All language subtitles for How.the.Universe.Works.S10E04.Dark.History.of.Earth.1080p.WEB.h264-KOMPOST

af Afrikaans
ak Akan
sq Albanian
am Amharic
ar Arabic
hy Armenian
az Azerbaijani
eu Basque
be Belarusian
bem Bemba
bn Bengali
bh Bihari
bs Bosnian
br Breton
bg Bulgarian
km Cambodian
ca Catalan
chr Cherokee
ny Chichewa
zh-CN Chinese (Simplified)
zh-TW Chinese (Traditional)
co Corsican
hr Croatian
cs Czech
da Danish
nl Dutch
en English
eo Esperanto
et Estonian
ee Ewe
fo Faroese
tl Filipino
fi Finnish
fr French
fy Frisian
gaa Ga
gl Galician
ka Georgian
de German
el Greek
gn Guarani
gu Gujarati
ht Haitian Creole
ha Hausa
haw Hawaiian
iw Hebrew
hi Hindi
hu Hungarian
is Icelandic
ig Igbo
id Indonesian
ia Interlingua
ga Irish
it Italian
ja Japanese
jw Javanese
kn Kannada
kk Kazakh
rw Kinyarwanda
rn Kirundi
kg Kongo
ko Korean
kri Krio (Sierra Leone)
ku Kurdish
ckb Kurdish (Soranî)
ky Kyrgyz
lo Laothian
la Latin
lv Latvian
ln Lingala
lt Lithuanian
loz Lozi
lg Luganda
ach Luo
mk Macedonian
mg Malagasy
ms Malay
ml Malayalam
mt Maltese
mi Maori
mr Marathi
mfe Mauritian Creole
mo Moldavian
mn Mongolian
sr-ME Montenegrin
ne Nepali
pcm Nigerian Pidgin
nso Northern Sotho
no Norwegian
nn Norwegian (Nynorsk)
oc Occitan
or Oriya
om Oromo
ps Pashto
fa Persian
pl Polish
pt-BR Portuguese (Brazil)
pt-PT Portuguese (Portugal)
pa Punjabi
qu Quechua
ro Romanian
rm Romansh
nyn Runyakitara
ru Russian
gd Scots Gaelic
sr Serbian
sh Serbo-Croatian
st Sesotho
tn Setswana
crs Seychellois Creole
sn Shona
sd Sindhi
si Sinhalese
sk Slovak
sl Slovenian
so Somali
es Spanish Download
es-419 Spanish (Latin American)
su Sundanese
sw Swahili
sv Swedish
tg Tajik
ta Tamil
tt Tatar
te Telugu
th Thai
ti Tigrinya
to Tonga
lua Tshiluba
tum Tumbuka
tr Turkish
tk Turkmen
tw Twi
ug Uighur
uk Ukrainian
ur Urdu
uz Uzbek
vi Vietnamese
cy Welsh
wo Wolof
xh Xhosa
yi Yiddish
yo Yoruba
zu Zulu
Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated: 1 00:00:01,201 --> 00:00:04,937 The earth is over 4.5 billion years old. 2 00:00:05,873 --> 00:00:09,240 Its history is shaped by disaster... 3 00:00:11,679 --> 00:00:13,044 after disaster. 4 00:00:14,080 --> 00:00:16,248 Asteroid and comet collisions, 5 00:00:16,283 --> 00:00:17,995 flares from the Sun. 6 00:00:18,018 --> 00:00:19,684 Mass extinctions, 7 00:00:19,753 --> 00:00:21,565 supernova explosions, 8 00:00:21,588 --> 00:00:23,567 cosmic ray bombardment. 9 00:00:23,591 --> 00:00:25,402 You name it, we've experienced it. 10 00:00:25,425 --> 00:00:27,585 It's kind of a miracle we're here at all. 11 00:00:29,530 --> 00:00:34,543 These violent events could be why Earth has life 12 00:00:34,567 --> 00:00:37,814 We tend to thin of disaster as a bad thing, 13 00:00:37,838 --> 00:00:40,917 but out of chaos can come possibility. 14 00:00:40,941 --> 00:00:41,784 When we destroy something, 15 00:00:41,808 --> 00:00:44,942 we can also create something new. 16 00:00:46,746 --> 00:00:49,314 Earth has walked the line between survival.. 17 00:00:49,917 --> 00:00:51,417 And destruction. 18 00:00:51,918 --> 00:00:54,363 It's tipping that fine balance of luck 19 00:00:54,387 --> 00:00:57,256 between a good disaster and a bad disaster. 20 00:00:57,356 --> 00:01:02,094 Could catastrophe and chaos be the essential ingredient 21 00:01:02,228 --> 00:01:03,362 for life? 22 00:01:20,581 --> 00:01:22,046 2021. 23 00:01:22,082 --> 00:01:25,429 Scientists investigate something mysterious 24 00:01:25,453 --> 00:01:28,420 buried deep inside the earth 25 00:01:28,489 --> 00:01:32,156 It's a long hidden clue to our violent past. 26 00:01:34,061 --> 00:01:35,337 Deep down 27 00:01:35,361 --> 00:01:37,441 1,800 miles below the surface of the earth, 28 00:01:37,465 --> 00:01:39,997 our core is surrounded by fluid rock, 29 00:01:40,200 --> 00:01:41,365 but inside that, 30 00:01:41,734 --> 00:01:43,402 600 miles high 31 00:01:43,436 --> 00:01:44,546 and thousands of miles across 32 00:01:44,570 --> 00:01:46,450 are two denser regions, 33 00:01:46,473 --> 00:01:50,075 and they kind of cup the core of our planet like two hands. 34 00:01:51,679 --> 00:01:54,691 One of them is, you know, half the size of Australia, for crying out loud. 35 00:01:54,715 --> 00:01:56,835 So, I mean, they're big lumps down there. 36 00:01:56,884 --> 00:01:58,728 There's no reason they should be there. 37 00:01:58,752 --> 00:02:00,118 It's a mystery to us. 38 00:02:02,856 --> 00:02:03,900 To solve this mystery, 39 00:02:03,924 --> 00:02:06,436 scientists need to examine the rocks 40 00:02:06,459 --> 00:02:10,027 buried over 1,000 miles beneath the surface. 41 00:02:11,699 --> 00:02:14,843 We don't really know what these two big rocks are made of, 42 00:02:14,867 --> 00:02:15,844 sitting there on the core. 43 00:02:15,868 --> 00:02:17,646 However, we've been able to sample them. 44 00:02:17,670 --> 00:02:19,670 How in the world is that possible? 45 00:02:20,640 --> 00:02:23,341 Well, these blobs are actual feeding mantle plumes 46 00:02:23,377 --> 00:02:25,537 that are rising up through the mantle. 47 00:02:26,813 --> 00:02:29,292 So, volcanoes in Iceland and Samoa, for instance, 48 00:02:29,316 --> 00:02:32,718 will dredge up some of these lumps of rock from the mantle. 49 00:02:32,786 --> 00:02:35,965 It's a precious chance for us to sample some of that deep rock 50 00:02:35,989 --> 00:02:38,323 that we'd normally not get a chance to see. 51 00:02:41,262 --> 00:02:42,661 These rocks are old. 52 00:02:42,695 --> 00:02:44,228 Very old. 53 00:02:44,632 --> 00:02:47,031 It turns out that the samples in the lav 54 00:02:47,099 --> 00:02:49,612 that we think came from these blobs of rock in the mantle 55 00:02:49,637 --> 00:02:52,670 are 4.5 billion years old. 56 00:02:52,706 --> 00:02:55,373 That is as old as the age of the earth. 57 00:02:56,409 --> 00:02:58,420 So, they tell us something about, you know, 58 00:02:58,444 --> 00:03:02,359 how the internal structure of our planet was, uh, arranged 59 00:03:02,383 --> 00:03:04,394 in the earliest days of the formation of our planet, 60 00:03:04,418 --> 00:03:08,198 so getting samples from that time is very, very important. 61 00:03:08,222 --> 00:03:12,335 The age of the rocks may be a clue to their origin. 62 00:03:12,359 --> 00:03:16,995 They date back to a time of monstrous cosmic mayhem. 63 00:03:21,568 --> 00:03:22,778 4.5 billion years ago, 64 00:03:22,802 --> 00:03:25,236 the solar system was still a pretty wild place. 65 00:03:26,806 --> 00:03:29,352 We're approaching the end of the formation of planets. 66 00:03:29,376 --> 00:03:32,176 Earth would still be growing. 67 00:03:33,881 --> 00:03:37,248 Back then, you wouldn't necessarily recognize the earth. 68 00:03:38,718 --> 00:03:40,896 In fact, you wouldn't recognize the earth at all. 69 00:03:40,920 --> 00:03:42,132 For example, no moon. 70 00:03:42,156 --> 00:03:44,475 The earth did not have a moon when it first formed. 