1
00:00:06,560 --> 00:00:07,560
[birds tweeting]

2
00:00:07,640 --> 00:00:09,480
[water burbling]

3
00:00:11,560 --> 00:00:13,680
[snuffling, trumpeting]

4
00:00:15,560 --> 00:00:17,560
[tranquil music playing]

5
00:00:25,320 --> 00:00:27,920
[Morgan Freeman] <i>In the lives</i>
<i>of every creature on Earth…</i>

6
00:00:28,000 --> 00:00:29,480
-[heart beating]
-[whooshing]

7
00:00:29,560 --> 00:00:31,280
[tranquil vocalizing]

8
00:00:31,360 --> 00:00:32,840
<i>…are echoes…</i>

9
00:00:32,920 --> 00:00:34,160
[roars]

10
00:00:35,120 --> 00:00:38,880
<i>…of events that occurred</i>
<i>a long, long time ago.</i>

11
00:00:38,960 --> 00:00:41,000
[softly gibbering]

12
00:00:43,680 --> 00:00:45,600
<i>Events of unimaginable scale…</i>

13
00:00:47,920 --> 00:00:49,280
<i>and violent beauty…</i>

14
00:00:51,440 --> 00:00:54,240
<i>that connect all living things…</i>

15
00:00:54,320 --> 00:00:56,000
[dramatic vocalizing]

16
00:00:56,080 --> 00:00:58,760
<i>…their every action and decision,</i>

17
00:00:59,440 --> 00:01:00,920
<i>their every heartbeat,</i>

18
00:01:02,920 --> 00:01:05,720
<i>to the grandest story ever told.</i>

19
00:01:07,760 --> 00:01:12,400
<i>This is a tale 13.8 billion years</i>
<i>in the making…</i>

20
00:01:14,680 --> 00:01:17,160
<i>that has seen billions of stars</i>

21
00:01:18,240 --> 00:01:20,040
<i>and billions of worlds…</i>

22
00:01:22,240 --> 00:01:25,440
<i>live and die…</i>

23
00:01:27,920 --> 00:01:30,520
<i>to create the only planet we know of</i>

24
00:01:32,200 --> 00:01:34,880
<i>that is home to life.</i>

25
00:01:34,960 --> 00:01:36,840
[dramatic vocalizing continues]

26
00:01:39,200 --> 00:01:41,160
<i>From the stardust that built us…</i>

27
00:01:43,440 --> 00:01:46,640
<i>to the cosmic ingredients that sustain us…</i>

28
00:01:52,880 --> 00:01:56,400
<i>and the starlight that powers it all,</i>

29
00:01:57,960 --> 00:02:03,360
<i>this is the story of our universe.</i>

30
00:02:04,640 --> 00:02:06,640
[majestic orchestral music playing]

31
00:02:28,240 --> 00:02:30,240
[mysterious music playing]

32
00:02:30,320 --> 00:02:33,000
-[birds tweeting]
-[animals calling]

33
00:02:39,560 --> 00:02:40,800
<i>East Africa.</i>

34
00:02:46,160 --> 00:02:50,880
<i>It's where life's most vital connection</i>
<i>to the universe can be found.</i>

35
00:02:55,000 --> 00:02:57,280
<i>And a very special predator…</i>

36
00:03:00,400 --> 00:03:02,640
<i>named Wa Chini.</i>

37
00:03:06,000 --> 00:03:10,160
<i>Life for a cheetah</i>
<i>is a never-ending search for food…</i>

38
00:03:12,320 --> 00:03:13,680
<i>for vital energy.</i>

39
00:03:16,120 --> 00:03:21,400
<i>And this is one of the hardest places</i>
<i>on Earth for a predator to obtain it.</i>

40
00:03:26,600 --> 00:03:28,600
[sniffing]

41
00:03:31,000 --> 00:03:34,240
<i>The blistering sun</i>
<i>has driven away nearly everything</i>

42
00:03:34,320 --> 00:03:36,600
<i>from these dry, desolate plains.</i>

43
00:03:42,800 --> 00:03:46,840
<i>Any creature that remains here</i>
<i>struggles to survive.</i>

44
00:03:51,480 --> 00:03:53,600
<i>Wa Chini's sole focus…</i>

45
00:03:55,600 --> 00:03:57,280
[tense music playing]

46
00:03:57,360 --> 00:03:59,400
<i>…the only thing driving her…</i>

47
00:04:01,480 --> 00:04:02,920
[ominous music playing]

48
00:04:03,000 --> 00:04:04,080
<i>…is hunger.</i>

49
00:04:07,800 --> 00:04:10,800
<i>This simple, primal impulse</i>

50
00:04:10,880 --> 00:04:14,560
<i>stems from a deep connection</i>
<i>she has to her surroundings</i>

51
00:04:15,520 --> 00:04:18,680
<i>that extends beyond the Serengeti,</i>

52
00:04:19,280 --> 00:04:20,840
<i>beyond our planet</i>

53
00:04:22,000 --> 00:04:23,640
<i>to the universe itself.</i>

54
00:04:24,600 --> 00:04:26,080
[whooshing]

55
00:04:29,720 --> 00:04:31,800
<i>Every cell in Wa Chini's body…</i>

56
00:04:34,160 --> 00:04:36,800
<i>is linked to an ancient stream of energy…</i>

57
00:04:37,960 --> 00:04:38,960
[explosive crash]

58
00:04:39,920 --> 00:04:41,240
<i>…connecting her life</i>

59
00:04:42,920 --> 00:04:44,440
<i>to the heart of a star.</i>

60
00:04:45,440 --> 00:04:47,000
[distorted rumbling]

