The Terrifying Reality Of Reaching The Edge Of The Universe — Transcript

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1. 0:00You strap into the seat, look out the
2. 0:01window at the launch pad, and make a
3. 0:03decision that every reasonable person on
4. 0:05Earth would advise against. You are
5. 0:07going to fly in a straight line until
6. 0:08you hit the edge of the universe. The
7. 0:10engines ignite. The whole ship shakes
8. 0:12like a washing machine full of bricks.
9. 0:15Your body is pressed into the seat so
10. 0:16hard that lifting your arm feels like a
11. 0:18part-time job. 8 and 1/2 minutes later,
12. 0:21the shaking stops and you are floating.
13. 0:23You are in orbit. This feels like
14. 0:25progress. It is not. You have traveled
15. 0:28about 400 km. The universe has not
16. 0:31noticed. A few days later, the moon
17. 0:34slides past your window, gray and
18. 0:36silent. A few months after that, Mars.
19. 0:39Then the long, boring dark between the
20. 0:42planets. The sun shrinks with every
21. 0:44passing week until it stops looking like
22. 0:46a sun and starts looking like a very
23. 0:48bright star.
24. 0:49And here is your first problem. The
25. 0:51fastest object humans have ever sent out
26. 0:53of the solar system, Voyager 1, took
27. 0:56about 35 years just to reach
28. 0:58interstellar space. At that speed, the
29. 1:00nearest star would take you more than
30. 1:0270,000 years. You packed snacks for a
31. 1:04much shorter trip.
32. 1:06So you do what every science fiction
33. 1:08writer does when the numbers get rude.
34. 1:10You switch on an engine that does not
35. 1:12exist yet. A magical drive that never
36. 1:14runs out of fuel and pushes you forward
37. 1:17at a steady 1 G. That means the ship
38. 1:19accelerates at exactly the rate that
39. 1:21would make you fall on Earth.
40. 1:23Your feet settle onto the floor. You can
41. 1:25walk around. You can make coffee.
42. 1:27Gravity is back and it is now powered by
43. 1:29pure optimism. 1 G does not sound fast,
44. 1:32but it never stops. Every second, you go
45. 1:35a little faster than the second before.
46. 1:37After a few weeks, you are crossing the
47. 1:39old orbit of Pluto in the time it takes
48. 1:41to finish a podcast. After about a year,
49. 1:44you are traveling close to the speed of
50. 1:46light. This is where the universe starts
51. 1:48behaving strangely. You look out the
52. 1:50front window and something is wrong with
53. 1:52the stars. They are crowding together
54. 1:54ahead of you, bunching toward the center
55. 1:56of your view like they are all trying to
56. 1:58get into the same lift. They are also
57. 2:00changing color. The ones in front glow
58. 2:03bluer. The ones behind you stretch
59. 2:05toward red, thin out, and fade. Nothing
60. 2:08is wrong with the stars.
61. 2:10This is what the sky looks like when you
62. 2:11are moving that fast. Your own speed is
63. 2:13bending the light you see.
64. 2:15The second strange thing is quieter and
65. 2:17much worse. You check your clock. It
66. 2:19says you have been gone for a few years.
67. 2:21Then you check the message feed from
68. 2:23Earth. The messages are arriving slower
69. 2:25and slower, and the dates on them are
70. 2:27wrong. Not slightly wrong. Decades are
71. 2:30passing back home while your coffee is
72. 2:31still warm. That is time dilation. The
73. 2:34faster you go, the slower your clock
74. 2:36ticks compared to everyone you left
75. 2:38behind. From your seat, the trip feels
76. 2:41short.
77. 2:42From Earth, you are disappearing into
78. 2:43the future. Your family is getting older
79. 2:45in every message. Then the messages are
80. 2:48from your family's children. Then from
81. 2:50people you have never met who seem
82. 2:51politely confused about why you are
83. 2:53still out there. And then there is the
84. 2:55dust.
85. 2:56Space between the stars is not perfectly
86. 2:58empty. There is roughly one atom of
87. 3:00hydrogen floating around in every sugar
88. 3:02cube-size chunk of it. At walking speed,
89. 3:05that is nothing. At nearly the speed of
90. 3:07light, every one of those atoms slams
91. 3:09into the front of your ship like a tiny
92. 3:11particle beam. Together, they become a
93. 3:13constant storm of radiation pouring into
94. 3:15the nose of the ship. A single grain of
95. 3:17dust, smaller than a speck of flour,
96. 3:20would hit you with the energy of a bomb.
