WEBVTT 00:00:02.040 --> 00:00:09.060 Welcome to StarTalk, your place in the universe where science and pop culture collide. 00:00:10.360 --> 00:00:12.760 StarTalk begins right now. 00:00:16.740 --> 00:00:18.500 This is StarTalk. 00:00:19.340 --> 00:00:24.180 This episode is another installment in Things You Thought You Knew. 00:00:24.200 --> 00:00:28.600 And today, we're going to talk about billionaires in space. 00:00:28.840 --> 00:00:33.820 We're going to talk about how our brain is not wired to think in exponentials. 00:00:34.420 --> 00:00:39.860 And we're going to talk about what it takes to achieve orbit, all in this episode of StarTalk. 00:00:40.600 --> 00:00:42.220 So Chuck, I haven't checked in on you lately. 00:00:42.240 --> 00:00:43.220 What's been eating you? 00:00:43.620 --> 00:00:56.960 Well, you know, I'm not sure if it's something that's eating me, but I'm curious because a little while ago, you were on CNN and there was a lot of hoopla about man returning to space. 00:01:00.360 --> 00:01:03.880 That's true, billionaire returns to space. 00:01:03.900 --> 00:01:08.300 Actually, no, it's like this Cro-Magnon man, now we have billionaire man. 00:01:08.320 --> 00:01:09.800 This is so true. 00:01:09.820 --> 00:01:11.740 Billionaire man going to space. 00:01:12.020 --> 00:01:16.960 And now it looks like that's the new thing is that billionaires in space, you know. 00:01:16.980 --> 00:01:18.700 Okay, yeah, so what's your problem? 00:01:18.720 --> 00:01:20.200 So my problem is that... 00:01:20.220 --> 00:01:24.760 By the way, just to be clear, I was on Fareed Zakaria GPS just to give him a shout out. 00:01:25.060 --> 00:01:25.920 Yeah, he's a good guy. 00:01:25.940 --> 00:01:26.460 We all love him. 00:01:26.640 --> 00:01:27.720 That's your buddy. 00:01:29.500 --> 00:01:30.760 But here's the thing. 00:01:31.420 --> 00:01:37.960 So during that day on every single channel, the coverage was like the moon landing. 00:01:39.800 --> 00:01:41.020 Yeah, it's true. 00:01:41.200 --> 00:01:42.380 It was like... 00:01:43.100 --> 00:01:44.820 We interrupt this program. 00:01:47.460 --> 00:02:03.420 So I'm thinking like, yo, that's kind of like we went to the North Pole and then we did a Sarah Palin, like, you know, I could see the North Pole from my house, but then we said that was like we went there. 00:02:03.600 --> 00:02:06.320 Didn't we do better than this already? 00:02:07.360 --> 00:02:08.560 Okay, so what you mean... 00:02:08.580 --> 00:02:10.160 Let me unpack what you just said. 00:02:10.160 --> 00:02:29.660 So on the occasion that I was on CNN, it was Richard Branson who had a crew of six, including himself, who went into a suborbital flight, had a few minutes of weightlessness, and then because it's a space plane, a rocket plane, it could come back and land on a runway. 00:02:30.100 --> 00:02:33.860 Okay, so you're saying... 00:02:33.880 --> 00:02:35.040 Did we do that before? 00:02:35.800 --> 00:02:54.840 We did it 60 years ago with Alan Shepard, America's first astronaut basically, and he was launched from Cape Canaveral, launched him due east and plunked down in his capsule in the Atlantic Ocean, and we plucked him out with an aircraft carrier as we did with all the astronauts who landed in the water. 00:02:55.060 --> 00:02:56.500 So we did that 60 years ago. 00:02:56.620 --> 00:02:58.440 So why all the buzz? 00:02:58.680 --> 00:03:02.120 Because this is now done by a private enterprise. 00:03:03.400 --> 00:03:05.440 Virgin Galactic. 00:03:05.820 --> 00:03:10.960 So a private enterprise, it's a billionaire, he's on the jet. 00:03:11.080 --> 00:03:12.600 Well, that's how you knew it was going to work. 00:03:12.980 --> 00:03:14.380 That's how you knew it was going to work. 00:03:14.400 --> 00:03:15.460 That's how you knew it was going to work. 00:03:16.520 --> 00:03:19.080 So he has literal skin in the game. 00:03:19.580 --> 00:03:26.900 And for me, I'm not riding any billionaire's rocket anywhere until they send their mother and bring her back, or themselves, right? 00:03:26.920 --> 00:03:28.180 I mean, this counts. 00:03:28.640 --> 00:03:36.700 So this was remarkable publicity if you were thinking about signing up for the trip, and the man gets on the trip himself. 