1 00:00:15,547 --> 00:00:17,943 The universe, 2 00:00:17,943 --> 00:00:20,585 rather beautiful, isn't it? 3 00:00:20,585 --> 00:00:23,340 It's quite literally got everything, 4 00:00:23,340 --> 00:00:24,344 from the very big 5 00:00:24,344 --> 00:00:26,137 to the very small. 6 00:00:26,137 --> 00:00:29,050 Sure, there are some less than savory elements in there, 7 00:00:29,050 --> 00:00:32,133 but on the whole, scholars agree that its existence 8 00:00:32,133 --> 00:00:34,838 is probably a good thing. 9 00:00:34,838 --> 00:00:37,187 Such a good thing, that an entire field 10 00:00:37,187 --> 00:00:40,857 of scientific endeavor is devoted to its study. 11 00:00:40,857 --> 00:00:43,277 This is known as cosmology. 12 00:00:43,277 --> 00:00:46,238 Cosmologists look at what's out there in space 13 00:00:46,238 --> 00:00:50,287 and piece together the tale of how our universe evolved: 14 00:00:50,287 --> 00:00:51,548 what it's doing now, 15 00:00:51,548 --> 00:00:53,203 what it's going to be doing, 16 00:00:53,203 --> 00:00:55,795 and how it all began in the first place. 17 00:00:55,795 --> 00:00:58,000 It was Edwin Hubble who first noticed 18 00:00:58,000 --> 00:01:00,347 that our universe is expanding 19 00:01:00,347 --> 00:01:02,265 by noting that galaxies seem to be flying 20 00:01:02,265 --> 00:01:04,938 further and further apart. 21 00:01:04,938 --> 00:01:06,983 This implied that everything should have started 22 00:01:06,983 --> 00:01:08,892 with the monumental explosion 23 00:01:08,892 --> 00:01:10,486 of an infinitely hot, 24 00:01:10,486 --> 00:01:12,563 infinitely small point. 25 00:01:12,563 --> 00:01:15,393 This idea was jokingly referred to at the time 26 00:01:15,393 --> 00:01:17,328 as the "Big Bang," 27 00:01:17,328 --> 00:01:18,866 but as the evidence piled up, 28 00:01:18,866 --> 00:01:19,703 the notion 29 00:01:19,703 --> 00:01:20,950 and the name 30 00:01:20,950 --> 00:01:22,870 actually stuck. 31 00:01:22,870 --> 00:01:24,286 We know that after the Big Bang, 32 00:01:24,286 --> 00:01:25,580 the universe cooled down 33 00:01:25,580 --> 00:01:29,166 to form the stars and galaxies that we see today. 34 00:01:29,166 --> 00:01:31,223 Cosmologist have plenty of ideas 35 00:01:31,223 --> 00:01:32,905 about how this happened. 36 00:01:32,905 --> 00:01:35,613 But we can also probe the origins of the universe 37 00:01:35,613 --> 00:01:39,092 by recreating the hot, dense conditions that existed 38 00:01:39,092 --> 00:01:42,718 at the beginning of time in the laboratory. 39 00:01:42,718 --> 00:01:46,219 This is done by particle physicists. 40 00:01:46,219 --> 00:01:48,010 Over the past century, 41 00:01:48,010 --> 00:01:50,185 particle physicists have been studying 42 00:01:50,185 --> 00:01:53,988 matter and forces at higher and higher energies. 43 00:01:53,988 --> 00:01:55,607 Firstly with cosmic rays, 44 00:01:55,607 --> 00:01:57,862 and then with particle accelerators, 45 00:01:57,862 --> 00:01:59,655 machines that smash together 46 00:01:59,655 --> 00:02:02,408 subatomic particles at great energies. 47 00:02:02,408 --> 00:02:04,534 The greater the energy of accelerator, 48 00:02:04,534 --> 00:02:08,289 the further back in time they can effectively peek. 49 00:02:08,289 --> 00:02:10,875 Today, things are largely made up of atoms, 50 00:02:10,875 --> 00:02:13,378 but a hundreds of seconds after the Big Bang, 51 00:02:13,378 --> 00:02:15,570 it was too hot for electrons to join 52 00:02:15,570 --> 00:02:17,842 atomic nuclei to make atoms. 53 00:02:17,842 --> 00:02:19,884 Instead, the universe consisted of 54 00:02:19,884 --> 00:02:22,593 a swirling sea of subatomic matter. 55 00:02:22,593 --> 00:02:24,925 A few seconds after the Big Bang, 56 00:02:24,925 --> 00:02:26,209 it was hotter still, 57 00:02:26,209 --> 00:02:28,128 hot enough to overpower the forces 58 00:02:28,128 --> 00:02:30,828 that usually hold protons and neutrons together 59 00:02:30,828 --> 00:02:32,816 in atomic nuclei. 60 00:02:32,816 --> 00:02:35,632 Further back, microseconds after the Big Bang, 61 00:02:35,632 --> 00:02:38,315 and the protons and neutrons were only just beginning 62 00:02:38,315 --> 00:02:39,818 to form from quarks, 63 00:02:39,818 --> 00:02:41,812 one of the fundamental building blocks 64 00:02:41,812 --> 00:02:44,977 of the standard model of particle physics. 65 00:02:44,977 --> 00:02:45,941 Further back still, 66 00:02:45,941 --> 00:02:47,455 and the energy was too great even 67 00:02:47,455 --> 00:02:50,018 for the quarks to stick together. 68 00:02:50,018 --> 00:02:53,056 Physicists hope that by going to even greater energies, 69 00:02:53,056 --> 00:02:54,641 they can see back to a time 70 00:02:54,641 --> 00:02:57,587 when all the forces were one in the same, 71 00:02:57,587 --> 00:02:58,755 which would make understanding 72 00:02:58,755 --> 00:03:01,710 the origins of the universe a lot easier. 73 00:03:01,710 --> 00:03:05,094 To do that, they'll not only need to build bigger colliders, 74 00:03:05,094 --> 00:03:07,512 but also work hard to combine our knowledge 75 00:03:07,512 --> 00:03:09,193 of the very, very big 76 00:03:09,193 --> 00:03:11,642 with the very, very small 77 00:03:11,642 --> 00:03:13,508 and share these fascinating insights 78 00:03:13,508 --> 00:03:14,741 with each other and with, 79 00:03:14,741 --> 00:03:16,707 well, you. 80 00:03:16,707 --> 00:03:18,603 And that's how it should be! 81 00:03:18,603 --> 00:03:19,974 Because, after all, 82 00:03:19,974 --> 00:03:21,784 when it comes to our universe, 83 00:03:21,784 --> 00:03:25,060 we're all in this one together.