97. 3:22So your ship needs a thick shield on the
98. 3:23front, and you need to stay behind it.
99. 3:26The fastest ship in history is now also
100. 3:28a ship where you are not allowed to sit
101. 3:30near the window. Still, the shield
102. 3:32holds. And when you finally look back,
103. 3:34you see something no human has ever seen
104. 3:36with their own eyes. The Milky Way. Not
105. 3:39as a pale stripe across the night sky,
106. 3:41but the whole thing. A huge glowing
107. 3:43spiral. Hundreds of billions of stars
108. 3:46hanging behind you in the black.
109. 3:48Somewhere in one of those arms is a
110. 3:49small yellow star you used to call the
111. 3:51sun. You cannot find it. Nobody could.
112. 3:54You have left the galaxy.
113. 3:56What is out here is the emptiest place
114. 3:58you have ever been. Between galaxies,
115. 4:00there are no stars nearby at all. The
116. 4:03darkness is so complete that the faint
117. 4:04smudges of other galaxies are the only
118. 4:06lights in the sky. The temperature
119. 4:08outside the hull is a few degrees above
120. 4:10absolute zero. The last of the warmth of
121. 4:12the universe is a faint glow left over
122. 4:14from the beginning of time. Ahead of
123. 4:16you, one smudge grows larger, Andromeda,
124. 4:19our closest big neighbor galaxy, about 2
125. 4:21and 1/2 million light-years away. Light
126. 4:24itself needs 2 and 1/2 million years to
127. 4:25make this trip.
128. 4:27For you, thanks to time dilation, the
129. 4:30ride takes only a couple of decades on
130. 4:31your clock.
131. 4:32You fly past Andromeda's spiral arms
132. 4:34with one hand on the controls and the
133. 4:36other holding a coffee that has gone
134. 4:38cold for the 4,000th time. Back on
135. 4:40Earth, 2 and 1/2 million years have
136. 4:42passed. Every language you know is gone.
137. 4:45Every country you know is gone. Humans
138. 4:47may be gone. You will never know because
139. 4:50the message feed has been silent for a
140. 4:51very long time. You are now the most
141. 4:54distant human who has ever existed and
142. 4:56you have barely started. If you're
143. 4:58enjoying this video, please hit the
144. 5:00subscribe button. It genuinely helps
145. 5:02keep the channel alive. You keep going
146. 5:05past more galaxies, past whole clusters
147. 5:07of galaxies, hundreds and thousands of
148. 5:10them packed together like glowing
149. 5:11swarms,
150. 5:13past long threads of galaxies stretching
151. 5:15across space like the strands of a
152. 5:17gigantic web with enormous empty voids
153. 5:19in between.
154. 5:21And slowly, you start to notice the
155. 5:22thing that will ruin your entire
156. 5:24mission.
157. 5:25The galaxies ahead of you are moving
158. 5:27away.
159. 5:28Not because of anything you did. Every
160. 5:30distant galaxy is drifting away from
161. 5:32every other distant galaxy, and the
162. 5:34farther away a galaxy is, the faster it
163. 5:36seems to retreat. The universe is
164. 5:38expanding. Space itself is stretching
165. 5:41between everything like dough rising in
166. 5:43an oven with raisins pulling apart.
167. 5:46At first, this is a minor annoyance.
168. 5:48Your destination keeps getting a little
169. 5:49farther away while you travel toward it.
170. 5:51Fine. You are fast. But here is the part
171. 5:54almost nobody expects. The expansion is
172. 5:57not slowing down. It is speeding up.
173. 5:59Something in the universe, which
174. 6:01scientists call dark energy, is pushing
175. 6:03space apart faster and faster. Galaxies
176. 6:06that are far enough away are now being
177. 6:08carried away from you faster than light
178. 6:10could ever travel toward them.
179. 6:12That is not a typo. Nothing can move
180. 6:14through space faster than light. But
181. 6:16space itself can stretch faster than
182. 6:18that. You are not racing the galaxies.
183. 6:21You are racing the floor they are
184. 6:22standing on. So you push harder. 1 G
185. 6:26forever. You are traveling ridiculously
186. 6:28close to the speed of light, and it does
187. 6:30not matter.
188. 6:31There is a limit.
189. 6:33Right now, everything more than roughly
190. 6:3516 billion light years away is
191. 6:37permanently out of reach. Not just for
192. 6:39you, for everyone. For light itself.