00:03:37.020 --> 00:03:40.700 So I think all of that worked, and the man likes to live. 00:03:41.340 --> 00:03:43.520 What's the French, joie de vivre? 00:03:45.860 --> 00:03:46.720 Yeah, love of life. 00:03:47.080 --> 00:03:51.640 And so that was the celebration of the day. 00:03:52.160 --> 00:03:55.220 Now, so how far did they go? 00:03:55.240 --> 00:03:57.860 Because they kept saying, going to the space, space. 00:03:58.460 --> 00:03:59.980 And I'm an astrophysicist. 00:04:00.300 --> 00:04:01.920 I know what space is. 00:04:02.340 --> 00:04:05.020 And they called it the first commercial space flight. 00:04:07.340 --> 00:04:12.340 Well, except Elon has sent his own spaceships into orbit. 00:04:12.800 --> 00:04:14.580 And it was commercial in that sense. 00:04:14.740 --> 00:04:16.420 So I don't know what they would mean by that. 00:04:17.240 --> 00:04:19.720 So what do they mean by space? 00:04:19.740 --> 00:04:22.980 Well, he went up about 50 miles, something like that, around there. 00:04:23.300 --> 00:04:28.660 And that's lower than the internationally agreed altitude, by the way, just so you know. 00:04:29.160 --> 00:04:37.920 The Air Force recognizes that as space, but internationally, it's a little higher, 62 miles, which comes out to be a clean 100 kilometers. 00:04:37.940 --> 00:04:42.480 So wait a minute, you mean to tell me that he couldn't tack on 12 lousy miles? 00:04:44.160 --> 00:04:48.600 It takes a lot more energy to keep ascending away from Earth's gravity. 00:04:48.800 --> 00:04:49.800 He'd need a bigger rock. 00:04:49.820 --> 00:04:51.480 We're gonna need a bigger rocket, okay? 00:04:51.760 --> 00:05:01.060 You take a look at his size, the size of his rockets relative to Jeff Bezos' rocket, one is way bigger than the other, just in terms of sort of launch mass, okay? 00:05:01.160 --> 00:05:02.980 Somebody's compensating for something. 00:05:06.120 --> 00:05:07.400 I said, is Chuck gonna go there? 00:05:07.420 --> 00:05:08.440 Yeah, he went there. 00:05:08.460 --> 00:05:08.980 Of course. 00:05:09.480 --> 00:05:10.340 Chuck went there. 00:05:12.760 --> 00:05:13.580 So here's the thing. 00:05:13.880 --> 00:05:15.640 So what happens at 100 kilometers? 00:05:16.460 --> 00:05:19.240 You ascend high enough so that there's so few air molecules. 00:05:19.260 --> 00:05:21.600 I think we've talked about this on a previous explainer. 00:05:21.720 --> 00:05:26.300 There's so few air molecules that there's nothing there to scatter sunlight. 00:05:27.160 --> 00:05:30.880 And the blue sky, sky blue is scattered sunlight. 00:05:31.180 --> 00:05:35.720 If you remove the atmosphere because you're so high up, then there's nothing there to scatter it. 00:05:35.740 --> 00:05:38.040 There is no blue sky because there's no sky. 00:05:38.060 --> 00:05:46.180 And then the nighttime universe reveals itself, while the sun is also in the sky at the same time. 00:05:46.480 --> 00:05:52.740 So they classify that as space, the boundary between our atmosphere and space. 00:05:52.760 --> 00:06:02.820 So if you get far enough out of Earth, far enough away from Earth, and you're like, yo, I think we're in a black neighborhood, you made it to space. 00:06:02.840 --> 00:06:06.340 Oh, because the sky loses its brightness. 00:06:06.360 --> 00:06:07.300 The sky literally goes black. 00:06:12.200 --> 00:06:13.740 You're in a black neighborhood. 00:06:13.760 --> 00:06:16.080 Damn, Chuck, why's everything got to be... 00:06:16.720 --> 00:06:19.060 Chuck, I thought you were in therapy for this. 00:06:19.720 --> 00:06:22.440 I am, I am. 00:06:22.460 --> 00:06:25.720 But anyway, for those of you out there, they're called jokes. 00:06:25.820 --> 00:06:27.040 Don't write me a thing. 00:06:27.720 --> 00:06:29.900 Stop being racial, Chuck. 00:06:30.040 --> 00:06:31.380 I live in America, what you want? 00:06:35.380 --> 00:06:37.620 All right, so here's the thing, okay? 00:06:38.000 --> 00:06:41.960 So you're in space, that's what we want to call that space. 00:06:41.980 --> 00:06:43.940 Okay, 62 miles, 100 kilometers. 00:06:43.960 --> 00:06:45.660 You're not weightless, though. 00:06:45.680 --> 00:06:48.560 People equate being in space with being weightless. 00:06:48.760 --> 00:06:51.660 You're only weightless if you're in free fall, okay? 00:06:52.140 --> 00:06:57.940 So if at that moment he cuts off his engines and they fall, then you're weightless. 