that you can accurately observe on that object. And the smaller that angle is, the, the better your, is your resolution. That's all. So, for example, if you don't, if you're not, if you're not wearing your glasses, but you should, and you take a look at a lawn, it'll just look like a green carpet.

• 26:05Speaker 01

  Yeah.

• 26:05Neil deGrasse Tyson?

  Put on your glasses, you see blades of grass.

• 26:08Speaker 01

  Mm-hmm.

• 26:08Neil deGrasse Tyson?

  If you had even better resolution, you'd see insects crawling within it. And then you could see the cells, and then you could see... So, you can imagine having much better vision than even perfect human vision, and you'd see right on down to the threads in the, in the fibers of the grass. So, this is the challenge of big telescopes. You want a big telescope to, to accomplish this. The frontier of this is we're gonna float telescopes in space and have a baseline that's wider than the diameter of the Earth. Well, chew on that.

• 26:43Neil deGrasse Tyson?

  You're listening to StarTalk Radio. Stay tuned. More up next.

• 27:00Neil deGrasse Tyson?

  Welcome back. Here's more of StarTalk.

• 27:06Speaker 01

  So, we were talking about telescopes, and we were talking about the size of telescopes, how that affects it.

• 27:10Neil deGrasse Tyson?

  Size, uh, size matters.

• 27:12Speaker 01

  Size matters for telescopes.

• 27:13Neil deGrasse Tyson?

  Yeah, it does matter.

• 27:14Speaker 01

  And now, I...

• 27:15Neil deGrasse Tyson?

  Bigger is better.

• 27:16Speaker 01

  What about material-wise? Like, what it's created from?

• 27:19Neil deGrasse Tyson?

  Oh, perfect. Here's the problem. There's a limit to how big you can make a telescope on Earth because it's subject to gravity. The 1G force of gravity. Structurally, that's why the largest radio telescope in the world is sitting in a crater that cradles it. The, you couldn't, the size of that telescope is so large, you could not hold it up. And steer it. In fact, it's an unsteerable telescope. You have to wait for stuff to drift into its field of view. This is the Arcebo Radio Telescope in Puerto Rico. Have to wait for stuff to drift into its field of view just to observe it.

• 27:52Speaker 01

  Is it because the material is so heavy?

• 27:54Neil deGrasse Tyson?

  No, it's that the, well, not that the material itself is heavy, but the size of the structure is so unwieldy.

• 28:00Speaker 01

  Gotcha.

• 28:01Neil deGrasse Tyson?

  Given the gravitational forces that operate, that you just, we have no knowledge of materials that could sustain it. So what we learned is, forget Earth's surface, go into orbit where you have zero G.

• 28:13Speaker 01

  Right.

• 28:13Neil deGrasse Tyson?

  And when you have zero G, the structural integrity of your materials is no longer relevant. Not, at least with regard to the stress of weight. Because you're, it still matters in terms of temperature fluctuations and things, because it gets hot and cold as it goes in and out of Earth's shadow. But other than that, you can make structures that are otherwise unstable. In fact, the Hubble telescope, if brought to Earth, would be unusable as a telescope because it is not structurally stable under its own weight.

• 28:41Speaker 01

  Wow, I never knew that.

• 28:43Neil deGrasse Tyson?

  So, and not only that, in terms of the detectors and the, um, the material that focuses the light. For regular light, you'd use glass, it's very reflective, it's a familiar surface that you put the silver coating on and it reflects. Radio waves, you don't need glass, you can just use wire mesh. The, the, the size of the hole in your surface just has to be smaller than the wavelength of light that you're trying to reflect.

• 29:06Speaker 01

  Interesting.

• 29:07Neil deGrasse Tyson?

  So that's all.

• 29:07Speaker 01

  Now, was the Hubble, was the Hubble built in, finished in space if it was structurally unsound?

• 29:12Neil deGrasse Tyson?

  Oh, no, no, sorry. So it was.

• 29:14Speaker 01

  Or it was just unusable?

• 29:15Neil deGrasse Tyson?

  It was unusable.

• 29:15Speaker 01

  Gotcha, but it wouldn't have like fallen apart.

• 29:18Neil deGrasse Tyson?

  It's a steerable telescope.

• 29:19Speaker 01

  I thought it was like a couch that you have to build in the room or something.

• 29:23Neil deGrasse Tyson?

  Yeah. Yeah. So when it was opened up and the, and the solar panels were exposed, then you have a zero G telescope. The space station itself is, is structurally unstable. I wonder, that's a thing of the size of a football field. With booms hanging out and solar panels and pieces screwed in together. There's no way that could sustain itself in any kind of force of gravity at all.

• 29:47Speaker 01

  That's a nice, yeah, that's a freeing thing. This question is from Facebook from Watson McKeel. And the question is, could there be, could there ever be such a thing as a gravity telescope? A device that could measure not the effects of gravity, but gravity itself? Or dark matter or dark energy telescope? And what would the universe look like through one of those devices?

• 30:08Neil deGrasse Tyson?

  Okay, so it's an interesting question, just to see the gravity field. Right now, we only know gravity by its influence on the movement of other objects. Right, so in a sense, all the telescopes and the software and the detectors that have been brought to bear to discover exoplanets, in a way, those were gravity telescopes. We were observing the response of the host star to the tugging upon it of the planet in orbit around it. So we're observing the effects of gravity through the light emitted by the host star.

• 30:45Speaker 01

  This is, is this almost asking, is there a way to show the negative space?

• 30:49Neil deGrasse Tyson?

  Yeah, I don't know, we have no way, no, I don't know any way to show that. But we do have what are called, there's the Laser Interferometric Gravity Wave Observatory, abbreviated LIGO. And that's a telescope that's to observe, that's a telescope to observe, that's a telescope to observe ripples in the fabric of space and time that come our way. And this is predicted by Einstein. Einstein said there should be something called gravity waves.

• 31:20Speaker 01

  He was ahead of everything.

• 31:22Neil deGrasse Tyson?

  Maybe he came from the future into the past and showed up looking pretty cool.

• 31:26Speaker 01

  And then it was like, oh yeah, I know this is.

• 31:28Neil deGrasse Tyson?

  Trivial.

• 31:29Speaker 01

  I guess, yeah, maybe the Bears are gonna win in 85, maybe, I don't know, maybe.

• 31:32Neil deGrasse Tyson?

  The Bears. So, so what you have there is if two black holes collide, that's an awesome disturbance in the fabric of spacetime. And that ripple moves through space and it comes across the telescope. The telescope can then measure it. The birth of the universe itself has a gravitational signature. These gravity wave telescopes would be brought to bear to observe them. But otherwise, just to see gravity sitting there in empty space, I don't know of any way to do that.

• 32:00Speaker 01

  And what about observing dark energy or dark matter?

• 32:02Neil deGrasse Tyson?

  Oh, well, we're, again, we're observing the effects of dark energy and dark matter.

• 32:07Speaker 01

  And that's the effect of when you see the universe expanding.

• 32:10Neil deGrasse Tyson?

  Exactly.

• 32:13Neil deGrasse Tyson?

  Thanks for listening to StarTalk Radio. I hope you enjoyed this episode. Many thanks to our comedian, our guests, our experts, and I've been your host, Neil Begrass Tyson. Until next time, I bid you to keep looking up.