We Asked Neil Degrasse Tyson 19 Tough Questions — Transcript

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1. 0:00ingredients of life itself.
2. 0:03You know, hydrogen is in our bodies that
3. 0:05was birthed in the big bang. And then we
4. 0:08have carbon, nitrogen, oxygen, silicon,
5. 0:11iron. Those elements did not come from
6. 0:14the big bang. They came from stars.
7. 0:17It's not just figuratively true. It's
8. 0:19literally true that we are stardust.
9. 0:28Hi, I'm Neil Degrasse Tyson, your
10. 0:30personal astrophysicist,
11. 0:32and I'm here to answer questions from
12. 0:35the honesty box.
13. 0:38Here we go. First question.
14. 0:41Could a comet or asteroid destroy Earth?
15. 0:44A comet and asteroid will take out life
16. 0:46on Earth, but Earth itself will be just
17. 0:50fine. So when people say, especially
18. 0:53people in the green movement, we need to
19. 0:55save Earth. Save planet Earth.
20. 0:58You have no idea how resilient planet
21. 1:01Earth is.
22. 1:02It got slammed by a Mars-sized
23. 1:05protolanet, made the moon, and Earth is
24. 1:07still here. What you really mean is,
25. 1:10will it destroy life on Earth? It's done
26. 1:13it before. It'll do it again unless we
27. 1:18figure out a way to deflect the
28. 1:19asteroids. I don't want to be the
29. 1:21laughingstock of the galaxy to be the
30. 1:23only species that went extinct from an
31. 1:26asteroid yet we also had a space
32. 1:29program. That's just embarrassing. Like
33. 1:32no.
34. 1:34Do aliens exist?
35. 1:37Don't know. We're looking for them.
36. 1:40What I'm pretty sure is that they have
37. 1:42yet to visit Earth because if they did,
38. 1:44it would be odd that they only visit US
39. 1:48government facilities.
40. 1:50Okay, so maybe they do exist and they
41. 1:52have visited, but they are inherently
42. 1:54fuzzy and they target restricted naval
43. 1:58airspace, but only of the US government.
44. 2:01Prove the earth is not flat.
45. 2:05Prove it. H
46. 2:09Prove the Earth is not flat.
47. 2:13Okay. Uh,
48. 2:16do you have tall buildings where you
49. 2:20are?
50. 2:21If you do, and a sight line to the
51. 2:24horizon, positions people from the
52. 2:27ground floor up to the top floor and
53. 2:29have someone hanging out in the roof.
54. 2:31And all you have to do is at a sunset,
55. 2:35when you have a clear view to the
56. 2:36western horizon,
57. 2:39have each person looking out the window,
58. 2:41when they see the sun set below the
59. 2:44horizon, have them raise their hand or
60. 2:46shout out. And you will see one by one
61. 2:51in sequence each person raise their hand
62. 2:54until the person does so from the roof.
63. 2:58That tells you that the sun is
64. 3:00disappearing behind a curved surface.
65. 3:04And if Earth were flat, when the sun set
66. 3:06below that edge, everyone would raise
67. 3:09their hands simultaneously.
68. 3:11Or you could look at photos from NASA.
69. 3:15What's something about the universe that
70. 3:18makes you emotional?
71. 3:21All of it. But especially the fact that
72. 3:24the ingredients of life itself,
73. 3:28you know, hydrogen is in our bodies that
74. 3:30was birthed in the big bang. And then we
75. 3:33have carbon, nitrogen, oxygen, silicon,
76. 3:36iron. Those elements did not come from
77. 3:39the big bang. They came from stars
78. 3:41forged in their core from thermonuclear
79. 3:43fusion. And those stars happen to be the
80. 3:45stars that also explode, scattering that
81. 3:48enrichment across the galaxy, allowing
82. 3:50subsequent generations of stars
83. 3:54to have planets,
84. 3:56some of which have the right ingredients
85. 3:59for life.
86. 4:01What is biology but highly complex
87. 4:05chemistry?
88. 4:07And there's no understanding of
89. 4:08chemistry without physics.
90. 4:10So all of this comes together
91. 4:14And so these ingredients
92. 4:16that comprise us were birthed in stars.
93. 4:21It's not just figuratively true. It's
94. 4:23literally true that we are stardust.
95. 4:29We are alive in the universe
96. 4:33and the universe is alive within us.
97. 4:36That is a gift from 20th century
98. 4:39astrophysics
99. 4:41to modern civilization that borders on
100. 4:43the spiritual.
101. 4:46That makes me emotional.