00:06:58.100 --> 00:06:58.600 Got you. 00:06:58.960 --> 00:07:00.120 For as long as you're falling. 00:07:00.140 --> 00:07:00.480 Right. 00:07:01.040 --> 00:07:10.780 Okay, but there's a point where the atmosphere gets thick enough again, and in the case of Richard Branson's rocket, it was also an airplane, it had airfoil. 00:07:10.800 --> 00:07:21.660 So as it starts hitting atmosphere, then the control surfaces of his wings begin to take effect, and then it can actually do a descent as an airplane. 00:07:22.060 --> 00:07:24.660 But the moment it does that, you are no longer weightless. 00:07:24.680 --> 00:07:25.240 Right. 00:07:25.880 --> 00:07:28.220 Okay, so I just want to make that clear. 00:07:28.240 --> 00:07:34.860 The weightlessness is simply for being in free fall, not for being in what people are calling space. 00:07:34.880 --> 00:07:35.160 Space. 00:07:35.440 --> 00:07:38.440 It's not like you hit space, I'm weightless, oh my gosh, I'm weightless. 00:07:38.500 --> 00:07:40.200 No, no, are you rocket firing? 00:07:40.220 --> 00:07:40.520 No. 00:07:40.780 --> 00:07:42.400 Are you a plane? 00:07:42.660 --> 00:07:45.100 No, you're just falling, you're weightless over that time. 00:07:45.200 --> 00:07:49.760 It's just like, what is it, the parachute drop or whatever it is at the amusement park. 00:07:49.960 --> 00:07:55.160 When they just drop the floor out under you, you are weightless until some parachute opens. 00:07:55.180 --> 00:07:58.020 But over that time, you're weightless, basically weightless. 00:07:58.340 --> 00:07:58.840 Okay? 00:07:59.500 --> 00:08:01.700 Now, if you fall long enough, then the air resists you. 00:08:02.340 --> 00:08:05.180 But while you're accelerating, you're weightless. 00:08:05.200 --> 00:08:06.240 And so that's the experience. 00:08:06.260 --> 00:08:06.960 So now, here's the thing. 00:08:07.980 --> 00:08:12.240 Do you need to go up 62 miles, 100 kilometers, to see the night sky? 00:08:12.620 --> 00:08:14.520 No, you can just wait until the sun sets. 00:08:14.940 --> 00:08:15.740 Oh, my God. 00:08:16.060 --> 00:08:17.540 That's terrible. 00:08:18.820 --> 00:08:20.300 I'm just telling like it is, Chuck. 00:08:20.320 --> 00:08:21.540 I'm just so happy that... 00:08:21.560 --> 00:08:25.060 This is why you have me as your man here. 00:08:25.180 --> 00:08:32.800 I am so happy that neither Bezos or Branson are watching this right now. 00:08:32.880 --> 00:08:37.060 I'm just saying, so to say, oh, I can now see the night sky. 00:08:37.740 --> 00:08:38.700 I'm in space. 00:08:39.740 --> 00:08:43.520 After sunset, you're seeing exactly the same damn night sky. 00:08:45.000 --> 00:08:48.580 So then the next side of it is you're getting to be weightless for a couple of minutes. 00:08:48.800 --> 00:08:50.680 Well, we have what's called the vomit comet. 00:08:50.700 --> 00:08:52.000 Yes, the airplane. 00:08:52.020 --> 00:08:58.720 And without going into space, but it goes to a high enough altitude, and then it just sort of shuts off its engines and then drops. 00:08:58.900 --> 00:09:03.140 Or there are ways to control it so that the engines can simulate a free fall. 00:09:03.380 --> 00:09:05.780 But in that period, you're weightless. 00:09:05.800 --> 00:09:07.760 In fact, they filmed all of Apollo 13. 00:09:08.200 --> 00:09:13.460 Although I was told all of the weightless scenes in Apollo 13 were actually filmed in the Vomit Comet. 00:09:13.480 --> 00:09:15.460 Wow, so they were actually weightless. 00:09:15.480 --> 00:09:17.420 They were actually weightless, not on cables. 00:09:17.960 --> 00:09:21.960 That is the level of commitment that you have to respect. 00:09:22.040 --> 00:09:24.120 Yes, yes, yes. 00:09:24.420 --> 00:09:30.340 And you only get like 20 minutes of pop, so you have to just keep doing that, to get all your footage. 00:09:30.660 --> 00:09:32.980 You can't say, oh, let's get another take just for safety. 00:09:33.000 --> 00:09:35.900 No, that's all you're getting because I'm ready to throw up all over your head. 00:09:35.920 --> 00:09:36.980 Perfect, let's do it again. 00:09:39.000 --> 00:09:40.180 Perfect, let's do it again. 00:09:40.200 --> 00:09:46.580 Alright, so the night sky you're going to get after sunset, the weightlessness you can get on a vomit comet. 