1 00:00:00,270 --> 00:00:12,440 Music 2 00:00:12,460 --> 00:00:16,480 Narrator: Every day or two, on average, satellites detect 3 00:00:16,500 --> 00:00:20,550 a massive explosion somewhere in the sky. These are gamma-ray 4 00:00:20,570 --> 00:00:24,620 bursts, the brightest blasts in the universe. They're thought to be 5 00:00:24,640 --> 00:00:28,690 caused by jets of matter moving near the speed of light associated with the births 6 00:00:28,710 --> 00:00:32,750 of black holes. Gamma-ray bursts that last longer than two seconds 7 00:00:32,770 --> 00:00:36,830 are the most common and are thought to result from the death of a massive star. 8 00:00:36,850 --> 00:00:41,040 Shorter bursts proved much more elusive. In fact, 9 00:00:41,060 --> 00:00:45,060 even some of their basic properties were unknown until NASA's Swift satellite 10 00:00:45,080 --> 00:00:49,160 began work in 2004. Astronomers suspected that crashing 11 00:00:49,180 --> 00:00:53,210 neutron stars could explain short bursts. 12 00:00:53,230 --> 00:00:57,310 A neutron star is what remains when a star several times the mass 13 00:00:57,330 --> 00:01:01,390 of the sun collapses and explodes. With more than the sun's 14 00:01:01,410 --> 00:01:05,430 mass packed in a sphere less than 18 miles across, these objects are 15 00:01:05,450 --> 00:01:09,510 incredibly dense. Just a sugar-cube-size piece of neutron star 16 00:01:09,530 --> 00:01:13,560 can weigh as much as all the water in the Great Lakes. When two 17 00:01:13,580 --> 00:01:17,660 orbiting neutron stars collide, they merge and form a black hole, releasing 18 00:01:17,680 --> 00:01:21,680 enormous amounts of energy in the process. Armed with state-of-the-art 19 00:01:21,700 --> 00:01:25,700 supercomputer models, scientists have shown that colliding neutron stars 20 00:01:25,720 --> 00:01:29,760 can produce the energetic jet required for a gamma-ray burst. 21 00:01:29,780 --> 00:01:33,830 Earlier simulations demonstrated that mergers could make black holes. Others 22 00:01:33,850 --> 00:01:37,910 had shown that the high-speed particle jets needed to make a gamma-ray burst would 23 00:01:37,930 --> 00:01:41,960 continue if placed in the swirling wreckage of a recent merger. 24 00:01:41,980 --> 00:01:46,000 Now, the simulations reveal the middle step of the process 25 00:01:46,020 --> 00:01:50,070 --how the merging stars' magnetic field organizes itself 26 00:01:50,090 --> 00:01:54,110 into outwardly directed components capable of forming a jet. 27 00:01:54,130 --> 00:01:58,150 The Damiana supercomputer at Germany's Max Planck Institute for Gravitational 28 00:01:58,170 --> 00:02:02,230 Physics needed six weeks to reveal the details of a process that 29 00:02:02,250 --> 00:02:06,270 unfolds in just 35 thousandths of a second. 30 00:02:06,290 --> 00:02:10,360 The new simulation shows two neutron stars merging to 31 00:02:10,380 --> 00:02:14,420 form a black hole surrounded by super-hot plasma. On 32 00:02:14,440 --> 00:02:18,480 the left is a map of the density of the stars as they scramble their matter into a dense, 33 00:02:18,500 --> 00:02:22,630 hot cloud of swirling debris. On the right is a map of 34 00:02:22,650 --> 00:02:26,670 the magnetic fields, with blue representing magnetic strength a billion times 35 00:02:26,690 --> 00:02:30,720 greater than the sun's. The simulation 36 00:02:30,740 --> 00:02:34,760 shows the same disorderly behavior of the matter and magnetic fields. 37 00:02:34,780 --> 00:02:38,810 Both structures gradually become more organized, but what's important 38 00:02:38,830 --> 00:02:42,880 here is the white magnetic field. Amidst this incredible 39 00:02:42,900 --> 00:02:46,940 turmoil, the white field has taken on the character of a jet, although 40 00:02:46,960 --> 00:02:50,980 no matter is flowing through it when the simulation ends. 41 00:02:51,000 --> 00:02:55,020 Showing that magnetic fields suddenly become organized as jets 42 00:02:55,040 --> 00:02:59,070 provides scientists with the missing link. It confirms that 43 00:02:59,090 --> 00:03:03,130 merging neutron stars can indeed produce short gamma-ray bursts. 44 00:03:03,150 --> 00:03:07,190 At this moment, somewhere across the cosmos, it's about 45 00:03:07,210 --> 00:03:11,210 to happen again. [Explosion]