102. 4:48How many molecules are there in a glass
103. 4:50of water? Ooh, there's bajillions
104. 4:55in a glass of water.
105. 4:57All I will tell you is that there are
106. 4:59more molecules in a glass of water
107. 5:02than there are glasses of water in all
108. 5:04the world's oceans.
109. 5:07Think about that. When you drink that
110. 5:09glass of water and those molecules come
111. 5:11out of your body in any one of a
112. 5:13halfozen ways,
113. 5:16those water molecules go back into the
114. 5:18environment. There's enough water
115. 5:19molecules that came back out of your
116. 5:20body to scatter into every other glass
117. 5:24than anyone draws from the world's water
118. 5:26supply.
119. 5:27Given enough time, it gets completely
120. 5:29mixed. That means every glass of water
121. 5:31you drink, there are molecules that pass
122. 5:35through the kidneys
123. 5:37of King Henry VII, Winston Churchill.
124. 5:43Pick your favorite historical character.
125. 5:45So you want to talk about the oneness of
126. 5:48all life on Earth, the water molecules
127. 5:50through your system captures that fact.
128. 5:54Why was Pluto demoted?
129. 5:58It had it coming. I mean, come on. Most
130. 6:01people who are Pluto lovers don't know
131. 6:03the following facts. Ready? Okay. A,
132. 6:09more than half of Pluto's volume is ice.
133. 6:12If Pluto were where Earth is right now,
134. 6:14it would grow a tail because heat from
135. 6:16the sun would evaporate that ice. It
136. 6:19would have a tail. That's no kind of
137. 6:20behavior for a planet. Not only that,
138. 6:22Pluto's orbit crosses the orbit of
139. 6:25another planet.
140. 6:27No other planet does that. You know what
141. 6:28does do that? Comets. You know, comets
142. 6:30are made of ice. Pluto is not
143. 6:34necessarily the biggest thing in its
144. 6:36orbit. There are other objects that
145. 6:38rival Pluto in size. It does not own its
146. 6:41orbital space. In fact, we concluded
147. 6:46Pluto was the one of the larger objects
148. 6:49of a new swath of real estate discovered
149. 6:52in the universe
150. 6:53called the Kyper belt of icy bodies. The
151. 6:58Kyper belt of comets. So yeah, Pluto's
152. 7:01happier there because it's one of the
153. 7:03it's one it's like the king of the
154. 7:04comets instead of the puniest planet.
155. 7:08Is intelligent life an evolutionary
156. 7:11fluke or an inevitability?
157. 7:16Oo. Well, a couple of things.
158. 7:19How inevitable could intelligence be? If
159. 7:21we are the only intelligent life on
160. 7:23Earth and Earth has been around for 4.8
161. 7:25billion years. If it were inevitable,
162. 7:28you think it would show up more
163. 7:30frequently in the tree of life, but it
164. 7:34hasn't.
165. 7:35So, it's not clear how inevitable
166. 7:39it is. If aliens came to visit looking
167. 7:42for intelligent life and they arrived
168. 7:45half a million years ago, that's tiny
169. 7:48compared with the history of the Earth.
170. 7:50We're not here yet. And they wouldn't
171. 7:53find any intelligent life. So, it's not
172. 7:57clear how inevitable it is. What you
173. 8:00don't want, what could likely happen,
174. 8:03especially lately, is aliens come to
175. 8:05Earth and they go home and report back.
176. 8:09There's no sign of intelligent life on
177. 8:11Earth. When will the universe end?
178. 8:17Not in fire, but in ice,
179. 8:21and not with a bang, but with a whimper.
180. 8:26We are on a one-way expansion trip.
181. 8:30never to cease, never to slow.
182. 8:34And if dark energy has its way with us
183. 8:36in 10 to the 22 years, the expansion of
184. 8:41the universe would have accelerated so
185. 8:43rapidly
186. 8:45that it would have ripped the very
187. 8:47fabric of space and time itself. And we
188. 8:50call that the big rip.
189. 8:53I don't even want to know what that
190. 8:55looks like. What happens when we die?
191. 8:59I can answer if you're religious, you go
192. 9:02to heaven and you hang out with all your
193. 9:04relatives. I can answer this as a
194. 9:06physicist. We are warm-blooded
195. 9:08creatures, which means my skin
196. 9:09temperature
197. 9:11is nearly 100° F
198. 9:15and the room I'm in is not. The room I'm
199. 9:18in is 70° F. Okay. So in Celsius body
200. 9:23temperature is like 37 but room
201. 9:26temperature for you is like 20 23
202. 9:29degrees. So you are maintaining a
203. 9:32temperature difference every waking
204. 9:34moment of your life.