00:09:46.840 --> 00:09:50.220 So now how high up are they relative to the Earth? 00:09:50.240 --> 00:09:51.420 Are they going to see the curvature? 00:09:51.640 --> 00:09:53.520 I did a calculation, the answer is no. 00:09:54.100 --> 00:09:56.700 Okay, so let's run this back again. 00:09:57.200 --> 00:10:01.380 So Chuck, schoolroom globe, about a foot across, right? 00:10:02.720 --> 00:10:09.140 The space station, if you're going to find that orbiting, it would be about a centimeter above the surface, about 3 eighths of an inch. 00:10:10.080 --> 00:10:13.160 That's the International Space Station, 3 eighths of an inch. 00:10:13.240 --> 00:10:15.360 All right, that's 250 miles. 00:10:15.700 --> 00:10:19.240 So Branson went a fifth of that. 00:10:20.080 --> 00:10:22.040 So what's a fifth of a centimeter? 00:10:22.360 --> 00:10:29.720 That's two millimeters, which is just a little less than a sixteenth of an inch. 00:10:29.740 --> 00:10:38.480 So if you got a ruler, or any standard American ruler, it doesn't even have the marking. 00:10:38.500 --> 00:10:40.740 There's no demarcation to say this is where we are. 00:10:40.760 --> 00:10:50.200 Well, because the first marker is farther away than the height that Richard Branson ascended above Earth. 00:10:50.380 --> 00:10:54.340 So Richard Branson, you must be this tall to ride this ride. 00:11:00.580 --> 00:11:02.920 No, so I'm just putting out there, I'm just saying. 00:11:04.420 --> 00:11:08.880 It's truth and we can be honest about it. 00:11:08.900 --> 00:11:12.980 Now, by the way, if people want to do this and pay a quarter million dollars, I don't have a problem. 00:11:13.160 --> 00:11:14.940 Open up a whole new tourist industry. 00:11:15.240 --> 00:11:16.400 No problem. 00:11:17.860 --> 00:11:25.000 By the way, Jeff Bezos' rocket, you may have seen, does not land as an airplane because it's basically a capsule. 00:11:25.300 --> 00:11:33.620 So that has to be retrieved and brought back to its destination, just the way Alan Shepard did in 1961. 00:11:34.280 --> 00:11:39.280 But in each case, there's a period of time where they are weightless and that's what people are paying for. 00:11:39.520 --> 00:11:41.520 And Bezos' cabin has bigger windows. 00:11:41.940 --> 00:11:45.760 So again, there is this billionaire competition thing going on. 00:11:45.920 --> 00:11:48.340 I enjoy it on the sidelines here. 00:11:48.360 --> 00:12:11.240 It sounds to me the way you have just described this is you could save yourself $249,990 by going to Six Flags and riding any one of them roller coasters. 00:12:11.260 --> 00:12:12.100 Okay, one other thing. 00:12:12.400 --> 00:12:20.020 So as you may remember, there's an airplane that's taking off that deploys the rocket plane. 00:12:20.620 --> 00:12:23.600 And they go up to like 40 something thousand feet, and the rocket plane takes off. 00:12:24.260 --> 00:12:29.800 The rocket plane is in free fall until the engines kick in, so they'll actually be weightless for a little period of time there. 00:12:30.160 --> 00:12:33.180 And then the rockets kick in, and they experience about three Gs. 00:12:33.500 --> 00:12:39.960 Three Gs is sort of good housekeeping approved G forces on the human body. 00:12:40.400 --> 00:12:43.460 So that's the maximum you're going to get at an amusement park. 00:12:43.900 --> 00:12:47.360 That's what they subject the shuttle astronauts to. 00:12:49.060 --> 00:12:53.300 They could accelerate you faster than that, but they don't need to, and so they don't. 00:12:53.620 --> 00:12:55.960 And so three Gs is like, you know, nice... 00:12:57.200 --> 00:13:00.480 As King Dakar at Great Adventure. 00:13:01.000 --> 00:13:01.620 Yeah, yeah. 00:13:01.640 --> 00:13:05.920 So it's within the realm of what we have all experienced if you're a fan of amusement parks. 00:13:06.060 --> 00:13:07.140 So that's what it is. 00:13:09.680 --> 00:13:10.860 But more power to them. 00:13:10.880 --> 00:13:11.380 Somebody's got it. 00:13:11.400 --> 00:13:12.440 I'm glad somebody's doing it. 00:13:12.460 --> 00:13:12.800 Yeah. 00:13:12.800 --> 00:13:14.180 I'd rather watch them do it. 00:13:14.200 --> 00:13:16.260 And that's why... 00:13:16.280 --> 00:13:19.420 I should put this. 00:13:21.560 --> 00:13:25.920 I never want to interfere with someone who is trying to advance a frontier. 