71 00:03:45,725 --> 00:03:50,094 The young earth orbits the S with other infant planets. 72 00:03:51,564 --> 00:03:55,366 One of them is an object scientists call Theia... 73 00:03:57,237 --> 00:04:00,938 and it's on a collision course with our home. 74 00:04:06,879 --> 00:04:09,825 The Theia collision would ha been a spectacular event. 75 00:04:09,849 --> 00:04:10,993 It would've been one of the coolest things 76 00:04:11,018 --> 00:04:12,361 you could possibly witness 77 00:04:12,385 --> 00:04:13,930 in the origin of the solar system, 78 00:04:13,954 --> 00:04:16,394 certainly the biggest event in the history of the earth. 79 00:04:20,627 --> 00:04:22,838 The Theia event is 80 00:04:22,862 --> 00:04:26,076 something that completely reshaped the earth. 81 00:04:26,100 --> 00:04:29,668 The planet that the earth was before the Theia event 82 00:04:29,735 --> 00:04:31,202 is gone forever. 83 00:04:31,672 --> 00:04:33,983 The impact melts rock 84 00:04:34,007 --> 00:04:38,276 and throws out over a billio billion tons of debris. 85 00:04:39,545 --> 00:04:41,858 During this incredible collision, 86 00:04:41,882 --> 00:04:43,893 these two planets were literally broken apart 87 00:04:43,917 --> 00:04:46,696 and combined into one big planet. 88 00:04:46,720 --> 00:04:49,365 Huge chunks of Theia stayed together 89 00:04:49,389 --> 00:04:52,391 as the now molten earth began to form anew. 90 00:04:52,893 --> 00:04:55,004 Now, we can kind of paint a picture 91 00:04:55,028 --> 00:04:56,773 of where these big lumps of rock might have come from. 92 00:04:56,797 --> 00:04:58,975 They're very old. 93 00:04:58,999 --> 00:05:02,033 They're, in fact, the same age as that large impact event. 94 00:05:03,237 --> 00:05:04,869 They could be pieces of Thei 95 00:05:07,173 --> 00:05:11,310 The giant slabs of Theia sink down into our planet... 96 00:05:12,646 --> 00:05:16,380 and lie undiscovered for billions of years. 97 00:05:21,355 --> 00:05:26,935 Earth reforms from the ruin of both planets. 98 00:05:26,959 --> 00:05:30,507 Now, you might think that a collision like this is just devastating, 99 00:05:30,531 --> 00:05:31,829 there's no upside at all, 100 00:05:31,898 --> 00:05:33,810 but there's some things that came out of this collision 101 00:05:33,834 --> 00:05:37,235 that may have led to the possibility of life. 102 00:05:38,639 --> 00:05:40,649 When these two planets combined, 103 00:05:40,673 --> 00:05:45,143 parts of Theia's iron core merged with Earth's. 104 00:05:46,612 --> 00:05:48,858 So, that means that Earth collected a much bigger core 105 00:05:48,882 --> 00:05:50,659 than it might have possessed on its own. 106 00:05:50,683 --> 00:05:51,860 This is good news for us 107 00:05:51,884 --> 00:05:54,245 because the core is the source of the magnetic field 108 00:05:54,286 --> 00:05:56,298 that protects us. 109 00:05:56,322 --> 00:05:59,423 Liquid metal flowing around in the outer core 110 00:05:59,492 --> 00:06:02,026 generates Earth's magnetic field... 111 00:06:02,762 --> 00:06:05,262 a protective shield from the Sun. 112 00:06:08,302 --> 00:06:10,646 The Sun can actual output billions of tons 113 00:06:10,670 --> 00:06:14,139 of high-energy protons and electrons in a single burp. 114 00:06:15,641 --> 00:06:18,120 That, eventually, would hav stripped away our atmosphere 115 00:06:18,144 --> 00:06:19,889 If it weren't for that active core 116 00:06:19,913 --> 00:06:20,923 and that magnetic field, 117 00:06:20,947 --> 00:06:22,492 we would look like Mars, 118 00:06:22,516 --> 00:06:25,562 just sort of a bare and barren desert. 119 00:06:25,586 --> 00:06:27,786 Thanks to Theia's extra iron, 120 00:06:27,853 --> 00:06:31,122 Earth's molten outer core is large... 121 00:06:31,959 --> 00:06:33,737 so it cools slowly, 122 00:06:33,761 --> 00:06:35,672 staying molten, 123 00:06:35,696 --> 00:06:39,965 and keeps on generating a strong magnetic shield. 124 00:06:41,668 --> 00:06:43,012 Because of that collision, 125 00:06:43,036 --> 00:06:45,202 the extra iron, the extra heat, 126 00:06:45,271 --> 00:06:46,872 we've stayed active. 127 00:06:46,939 --> 00:06:47,817 We have a magnetic field. 128 00:06:47,841 --> 00:06:49,574 We are protected, 129 00:06:49,608 --> 00:06:52,276 and, in fact, that's why we're here talking about it. 130 00:06:53,680 --> 00:06:57,761 The catastrophic impact helped life in other ways. 131 00:06:57,784 --> 00:07:00,096 The Theia event was absolutely huge, 132 00:07:00,120 --> 00:07:04,600 and not an impact like a 100-mile asteroid making a big crater in the desert, 133 00:07:04,625 --> 00:07:07,836 but a planet hitting a planet, 134 00:07:07,860 --> 00:07:11,807 causing a huge disk of debris spread out from the earth, 135 00:07:11,831 --> 00:07:13,999 out of which formed the Moon 136 00:07:18,771 --> 00:07:19,937 After the collision, 137 00:07:20,005 --> 00:07:22,406 the earth tilts on its side 138 00:07:22,442 --> 00:07:24,475 and spins incredibly fast. 139 00:07:26,579 --> 00:07:29,247 A day only lasts a few hours 140 00:07:31,884 --> 00:07:35,298 The earth itself rotates slightly on its side, 141 00:07:35,322 --> 00:07:38,701 and, if left to its own devices, 142 00:07:38,725 --> 00:07:43,939 would, in fact, experience unpredictable, chaotic wobbling. 143 00:07:43,963 --> 00:07:45,908 The fact that the Moon is there 144 00:07:45,932 --> 00:07:47,409 stabilizes the earth, 145 00:07:47,433 --> 00:07:49,935 stabilizes our climate. 146 00:07:51,605 --> 00:07:55,084 The Moon's gravitational pull on our oceans 147 00:07:55,108 --> 00:07:59,009 creates tides and slows down the earth's spin... 148 00:07:59,745 --> 00:08:03,793 creating a world primed for life. 149 00:08:03,817 --> 00:08:07,463 We actually owe quite a bit to the Moon and Theia, 150 00:08:07,487 --> 00:08:08,697 its progenitor, 151 00:08:08,721 --> 00:08:12,990 for making Earth a hospitable planet for life. 152 00:08:13,860 --> 00:08:15,826 A giant collision 4.5 billion years ago 153 00:08:15,896 --> 00:08:18,663 sounds like a catastrophe, 154 00:08:18,731 --> 00:08:21,211 but it was probably the best thing to happen to the earth. 155 00:08:22,769 --> 00:08:24,547 Theia, I would shake your ha 156 00:08:24,571 --> 00:08:27,038 because we have a lot to owe you. 157 00:08:28,442 --> 00:08:31,442 We also owe the science of chance 158 00:08:31,978 --> 00:08:33,490 because we lucked out 159 00:08:33,514 --> 00:08:36,493 with a one in a million impact. 160 00:08:36,517 --> 00:08:38,794 If the impact from Theia had been a little bit harder, 161 00:08:38,818 --> 00:08:41,630 the earth may not have recovered as well as it did, 162 00:08:41,654 --> 00:08:44,500 and we may not be here to talk about it right now. 163 00:08:44,524 --> 00:08:46,735 If it had been a little bit less forceful, 164 00:08:46,759 --> 00:08:50,038 then the impact of it may no have made the changes 165 00:08:50,062 --> 00:08:52,642 that we think were needed for us to be here now. 166 00:08:52,665 --> 00:08:54,644 We got lucky. 