205. 9:37If you died
206. 9:39your body would cool to air temperature.
207. 9:43That's why if you've ever touched a
208. 9:45corpse in a casket the first thing you
209. 9:47notice, oh it feels cold. No, it's
210. 9:49actually air temperature. It feels cold
211. 9:52compared to when you normally touch a
212. 9:54human body. All right. Why does the body
213. 9:56temperature drop? Because you're no
214. 9:58longer metabolizing energy. The only
215. 10:00reason why we consume food other than
216. 10:02the nourishment is to have energy to
217. 10:04maintain this body temperature
218. 10:05difference.
219. 10:07Okay. Also, we have neurosaptic
220. 10:09activities in our brain. We have
221. 10:11thoughts. We have a consciousness.
222. 10:13Let's say you die by a series of many
223. 10:15strokes.
224. 10:19You know the person to whom this is
225. 10:21happening
226. 10:22and bit by bit their personality goes
227. 10:26away. They lose their ability to
228. 10:28recognize you. They
229. 10:31they don't know how to speak. They don't
230. 10:35know where they are.
231. 10:38Their consciousness fades. And you're
232. 10:40witness to this. If you do a scan of
233. 10:43their brain, you'll see parts of the
234. 10:45brain shutting off.
235. 10:47because they're not activated by oxygen.
236. 10:50That's what strokes do, of course.
237. 10:53Then the person dies
238. 10:56and the metabolism stops.
239. 10:59You put them in the earth,
240. 11:02the molecules still contain energy
241. 11:07and those molecules are dined upon by
242. 11:09microorganisms in the earth
243. 11:12and you are given back to the ecosystem.
244. 11:15You're given back to the circle of life.
245. 11:21I choose to be buried for that reason. I
246. 11:24spent my whole life dying upon flora and
247. 11:26fauna. It's about time I gave back to
248. 11:28them in death.
249. 11:32So when we die, I'm not given reason to
250. 11:34think
251. 11:36that
252. 11:38your state of mind in death is any
253. 11:41different from your state of mind before
254. 11:43you were born.
255. 11:45Before you were born, you were saying,
256. 11:46"Where am I? How come I'm not?" No, you
257. 11:48just, it's a state of non-existence.
258. 11:51After you die, state of non-existence.
259. 11:55So that's what science says about death.
260. 12:00But death is so scary to so many people.
261. 12:04We fear death because we're born knowing
262. 12:07only life. Is teleportation
263. 12:11possible? What you'd have to do? You
264. 12:13have to be like demolecularized,
265. 12:15turn into a beam of energy, and they
266. 12:17beam the energy to another location,
267. 12:20retaining all the information that is
268. 12:22you, cuz you kind of lose that
269. 12:25information when you convert matter into
270. 12:27energy. But you have to somehow retain
271. 12:29it and then reassemble your atoms. I'm
272. 12:32waiting for the future where we invent
273. 12:34wormholes. Then you just step through to
274. 12:37the destination. No dematerializing, no
275. 12:40reassembling your atoms and putting back
276. 12:42the information of all your
277. 12:44neurosynapses that makes you you in your
278. 12:46mind. You just step through the wormhole
279. 12:48and you arrive. So teleportation.
280. 12:53Yeah, I I I don't think it'll ever
281. 12:55happen
282. 12:57for the information problem that it
283. 13:00poses. Or just warp drives to get to
284. 13:02where you're going. Just warp space. You
285. 13:05know how warp drives work? I'm here and
286. 13:07I want to get there. And that takes a
287. 13:09long time. So you curve space and then
288. 13:12you you jump through that short distance
289. 13:15and then you uncurve it. That's how you
290. 13:17can get across the galaxy during the TV
291. 13:19commercials. Is there life on Mars?
292. 13:22We're looking. It wouldn't be on the
293. 13:24surface. There's a high ultraviolet flux
294. 13:28from the sun protected here on Earth by
295. 13:31our ozone. No such protection on Mars.
296. 13:34Ultraviolet is hazardous to biology. If
297. 13:37there's life on Mars, maybe it's in the
298. 13:39waters that are beneath the surface in
299. 13:42like an aquifer, something such as that.
300. 13:46How does the Earth spin? Everything
301. 13:47spins. Everything. Particles,
302. 13:51planets,
303. 13:54stars, galaxies, everything. When they
304. 13:58form,
305. 13:59they form from larger gas clouds in the
306. 14:03universe.
307. 14:04If the gas cloud has any motion at all
308. 14:08sideways, no matter how small,
309. 14:11as it collapses, that motion grows.