00:13:26.240 --> 00:13:26.640 Right. 00:13:27.360 --> 00:13:31.300 Even if I have skepticism, I'll share the skepticism if you ask what you did. 00:13:31.320 --> 00:13:31.540 Right. 00:13:31.800 --> 00:13:36.080 But I'm not going to run in front of the line saying, don't, not necessarily. 00:13:36.100 --> 00:13:44.400 I just let it go because there's spinoffs, there's all kinds of things that overall historically have been good for civilization and for culture. 00:13:44.700 --> 00:13:47.160 And so I tip my hat to all of what they're doing. 00:13:47.200 --> 00:13:49.040 It's like, look, you're rich, right? 00:13:49.240 --> 00:13:50.900 You got to find something to do with your money. 00:13:51.220 --> 00:13:53.860 Somebody comes along and says, hey, you like motorcycles, right? 00:13:53.880 --> 00:13:55.260 You're like, I love motorcycles. 00:13:55.280 --> 00:13:57.620 They're like, I got a brand new motorcycle for you. 00:13:57.880 --> 00:13:58.960 It's human powered. 00:13:59.100 --> 00:14:01.680 You get on it and you just pedal really, really hard. 00:14:02.080 --> 00:14:05.320 And it only costs $250,000. 00:14:09.460 --> 00:14:12.160 By the way, Elon is not fooled by any of this. 00:14:12.160 --> 00:14:16.560 Because you don't hear Elon say, I want to just put people into suborbital paths. 00:14:16.660 --> 00:14:17.620 What is Elon saying? 00:14:17.640 --> 00:14:18.200 Go to Mars. 00:14:18.580 --> 00:14:19.160 Go to Mars. 00:14:19.180 --> 00:14:20.140 He's saying go to Mars. 00:14:20.420 --> 00:14:26.540 Yeah, and just to put this back on perspective, so Richard Branson went two millimeters above a schoolroom globe. 00:14:28.540 --> 00:14:30.400 Jeff Bezos, a little higher. 00:14:30.640 --> 00:14:33.780 The space station is one centimeter above the globe. 00:14:34.120 --> 00:14:36.160 The moon, 30 feet away. 00:14:37.320 --> 00:14:38.560 Mars, a mile away. 00:14:38.580 --> 00:14:39.500 Oh, my goodness. 00:14:40.140 --> 00:14:40.620 There it is. 00:14:40.640 --> 00:14:42.100 So on scale, yo. 00:14:42.460 --> 00:14:49.320 So when you say let's go into space, and you tell that to an astrophysicist, I have a different answer for you than 50 miles up. 00:14:49.340 --> 00:14:49.940 That's all I'm saying. 00:14:50.100 --> 00:14:51.380 Why you pull all this out of me? 00:14:52.860 --> 00:14:54.120 I'm minding my own damn business. 00:14:54.140 --> 00:14:55.280 I'm so glad we did this, though. 00:14:55.780 --> 00:14:56.960 Take that, billionaire. 00:14:57.760 --> 00:15:07.660 All right, Chuck, we got to take a break there, but when we come back, we're going to talk about achieving orbit, all that it takes. 00:15:22.970 --> 00:15:25.630 I'm Joel Cherico, and I make pottery. 00:15:26.190 --> 00:15:29.590 You can see my pottery on my website, cosmicmugs.com. 00:15:29.810 --> 00:15:33.270 Cosmic Mugs, art that lets you taste the universe every day. 00:15:33.910 --> 00:15:35.890 And I support Star Talk on Patreon. 00:15:36.370 --> 00:15:38.570 This is Star Talk with Neil deGrasse Tyson. 00:15:47.612 --> 00:15:51.192 We're back, StarTalk, the Things You Thought You Knew edition. 00:15:52.032 --> 00:15:55.052 And for this segment, we're gonna talk about achieving orbit. 00:15:55.972 --> 00:15:56.312 Chuck. 00:15:57.912 --> 00:15:58.732 You ever been in orbit? 00:16:00.632 --> 00:16:01.152 Okay. 00:16:01.172 --> 00:16:01.932 No, the answer's no. 00:16:02.012 --> 00:16:02.292 Just... 00:16:04.912 --> 00:16:05.832 I'll answer for you. 00:16:06.952 --> 00:16:11.832 You know, I was just thinking about a couple nights where I partied really hard, man. 00:16:12.612 --> 00:16:13.872 Party down, all right. 00:16:13.892 --> 00:16:15.972 Yeah, so, but of course not, yes. 00:16:15.972 --> 00:16:20.012 Okay, so I want to just tell you a little bit of the history of orbits. 00:16:20.552 --> 00:16:21.752 It's just, for me, it's fascinating. 00:16:21.772 --> 00:16:24.632 I don't know if you'll find it fascinating, but it's fascinating to me. 00:16:25.452 --> 00:16:29.192 And it's my show, so I get to do it. 00:16:30.272 --> 00:16:32.672 You get your own show, you could edit this out, okay? 00:16:32.812 --> 00:16:38.192 All right, so, Isaac Newton, my man, all right. 