1 00:00:14,351 --> 00:00:16,539 Have you ever been floating in a swimming pool, 2 00:00:16,539 --> 00:00:18,089 all comfy and warm, thinking, 3 00:00:18,089 --> 00:00:20,247 "Man, it'd be cool to be an astronaut! 4 00:00:20,247 --> 00:00:21,706 You could float out in outer space, 5 00:00:21,706 --> 00:00:23,366 look down at the Earth and everything. 6 00:00:23,366 --> 00:00:24,699 It'd be so neat!" 7 00:00:24,699 --> 00:00:26,355 Only that's not how it is at all. 8 00:00:26,355 --> 00:00:27,674 If you are in outer space, 9 00:00:27,674 --> 00:00:28,934 you are orbiting the Earth, 10 00:00:28,934 --> 00:00:31,170 it's called free fall. 11 00:00:31,170 --> 00:00:32,468 You're actually falling towards the Earth. 12 00:00:32,468 --> 00:00:33,890 Alright, think about this for a moment. 13 00:00:33,890 --> 00:00:35,488 That's the feeling you get 14 00:00:35,488 --> 00:00:37,450 if you're going over the top of a roller coaster, 15 00:00:37,450 --> 00:00:40,286 going, like, "Whoooooaaaahhhh!" 16 00:00:40,286 --> 00:00:41,602 Only you're doing this the whole time 17 00:00:41,602 --> 00:00:42,871 you're orbiting the Earth 18 00:00:42,871 --> 00:00:43,490 for two, 19 00:00:43,490 --> 00:00:44,021 three, 20 00:00:44,021 --> 00:00:44,619 four 21 00:00:44,619 --> 00:00:45,147 hours, 22 00:00:45,147 --> 00:00:45,610 days, 23 00:00:45,610 --> 00:00:46,658 whatever it takes, right? 24 00:00:46,658 --> 00:00:48,371 So, how does orbiting work? 25 00:00:48,371 --> 00:00:50,320 Let's take a page from Isaac Newton. 26 00:00:50,320 --> 00:00:51,369 He had this idea, 27 00:00:51,369 --> 00:00:52,441 a little mental experiment. 28 00:00:52,441 --> 00:00:53,905 You take a cannon, 29 00:00:53,905 --> 00:00:54,994 you put it on top of a hill. 30 00:00:54,994 --> 00:00:56,283 If you shoot the cannon ball, 31 00:00:56,283 --> 00:00:57,980 it goes a little bit away. 32 00:00:57,980 --> 00:00:58,774 But if you shoot it harder, 33 00:00:58,774 --> 00:01:01,620 it goes far enough so that it lands 34 00:01:01,620 --> 00:01:03,837 a little bit past the curvature of Earth. 35 00:01:03,837 --> 00:01:04,620 Well, you can imagine 36 00:01:04,620 --> 00:01:06,596 if you shot it really, really, really hard, 37 00:01:06,596 --> 00:01:08,916 it would go all the way around the Earth 38 00:01:08,916 --> 00:01:10,047 and come back, boom! 39 00:01:10,047 --> 00:01:11,886 and, like, hit you in the backside or something. 40 00:01:11,886 --> 00:01:13,109 Let's zoom way back 41 00:01:13,109 --> 00:01:14,632 and put you in a little satellite 42 00:01:14,632 --> 00:01:16,215 over the North Pole of the Earth 43 00:01:16,215 --> 00:01:17,591 and consider north to be up. 44 00:01:17,591 --> 00:01:19,465 You're going to fall down and hit the Earth. 45 00:01:19,465 --> 00:01:23,795 But you are actually moving sideways really fast. 46 00:01:23,795 --> 00:01:24,962 So, when you fall down, 47 00:01:24,962 --> 00:01:26,339 you're going to miss. 48 00:01:26,339 --> 00:01:28,207 You're going to end up on the side of the Earth, 49 00:01:28,207 --> 00:01:29,560 falling down, 50 00:01:29,560 --> 00:01:32,558 and now the Earth is pulling you back in sideways. 51 00:01:32,558 --> 00:01:33,819 Alright, and so it's pulling you back in 52 00:01:33,819 --> 00:01:34,714 and you fall down, 53 00:01:34,714 --> 00:01:36,625 and so you miss the Earth again, 54 00:01:36,625 --> 00:01:38,153 and now you're under the Earth. 55 00:01:38,153 --> 00:01:39,375 And the Earth is going to pull you up, 56 00:01:39,375 --> 00:01:40,907 but you're moving sideways still. 57 00:01:40,907 --> 00:01:42,463 So, you're going to miss the Earth again. 58 00:01:42,463 --> 00:01:43,961 Now, you're on the other side of the Earth, 59 00:01:43,961 --> 00:01:46,686 moving upward and the Earth's pulling you sideways. 60 00:01:46,686 --> 00:01:48,765 Alright, so you're going to fall sideways, 61 00:01:48,765 --> 00:01:51,210 but you're going to be moving up and so you'll miss. 62 00:01:51,210 --> 00:01:53,024 And now you're back on top of the Earth again, 63 00:01:53,024 --> 00:01:54,333 over the North Pole, 64 00:01:54,333 --> 00:01:56,582 going sideways and falling down, 65 00:01:56,582 --> 00:01:57,728 and yep, you guessed it. 66 00:01:57,728 --> 00:02:01,059 You'll keep missing because you're moving so fast. 67 00:02:01,059 --> 00:02:03,483 In this way, astronauts orbit the Earth. 68 00:02:03,483 --> 00:02:05,642 They're always falling towards the Earth, 69 00:02:05,642 --> 00:02:07,312 but they're always missing, 70 00:02:07,312 --> 00:02:09,574 and therefore, they're falling all the time. 71 00:02:09,574 --> 00:02:10,486 They feel like they're falling, 72 00:02:10,486 --> 00:02:12,261 so you just have to kind of get over it. 73 00:02:12,261 --> 00:02:16,395 So, technically, if you ran fast enough and tripped, 74 00:02:16,395 --> 00:02:18,907 you could miss the Earth. 75 00:02:18,907 --> 00:02:20,169 But there's a big problem. 76 00:02:20,169 --> 00:02:24,006 First, you have to be going 8 kilometers a second. 77 00:02:24,006 --> 00:02:26,262 That's 18,000 miles an hour, 78 00:02:26,262 --> 00:02:28,881 just over Mach 23! 79 00:02:28,881 --> 00:02:29,836 The second problem: 80 00:02:29,836 --> 00:02:31,263 If you're going that fast, 81 00:02:31,263 --> 00:02:32,931 yes, you would orbit the Earth 82 00:02:32,931 --> 00:02:34,426 and come back where you came from, 83 00:02:34,426 --> 00:02:36,560 but there's a lot of air in the way, 84 00:02:36,560 --> 00:02:37,978 alright, much less people and things. 85 00:02:37,978 --> 00:02:40,099 So, you would burn up due to atmospheric friction. 86 00:02:40,099 --> 00:02:43,704 So, I do not recommend this.