310. 14:16It's called the conservation of angular
311. 14:19momentum. We all know this. We've all
312. 14:21seen it. We've seen it with ice skaters
313. 14:25where they come to make a spin and their
314. 14:28arms are outstretched
315. 14:30and as they bring in their arms, what
316. 14:31happens? They spin faster and faster and
317. 14:35faster and they can take their arms and
318. 14:38put it up above their head so that their
319. 14:39arms get even closer to the axis of
320. 14:42rotation and they spin really, really
321. 14:44fast.
322. 14:45If you want to reverse that, then you
323. 14:48just extend your arms back again. So
324. 14:51that ending posture, that ending panache
325. 14:56at the end of the spin, they have to do
326. 14:57that otherwise they keep spinning. So
327. 15:01when you see an ice skater do that, just
328. 15:03keep that in mind. Everything spins and
329. 15:05when it spins that something has to stop
330. 15:07it and it'll spin forever basically.
331. 15:12Okay? Or when you spin a top or anything
332. 15:14on the there's friction between it and
333. 15:16the surface so it eventually slows down.
334. 15:19In space, there's no friction, so we
335. 15:22good. Who is the goat of science?
336. 15:26Greatest of all time, Isaac Newton. Duh.
337. 15:30He's your boy, Isaac Newton, buried in
338. 15:33Westminster Abbey. He discovered the
339. 15:35laws of optics, the laws of gravity,
340. 15:40singinghandedly invented integral and
341. 15:43differential calculus practically on a
342. 15:45dare. because someone said, "Ike, why do
343. 15:49the planets orbit in ellipses rather
344. 15:51than perfect circles?" And I don't know.
345. 15:53I I get back to you. And then he figures
346. 15:56out why. And his friend says, "Well, how
347. 15:58did you figure this out?" Well, I had to
348. 15:59invent calculus to answer that. Well, he
349. 16:03did all that by the time he turned 26.
350. 16:09And by all evidence, in case you're
351. 16:12wondering whether you will ever achieve
352. 16:14this yourself, by all evidence, he died
353. 16:17a virgin.
354. 16:20These things come with costs.
355. 16:23Isaac Newton. No bow to doubt it.
356. 16:28Is time travel possible?
357. 16:32We are already time traveling into the
358. 16:35future.
359. 16:37one second at a time. The problem though
360. 16:40is we are prisoners of our own present,
361. 16:44forever transitioning between our
362. 16:46inaccessible past and our unknowable
363. 16:49future.
364. 16:52So you will always age at 1 second per
365. 16:55second. The question is what is the rate
366. 16:58that you are aging compared to places
367. 17:01around you? Because not everyone
368. 17:04experiences the same timeline.
369. 17:07Not everyone experiences the same the
370. 17:09same rate of progress of time. If you're
371. 17:14in a strong gravitational field, time
372. 17:17ticks more slowly for you. If you travel
373. 17:20fast, time ticks more slowly for you
374. 17:23relative to others looking on. So
375. 17:29that's that's all we've got. However, if
376. 17:32you can make a wormhole,
377. 17:36there's a way to time travel through the
378. 17:37wormhole. But we don't have wormholes
379. 17:40yet. Stephen Hawkings suggested if you
380. 17:43go back in time to your own timeline,
381. 17:46you might accidentally disrupt your
382. 17:49timeline, prevent your parents from
383. 17:50meeting, and then you're never born so
384. 17:52that you don't exist to go back and
385. 17:55disrupt your own timeline. So that's a
386. 17:57paradox. So Stephvens Hawking said, "We
387. 18:00can't have these paradox." So maybe one
388. 18:01day we will discover something he called
389. 18:03a time travel conjecture which prevents
390. 18:06us from traveling in time just to avoid
391. 18:10that that very outcome. So a favorite
392. 18:15subject of science fiction writers by
393. 18:17the way and best among them best Doctor
394. 18:21Who they do okay uh there's some fun
395. 18:24time uh travel things going on there but
396. 18:28I would say in terms of movies
397. 18:30definitely Back to the Future if you
398. 18:32haven't seen it check it out are UFOs
399. 18:34real? If you see something in the sky
400. 18:38and you don't know what it is, it's
401. 18:40real. It's a real UFO because the U
402. 18:44stands for unidentified.
403. 18:46UFO. I see a flying object. I don't know
404. 18:50what it is. It's real.
405. 18:52So that question, are they real? Almost
406. 18:56doesn't make sense. Of course it's real.
407. 18:59You don't know what you're looking at.
408. 19:00It's a UFO. Okay.