00:16:38.212 --> 00:16:40.572 He was around in the 1600s, early 1700s. 00:16:41.032 --> 00:16:47.012 He, an English scientist, physicist, natural philosopher, they were called back then. 00:16:47.652 --> 00:16:53.792 Deepest thinker I've ever known, I've ever read on all of the operations of nature. 00:16:54.552 --> 00:17:08.132 And he's sitting there and sees an apple fall from an apple tree in his backyard in Lincolnshire, which is in very outskirts of London, sorry, of Cambridge. 00:17:08.172 --> 00:17:10.732 But it's in the countryside of England, okay? 00:17:11.572 --> 00:17:12.972 It's a childhood home where he grew up. 00:17:13.112 --> 00:17:14.212 There's an apple orchard there. 00:17:14.752 --> 00:17:15.092 All right. 00:17:15.812 --> 00:17:19.352 Did I tell you I was gifted a clipping from that tree? 00:17:20.832 --> 00:17:21.952 I actually saw the tree. 00:17:22.112 --> 00:17:22.792 You saw the tree? 00:17:23.752 --> 00:17:24.452 Yes, yes. 00:17:24.472 --> 00:17:25.292 I actually saw the tree. 00:17:25.312 --> 00:17:26.412 Okay, yeah, that was a whole other thing. 00:17:26.432 --> 00:17:27.752 We gotta dig that out of the archives. 00:17:27.772 --> 00:17:29.032 I think we've told him some of that. 00:17:29.392 --> 00:17:30.432 I saw the sapling. 00:17:30.452 --> 00:17:32.292 It was a sapling, yeah, yeah. 00:17:32.292 --> 00:17:35.472 I saw the sapling, which by the way, is still being cared for. 00:17:35.492 --> 00:17:37.852 At the New York Botanical Gardens. 00:17:37.872 --> 00:17:38.272 I donated for it. 00:17:38.292 --> 00:17:39.372 At the New York Botanical Gardens. 00:17:39.612 --> 00:17:40.412 Up in the Bronx. 00:17:40.412 --> 00:17:40.932 Up in the Bronx. 00:17:41.932 --> 00:17:45.092 Okay, so he's there and he sees an apple fall to the earth. 00:17:45.732 --> 00:17:46.812 Didn't hit him in the head. 00:17:46.832 --> 00:17:47.972 That's just a tale. 00:17:48.852 --> 00:17:52.272 And in the sky is the moon, okay? 00:17:53.032 --> 00:18:01.472 So he thinks to himself, is there some way to connect the falling apple with the orbiting moon? 00:18:02.692 --> 00:18:11.292 Is there some single understanding that renders these two things that I'm looking at the same? 00:18:13.012 --> 00:18:19.232 Most people will look at it and say, well, there's something different going on in the moon than for the apple, because the apple landed on earth on the ground. 00:18:19.532 --> 00:18:22.232 Right, and the moon stays up there all the time. 00:18:22.432 --> 00:18:24.172 Okay, so clearly it's different. 00:18:24.792 --> 00:18:26.272 But we're talking about Isaac Newton. 00:18:27.112 --> 00:18:31.952 And so he said, let's do an experiment, a thought experiment. 00:18:32.912 --> 00:18:38.812 Let's go to a mountaintop and take the apple and just sort of drop it. 00:18:39.552 --> 00:18:42.632 Okay, it'll fall to the ground, to the earth, the way it does in his backyard. 00:18:43.192 --> 00:18:48.352 But now let's sort of fire it from a cannon at ever increasing speeds. 00:18:48.552 --> 00:18:50.012 So you do that horizontally. 00:18:50.312 --> 00:18:53.172 So you do this, it'll fall farther and farther away from you. 00:18:53.192 --> 00:18:54.032 That makes sense, right? 00:18:54.052 --> 00:18:58.772 Right, so the faster it ejects from the cannon, the farther it will go. 00:18:58.792 --> 00:19:01.292 We'll just keep doing this exercise. 00:19:01.992 --> 00:19:06.552 And you keep doing it, and the apple starts following the curvature of the earth. 00:19:07.572 --> 00:19:12.692 And maybe it falls a thousand miles away, but then hits the ground. 00:19:13.092 --> 00:19:15.032 Well, how about, make it faster. 00:19:15.052 --> 00:19:19.552 How about 10,000 miles away and it hits the ground? 00:19:20.332 --> 00:19:21.672 Well, let's keep doing this. 00:19:22.652 --> 00:19:35.392 Oh my gosh, is there a speed where I can eject it so fast that it goes entirely around the earth and hits me in the back of the head? 00:19:35.412 --> 00:19:36.852 Boomer apple. 00:19:38.392 --> 00:19:49.192 And wait a minute, if there is such a speed and it's about to hit me in the back of the head and I duck, then it will just continue. 00:19:49.212 --> 00:19:50.592 Nice. 00:19:51.592 --> 00:19:53.432 So he said there must be such a speed. 