61
00:04:47,080 --> 00:04:48,480
[loud crashing]

62
00:04:49,840 --> 00:04:53,640
<i>This unbroken stream</i>
<i>spans vast reaches of space…</i>

63
00:04:58,240 --> 00:05:02,160
<i>and stretches back 13.8 billion years.</i>

64
00:05:02,640 --> 00:05:05,000
[whooshing]

65
00:05:11,440 --> 00:05:13,120
[dramatic music playing]

66
00:05:13,200 --> 00:05:18,280
<i>Ancient energy that existed</i>
<i>at the origin of our universe</i>

67
00:05:20,120 --> 00:05:21,360
<i>powers everything.</i>

68
00:05:23,200 --> 00:05:24,480
<i>Every planet.</i>

69
00:05:26,320 --> 00:05:27,280
<i>Every star.</i>

70
00:05:30,480 --> 00:05:31,400
<i>Every life.</i>

71
00:05:40,200 --> 00:05:42,680
<i>Wa Chini is hunting for energy…</i>

72
00:05:46,080 --> 00:05:47,640
<i>but not just for herself.</i>

73
00:05:47,720 --> 00:05:48,640
[cubs mewling]

74
00:05:49,440 --> 00:05:52,040
<i>A mother of two five-month-old cubs,</i>

75
00:05:53,800 --> 00:05:56,880
<i>she's desperate to feed her hungry family.</i>

76
00:06:04,400 --> 00:06:07,520
<i>It's dry season, and food is scarce.</i>

77
00:06:08,920 --> 00:06:12,000
<i>And yet, energy is more abundant</i>
<i>than ever.</i>

78
00:06:13,160 --> 00:06:14,400
[growls softly]

79
00:06:15,920 --> 00:06:17,880
<i>It's just hiding in plain sight.</i>

80
00:06:21,280 --> 00:06:25,680
<i>The largest, brightest, hottest object</i>
<i>in our solar system…</i>

81
00:06:28,240 --> 00:06:29,240
<i>the sun.</i>

82
00:06:29,720 --> 00:06:31,720
[rumbling]

83
00:06:31,800 --> 00:06:34,560
[distorted synth music playing]

84
00:06:41,240 --> 00:06:45,600
<i>Huge loops of searingly hot plasma erupt</i>
<i>from its surface.</i>

85
00:06:51,960 --> 00:06:57,560
<i>Our sun blasts out the energy</i>
<i>of four and a half trillion atomic bombs</i>

86
00:06:57,640 --> 00:06:58,960
<i>every second…</i>

87
00:07:01,560 --> 00:07:04,280
<i>sending more power</i>
<i>to our planet in an hour</i>

88
00:07:04,880 --> 00:07:07,960
<i>than the entire world consumes in a year.</i>

89
00:07:12,520 --> 00:07:16,240
<i>But as impressive</i>
<i>as this gigantic fireball is…</i>

90
00:07:18,680 --> 00:07:21,520
<i>Wa Chini cannot eat sunlight.</i>

91
00:07:21,600 --> 00:07:23,680
[tense music playing]

92
00:07:23,760 --> 00:07:26,320
<i>She only eats things that run…</i>

93
00:07:29,280 --> 00:07:30,520
<i>like gazelle.</i>

94
00:07:31,200 --> 00:07:32,880
[growling softly]

95
00:07:38,760 --> 00:07:41,440
<i>Her spotted coat provides camouflage,</i>

96
00:07:42,480 --> 00:07:44,760
<i>essential for stalking prey.</i>

97
00:07:58,200 --> 00:08:03,640
<i>With few places to hide,</i>
<i>getting closer isn't an option.</i>

98
00:08:07,400 --> 00:08:09,400
[tense music intensifies]

99
00:08:15,640 --> 00:08:18,920
<i>Luckily, Wa Chini</i>
<i>has a trick up her sleeve.</i>

100
00:08:22,400 --> 00:08:24,480
[action music playing]

101
00:08:26,280 --> 00:08:29,800
<i>Cheetah are the fastest animals on land.</i>

102
00:08:29,880 --> 00:08:30,840
[breathing heavily]

103
00:08:32,160 --> 00:08:35,360
<i>From zero to a hundred</i>
<i>in just three seconds…</i>

104
00:08:37,480 --> 00:08:40,800
<i>but gazelles are a pretty close second.</i>

105
00:08:45,080 --> 00:08:47,280
<i>Wa Chini uses up a lot of energy…</i>

106
00:08:59,960 --> 00:09:01,280
<i>but gains nothing.</i>

107
00:09:05,400 --> 00:09:08,880
<i>An adult cheetah can survive</i>
<i>for over a week without a meal.</i>

108
00:09:08,960 --> 00:09:10,440
[panting]

109
00:09:12,600 --> 00:09:17,120
<i>But cubs, they can go no longer</i>
<i>than a few days.</i>

110
00:09:17,680 --> 00:09:18,680
[chirps]

111
00:09:24,080 --> 00:09:29,360
<i>And these two</i>
<i>are getting very, very hungry.</i>

112
00:09:37,840 --> 00:09:40,920
<i>Hunting at such great speeds</i>
<i>is incredibly depleting.</i>

113
00:09:43,200 --> 00:09:46,480
<i>Wa Chini's energy reserves</i>
<i>are now dangerously low.</i>

114
00:09:50,680 --> 00:09:54,200
<i>It will be hours</i>
<i>before she has the strength to hunt again.</i>

115
00:10:00,200 --> 00:10:04,000
<i>Wa Chini and her cubs</i>
<i>are running on empty.</i>