167 00:08:54,668 --> 00:08:57,712 Most planets don't get to survive a collision like that 168 00:08:57,736 --> 00:09:00,205 and get a bonus moon out of the deal. 169 00:09:03,543 --> 00:09:06,054 Earth's huge collision with Theia 170 00:09:06,078 --> 00:09:09,080 was not our planet's first brush with danger. 171 00:09:10,783 --> 00:09:12,984 An earlier explosive event 172 00:09:13,052 --> 00:09:14,864 could have stopped the solar system 173 00:09:14,888 --> 00:09:17,121 from sparking into life... 174 00:09:17,423 --> 00:09:20,457 and the earth from formin 175 00:09:31,837 --> 00:09:36,374 Supernovas are one of the universe's most destructive events... 176 00:09:37,844 --> 00:09:40,211 releasing, in one second. 177 00:09:41,114 --> 00:09:43,860 As much energy as our sun will 178 00:09:43,884 --> 00:09:46,051 in its entire lifetime. 179 00:09:47,386 --> 00:09:49,932 But rather than wipe us out 180 00:09:49,956 --> 00:09:53,457 supernovas may have kick-started the solar syste 181 00:09:53,793 --> 00:09:54,970 4.6 billion years ago, 182 00:09:54,994 --> 00:09:57,340 the solar system's not even really the solar system. 183 00:09:57,364 --> 00:09:59,563 It's the precursor of the solar system. 184 00:10:01,934 --> 00:10:06,403 So, what we ha was a cloud of gas and dust collapsing in on itself, 185 00:10:06,472 --> 00:10:08,206 forming the Sun in the cente 186 00:10:08,575 --> 00:10:09,751 a big, flat disk around it 187 00:10:09,775 --> 00:10:13,855 out of which all the planets were forming. 188 00:10:13,879 --> 00:10:18,094 There are all kind of vast clouds of dust and g floating around the Galaxy. 189 00:10:18,118 --> 00:10:20,596 What actually causes them to start collapsing 190 00:10:20,620 --> 00:10:22,030 and forming new stars? 191 00:10:22,054 --> 00:10:25,134 Well, you have to give that cloud a push. 192 00:10:25,158 --> 00:10:29,961 Scientists think this push could be a stellar blast... 193 00:10:31,530 --> 00:10:33,465 a supernova. 194 00:10:34,934 --> 00:10:39,370 Supernova are some of the most powerfu events in the universe. 195 00:10:41,607 --> 00:10:46,311 One explosion can light up brighter than a galaxy. 196 00:10:46,879 --> 00:10:50,749 So, not only do they eject elements and material, 197 00:10:50,783 --> 00:10:53,485 they also eject a lot of light and energy. 198 00:10:53,552 --> 00:10:56,865 A supernova explosion sends a shock wave 199 00:10:56,889 --> 00:11:01,426 racing out into space at 18,000 miles per second. 200 00:11:04,898 --> 00:11:07,110 The shock wave from a nearby supernova 201 00:11:07,134 --> 00:11:08,633 compresses material together 202 00:11:08,668 --> 00:11:11,101 until it begins to collapse under its own gravity. 203 00:11:14,807 --> 00:11:17,442 Was this how our solar system started? 204 00:11:19,245 --> 00:11:21,846 So far, it's been really difficult to find, uh, evidence 205 00:11:21,881 --> 00:11:23,414 that there was some supernova, 206 00:11:23,482 --> 00:11:24,460 or point to something that happened 207 00:11:24,484 --> 00:11:27,719 that really kick-started the solar system. 208 00:11:27,754 --> 00:11:32,256 The ancient supernova blast faded away a long time ago. 209 00:11:35,796 --> 00:11:37,673 Imagine a crime scen 210 00:11:37,697 --> 00:11:40,909 Now, imagine waiting 4.6 billion years 211 00:11:40,933 --> 00:11:42,399 after the crime is committed, 212 00:11:42,436 --> 00:11:43,946 and looking at it and going, 213 00:11:43,970 --> 00:11:44,547 "There's... There's nothing here. 214 00:11:44,571 --> 00:11:45,681 What are we doing?" 215 00:11:45,705 --> 00:11:48,273 Uh, that's kinda what we're trying to do here. 216 00:11:49,576 --> 00:11:52,277 Researchers from the University of Minnesota 217 00:11:52,312 --> 00:11:55,913 tried to solve this ancient crime... 218 00:11:55,981 --> 00:12:00,350 by studying asteroids that fell to Earth as meteorites. 219 00:12:00,385 --> 00:12:04,167 Asteroids are critical for understanding the early solar system, 220 00:12:04,191 --> 00:12:07,769 and this is because they have frozen in place all the conditions 221 00:12:07,793 --> 00:12:10,605 that existed in that very early solar nebula, 222 00:12:10,629 --> 00:12:12,996 right at 4.5 billion years ago. 223 00:12:14,167 --> 00:12:16,712 The asteroids contain information 224 00:12:16,736 --> 00:12:21,338 about the time leading up to the birth of the Sun and the solar system. 225 00:12:23,610 --> 00:12:25,520 When a massive star ends its life as a supernova, 226 00:12:25,544 --> 00:12:27,657 it undergoes what we call nucleogenesis. 227 00:12:27,681 --> 00:12:30,826 In fact, we call it explosive nucleogenesis. 228 00:12:30,850 --> 00:12:34,764 Literally, the explosion is generating new types of nuclei, 229 00:12:34,788 --> 00:12:37,087 new elements, heavier elements. 230 00:12:38,625 --> 00:12:41,169 Well, it turns out the types of elements it makes 231 00:12:41,193 --> 00:12:43,161 depends on the star that blew up. 232 00:12:46,767 --> 00:12:49,644 The Minnesota tea ran computer simulations 233 00:12:49,668 --> 00:12:53,014 to investigate which elements form 234 00:12:53,038 --> 00:12:58,009 when a star up to 12 times the mass of the Sun explodes 235 00:12:59,779 --> 00:13:02,491 Then, they compared the results 236 00:13:02,515 --> 00:13:06,095 with analysis of elements found in asteroids 237 00:13:06,119 --> 00:13:09,153 dating back to the birth of the solar system. 238 00:13:09,990 --> 00:13:11,923 They match. 239 00:13:13,994 --> 00:13:18,529 So, the remains of this supernova was actual under our noses all along 240 00:13:18,597 --> 00:13:22,466 in the elements that have been in our solar system for ages. 241 00:13:23,235 --> 00:13:26,004 And perhaps in the earth as well. 242 00:13:27,706 --> 00:13:30,607 The earth has lots of rocks that's made of, uh, silicon. 243 00:13:30,677 --> 00:13:33,789 That's only produced in supernova explosions, 244 00:13:33,813 --> 00:13:35,124 and the very core of our earth, 245 00:13:35,148 --> 00:13:36,525 the thing that keeps us alive, 246 00:13:36,549 --> 00:13:37,994 that's iron, nickel. 247 00:13:38,018 --> 00:13:41,318 Again, you only get that in supernova explosions. 248 00:13:42,755 --> 00:13:44,700 In February 2021 249 00:13:44,724 --> 00:13:47,702 scientists shed light on the supernova explosions 250 00:13:47,726 --> 00:13:49,938 that helped seed our solar system 251 00:13:49,962 --> 00:13:53,197 and provided the materials to build our planet. 252 00:13:55,769 --> 00:13:58,014 The research examined fragments 253 00:13:58,038 --> 00:14:01,239 blasted off the giant space rock, Vesta... 254 00:14:02,775 --> 00:14:04,754 4.5 billion years ago, 255 00:14:04,778 --> 00:14:07,044 and later landed on Earth. 