00:19:54.492 --> 00:20:00.952 And so he invents the laws of gravity and calculus and all of this, and he figures out that speed. 00:20:01.572 --> 00:20:06.092 And that speed for Earth is about five miles per second. 00:20:07.372 --> 00:20:16.632 If you go sideways, neglecting air resistance, if you go, that's why you have to get high enough where there's no atmosphere, then you can go sideways at five miles a second. 00:20:16.732 --> 00:20:22.612 If you go five miles a second sideways, that's about 17,500 miles an hour. 00:20:24.672 --> 00:20:34.032 Then you're actually falling to Earth at exactly the rate that the curve of the Earth curves away from you. 00:20:36.052 --> 00:20:45.692 So to drop an apple is for the apple to be in free fall, but to send an apple into orbit is also to be in free fall. 00:20:46.052 --> 00:20:49.012 Right, it's just falling around the Earth. 00:20:49.012 --> 00:20:54.912 Well, no, no, it's falling towards the Earth, but the Earth has a curve and it never actually hits the Earth. 00:20:55.772 --> 00:21:01.272 So the falling apple and the orbiting moon are identical. 00:21:01.752 --> 00:21:06.152 The moon just happens to have a sideways velocity that the apple did not. 00:21:06.792 --> 00:21:08.012 That is okay. 00:21:08.872 --> 00:21:09.252 All right. 00:21:09.432 --> 00:21:11.812 And that's why astronauts are weightless. 00:21:12.372 --> 00:21:14.872 They're not weightless because they are in space. 00:21:15.192 --> 00:21:22.412 They're weightless because they are in free fall towards Earth in an orbit first described by Isaac Newton in 1687. 00:21:24.852 --> 00:21:49.732 Dude, that, first of all, I have a new respect for Isaac Newton because for you to look at an apple and say anything other than, I think it's lunchtime, and then take that apple and equate it to a celestial body that orbits us, the moon itself, I don't even know how you get to there. 00:21:50.512 --> 00:22:09.952 Yeah, at every time you think about what he said, what he thought, what he calculated, he goes higher and higher and higher on a scale of, and by the way, there's a plaque to him in the chapel at University of Cambridge, and there's a statue, and it's in Latin, and I loosely translate the Latin. 00:22:09.972 --> 00:22:12.832 It says, of all humans, there is no greater intellect. 00:22:13.852 --> 00:22:14.172 Wow. 00:22:14.332 --> 00:22:16.192 It's a loose translation of the Latin. 00:22:16.212 --> 00:22:17.132 That's a big statement. 00:22:18.612 --> 00:22:21.712 The more I read about it, the smartest man in the world ever. 00:22:21.772 --> 00:22:24.332 I'm saying the more I read about it, yeah. 00:22:24.632 --> 00:22:25.812 Yeah, I'm with, yes. 00:22:27.212 --> 00:22:30.752 Yes, I'm going with this, yes. 00:22:30.972 --> 00:22:35.512 So that's what an orbit is, and that's why you are weightless in space. 00:22:36.052 --> 00:22:38.472 I think we talked about this before, but now it has context. 00:22:38.712 --> 00:22:41.852 There's a recent movie, what's that movie that had moon pirates on it? 00:22:43.352 --> 00:22:44.632 Oh God, yes, Ad Astra. 00:22:44.732 --> 00:22:46.312 Ad Astra, Ad Astra. 00:22:48.532 --> 00:22:57.612 There were a lot of scenes where, okay, it took the astronauts three days to get to the moon because what they do is they get to five miles per second going in orbit around the earth. 00:22:57.632 --> 00:22:58.752 Now they want to escape the earth. 00:22:58.772 --> 00:22:59.552 You have to go faster. 00:23:00.572 --> 00:23:08.792 So you add another two miles per second to your speed, you hit seven miles per second, and now earth will no longer hold you, and you escape the earth. 00:23:08.812 --> 00:23:09.912 That's the escape velocity. 00:23:10.112 --> 00:23:11.232 That'll get you to the moon. 00:23:11.712 --> 00:23:14.292 You can coast to the moon at that speed. 00:23:14.392 --> 00:23:19.392 All right, the astronauts were weightless en route to the moon, because they were falling towards the moon. 00:23:21.452 --> 00:23:25.012 In Ad Astra, they're always firing their rock, oh, but it took them three days to get there. 00:23:25.392 --> 00:23:28.532 In Ad Astra, you can get to the moon in three hours if you wanted to. 00:23:28.552 --> 00:23:30.732 You just have to fire your rockets, right? 