116
00:10:10,920 --> 00:10:12,200
[whooshing]

117
00:10:15,680 --> 00:10:17,000
[whimsical music playing]

118
00:10:20,720 --> 00:10:21,960
[softly rumbles]

119
00:10:22,040 --> 00:10:25,400
<i>Animals all over the planet fight</i>
<i>the same ongoing battle</i>

120
00:10:26,480 --> 00:10:27,760
<i>between consuming…</i>

121
00:10:31,320 --> 00:10:32,800
<i>and using energy.</i>

122
00:10:38,160 --> 00:10:40,000
<i>No matter your strategy,</i>

123
00:10:40,080 --> 00:10:41,960
<i>be it fast or slow,</i>

124
00:10:47,080 --> 00:10:50,000
<i>your next meal is never guaranteed.</i>

125
00:10:55,600 --> 00:10:57,000
[squawking]

126
00:10:59,280 --> 00:11:03,560
<i>Hunger is something</i>
<i>all of us must overcome.</i>

127
00:11:09,920 --> 00:11:11,920
[somber music playing]

128
00:11:12,600 --> 00:11:14,920
<i>Having recovered from her last chase,</i>

129
00:11:15,920 --> 00:11:18,520
<i>Wa Chini is looking</i>
<i>for her next opportunity.</i>

130
00:11:22,920 --> 00:11:24,400
<i>Like all cheetah mothers,</i>

131
00:11:26,040 --> 00:11:27,920
<i>she's parenting solo.</i>

132
00:11:31,680 --> 00:11:33,600
<i>To keep her young cubs well-fed,</i>

133
00:11:34,320 --> 00:11:36,560
<i>she should make a kill every day.</i>

134
00:11:38,240 --> 00:11:40,920
<i>But it's taken her so long to recover</i>

135
00:11:42,240 --> 00:11:44,080
<i>that the sun is now setting.</i>

136
00:11:48,160 --> 00:11:50,160
[majestic vocalizing]

137
00:11:53,720 --> 00:11:55,280
<i>As the light fades,</i>

138
00:11:56,480 --> 00:11:58,760
<i>so does this family's hopes of a meal.</i>

139
00:12:01,440 --> 00:12:03,440
[ominous music plays]

140
00:12:05,880 --> 00:12:07,360
<i>As Earth rotates…</i>

141
00:12:09,960 --> 00:12:15,200
<i>the Serengeti turns away from the sun</i>
<i>and into darkness.</i>

142
00:12:21,520 --> 00:12:24,760
<i>It's a powerful reminder</i>
<i>of life's connection to the sun.</i>

143
00:12:25,240 --> 00:12:27,240
[dramatic music playing]

144
00:12:29,200 --> 00:12:32,840
<i>Our story is the sun's story.</i>

145
00:12:35,160 --> 00:12:36,520
<i>Long, long ago…</i>

146
00:12:37,000 --> 00:12:38,360
[whooshing]

147
00:12:39,760 --> 00:12:44,440
<i>…our solar system was even colder</i>
<i>and darker than it is today.</i>

148
00:12:56,880 --> 00:13:01,960
<i>And yet, these were the perfect conditions</i>
<i>for the birth of a star.</i>

149
00:13:05,200 --> 00:13:07,760
<i>At temperatures close to absolute zero,</i>

150
00:13:08,640 --> 00:13:11,840
<i>the force of gravity began pulling dust</i>
<i>and gas together…</i>

151
00:13:11,920 --> 00:13:12,960
[rumbling]

152
00:13:13,040 --> 00:13:14,160
[wind howling]

153
00:13:14,240 --> 00:13:15,760
<i>…into a massive cloud.</i>

154
00:13:22,880 --> 00:13:24,720
<i>The cloud collapsed inwards,</i>

155
00:13:24,800 --> 00:13:28,240
<i>crushing itself into</i>
<i>a glowing hot ball of gas.</i>

156
00:13:32,240 --> 00:13:33,600
<i>A protostar.</i>

157
00:13:35,880 --> 00:13:37,880
[rumbling, whooshing]

158
00:13:39,200 --> 00:13:40,800
[roaring blast]

159
00:13:40,880 --> 00:13:45,160
<i>Like Wa Chini, this star in the making</i>
<i>had a ferocious hunger…</i>

160
00:13:48,000 --> 00:13:51,320
<i>pulling in so much gas</i>
<i>that jets of hot matter</i>

161
00:13:52,360 --> 00:13:54,760
<i>were propelled from its poles,</i>

162
00:13:56,280 --> 00:13:58,960
<i>stretching out light years into space.</i>

163
00:13:59,480 --> 00:14:01,480
[whooshing]

164
00:14:02,280 --> 00:14:08,320
<i>The infant star continued to grow</i>
<i>for 30 million years…</i>

165
00:14:09,480 --> 00:14:11,480
[dramatic vocalizing]

166
00:14:19,440 --> 00:14:20,680
<i>…until finally,</i>

167
00:14:21,880 --> 00:14:26,200
<i>it became hot enough</i>
<i>to generate power all on its own.</i>

168
00:14:29,360 --> 00:14:30,320
<i>Our sun.</i>

169
00:14:33,280 --> 00:14:37,160
<i>Its golden rays</i>
<i>have now shone brilliantly and steadily…</i>

170
00:14:39,200 --> 00:14:41,640
<i>for 4.6 billion years.</i>

171
00:14:47,400 --> 00:14:51,960
<i>It's just one star</i>
<i>in a galaxy of billions.</i>