256 00:14:11,116 --> 00:14:13,562 These asteroid fragments contain the fingerprints 257 00:14:13,586 --> 00:14:14,885 of not one, 258 00:14:14,953 --> 00:14:19,691 but at least two supernova explosions. 259 00:14:19,759 --> 00:14:26,096 Our solar system was seeded, was enriched, by at least two separate supernova explosions. 260 00:14:26,365 --> 00:14:27,831 That's incredibly lucky 261 00:14:27,866 --> 00:14:32,135 because that is what delivers the ingredients necessary for life. 262 00:14:33,974 --> 00:14:37,620 Scientists believ that these two supernovas 263 00:14:37,644 --> 00:14:40,088 may have enriched different parts 264 00:14:40,113 --> 00:14:41,657 of the infant solar system. 265 00:14:41,681 --> 00:14:43,893 One provided the materials 266 00:14:43,917 --> 00:14:46,317 that helped form the outer gas planets. 267 00:14:48,788 --> 00:14:52,768 The other supernova seeded the inner solar system 268 00:14:52,792 --> 00:14:56,027 with elements that built the rocky planets, 269 00:14:56,363 --> 00:14:57,995 including the earth. 270 00:15:00,600 --> 00:15:03,934 Once again, our fate came down to pure chance. 271 00:15:04,770 --> 00:15:08,817 A series of extraordinarily violent supernova blasts 272 00:15:08,841 --> 00:15:11,687 gave the solar system the kick-start it needed 273 00:15:11,711 --> 00:15:14,412 and the elements to build the planets 274 00:15:14,480 --> 00:15:17,749 without destroying our future home. 275 00:15:17,817 --> 00:15:21,062 It's a fine line between being too close to a supernova, 276 00:15:21,086 --> 00:15:23,888 which will just shred your pre-stellar cloud... 277 00:15:23,956 --> 00:15:27,236 and not too far away that you don't get any of the good stuff. 278 00:15:29,261 --> 00:15:33,042 Supernova play both creation stories 279 00:15:33,066 --> 00:15:34,009 and destruction stories. 280 00:15:34,033 --> 00:15:35,399 They play both roles. 281 00:15:37,336 --> 00:15:38,514 We lucked out. 282 00:15:38,538 --> 00:15:41,918 This chapter of the story ends well. 283 00:15:41,942 --> 00:15:46,311 The solar system gets the ingredients it needs to build planets. 284 00:15:47,147 --> 00:15:49,746 Earth forms in a good location, 285 00:15:49,782 --> 00:15:51,081 close to its star. 286 00:15:52,851 --> 00:15:54,351 The future looks bright, 287 00:15:54,788 --> 00:15:55,953 but then, 288 00:15:56,022 --> 00:15:58,322 the biggest bombardment in history 289 00:15:58,625 --> 00:16:01,091 smashes into the earth. 290 00:16:12,772 --> 00:16:15,105 From the moment our planet formed... 291 00:16:16,809 --> 00:16:18,142 we've been under fire. 292 00:16:22,448 --> 00:16:23,792 2021. 293 00:16:23,816 --> 00:16:27,051 A fireball streaks across the night sky in Europe. 294 00:16:28,855 --> 00:16:30,131 2018. 295 00:16:30,155 --> 00:16:35,104 A 1,500-ton meteor explodes over the Bering Sea 296 00:16:35,128 --> 00:16:38,462 with 10 times the energy of an atomic bomb. 297 00:16:41,835 --> 00:16:43,067 2013. 298 00:16:43,135 --> 00:16:45,480 An asteroid explodes over Russia, 299 00:16:45,504 --> 00:16:48,038 injuring over 1,000 people. 300 00:16:50,610 --> 00:16:53,121 The earth is hit by quite a few asteroids every day. 301 00:16:53,145 --> 00:16:53,822 You see them as shooting stars, 302 00:16:53,846 --> 00:16:55,413 meteors in the sky. 303 00:16:56,316 --> 00:17:00,096 These events are violent and destructive 304 00:17:00,120 --> 00:17:05,957 but these space invaders also brought something every living planet needs: 305 00:17:05,991 --> 00:17:07,737 volatiles. 306 00:17:07,760 --> 00:17:08,971 When we say volatiles, 307 00:17:08,994 --> 00:17:11,173 what we mean are elements that are really light 308 00:17:11,196 --> 00:17:12,674 and easily moved around. 309 00:17:12,699 --> 00:17:13,776 Often, they're gases, 310 00:17:13,799 --> 00:17:16,846 so that's oxygen, and water, and carbon dioxide, 311 00:17:16,869 --> 00:17:18,580 and just all those light elements 312 00:17:18,605 --> 00:17:21,517 that are really important building blocks for life. 313 00:17:21,540 --> 00:17:24,953 These elements ar abundant on our planet today 314 00:17:24,978 --> 00:17:28,913 but were not when it first formed. 315 00:17:28,948 --> 00:17:31,848 From observing other solar systems forming all around us in space, 316 00:17:31,884 --> 00:17:35,385 we know that planets as close to their stars as we are to the Sun, 317 00:17:35,454 --> 00:17:37,654 when they form, they're very hot and dry. 318 00:17:37,722 --> 00:17:39,734 There's probably some littl bit of water around there, 319 00:17:39,759 --> 00:17:41,259 but really not very much. 320 00:17:42,662 --> 00:17:43,972 So, what this means 321 00:17:43,997 --> 00:17:47,498 is any volatiles will basically be boiled away. 322 00:17:47,567 --> 00:17:49,677 If you have a molten surface, 323 00:17:49,701 --> 00:17:53,003 anything like water is gonna get boiled away. 324 00:17:54,773 --> 00:17:57,741 Young Earth was a dry planet, 325 00:17:57,777 --> 00:18:01,144 devoid of all the precious volatiles needed for life. 326 00:18:02,315 --> 00:18:07,351 These materials must have been delivered to Earth after its formation. 327 00:18:11,490 --> 00:18:15,960 We think volatiles arrived in the early days of the solar system... 328 00:18:16,829 --> 00:18:19,407 when the giant planets, including Jupiter, 329 00:18:19,432 --> 00:18:20,998 moved around... 330 00:18:21,835 --> 00:18:24,367 and stirred up the conten of the solar system. 331 00:18:26,405 --> 00:18:27,648 As Jupiter moves, 332 00:18:27,673 --> 00:18:29,919 its gravity is pulling on all the objects in there 333 00:18:29,942 --> 00:18:31,586 basically speeding them up, 334 00:18:31,611 --> 00:18:33,655 and there's a little bit of chaos there in the first place, 335 00:18:33,680 --> 00:18:36,079 but now, Jupiter is basically supercharging it. 336 00:18:36,915 --> 00:18:40,796 Jupiter's path sends countless asteroids and comets 337 00:18:40,819 --> 00:18:43,320 on a collision course with the earth. 338 00:18:44,891 --> 00:18:47,023 It would have been utterly chaotic. 339 00:18:47,093 --> 00:18:49,270 This is a rain of large objects 340 00:18:49,295 --> 00:18:50,894 onto all of the inner planets, 341 00:18:51,029 --> 00:18:56,000 but these objects that came screaming into Earth were gigantic. 342 00:18:57,703 --> 00:18:59,848 Four billion years ago, 343 00:18:59,873 --> 00:19:03,007 a storm of giant asteroids and comets 344 00:19:03,041 --> 00:19:04,142 hits the earth. 345 00:19:05,010 --> 00:19:08,045 Some are tens of miles wide 346 00:19:08,448 --> 00:19:09,913 They bring the volatiles 347 00:19:09,981 --> 00:19:11,660 that help fill the earth's oceans 348 00:19:11,683 --> 00:19:13,951 and build its atmosphere... 