1 00:00:01,000 --> 00:00:12,119 [music] 2 00:00:12,119 --> 00:00:14,900 If you've had any interested in physics at all you've heard about a thing called the 3 00:00:14,900 --> 00:00:16,990 Higgs boson. 4 00:00:16,990 --> 00:00:19,859 But just what is it then why is it interesting? 5 00:00:19,859 --> 00:00:24,060 In 1964 a physicist by the name of Peter Higgs 6 00:00:24,060 --> 00:00:26,969 took some ideas that were floating around at the time, 7 00:00:26,969 --> 00:00:30,899 added an insight or two of his own, and proposed that there was an energy field 8 00:00:30,899 --> 00:00:33,400 that permeated the entire universe. 9 00:00:33,400 --> 00:00:36,570 This energy field is now called the "Higgs field." 10 00:00:36,570 --> 00:00:40,160 The reason he proposed this field was that nobody understood why some 11 00:00:40,160 --> 00:00:43,220 subatomic particles had a great deal of mass 12 00:00:43,220 --> 00:00:46,270 while others had little and some had none at all! 13 00:00:46,270 --> 00:00:49,270 The energy field that Higgs proposed would interact 14 00:00:49,270 --> 00:00:52,500 with the sub-atomic particles and give them their mass. Very massive particles 15 00:00:52,500 --> 00:00:57,560 would interact a lot of the field while massless particles wouldn't interact at all. 16 00:00:57,560 --> 00:01:02,050 To better understand the idea, we can use the analogy of water and swimmers. 17 00:01:02,050 --> 00:01:05,089 In our analogy the water serves the role 18 00:01:05,089 --> 00:01:06,390 of the Higgs field. 19 00:01:06,390 --> 00:01:10,260 A barracuda, being supremely streamlined, interacts only slightly with 20 00:01:10,260 --> 00:01:13,140 the field and can move through it very easily. 21 00:01:13,140 --> 00:01:16,800 The barracuda would then be similar to a low-mass particle. 22 00:01:16,800 --> 00:01:20,710 In contrast, my buddy Eddie, no stranger to doughnuts 23 00:01:20,710 --> 00:01:23,510 can only move very slowly through the water. 24 00:01:23,510 --> 00:01:28,120 In our analogy, Eddie is a massive particle made massive by interacting a lot with 25 00:01:28,120 --> 00:01:29,430 the water. 26 00:01:29,430 --> 00:01:33,759 The lightest of the familiar subatomic particles is the electron, while in the subatomic 27 00:01:33,759 --> 00:01:36,810 world the king of mass is the top quark. 28 00:01:36,810 --> 00:01:39,740 It weighs about as much as an entire atom of gold, 29 00:01:39,740 --> 00:01:43,320 about three hundred and fifty thousand times more than the electron! 30 00:01:43,320 --> 00:01:46,520 I'd like to stress that we believe the top quark is not more massive because 31 00:01:46,520 --> 00:01:48,130 it's bigger. It's not! 32 00:01:48,130 --> 00:01:52,490 In fact, we believe that both the top quark and the electron are exactly the same size! 33 00:01:52,490 --> 00:01:55,700 Indeed, they both have zero size! 34 00:01:55,700 --> 00:01:59,250 The top quark is more massive than the electron simply because it interacts 35 00:01:59,250 --> 00:02:01,380 more with the Higgs field. Actually, 36 00:02:01,380 --> 00:02:03,050 if the Higgs field didn't exist, 37 00:02:03,050 --> 00:02:07,880 neither of these particles would have any mass at all! 38 00:02:07,880 --> 00:02:09,229 Now, in the press 39 00:02:09,229 --> 00:02:12,839 you don't hear about the Higgs field but rather the Higgs boson. 40 00:02:12,839 --> 00:02:14,829 How are these two things related? 41 00:02:14,829 --> 00:02:19,189 The Higgs boson is the smallest bit of the Higgs field. 42 00:02:19,189 --> 00:02:23,029 To understand how that works we should again return to water. 43 00:02:23,029 --> 00:02:25,139 Everyone knows what water is. 44 00:02:25,139 --> 00:02:29,790 If you're immersed in it you know that water is everywhere. It's a continuous medium 45 00:02:29,790 --> 00:02:31,949 and there are no holes in it. 46 00:02:31,949 --> 00:02:37,849 We also know that water is made of molecules - specifically H20. 47 00:02:37,849 --> 00:02:41,469 If you hold these two ideas in your head with the realization that water consists 48 00:02:41,469 --> 00:02:44,819 of countless individual molecules you can now begin to appreciate 49 00:02:44,819 --> 00:02:46,789 the Higgs boson. 50 00:02:46,789 --> 00:02:51,139 The Higgs field that gives subatomic particles their mass is made of countless individual 51 00:02:51,139 --> 00:02:55,709 Higgs bosons, just like water is made of individual molecules. 52 00:02:55,709 --> 00:02:59,069 You should keep in mind that the Higgs boson hasn't been discovered yet, and 53 00:02:59,069 --> 00:03:03,789 what I'm describing is simply the most popular idea as to why subatomic 54 00:03:03,789 --> 00:03:07,159 particles have the masses that they do. 55 00:03:07,159 --> 00:03:08,439 As I speak 56 00:03:08,439 --> 00:03:12,669 my colleagues and I are studying data taken at huge particle accelerators to see if 57 00:03:12,669 --> 00:03:15,000 this idea is true. 58 00:03:15,000 --> 00:03:19,000 Stay tuned! 59 00:03:19,000 --> 99:59:59,999 [music]