00:23:30.752 --> 00:23:33.652 You're not gonna, but then you're not in free fall to the moon. 00:23:34.612 --> 00:23:41.412 If you're firing your rockets, you have gravity artificially created by the rockets inside your vessel. 00:23:42.352 --> 00:23:47.332 As long as your rockets are burning, you will feel that acceleration and it is as though you created gravity. 00:23:47.352 --> 00:23:48.312 It creates like a gravity. 00:23:48.332 --> 00:23:50.072 It creates like a source of gravity. 00:23:50.092 --> 00:23:53.632 And all the scenes where they're firing their rockets, everybody's floating inside their space. 00:23:53.692 --> 00:23:54.732 They got that wrong. 00:23:54.892 --> 00:23:55.672 They got it wrong. 00:23:55.692 --> 00:24:00.672 Plum wrong because they think being in space equals being weightless and that's just false. 00:24:00.692 --> 00:24:08.032 Speaking of Newton, that makes sense because you are the reaction to the action of the rocket being pushed. 00:24:08.052 --> 00:24:09.452 You were now against it. 00:24:09.612 --> 00:24:10.032 Correct. 00:24:10.132 --> 00:24:11.032 So there you go. 00:24:12.312 --> 00:24:17.552 That your reaction to the action is manifested as your weight. 00:24:18.072 --> 00:24:20.472 As your weight and kind of an artificial gravity. 00:24:20.712 --> 00:24:23.272 And by the way, I like that movie. 00:24:23.292 --> 00:24:24.972 Thanks for ruining that for me. 00:24:33.706 --> 00:24:39.686 By www.zeoranger.co.uk So anyhow, I just want to make it clear what's going on if you want to think about space as being a place where you are weightless. 00:24:40.246 --> 00:24:43.546 It is only so because we drift to our destination. 00:24:43.926 --> 00:24:47.426 You don't run your, so when you're in orbit, you don't need rockets to sustain orbit. 00:24:48.266 --> 00:24:54.806 You just duck every time you come past Isaac Newton's head, all right, and you'll just keep, and so in order to come out of orbit, here's the difference now. 00:24:55.226 --> 00:25:00.626 To come out of orbit, you have to fire some kind of retro rocket to slow yourself down. 00:25:01.786 --> 00:25:05.706 Okay, and as you slow down, you can't maintain that orbit. 00:25:05.726 --> 00:25:13.306 You drop to a lower elevation, and eventually you start hitting atmosphere, and then the atmosphere drags you down to earth. 00:25:14.366 --> 00:25:16.246 But how about the very high speeds that you had? 00:25:16.266 --> 00:25:17.066 That's kinetic energy. 00:25:17.086 --> 00:25:18.186 You gotta dissipate that somehow. 00:25:18.306 --> 00:25:19.226 You need heat shields. 00:25:20.286 --> 00:25:22.126 We did a whole show on heat shields. 00:25:22.266 --> 00:25:23.506 Yeah, that was pretty cool. 00:25:23.626 --> 00:25:26.326 Okay, you need those heat shields to dissipate. 00:25:26.346 --> 00:25:27.566 Onion layers that come off. 00:25:27.586 --> 00:25:29.406 No, you remember, Chuck, good memory, Chuck. 00:25:29.626 --> 00:25:32.346 So, you ablate the heat shields. 00:25:32.566 --> 00:25:37.406 This eats up your kinetic energy that you had for going 17,500 miles an hour, okay? 00:25:37.426 --> 00:25:38.386 Atmospheric breaks. 00:25:38.606 --> 00:25:40.866 Breaks, it's aerobraking is exactly what it is. 00:25:41.846 --> 00:25:43.226 All right, so let me ask you this. 00:25:43.246 --> 00:25:43.726 No, wait, wait, wait. 00:25:43.746 --> 00:25:59.586 So that means any spaceship where all you did was go up above the atmospheric line into, quote, space and then come back to Earth, you don't need heat shields because you didn't go 17,000, 18,000 miles an hour. 00:25:59.606 --> 00:26:00.726 Right, exactly. 00:26:00.746 --> 00:26:11.106 You don't need heat shields, you just, so it's a completely different design of rocket to do a suborbital thing and land as an airplane as it does going into orbit. 00:26:11.286 --> 00:26:12.706 The shuttle pulled that off. 00:26:13.346 --> 00:26:16.166 The shuttle landed on a runway, but it also went into orbit. 00:26:16.286 --> 00:26:17.226 And so what did it have? 00:26:17.406 --> 00:26:19.026 Its entire belly. 00:26:19.426 --> 00:26:25.766 The shuttle, the space shuttle pulled that off because it had wings and it landed like an airplane, but it also went into orbit. 00:26:25.926 --> 00:26:27.006 How did it get out of orbit? 00:26:27.026 --> 00:26:27.746