349 00:19:15,154 --> 00:19:17,922 but cosmic deliveries can both give 350 00:19:17,990 --> 00:19:19,356 and take. 351 00:19:20,826 --> 00:19:22,904 The importance of impacts for atmosphere 352 00:19:22,929 --> 00:19:23,939 could go either way. 353 00:19:23,962 --> 00:19:25,840 You could have a... A really big, 354 00:19:25,865 --> 00:19:27,298 really powerful impact... 355 00:19:28,101 --> 00:19:29,444 that blows away the atmosphere 356 00:19:29,469 --> 00:19:31,913 of a small, fledgling planet 357 00:19:31,938 --> 00:19:36,018 or you could have a bunch of small impacts of water-rich asteroids 358 00:19:36,041 --> 00:19:38,820 that are simply contributing water, and volatiles, 359 00:19:38,845 --> 00:19:40,522 and new chemicals to the surface 360 00:19:40,547 --> 00:19:43,959 that might help the atmosphe that's already there. 361 00:19:43,982 --> 00:19:45,894 When you think about an object coming to Earth, 362 00:19:45,919 --> 00:19:47,962 is it gonna land on Earth, 363 00:19:47,987 --> 00:19:49,731 and if it does land, 364 00:19:49,756 --> 00:19:53,434 is it gonna be a... An erosive event, 365 00:19:53,459 --> 00:19:55,692 where material is lost from the earth, 366 00:19:55,760 --> 00:19:57,739 or is it gonna be an accretion event, 367 00:19:57,762 --> 00:20:00,608 where the earth gains material? 368 00:20:00,633 --> 00:20:02,593 Well, the devil's in the details. 369 00:20:03,836 --> 00:20:06,804 Details like the size of the impactor. 370 00:20:06,838 --> 00:20:08,784 One study suggests 371 00:20:08,807 --> 00:20:13,655 that asteroids between 60 fe and 3,300 feet wide 372 00:20:13,680 --> 00:20:17,347 add more to the atmosphere than they take away. 373 00:20:24,891 --> 00:20:28,291 And speed at the point of impact also matters. 374 00:20:29,362 --> 00:20:31,640 Asteroids are orbiting the sun. 375 00:20:31,663 --> 00:20:34,576 And when they fall towards the sun, they are gaining speed, 376 00:20:34,599 --> 00:20:36,545 they're gaining velocity. 377 00:20:36,568 --> 00:20:40,037 Imagine dropping a coin into one of those spiral wells. 378 00:20:40,973 --> 00:20:42,550 As the coin gets closer and closer to the middle, 379 00:20:42,575 --> 00:20:45,041 it spins up faster and faste 380 00:20:47,747 --> 00:20:50,593 The closer an asteroid gets to the sun 381 00:20:50,616 --> 00:20:53,576 the stronger the sun's gravitational pull... 382 00:20:54,519 --> 00:20:57,121 and the faster the asteroid travels. 383 00:20:59,726 --> 00:21:01,936 So proximity to your star 384 00:21:01,961 --> 00:21:05,000 is a vital factor in how intense any impacts will be. 385 00:21:14,173 --> 00:21:15,673 It's possibl that the Earth 386 00:21:15,708 --> 00:21:18,086 is the right distance from its host star 387 00:21:18,111 --> 00:21:19,288 so that when an impact happens, 388 00:21:19,311 --> 00:21:22,191 the energy isn't insanely high. 389 00:21:22,214 --> 00:21:26,049 It's just the right amount that it's the right speed to make everything work. 390 00:21:27,720 --> 00:21:30,699 Supernovas seed the solar system 391 00:21:30,722 --> 00:21:33,824 with the elements to build the planets. 392 00:21:33,859 --> 00:21:39,642 Asteroids and comets delive volatile chemicals to the surface of the Earth 393 00:21:39,665 --> 00:21:44,480 Together they create a habitable environment. 394 00:21:44,503 --> 00:21:49,451 So we need those impacts to happen to have life on Earth. 395 00:21:49,474 --> 00:21:54,722 Disasters create a planet primed for life. 396 00:21:54,747 --> 00:21:57,615 But it appears that even mor mayhem and chaos 397 00:21:57,682 --> 00:22:01,951 are needed to trigger life itself. 398 00:22:10,863 --> 00:22:14,065 An asteroid tear through the solar system, 399 00:22:14,133 --> 00:22:18,169 hurdling through space at 40,000 miles an hour. 400 00:22:19,905 --> 00:22:21,016 It's destination, 401 00:22:21,039 --> 00:22:22,338 Earth. 402 00:22:23,742 --> 00:22:27,211 Will this space rock inflic unimaginable damage... 403 00:22:27,946 --> 00:22:31,015 or will it bring the spark of life? 404 00:22:34,787 --> 00:22:36,531 This idea of a spark of life, 405 00:22:36,556 --> 00:22:37,665 we've all kinda seen it 406 00:22:37,690 --> 00:22:39,990 in the Frankenstein movies, right? "It's alive!" 407 00:22:40,559 --> 00:22:43,594 This comes from legend, from myth, from history 408 00:22:43,628 --> 00:22:46,575 that there's some sort of a spark that differentiates 409 00:22:46,598 --> 00:22:49,677 cold inanimate matter from living stuff. 410 00:22:49,701 --> 00:22:52,369 And in some sense it's kind of true. 411 00:22:56,108 --> 00:22:59,488 On Earth, we thin this spark may have arrived 412 00:22:59,511 --> 00:23:01,945 over 4 billion years ago. 413 00:23:04,683 --> 00:23:07,817 The Hadean Eon was the time from the Earth's formation 414 00:23:07,886 --> 00:23:10,186 about 4.6 billion years ago 415 00:23:10,221 --> 00:23:11,733 to about 4 billion years ago. 416 00:23:11,758 --> 00:23:14,424 It's named after literally Hades. 417 00:23:14,460 --> 00:23:18,229 So the conditions on Earth were literally hellish. 418 00:23:20,566 --> 00:23:23,701 It was hot and soupy, a lot of water vapor around 419 00:23:23,769 --> 00:23:26,369 high pressure atmosphere, very intense heat. 420 00:23:26,806 --> 00:23:28,506 You wouldn't survive. 421 00:23:28,574 --> 00:23:30,814 The planet would literally kill you back then. 422 00:23:34,447 --> 00:23:37,859 It's shocking. And I mean, really shocking 423 00:23:37,884 --> 00:23:40,923 that the evidence of first life that we have on Earth 424 00:23:40,952 --> 00:23:42,952 dates to the Hadean Eon. 425 00:23:42,988 --> 00:23:45,601 This was a terrible place, 426 00:23:45,625 --> 00:23:48,871 molten and poisonous and awful. 427 00:23:48,894 --> 00:23:52,195 And yet life somehow arose in all of that mess. 428 00:23:54,967 --> 00:23:56,933 June 2020, 429 00:23:57,001 --> 00:23:59,769 Japanese scientists simulat the conditions 430 00:23:59,838 --> 00:24:02,038 of this hellish planet... 431 00:24:02,842 --> 00:24:06,922 and then try to recreate the spark of life. 432 00:24:06,945 --> 00:24:09,691 So what the scientists were trying to do was mimic those conditions 433 00:24:09,714 --> 00:24:11,080 and see what would happen. 434 00:24:11,150 --> 00:24:13,929 If you smash a meteorite into the ocean back then, 435 00:24:13,952 --> 00:24:15,730 could it produce sort of the same chemicals 436 00:24:15,753 --> 00:24:18,933 that we see life using today? 437 00:24:18,958 --> 00:24:23,905 They use a mix of carbon dioxide, nitrogen water, and iron 438 00:24:23,930 --> 00:24:27,030 to replicate the Hadean environment. 439 00:24:29,568 --> 00:24:35,017 Firing a mini meteor at 2,000 miles an hour into this chemical soup 440 00:24:35,040 --> 00:24:39,210 triggers a reaction between the basic organic elements.. 441 00:24:40,480 --> 00:24:43,047 Creating amino acids. 442 00:24:44,517 --> 00:24:47,930 We call amino acids the building blocks of life. 443 00:24:47,953 --> 00:24:49,897 Really they're the building blocks of proteins. 