172
00:14:57,360 --> 00:15:00,760
<i>And yet, it is a most special one…</i>

173
00:15:03,120 --> 00:15:06,080
<i>because it is the one</i>
<i>that delivers heat and light…</i>

174
00:15:08,440 --> 00:15:10,640
<i>to this incredible, vibrant planet.</i>

175
00:15:10,720 --> 00:15:12,720
[birds tweeting]

176
00:15:23,680 --> 00:15:27,760
<i>Every living thing in the Serengeti</i>
<i>depends on the sun for its energy.</i>

177
00:15:29,800 --> 00:15:34,080
<i>Wa Chini's cubs are drained,</i>
<i>beyond hungry now.</i>

178
00:15:34,160 --> 00:15:35,120
[purring]

179
00:15:35,200 --> 00:15:37,280
<i>They need to eat today.</i>

180
00:15:39,000 --> 00:15:44,160
<i>But all Wa Chini can provide this morning</i>
<i>is precious TLC.</i>

181
00:15:45,800 --> 00:15:47,520
<i>In this parched land,</i>

182
00:15:48,560 --> 00:15:52,440
<i>our sun both gives and takes.</i>

183
00:15:53,640 --> 00:15:57,120
<i>Its fierce energy is what life needs.</i>

184
00:15:58,320 --> 00:16:02,280
<i>But it also has the power to destroy.</i>

185
00:16:06,600 --> 00:16:12,320
<i>It was never going to be easy living</i>
<i>this close to a giant nuclear reactor.</i>

186
00:16:16,120 --> 00:16:18,120
[whooshing]

187
00:16:21,280 --> 00:16:24,160
<i>To understand the source</i>
<i>of this unbearable heat,</i>

188
00:16:25,360 --> 00:16:28,040
<i>we must peer into the inferno…</i>

189
00:16:28,120 --> 00:16:30,120
[rumbling]

190
00:16:31,760 --> 00:16:33,760
[whooshing]

191
00:16:37,240 --> 00:16:40,240
<i>…beneath the outer layers</i>
<i>of bubbling hot plasma…</i>

192
00:16:45,960 --> 00:16:50,120
<i>650 thousand kilometers down…</i>

193
00:16:54,920 --> 00:16:57,120
<i>to the core of our sun.</i>

194
00:17:00,840 --> 00:17:04,840
<i>Our star's heart</i>
<i>would seem surprisingly calm…</i>

195
00:17:07,040 --> 00:17:10,880
<i>but on an atomic level, it's pure chaos.</i>

196
00:17:11,640 --> 00:17:13,640
[whooshing]

197
00:17:14,360 --> 00:17:18,280
<i>This is the hottest part</i>
<i>of our solar system.</i>

198
00:17:21,000 --> 00:17:24,440
<i>Temperatures here</i>
<i>reach 15 million degrees Celsius…</i>

199
00:17:27,640 --> 00:17:32,200
<i>creating the conditions for an event</i>
<i>that can happen almost nowhere else.</i>

200
00:17:32,280 --> 00:17:33,400
[distorted buzzing]

201
00:17:34,560 --> 00:17:36,520
[crunching, rumbling]

202
00:17:36,600 --> 00:17:39,560
<i>Atoms collide at high speed and fuse…</i>

203
00:17:42,960 --> 00:17:44,240
[explosive blast, whoosh]

204
00:17:45,160 --> 00:17:47,000
<i>…releasing pure energy.</i>

205
00:17:53,400 --> 00:17:54,680
[dramatic music playing]

206
00:17:54,760 --> 00:17:59,040
<i>This process is called nuclear fusion</i>

207
00:17:59,880 --> 00:18:02,320
<i>and is what makes our sun shine.</i>

208
00:18:04,960 --> 00:18:06,400
[whooshing]

209
00:18:06,480 --> 00:18:11,120
<i>In fact, it's what powers</i>
<i>all the stars in our universe.</i>

210
00:18:15,200 --> 00:18:20,320
<i>This energy released by stars can be</i>
<i>traced back to the beginning of time…</i>

211
00:18:25,480 --> 00:18:27,240
<i>when there was no matter,</i>

212
00:18:27,840 --> 00:18:32,080
<i>and all that existed</i>
<i>in the entire universe was energy.</i>

213
00:18:35,120 --> 00:18:39,000
<i>And every bit of it lives on</i>
<i>in our universe today.</i>

214
00:18:42,280 --> 00:18:44,280
[invigorating music playing]

215
00:18:46,600 --> 00:18:48,440
<i>As sunlight hits the Serengeti,</i>

216
00:18:49,880 --> 00:18:53,280
<i>energy that's been flowing</i>
<i>for 13.8 billion years</i>

217
00:18:54,880 --> 00:18:58,240
<i>finds its way to Wa Chini and her cubs</i>

218
00:18:59,040 --> 00:19:03,240
<i>and continues its journey</i>
<i>through their environment.</i>

219
00:19:04,880 --> 00:19:08,080
<i>It is never created or destroyed.</i>

220
00:19:09,000 --> 00:19:12,840
<i>It is simply transformed endlessly.</i>

221
00:19:14,240 --> 00:19:18,840
<i>But Wa Chini and her Cubs</i>
<i>can only access this energy in one form…</i>

222
00:19:23,560 --> 00:19:24,720
<i>meat.</i>

223
00:19:24,800 --> 00:19:26,080
[sniffing]

224
00:19:26,920 --> 00:19:28,920
[tense music playing]

225
00:19:31,640 --> 00:19:33,120
[mewling]

226
00:19:33,800 --> 00:19:36,400
<i>And there are rival predators out here…</i>

227
00:19:39,200 --> 00:19:43,480
<i>who could snatch not just her food</i>
<i>but her cubs as well.</i>