193. 6:42A beam of light leaving Earth today will
194. 6:44never arrive there. No matter how long
195. 6:46you fly, no matter how much fuel your
196. 6:48imaginary engine burns, you will never
197. 6:51cross that line.
198. 6:53Scientists call it the cosmic event
199. 6:54horizon. You can call it the moment your
200. 6:57plan officially became a hobby.
201. 6:59And now the really strange part. Looking
202. 7:01back from Earth, astronomers can see
203. 7:03things much farther away than that. The
204. 7:06observable universe stretches about 46
205. 7:08billion light years in every direction.
206. 7:11Light that left those places long ago
207. 7:12has already reached us. You can see
208. 7:15things you can never touch. You can look
209. 7:17at galaxies, map them, give them names,
210. 7:19and still never ever arrive.
211. 7:22So what about the edge? The actual edge?
212. 7:24The wall? The place where the universe
213. 7:26stops?
214. 7:28Here is the answer you were not hoping
215. 7:29for. As far as anyone can tell, there is
216. 7:32no edge. The farthest thing you can see
217. 7:34from Earth is a faint glow called the
218. 7:36cosmic microwave background. It looks
219. 7:38like a wall at the end of everything.
220. 7:40But it is not a wall in space. It is a
221. 7:43wall in time. It is the oldest light
222. 7:45there is, released when the whole
223. 7:46universe was hot and glowing, roughly
224. 7:48380,000 years after it began.
225. 7:51You are not looking at the end of the
226. 7:53universe. You are looking at its baby
227. 7:54photo.
228. 7:55And the observable universe is not a
229. 7:57room with walls.
230. 7:58It is a bubble centered on whoever is
231. 8:00doing the observing. On Earth, the
232. 8:02bubble is centered on Earth. On your
233. 8:04ship, it is centered on you.
234. 8:06Every time you move, the bubble moves
235. 8:08with you. You fly toward the edge, and
236. 8:10the edge comes with you, like the
237. 8:12horizon on a road trip. You can chase it
238. 8:14for billions of years and never get
239. 8:16closer.
240. 8:17So, you slow down, look around, and here
241. 8:20is what you find. Galaxies in every
242. 8:22direction, the same kinds of spirals and
243. 8:25blobs you left behind, spread out more
244. 8:27or less evenly across the dark. No sign
245. 8:30that says end.
246. 8:31No glowing boundary, no cliff. The
247. 8:34universe out here looks almost exactly
248. 8:36like the universe back home. As far as
249. 8:38anyone knows, it either goes on forever,
250. 8:40or it curves back on itself in a way
251. 8:42that has no edge at all, like the
252. 8:44surface of a ball, where you can walk
253. 8:46forever without falling off.
254. 8:48You have traveled farther than any human
255. 8:50could imagine to discover that you are
256. 8:52standing in the middle again.
257. 8:54Then, you think about home.
258. 8:56From your clock, a human lifetime might
259. 8:58have passed. From the universe's point
260. 9:00of view, billions of years are gone. The
261. 9:03sun was always going to swell into a red
262. 9:05giant someday, a few billion years from
263. 9:07when you left. It probably already has.
264. 9:10Earth is either scorched, swallowed, or
265. 9:13something completely different from the
266. 9:14world you knew.
267. 9:16And even if you wanted to tell someone
268. 9:17where you are, you cannot. You are now
269. 9:20far enough away that any signal you send
270. 9:22home will be carried off by the
271. 9:23expansion of space before it ever gets
272. 9:25there. Your message would chase the
273. 9:27Milky Way forever and never catch up.
274. 9:30You are not lost. You know exactly where
275. 9:32you are. It is just that nobody else
276. 9:34will ever be able to know. So, this is
277. 9:36what actually happens if you try to
278. 9:37reach the edge of the universe. You
279. 9:39leave your planet, your star, and your
280. 9:41galaxy.
281. 9:42You watch the stars bend in front of
282. 9:44you, and your family age in fast
283. 9:45forward. You fly through a radiation
284. 9:47storm, cross the emptiest places that
285. 9:49exist, and outlive every civilization
286. 9:52you ever heard of. And at the end of it
287. 9:54all, the universe hands you a very
288. 9:55polite answer.
289. 9:57There is no edge to reach. There is only
290. 9:59more universe, a horizon that moves
291. 10:01every time you do, and a cold cup of
292. 10:03coffee that has now technically been
293. 10:05cold for billions of years.
294. 10:07Somewhere out there, you are still
295. 10:08flying, and somehow, you are still in
296. 10:11the middle.