444 00:24:49,922 --> 00:24:52,423 And life needs proteins to exist. 445 00:24:52,490 --> 00:24:53,868 But that's why they're so important. 446 00:24:53,893 --> 00:24:56,059 Without amino acids, there's no proteins, 447 00:24:56,127 --> 00:24:58,461 without proteins, no life as we know it. 448 00:25:00,799 --> 00:25:02,344 The experiment proves 449 00:25:02,367 --> 00:25:06,303 that meteorite impacts can help build the components for life. 450 00:25:09,775 --> 00:25:12,108 But for these building block to come together 451 00:25:12,176 --> 00:25:14,021 and create life, 452 00:25:14,046 --> 00:25:15,412 we need more. 453 00:25:17,182 --> 00:25:18,759 It's like making a cake. 454 00:25:18,784 --> 00:25:21,896 You can put together the oil, and the flour, and the butter, and the sugar, 455 00:25:21,921 --> 00:25:22,931 but if you don't put it in an oven, 456 00:25:22,954 --> 00:25:24,633 you're not gonna end up with a cake. 457 00:25:24,656 --> 00:25:26,777 You're gonna end up with something else. 458 00:25:26,992 --> 00:25:29,805 We thought that the violence of asteroid impacts 459 00:25:29,828 --> 00:25:32,363 prevented life from forming 460 00:25:35,268 --> 00:25:40,003 Now, we think they could be an essential ingredient. 461 00:25:40,972 --> 00:25:43,719 If the asteroid impact is big enough and fast enoug 462 00:25:43,742 --> 00:25:46,076 it can punch right through the crust. 463 00:25:47,980 --> 00:25:49,958 Then you're getting geothermal heat, 464 00:25:49,981 --> 00:25:52,348 heat the bubbles up from the mantle. 465 00:25:52,417 --> 00:25:56,731 And it is certainly possibl to get an asteroid impact that big. 466 00:25:56,756 --> 00:26:01,869 Large meteorite impacts can create hydrothermal vent 467 00:26:01,894 --> 00:26:05,328 which some scientists believ were the cradles of life. 468 00:26:06,365 --> 00:26:09,611 They provide warm, wet environments 469 00:26:09,634 --> 00:26:13,237 and bring up chemicals from deep inside the Earth's crust... 470 00:26:14,973 --> 00:26:18,275 the perfect place for life to begin. 471 00:26:20,179 --> 00:26:22,691 As bad as those conditions seem to us, 472 00:26:22,714 --> 00:26:27,895 to the molecules that are beginning to combin and do their thing, 473 00:26:27,920 --> 00:26:30,054 that was a wonderful place to be. 474 00:26:30,122 --> 00:26:31,767 That could actually be that the conditions 475 00:26:31,790 --> 00:26:33,701 that are best for early life 476 00:26:33,726 --> 00:26:36,426 might actually be those just after an impact. 477 00:26:37,563 --> 00:26:40,741 So you have sort of this petri dish environment 478 00:26:40,766 --> 00:26:43,267 in which life could really thrive. 479 00:26:47,272 --> 00:26:48,450 These vents might be similar 480 00:26:48,473 --> 00:26:52,041 to those we see in the oceans today. 481 00:26:53,211 --> 00:26:57,025 These hydrothermal vents provide little window 482 00:26:57,048 --> 00:27:00,517 into what the conditions on the primordial Earth would've been like. 483 00:27:00,553 --> 00:27:02,564 And the sort of chemistry 484 00:27:02,587 --> 00:27:05,588 that goes on in those hydrothermal fluids 485 00:27:05,625 --> 00:27:10,160 seems to be the right kind of chemistry for creating life. 486 00:27:12,798 --> 00:27:16,000 Once again, Earth got lucky. 487 00:27:17,936 --> 00:27:22,006 Impacts that could've destroyed everything... 488 00:27:22,642 --> 00:27:26,943 may have helped spark life into existence. 489 00:27:28,381 --> 00:27:31,125 I once hear this quote from Confucious.. 490 00:27:31,150 --> 00:27:35,318 That creation is quiet but destruction is loud. 491 00:27:36,689 --> 00:27:38,700 Well, these impacts 492 00:27:38,723 --> 00:27:43,093 were both destructive, but they also may have been creators. 493 00:27:43,762 --> 00:27:47,064 Earth leaves behi the Hadean age. 494 00:27:47,767 --> 00:27:51,313 The planet calms, and life takes hold. 495 00:27:51,336 --> 00:27:55,506 But disaster is our constant companion 496 00:27:55,540 --> 00:28:00,443 as we prepare to face a stor of deadly cosmic bullets. 497 00:28:12,758 --> 00:28:16,070 The universe is a dangerous place for lif 498 00:28:16,095 --> 00:28:18,429 There are asteroid impacts.. 499 00:28:22,067 --> 00:28:24,000 Black holes... 500 00:28:25,738 --> 00:28:27,203 and exploding stars. 501 00:28:29,174 --> 00:28:31,486 But public enemy No. 1 502 00:28:31,509 --> 00:28:32,842 cosmic rays... 503 00:28:35,047 --> 00:28:39,627 lethal energic particles born in violent events. 504 00:28:39,652 --> 00:28:42,864 Cosmic rays are incredibly small 505 00:28:42,887 --> 00:28:46,034 but travel so fast, near the speed of light, 506 00:28:46,057 --> 00:28:49,292 but they can tear through our DNA and damage I 507 00:28:49,894 --> 00:28:51,573 Your full of DNA. 508 00:28:51,596 --> 00:28:53,741 If that DNA gets broken apart, guess what happens? 509 00:28:53,766 --> 00:28:57,045 That could lead to cancer and death. 510 00:28:57,068 --> 00:29:01,583 At first glance, these cosmic rays are the worst things for life. 511 00:29:01,606 --> 00:29:03,106 They're terrible. 512 00:29:03,742 --> 00:29:05,976 Despite their frighting rap sheet, 513 00:29:06,044 --> 00:29:10,213 cosmic rays may have played a crucial roll in the evolution of life. 514 00:29:14,452 --> 00:29:16,019 2020, 515 00:29:16,054 --> 00:29:18,567 scientists at New York and Stanford universities 516 00:29:18,590 --> 00:29:23,093 investigate biological molecules that have a twin... 517 00:29:24,195 --> 00:29:28,365 mirror image versions called chiral molecules. 518 00:29:29,468 --> 00:29:31,613 The concept of chirality in chemistry 519 00:29:31,636 --> 00:29:33,548 is when you have two molecules, two chemicals, 520 00:29:33,572 --> 00:29:34,915 that are physically the same 521 00:29:34,940 --> 00:29:37,540 They're made of exactly the same things, 522 00:29:37,576 --> 00:29:38,886 but their structure is different. 523 00:29:38,911 --> 00:29:40,721 And they're not just different, 524 00:29:40,746 --> 00:29:42,590 they're reflections of each other. 525 00:29:42,615 --> 00:29:44,192 It's literally called handedness 526 00:29:44,215 --> 00:29:45,559 because look here's my right hand 527 00:29:45,584 --> 00:29:47,762 with my thumb over here and my fingers over here, 528 00:29:47,787 --> 00:29:50,765 here's my left hand with my thumb over here and my fingers over here. 529 00:29:50,788 --> 00:29:53,468 I can't wear a left glove on my right hand. 530 00:29:53,491 --> 00:29:56,938 There's nothing I can do to make these guys the same. 531 00:29:56,961 --> 00:29:59,807 And it turns out this is true not just for hands, 532 00:29:59,832 --> 00:30:05,169 but also for large number of simple organic compounds, 533 00:30:05,203 --> 00:30:08,415 things like amino acids or sugars, 534 00:30:08,440 --> 00:30:12,342 which are the building blocks of all life on Earth. 