228
00:19:45,440 --> 00:19:47,440
[sniffing]

229
00:19:50,440 --> 00:19:52,440
[breathing heavily]

230
00:19:58,080 --> 00:19:59,960
<i>If they don't feed soon,</i>

231
00:20:01,000 --> 00:20:02,480
<i>they will die regardless.</i>

232
00:20:03,360 --> 00:20:05,040
[action music playing]

233
00:20:11,840 --> 00:20:13,200
[growling]

234
00:20:23,480 --> 00:20:26,560
<i>It's a meager snack,</i>
<i>but after two days without food,</i>

235
00:20:27,080 --> 00:20:28,480
<i>it's a lifesaver.</i>

236
00:20:32,480 --> 00:20:35,840
<i>But more than 10%</i>
<i>of cheetah kills are stolen.</i>

237
00:20:35,920 --> 00:20:38,280
[hisses, growls]

238
00:20:40,280 --> 00:20:43,920
<i>Wa Chini must defend every scrap</i>
<i>of energy she captures…</i>

239
00:20:45,560 --> 00:20:46,920
[growls, hisses]

240
00:20:47,840 --> 00:20:49,880
<i>…because when energy is scarce,</i>

241
00:20:50,720 --> 00:20:53,160
<i>competition is fierce.</i>

242
00:20:53,640 --> 00:20:55,040
[whooshing]

243
00:20:57,080 --> 00:21:00,920
<i>Wa Chini's struggle to survive</i>
<i>and sustain her family is repeated</i>

244
00:21:01,400 --> 00:21:03,440
<i>day after day…</i>

245
00:21:03,520 --> 00:21:05,120
[whooshing]

246
00:21:06,040 --> 00:21:07,840
<i>…month after month.</i>

247
00:21:11,360 --> 00:21:13,360
[majestic music playing]

248
00:21:17,880 --> 00:21:21,520
<i>Every meal is a fight.</i>

249
00:21:27,320 --> 00:21:30,440
<i>In the battle between using</i>
<i>and acquiring energy…</i>

250
00:21:32,560 --> 00:21:35,080
<i>Wa Chini is only just breaking even.</i>

251
00:21:40,400 --> 00:21:45,600
<i>Dry season on the Serengeti</i>
<i>is defined by constant hunger.</i>

252
00:21:46,600 --> 00:21:48,840
[thunder crashing, booming]

253
00:21:52,040 --> 00:21:53,760
<i>But change is in the air.</i>

254
00:21:54,400 --> 00:21:55,480
[wind gusting]

255
00:21:55,560 --> 00:22:00,680
<i>The sun's heat has pulled</i>
<i>what moisture there is high into the sky.</i>

256
00:22:02,360 --> 00:22:03,920
[wind whistling]

257
00:22:05,080 --> 00:22:06,560
<i>And what goes up</i>

258
00:22:07,880 --> 00:22:11,120
<i>must eventually come down.</i>

259
00:22:14,680 --> 00:22:17,440
<i>Rains sweep across the plains</i>

260
00:22:18,360 --> 00:22:20,880
<i>and bring dry season to an end.</i>

261
00:22:26,640 --> 00:22:28,280
<i>As the clouds clear,</i>

262
00:22:29,960 --> 00:22:31,760
<i>a glimmer of hope appears.</i>

263
00:22:44,120 --> 00:22:47,400
<i>A single blade of grass</i>
<i>cannot feed Wa Chini's family…</i>

264
00:22:49,920 --> 00:22:51,840
<i>but deep within its cells</i>

265
00:22:52,360 --> 00:22:54,480
<i>lies the answer to their hunger.</i>

266
00:22:55,200 --> 00:22:56,640
[whooshing]

267
00:22:56,720 --> 00:22:58,720
[stirring music playing]

268
00:23:06,520 --> 00:23:09,080
<i>Here, there's a hidden world.</i>

269
00:23:15,000 --> 00:23:21,600
<i>Microscopic stacks called grana bask</i>
<i>in the warm rays from the sun.</i>

270
00:23:32,800 --> 00:23:37,600
<i>Their surface is covered with a forest</i>
<i>of tiny, light-harvesting proteins</i>

271
00:23:38,880 --> 00:23:42,720
<i>that capture energy from our nearest star.</i>

272
00:23:47,800 --> 00:23:50,720
<i>They're packed with</i>
<i>the green pigment chlorophyll,</i>

273
00:23:52,400 --> 00:23:55,040
<i>which absorbs rays of light.</i>

274
00:24:00,000 --> 00:24:02,240
<i>Through the magic of photosynthesis…</i>

275
00:24:12,640 --> 00:24:15,200
<i>water combines with carbon dioxide…</i>

276
00:24:18,320 --> 00:24:21,360
<i>and sunbeams are spun into sugar.</i>

277
00:24:38,440 --> 00:24:43,160
<i>In a matter of days,</i>
<i>the once parched plains are painted green.</i>

278
00:24:51,480 --> 00:24:55,440
<i>Billions of blades of grass</i>
<i>now soak up the boundless sunlight.</i>

279
00:25:00,480 --> 00:25:04,960
<i>And the universe's energy</i>
<i>becomes embedded in the landscape.</i>