409. 19:04You want to know if UFOs are aliens?
410. 19:06That's different. And I see no
411. 19:09convincing evidence that we have ever
412. 19:11been visited. And why there's so many
413. 19:14sightings? Because most people don't
414. 19:16know what goes on above their heads.
415. 19:19If you go to the community of amateur
416. 19:21astronomers who are out back with their
417. 19:23telescope every night, ask them how many
418. 19:26UFOs they've seen. Chances are the UFO
419. 19:29you saw to them is an IFO, identified
420. 19:32flying object.
421. 19:35I'm waiting for the high resolution
422. 19:36image of aliens walking off a flying
423. 19:38saucer. Then we can talk. Until then,
424. 19:41showing me fuzzy images of lights in the
425. 19:44sky during twilight or any other time of
426. 19:47day. I I need better evidence than that.
427. 19:49I'm sorry. Keep looking. What's more
428. 19:52important? Exploring space or fixing
429. 19:54Earth?
430. 20:02Let's go back to the caves
431. 20:0520,000 years ago. We're all in the cave
432. 20:08and
433. 20:11the lads in the cave peer through the
434. 20:14front door and they look out and they
435. 20:17see mountains and valleys and hills and
436. 20:19trees with fruit on it and and the sky
437. 20:22and they want to go explore
438. 20:25outside the cave, but they don't have
439. 20:27permission. So they go back into the
440. 20:29cave and talk to the cave elders. Back
441. 20:32then the cave elders would be 30 years
442. 20:36old. The c half of everyone in that day
443. 20:40was dead before they turned 30. So they
444. 20:43go to the cave elders and they say we
445. 20:44want to go explore outside. And the cave
446. 20:47elder they they meet other cave elders
447. 20:50and they come back and conclude no
448. 20:54you cannot leave the cave because we
449. 20:56have cave problems. you need to solve
450. 20:58first.
451. 21:00Only then can you go outside the cave
452. 21:02door.
453. 21:04That's what you sound like.
454. 21:07Point is, you do both.
455. 21:10You don't just do one or the other. You
456. 21:11fix Earth and explore.
457. 21:14There could be solutions out there that
458. 21:16can help solve problems here on Earth.
459. 21:20Unless you somehow think Earth is so big
460. 21:22and amazing that all our solutions are
461. 21:24contained here. But if you study the
462. 21:26universe,
463. 21:29this is Earth and this is the universe
464. 21:32and you're saying don't study that, only
465. 21:34study this. Then we'll solve our
466. 21:36problems. Get real.
467. 21:39Does anything scare you? Yes.
468. 21:43I fear that our species as it currently
469. 21:48manifests in this world.
470. 21:51I fear that we lack the wisdom
471. 21:57to become the shepherds
472. 21:59of our powers over nature that we need
473. 22:02to be to ensure
474. 22:05that the world is still here for our
475. 22:07descendants.
476. 22:09That scares me.
477. 22:13Do you think most humans are unable to
478. 22:15grasp the fundamentals of the cosmos?
479. 22:21I'm going to ask a different question.
480. 22:23Is the human mind
481. 22:25smart enough
482. 22:27to fully understand the cosmos at all?
483. 22:31Maybe those who understand it best
484. 22:34understand a tiny little bit of this
485. 22:37larger truth and the human brain is just
486. 22:40too stupid to ever figure it out.
487. 22:42I lose sleep over that,
488. 22:45wondering
489. 22:47if we will ever
490. 22:49figure it all out. Or are we just sort
491. 22:52of pawing at the base of a mountain, not
492. 22:55seeing the glory of what lay before us?
493. 22:58I quote Isaac Newton, your man.
494. 23:01Sometimes I feel as though I'm a child
495. 23:04on the shore,
496. 23:06picking up one pebble that's shinier
497. 23:09than the next.
498. 23:12Yet the great ocean of undiscovered
499. 23:15truth lay before me.
500. 23:21What is the strangest thing about the
501. 23:23universe?
502. 23:25[Music]
503. 23:31That it's knowable at all.
504. 23:39Happy to serve your curiosity.
505. 23:42Neil deGrasse Tyson here. Over and out.
506. 23:46You don't try and go into space and up
507. 23:49to the moon and Mars and build space
508. 23:51stations and so on so you can escape the
509. 23:54earth when you've messed it up. It is
510. 23:55the opposite. The idea is that by going
511. 23:58into space, building infrastructure,
512. 24:00ultimately exist, accessing resources in
513. 24:02space, you save the earth because the
514. 24:05earth is the best place in the universe
515. 24:07because we evolved on it and it's
516. 24:09unique.