535 00:30:13,846 --> 00:30:16,958 Billions of years ago, early life may have had 536 00:30:16,981 --> 00:30:21,317 both left- and right-handed DNA and RNA. 537 00:30:22,555 --> 00:30:26,535 But life chose to use mostly right-handed molecule 538 00:30:26,558 --> 00:30:29,358 The reason may have been cosmic rays. 539 00:30:33,833 --> 00:30:37,267 When cosmic rays hit Earth's atmosphere... 540 00:30:38,436 --> 00:30:42,584 they degrade into even smaller subatomic particles 541 00:30:42,607 --> 00:30:44,040 called muons. 542 00:30:44,576 --> 00:30:48,757 Most muons spin in one direction. 543 00:30:48,780 --> 00:30:51,492 So we have these little muons, which are very energetic, 544 00:30:51,517 --> 00:30:53,427 and they're spinning a certain way. 545 00:30:53,451 --> 00:30:56,385 And when they hit a molecule they interact with it. 546 00:30:56,454 --> 00:30:59,467 They can disrupt it. They can change it. 547 00:30:59,490 --> 00:31:02,893 Some scientists believe these spinning muons 548 00:31:02,961 --> 00:31:07,263 interact more readily with right-handed DNA and RNA... 549 00:31:09,602 --> 00:31:12,536 triggering mutations. 550 00:31:12,604 --> 00:31:15,884 Some mutations are beneficia but they have to get a chanc 551 00:31:15,907 --> 00:31:19,320 So if you have right-handed molecules and left-handed molecules, 552 00:31:19,345 --> 00:31:21,288 and they're both being hit by muons, 553 00:31:21,313 --> 00:31:26,148 the one that's hit more gets more chances to have a beneficial mutation. 554 00:31:27,086 --> 00:31:30,832 Cosmic rays may have given right-handed life 555 00:31:30,855 --> 00:31:32,990 an evolutionary advantage. 556 00:31:34,058 --> 00:31:37,260 Left-handed life could not compete. 557 00:31:38,864 --> 00:31:39,773 It's like throwing dice. 558 00:31:39,798 --> 00:31:41,643 If you're trying to get double sixes, 559 00:31:41,666 --> 00:31:43,912 and the left hand only gets to throw ten times, 560 00:31:43,935 --> 00:31:46,580 and the right hand gets to throw 100 times, 561 00:31:46,605 --> 00:31:47,715 more likely to get double sixes 562 00:31:47,740 --> 00:31:50,307 with the right hand than the left hand. 563 00:31:51,876 --> 00:31:55,746 But the dice don't always land in our favor. 564 00:31:55,780 --> 00:32:00,182 359 million years ago, Earth's luck ran out. 565 00:32:00,952 --> 00:32:04,688 And cosmic rays may have lived up to their reputation 566 00:32:04,756 --> 00:32:07,257 as the baddest particle on the block. 567 00:32:09,862 --> 00:32:13,262 Earth's oceans were teeming with marine lif 568 00:32:15,867 --> 00:32:17,545 And by this period as well, 569 00:32:17,568 --> 00:32:22,616 plants had started to colonize onto the contents and landmasses, 570 00:32:22,641 --> 00:32:26,143 attracting animal life, insects, millipedes. 571 00:32:26,644 --> 00:32:29,423 And it's in this environmen 572 00:32:29,448 --> 00:32:33,394 the Earth experienced one of the greatest mass extensions 573 00:32:33,419 --> 00:32:35,152 in the history of life. 574 00:32:38,757 --> 00:32:44,894 Something killed off 97% of all vertebrae species. 575 00:32:44,930 --> 00:32:49,199 We call this wipeout the end Devonian extinction 576 00:32:53,505 --> 00:32:57,240 One possible explanation, a supernova. 577 00:32:58,242 --> 00:33:03,313 When some dying stars explod they fire out cosmic rays. 578 00:33:04,750 --> 00:33:09,486 This radiation bombards the upper atmospher of the Earth 579 00:33:09,520 --> 00:33:14,970 and drives the chemistry of nitrogen, turning into nitrogen dioxide, 580 00:33:14,993 --> 00:33:17,872 a gas which itself then reacts with the ozone layer 581 00:33:17,895 --> 00:33:20,096 and destroys it. 582 00:33:20,798 --> 00:33:22,810 Without the protective ozone layer, 583 00:33:22,835 --> 00:33:27,471 ultra violet radiation from the sun bombards Earth 584 00:33:28,574 --> 00:33:32,409 Radiation rains down for thousands of years... 585 00:33:33,945 --> 00:33:37,079 damaging the DNA of plants and animals. 586 00:33:40,318 --> 00:33:42,085 Many species die out. 587 00:33:45,691 --> 00:33:50,438 The end Devonian mass extinction mostly effected marine life 588 00:33:50,461 --> 00:33:55,565 This is where we see the greatest percentage of deaths. 589 00:33:55,634 --> 00:34:00,303 The oceans once populated by fish the size of school buses... 590 00:34:01,573 --> 00:34:05,041 now host fish no bigger than a sardine. 591 00:34:06,845 --> 00:34:10,891 These smaller fish reproduce quickly. 592 00:34:10,916 --> 00:34:12,159 In the challenging environment, 593 00:34:12,184 --> 00:34:17,286 they adapt and diversify faster than larger species. 594 00:34:17,322 --> 00:34:20,335 Mass extinction is not only wipe the slate clean 595 00:34:20,358 --> 00:34:24,693 and provide other animals and other life forms an opportunity, 596 00:34:24,762 --> 00:34:28,342 it creates a sort of chaoti and complex environment 597 00:34:28,367 --> 00:34:32,369 that drives natural selectio and evolution. 598 00:34:35,074 --> 00:34:38,552 If a supernova was to blame for this extinction event, 599 00:34:38,577 --> 00:34:44,081 scientists believe that the culprit was 65 light years away. 600 00:34:45,751 --> 00:34:50,253 Any closer and Earth's luck would've run out completely 601 00:34:50,989 --> 00:34:52,400 It seems the existence of life 602 00:34:52,423 --> 00:34:54,463 is always balanced on a knife edge. 603 00:34:55,994 --> 00:34:59,353 When an exploding star goes off a little bit too close to us... 604 00:35:01,032 --> 00:35:03,166 and we are all destroyed 605 00:35:05,804 --> 00:35:08,271 So there's this wonderful balance 606 00:35:08,306 --> 00:35:10,639 between just violent enough and too violent. 607 00:35:10,708 --> 00:35:15,344 And we have been lucky enough to dance on that edge for 4.5 billion years. 608 00:35:16,614 --> 00:35:20,416 This mass extinction reset life on Earth 609 00:35:20,452 --> 00:35:22,853 and paved the way for four-legged creatures, 610 00:35:22,920 --> 00:35:25,255 our distant ancestors. 611 00:35:28,827 --> 00:35:31,706 Cataclysmic events go hand in hand 612 00:35:31,730 --> 00:35:33,362 with human evolution. 613 00:35:33,798 --> 00:35:36,110 Some knocked us back 614 00:35:36,135 --> 00:35:40,949 and others like the event 66 million years ago 615 00:35:40,972 --> 00:35:42,371 gave us a push forward. 616 00:35:49,514 --> 00:35:50,891 66 million years ago 617 00:35:50,916 --> 00:35:54,451 a massive asteroid crashes into the Earth. 618 00:35:57,755 --> 00:36:01,402 It triggers a huge extinction event. 619 00:36:01,425 --> 00:36:05,094 Without it humans may have never evolved. 620 00:36:05,630 --> 00:36:07,297 At this time in Earth's history, 621 00:36:07,364 --> 00:36:10,844 we had these enormous plants and gigantic insects 622 00:36:10,869 --> 00:36:14,403 that actually would be incredibly terrifying if we saw them today. 