280
00:25:10,400 --> 00:25:11,920
<i>There's only one problem.</i>

281
00:25:14,480 --> 00:25:17,000
<i>Cheetahs can't eat grass.</i>

282
00:25:22,920 --> 00:25:25,800
<i>But far away in the northern woodlands,</i>

283
00:25:27,080 --> 00:25:28,280
<i>there are beasts…</i>

284
00:25:30,360 --> 00:25:31,440
<i>that do.</i>

285
00:25:34,080 --> 00:25:36,080
<i>Hundreds of thousands of them.</i>

286
00:25:38,880 --> 00:25:40,120
<i>Wildebeest.</i>

287
00:25:43,120 --> 00:25:48,320
<i>They have wide mouths,</i>
<i>flexible lips, and four stomachs</i>

288
00:25:49,040 --> 00:25:51,920
<i>that are perfectly adapted</i>
<i>to eating grass.</i>

289
00:25:52,000 --> 00:25:53,120
[lowing]

290
00:25:53,200 --> 00:25:55,200
[dramatic music playing]

291
00:26:01,080 --> 00:26:03,880
<i>The massive herds</i>
<i>are constantly on the move</i>

292
00:26:05,800 --> 00:26:07,640
<i>in search of fresh grazing.</i>

293
00:26:11,000 --> 00:26:14,080
<i>To find the grass, they follow the rain.</i>

294
00:26:17,800 --> 00:26:19,120
<i>Driven, like all of us…</i>

295
00:26:21,280 --> 00:26:22,320
<i>by hunger.</i>

296
00:26:25,240 --> 00:26:27,360
[lowing]

297
00:26:32,000 --> 00:26:34,520
<i>But if there is one rule in the Serengeti,</i>

298
00:26:36,200 --> 00:26:39,080
<i>it's that food never comes easy.</i>

299
00:26:48,000 --> 00:26:49,480
<i>The Mara River…</i>

300
00:26:52,120 --> 00:26:55,160
<i>home to some</i>
<i>of the largest crocodiles on Earth.</i>

301
00:26:55,840 --> 00:26:57,680
[ominous music playing]

302
00:26:59,080 --> 00:27:00,840
<i>It's a serious roadblock</i>

303
00:27:00,920 --> 00:27:04,080
<i>in the wildebeests' quest</i>
<i>for vital energy.</i>

304
00:27:16,160 --> 00:27:19,760
<i>To the south, Wa Chini spends</i>
<i>every available moment</i>

305
00:27:19,840 --> 00:27:22,200
<i>scouring the plains for something edible.</i>

306
00:27:31,400 --> 00:27:32,920
[growls]

307
00:27:33,000 --> 00:27:36,000
<i>After six months surviving</i>
<i>on a meager diet,</i>

308
00:27:37,680 --> 00:27:40,160
<i>one of her cubs</i>
<i>has managed to grow bigger…</i>

309
00:27:41,680 --> 00:27:44,080
-[cub mewls]
-[mother purring]

310
00:27:47,720 --> 00:27:50,760
<i>…and is even learning</i>
<i>some hunting skills of her own.</i>

311
00:27:57,000 --> 00:28:01,200
<i>But the other cub is nowhere to be seen.</i>

312
00:28:04,400 --> 00:28:06,760
[melancholic music playing]

313
00:28:07,400 --> 00:28:10,800
<i>Just five percent of cheetah cubs</i>
<i>make it into adulthood.</i>

314
00:28:13,680 --> 00:28:17,600
<i>Most lose their lives</i>
<i>to hungry lions and hyenas.</i>

315
00:28:17,680 --> 00:28:18,680
[growling]

316
00:28:25,200 --> 00:28:28,880
<i>This cub's future is far from guaranteed…</i>

317
00:28:32,880 --> 00:28:36,000
<i>even when energy is tantalizingly close.</i>

318
00:28:42,400 --> 00:28:44,360
<i>Amassed on the banks of the Mara,</i>

319
00:28:45,240 --> 00:28:48,160
<i>the wildebeest have</i>
<i>nowhere to go but forward.</i>

320
00:28:52,080 --> 00:28:55,160
<i>But someone needs to be first.</i>

321
00:28:55,240 --> 00:28:57,040
[hissing]

322
00:29:03,720 --> 00:29:05,680
[action music playing]

323
00:29:34,880 --> 00:29:37,080
<i>One and a half million wildebeest</i>

324
00:29:38,040 --> 00:29:40,560
<i>make this journey each year.</i>

325
00:29:44,280 --> 00:29:48,560
<i>And here, the battle between using</i>
<i>and consuming energy…</i>

326
00:29:50,680 --> 00:29:52,680
<i>plays out on an epic scale.</i>

327
00:30:08,120 --> 00:30:10,840
<i>For those lucky enough to make it across,</i>

328
00:30:12,400 --> 00:30:14,000
<i>this is only the beginning.</i>

329
00:30:23,200 --> 00:30:25,880
<i>Now, they must travel</i>
<i>hundreds of kilometers</i>

330
00:30:27,800 --> 00:30:28,800
<i>day and night</i>

331
00:30:30,040 --> 00:30:31,320
<i>for over two months…</i>

332
00:30:34,200 --> 00:30:35,880
<i>to get to the grassy plains.</i>

333
00:30:38,000 --> 00:30:40,000
[tranquil music playing]

334
00:30:48,600 --> 00:30:52,400
<i>Wa Chini eagerly awaits</i>
<i>the arrival of the wildebeest,</i>

335
00:30:53,920 --> 00:30:58,080
<i>but there is another migration</i>
<i>taking place that is critical</i>

336
00:30:58,160 --> 00:31:00,600
<i>to the survival of both animals.</i>

337
00:31:03,840 --> 00:31:08,360
<i>It's the journey</i>
<i>of unfathomable distance and time.</i>

338
00:31:11,640 --> 00:31:16,920
<i>And without it, every creature</i>
<i>on the Serengeti would go hungry.</i>

339
00:31:17,400 --> 00:31:19,160
[whooshing, crashing]

340
00:31:22,560 --> 00:31:24,160
[whooshing, crashing, buzzing]

341
00:31:24,240 --> 00:31:26,200
<i>In the core of our sun,</i>

342
00:31:26,280 --> 00:31:28,560
<i>as atoms collide and fuse,</i>

343
00:31:29,360 --> 00:31:34,360
<i>photons are released and stream outwards.</i>

344
00:31:34,960 --> 00:31:36,960
[majestic music playing]

345
00:31:38,800 --> 00:31:44,000
<i>These tiny packages of light energy</i>
<i>have zero mass</i>

346
00:31:44,080 --> 00:31:46,080
<i>and travel at the speed of light.</i>

347
00:31:47,800 --> 00:31:51,080
<i>But inside the unbelievably dense core,</i>

348
00:31:51,160 --> 00:31:55,080
<i>they're restrained, absorbed, scattered.</i>

349
00:31:58,200 --> 00:32:03,800
<i>A trip that would normally take</i>
<i>just two seconds can take a million years.</i>

350
00:32:10,960 --> 00:32:15,080
<i>It's a mind-boggling torturous struggle</i>
<i>to escape the sun.</i>

351
00:32:15,160 --> 00:32:17,880
[whooshing, crashing]

352
00:32:20,000 --> 00:32:23,400
<i>But slowly, the photons do rise</i>

353
00:32:25,200 --> 00:32:27,680
<i>upward through the sun's layers</i>

354
00:32:29,640 --> 00:32:31,880
<i>toward its raging hot surface…</i>

355
00:32:34,480 --> 00:32:37,200
<i>where they can finally be set free.</i>

356
00:32:37,280 --> 00:32:38,800
[whooshing accelerates]

357
00:32:38,880 --> 00:32:39,760
[electronic thud]

358
00:32:40,680 --> 00:32:43,360
<i>They radiate out in all directions…</i>

359
00:32:45,640 --> 00:32:46,880
<i>as starlight…</i>

360
00:32:53,720 --> 00:32:59,560
<i>traveling 150 million kilometers</i>
<i>in just over eight minutes.</i>

361
00:33:04,880 --> 00:33:06,640
<i>Arriving just in time…</i>

362
00:33:09,160 --> 00:33:12,720
<i>to meet the wildebeest</i>
<i>at the end of their journey.</i>

363
00:33:16,400 --> 00:33:22,800
<i>Each individual blade of grass absorbs</i>
<i>ten quadrillion photons every second…</i>

364
00:33:27,880 --> 00:33:33,480
<i>capturing enough energy overall</i>
<i>to feed these massive herds.</i>

365
00:33:37,720 --> 00:33:39,200
[whooshing]

366
00:33:43,760 --> 00:33:44,880
<i>From star…</i>

367
00:33:44,960 --> 00:33:46,160
[whooshing]

368
00:33:47,600 --> 00:33:48,640
<i>…to grass…</i>

369
00:33:52,280 --> 00:33:53,280
<i>to wildebeest…</i>

370
00:33:59,720 --> 00:34:02,560
<i>sunlight now provides them</i>
<i>with power to move…</i>

371
00:34:04,600 --> 00:34:05,600
<i>to grow…</i>

372
00:34:07,760 --> 00:34:08,880
<i>to reproduce.</i>

373
00:34:17,160 --> 00:34:20,200
<i>And the longer</i>
<i>they're out on the plains eating,</i>

374
00:34:21,040 --> 00:34:24,120
<i>the longer they're available to be eaten.</i>

375
00:34:24,200 --> 00:34:26,160
[tense music playing]

376
00:34:39,880 --> 00:34:45,120
<i>Rich, delicious, plentiful energy</i>

377
00:34:45,200 --> 00:34:47,600
<i>is finally within striking distance.</i>

378
00:34:50,480 --> 00:34:52,480
[tense music intensifies]

379
00:34:55,800 --> 00:34:58,160
<i>But with three million eyes watching…</i>

380
00:35:01,800 --> 00:35:03,880
<i>Wa Chini needs to move fast.</i>

381
00:35:06,560 --> 00:35:09,320
<i>Luckily, she's a cheetah.</i>

382
00:35:34,360 --> 00:35:35,880
[intense music ends]

383
00:35:59,240 --> 00:36:03,080
<i>At last, Wa Chini</i>
<i>gets a taste of starlight.</i>

384
00:36:06,640 --> 00:36:08,640
[peaceful music playing]

385
00:36:26,040 --> 00:36:27,480
<i>With every bite,</i>

386
00:36:27,560 --> 00:36:31,680
<i>proteins and fats imbued</i>
<i>with cosmic energy</i>

387
00:36:31,760 --> 00:36:33,680
<i>enter Wa Chini's bloodstream.</i>

388
00:36:39,840 --> 00:36:44,360
<i>Their final destination</i>
<i>are her body's cellular power plants,</i>

389
00:36:45,520 --> 00:36:46,720
<i>mitochondria…</i>

390
00:36:49,080 --> 00:36:52,720
<i>where one last transformation</i>
<i>will take place.</i>

391
00:37:00,840 --> 00:37:04,640
<i>Within each mitochondrion</i>
<i>is a surging landscape.</i>

392
00:37:08,720 --> 00:37:13,000
<i>Canyons of membranes rippling</i>
<i>with complex chemistry.</i>

393
00:37:15,080 --> 00:37:19,360
<i>It's here that the energy-rich food</i>
<i>reacts with oxygen</i>