623 00:36:17,141 --> 00:36:19,586 Pterosaurs sa through the air. 624 00:36:19,610 --> 00:36:22,144 Huge marine reptiles dominat the oceans. 625 00:36:22,648 --> 00:36:25,047 And the T. rex is the king of the world. 626 00:36:29,688 --> 00:36:33,422 Then a glowing object appear in the sky. 627 00:36:38,597 --> 00:36:39,806 I'm sitting on the beach 628 00:36:39,831 --> 00:36:43,777 what was then gonna be the Yucatan of Mexico 629 00:36:43,802 --> 00:36:46,414 enjoying a drink with a, you know, a little umbrella, 630 00:36:46,438 --> 00:36:49,905 but up there in the sky all of sudden 631 00:36:49,940 --> 00:36:52,909 approaching me at 40,000 miles an hour 632 00:36:52,945 --> 00:36:59,594 is Mount Everest glowing thousands of times more intensity than the sun... 633 00:36:59,617 --> 00:37:02,985 and it's just seconds away from dropping on my head. 634 00:37:03,789 --> 00:37:06,356 A 6 mile wide asteroid... 635 00:37:07,458 --> 00:37:10,025 slams into the Earth. 636 00:37:15,534 --> 00:37:21,170 The impact throws trillions of tons of rock and dust into the ai 637 00:37:23,074 --> 00:37:26,208 The rocks heat up as they fall back to Earth.. 638 00:37:27,346 --> 00:37:29,411 Setting the planet on fir 639 00:37:33,485 --> 00:37:37,387 That beach holiday suddenly turns into absolute nightmare. 640 00:37:39,056 --> 00:37:41,603 The impact also throws up soot, 641 00:37:41,626 --> 00:37:43,460 chocking the atmosphere. 642 00:37:44,630 --> 00:37:47,775 Now, the skies are blotted out by all these materials, 643 00:37:47,798 --> 00:37:52,068 so the sun is no longer shining brightly on the surface. 644 00:37:52,971 --> 00:37:56,306 Plants need sunlight to photosynthesize 645 00:37:57,775 --> 00:37:59,920 Without this vital energy source, 646 00:37:59,945 --> 00:38:02,112 many species die out. 647 00:38:04,782 --> 00:38:06,750 With their food source gone 648 00:38:06,818 --> 00:38:09,797 plant eating dinosaurs starv to death, 649 00:38:09,820 --> 00:38:12,389 followed by their predators 650 00:38:13,324 --> 00:38:16,603 It was a huge disruption to all of life on Earth. 651 00:38:16,628 --> 00:38:20,507 The dinosaurs have been around for 160 million years at this point. 652 00:38:20,532 --> 00:38:21,675 That's astronomical amount of time. 653 00:38:21,699 --> 00:38:24,034 And in one event, they're gone. 654 00:38:24,835 --> 00:38:28,750 Again the dice ro is in our favor. 655 00:38:28,773 --> 00:38:30,985 Most dinosaurs become extinc 656 00:38:31,009 --> 00:38:34,476 paving the way for the evolution of mammals... 657 00:38:35,746 --> 00:38:39,081 leading eventually to humans. 658 00:38:40,085 --> 00:38:44,865 Without the asteroid impact we wouldn't be here. 659 00:38:44,889 --> 00:38:48,034 As a furry primate on this planet, I kinda like the K-Pg impact, right? 660 00:38:48,059 --> 00:38:48,670 I'm here because of it. 661 00:38:48,693 --> 00:38:50,360 We all are. 662 00:38:52,797 --> 00:38:55,197 Some plants benefited from the asteroid strike. 663 00:38:56,867 --> 00:38:59,681 To learn out plants changed after the impact, 664 00:38:59,704 --> 00:39:05,052 Smithsonian scientist examined thousands of tropical plant fossils 665 00:39:05,077 --> 00:39:06,541 from the time of the die off 666 00:39:09,581 --> 00:39:13,115 This disaster opened the way for new types of plants to develop. 667 00:39:14,619 --> 00:39:17,864 It transforme the plant kingdom... 668 00:39:17,889 --> 00:39:21,257 producing a richer and more diverse global ecosystem. 669 00:39:21,626 --> 00:39:23,704 Before the asteroid strike, 670 00:39:23,728 --> 00:39:29,132 conifers and ferns dominate the tropical forests of South America. 671 00:39:29,967 --> 00:39:33,014 But afterwards, falling ash from the impact 672 00:39:33,038 --> 00:39:34,581 enriched the soil. 673 00:39:34,606 --> 00:39:39,041 And fast growing flowering plants took over. 674 00:39:40,579 --> 00:39:42,978 The impact was very hard to recover fro 675 00:39:43,047 --> 00:39:46,014 but it actually opened the opportunity 676 00:39:46,050 --> 00:39:47,494 for a greater diversity of plant life, 677 00:39:47,518 --> 00:39:50,119 which ultimately has benefited us as humans 678 00:39:50,155 --> 00:39:52,514 because it has allowed us to have more food sources. 679 00:39:54,559 --> 00:39:57,804 This new world order eventually gave rise 680 00:39:57,829 --> 00:39:59,606 to the modern Amazon Rainforest, 681 00:39:59,630 --> 00:40:05,001 home to 10% of all species on Earth. 682 00:40:06,771 --> 00:40:10,440 It really destroyed and rema our entire environment. 683 00:40:11,710 --> 00:40:13,855 The world grew back, of course it did, here we are, 684 00:40:13,878 --> 00:40:15,311 but it changed everything. 685 00:40:16,815 --> 00:40:21,628 And another age may be just around the corne 686 00:40:21,652 --> 00:40:23,563 We should absolutely expect 687 00:40:23,588 --> 00:40:25,900 that at some point in the future, 688 00:40:25,923 --> 00:40:28,568 and I'm not saying you should lose sleep over it, 689 00:40:28,592 --> 00:40:33,996 but at some point there will be another mass extinction. 690 00:40:36,934 --> 00:40:39,302 Maybe that will be the end our days. 691 00:40:40,505 --> 00:40:41,744 It's intriguing question is 692 00:40:41,773 --> 00:40:46,175 what might come after humans on planet Earth? 693 00:40:47,778 --> 00:40:51,581 Catastrophe may b the universe's recipe for li 694 00:40:51,615 --> 00:40:53,349 throughout the cosmos... 695 00:40:54,552 --> 00:40:57,887 one that every planet must follow. 696 00:40:57,956 --> 00:40:59,733 Looking at our own history, 697 00:40:59,757 --> 00:41:01,768 life thrives on catastrophes 698 00:41:01,793 --> 00:41:05,405 We need these disasters for evolution to work. 699 00:41:05,429 --> 00:41:09,510 So, hopefully, and I hate saying this, I know how it sounds, 700 00:41:09,534 --> 00:41:13,202 hopefully, these other plane have had terrible disasters as well. 701 00:41:14,806 --> 00:41:16,117 Think abo the word disaster. 702 00:41:16,141 --> 00:41:17,818 It means bad star. 703 00:41:17,842 --> 00:41:19,452 It means that something has gone wrong, 704 00:41:19,476 --> 00:41:20,755 something that's dangerous. 705 00:41:20,778 --> 00:41:24,146 We are children of disasters 706 00:41:25,483 --> 00:41:28,985 There's no way you get us without planets colliding... 707 00:41:30,387 --> 00:41:33,989 without asteroids and comets streaming through the atmosphere... 708 00:41:37,695 --> 00:41:40,576 without even stars exploding and supernovas. 709 00:41:44,802 --> 00:41:46,213 You are a child of that violence. 710 00:41:46,237 --> 00:41:49,951 That's part of the environment that we grew up in in a cosmic way. 711 00:41:49,974 --> 00:41:52,175 And I think that is tremendously beautiful. 59961

Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.