394
00:37:20,160 --> 00:37:21,960
<i>and is finally broken down…</i>

395
00:37:28,680 --> 00:37:33,960
<i>releasing our universe's energy</i>
<i>directly into Wa Chini's cells…</i>

396
00:37:34,880 --> 00:37:36,360
[whooshing]

397
00:37:38,440 --> 00:37:41,160
<i>…powering every action and thought,</i>

398
00:37:41,920 --> 00:37:43,640
<i>every little movement.</i>

399
00:37:45,720 --> 00:37:47,720
[panting]

400
00:37:51,160 --> 00:37:54,000
<i>The journey from star to cell is complete.</i>

401
00:37:59,000 --> 00:38:01,160
<i>Energy that once lit up the universe</i>

402
00:38:02,560 --> 00:38:05,960
<i>now gives Wa Chini and her cub</i>
<i>the gift of life.</i>

403
00:38:18,920 --> 00:38:20,200
<i>In green season,</i>

404
00:38:21,160 --> 00:38:22,880
<i>hunger is just a memory.</i>

405
00:38:32,880 --> 00:38:36,920
<i>Across the Serengeti,</i>
<i>energy is continually transformed…</i>

406
00:38:41,320 --> 00:38:43,960
<i>passing from one life to another,</i>

407
00:38:45,640 --> 00:38:48,480
<i>nourishing the entire ecosystem.</i>

408
00:38:51,400 --> 00:38:54,320
<i>Our sun is the ultimate provider.</i>

409
00:38:55,600 --> 00:38:58,160
<i>Everything feeds on starlight.</i>

410
00:38:59,000 --> 00:39:01,000
[tranquil vocalizing]

411
00:39:03,680 --> 00:39:07,320
<i>The trouble is,</i>
<i>there's nothing to feed the sun.</i>

412
00:39:08,160 --> 00:39:10,160
[rumbling]

413
00:39:10,920 --> 00:39:12,800
<i>And in five billion years,</i>

414
00:39:13,640 --> 00:39:15,280
<i>it will run out of fuel.</i>

415
00:39:16,200 --> 00:39:18,200
[ominous synth music playing]

416
00:39:19,840 --> 00:39:21,560
<i>As its core collapses,</i>

417
00:39:22,520 --> 00:39:24,000
<i>the sun will expand…</i>

418
00:39:26,680 --> 00:39:28,240
<i>and become a red giant…</i>

419
00:39:31,520 --> 00:39:36,560
<i>that will devour the inner planets,</i>
<i>Mercury and Venus.</i>

420
00:39:36,640 --> 00:39:38,600
[eerie vocalizing]

421
00:39:41,800 --> 00:39:43,840
<i>As it balloons out toward Earth,</i>

422
00:39:44,720 --> 00:39:48,080
<i>the extreme gravity</i>
<i>will rip our moon to shreds…</i>

423
00:39:51,560 --> 00:39:53,640
[crunching]

424
00:40:02,280 --> 00:40:05,280
<i>…leaving a ring of moon rock around Earth.</i>

425
00:40:10,480 --> 00:40:13,560
<i>The ultimate fate of our planet</i>
<i>is unknown.</i>

426
00:40:14,080 --> 00:40:15,440
[whooshing]

427
00:40:15,520 --> 00:40:17,520
[pensive music playing]

428
00:40:18,440 --> 00:40:21,720
<i>But there will be one last sunrise…</i>

429
00:40:25,640 --> 00:40:28,600
<i>before our star's outer layers blow away,</i>

430
00:40:30,320 --> 00:40:32,160
<i>and it takes its final breath.</i>

431
00:40:40,040 --> 00:40:43,920
<i>All that will remain is a dying ember,</i>

432
00:40:44,960 --> 00:40:46,560
<i>a white dwarf,</i>

433
00:40:46,640 --> 00:40:52,120
<i>barely the size of our Earth,</i>
<i>surrounded by a vast glowing cloud.</i>

434
00:40:55,400 --> 00:40:57,000
<i>A beacon to the universe.</i>

435
00:40:58,120 --> 00:41:00,280
<i>We were here.</i>

436
00:41:04,360 --> 00:41:05,480
<i>But right now,</i>

437
00:41:06,360 --> 00:41:09,560
<i>our star continues to shine down on us…</i>

438
00:41:10,360 --> 00:41:12,360
[wondrous music playing]

439
00:41:12,960 --> 00:41:16,200
<i>…and will for billions of years to come,</i>

440
00:41:17,200 --> 00:41:22,280
<i>its energy a vital force for all life.</i>

441
00:41:30,200 --> 00:41:32,240
<i>Next in the story of our universe,</i>

442
00:41:33,880 --> 00:41:35,640
<i>whether you are a blazing star…</i>

443
00:41:38,080 --> 00:41:39,760
<i>a vast black hole,</i>

444
00:41:40,920 --> 00:41:43,960
<i>or a chimpanzee learning the ropes,</i>

445
00:41:44,560 --> 00:41:46,280
<i>everything needs time.</i>

446
00:41:48,080 --> 00:41:51,920
<i>But what do you really know</i>
<i>about this mysterious dimension?</i>

447
00:41:53,200 --> 00:41:58,720
<i>Why does everything</i>
<i>have a past, present, and future?</i>

448
00:41:59,400 --> 00:42:00,800
<i>And would any of us be here…</i>

449
00:42:03,520 --> 00:42:04,640
<i>without time?</i>

450
00:42:05,120 --> 00:42:07,360
[heart beating]

451
00:42:09,640 --> 00:42:12,560
[dramatic ending theme playing]