1 00:00:00,000 --> 00:00:03,000 The Hubble Space Telescope has solved a long-standing puzzle 2 00:00:03,000 --> 00:00:11,000 by resolving giant but delicate filaments shaped by a strong magnetic field around the active galaxy NGC 1275. 3 00:00:11,000 --> 00:00:18,000 It is the most striking example so far of the influence of the immense tentacles of extragalactic magnetic fields. 4 00:00:38,000 --> 00:00:40,000 This is the Hubblecast! 5 00:00:40,000 --> 00:00:43,000 News and images from the NASA/ESA Hubble Space Telescope. 6 00:00:43,000 --> 00:00:49,000 Travelling through time and space with our host Doctor J a.k.a. Dr. Joe Liske. 7 00:00:49,000 --> 00:00:52,000 Hi and welcome to another episode of the Hubblecast! 8 00:00:52,000 --> 00:00:58,000 Today we are going to interrupt our series of seven Hubblecast Specials to bring you a breaking news story. 9 00:00:58,000 --> 00:01:04,000 Now this doesn’t happen very often, but the subject of today’s show is in fact completely invisible. 10 00:01:04,000 --> 00:01:09,000 And no, I’m not talking about dark matter, I’m talking about magnetic fields. 11 00:01:09,000 --> 00:01:14,000 Although most people are completely unaware of them, magnetic fields in fact surround us all the time. 12 00:01:14,000 --> 00:01:18,000 For starters, the Earth has a magnetic field of course, which any compass will show you. 13 00:01:18,000 --> 00:01:23,000 But power lines, and pretty much any electrical device also produces magnetic fields. 14 00:01:23,000 --> 00:01:28,000 And moreover, they’re not just down here on Earth, they’re also sprinkled throughout the Universe. 15 00:01:28,000 --> 00:01:30,000 Take our Sun for example. 16 00:01:30,000 --> 00:01:35,000 Particularly strong magnetic flares from our Sun can even disrupt radio communication down here on Earth, 17 00:01:35,000 --> 00:01:39,000 including your mobile phone calls and your favourite radio station. 18 00:01:44,000 --> 00:01:49,000 In the direction of the constellation Perseus we find the Perseus Cluster of galaxies. 19 00:01:49,000 --> 00:01:55,000 NGC 1275 in its centre is one of the closest giant elliptical galaxies. 20 00:01:55,000 --> 00:02:06,000 Its most spectacular feature is the lacy filigree of gaseous filaments reaching out beyond the galaxy into the multi-million degree x-ray emitting gas that pervades the cluster. 21 00:02:06,000 --> 00:02:11,000 This is an active galaxy, hosting a super-massive black hole at its core, 22 00:02:11,000 --> 00:02:15,000 which blows bubbles of material into the surrounding cluster gas. 23 00:02:15,000 --> 00:02:22,000 Exploiting Hubble’s view, a team of astronomers led by Andy Fabian from the University of Cambridge in the United Kingdom, 24 00:02:22,000 --> 00:02:28,000 have for the first time resolved individual threads of gas which make up the filaments. 25 00:02:32,000 --> 00:02:36,000 So the amount of gas in one of these threads is about one million times the mass of the Sun. 26 00:02:36,000 --> 00:02:42,000 They are only about 200 light-years across, but they are very straight, and they can extend for up to 20,000 light-years. 27 00:02:42,000 --> 00:02:50,000 These filaments are formed when cold gas from the core of the galaxy is dragged out in the wake of the rising bubbles blown by the black hole. 28 00:02:50,000 --> 00:02:56,000 But the really interesting thing is that these filaments appear to be able to survive for up to 100 million years. 29 00:02:56,000 --> 00:02:59,000 And that’s what had astronomers really puzzled. 30 00:02:59,000 --> 00:03:08,000 How is it possible that these delicate filamentary structures can survive in the hostile high-energy environment of the galaxy cluster for so long? 31 00:03:08,000 --> 00:03:13,000 Either they should have heated up, dispersed and evaporated in a very short period of time, 32 00:03:13,000 --> 00:03:19,000 or if they are somehow shielded, they should have collapsed under their own weight and formed stars long ago. 33 00:03:21,000 --> 00:03:27,000 The new study published in Nature on the 21st August 2008 gives the explanation. 34 00:03:27,000 --> 00:03:32,000 Magnetic fields provide a skeletal structure strong enough to resist gravitational collapse, 35 00:03:32,000 --> 00:03:35,000 preventing the filaments from forming into stars. 36 00:03:35,000 --> 00:03:42,000 These magnetic fields have been able to contain and suspend the peculiarly long threads for over 100 million years. 37 00:03:44,000 --> 00:03:45,000 Well, there you have it! 38 00:03:45,000 --> 00:03:50,000 But why is it so important that scientists have resolved these fine filamentary structures? 39 00:03:50,000 --> 00:03:56,000 Well, first of all it’s allowed them to finally measure the strength of an extragalactic magnetic field. 40 00:03:56,000 --> 00:04:05,000 But in addition to that, these filaments are clear evidence of the intricate relationship between the central super-massive black hole and the surrounding cluster gas. 41 00:04:05,000 --> 00:04:14,000 Understanding this relationship provides us with important clues on how the giant black hole interacts with, and affects their surrounding environment. 42 00:04:14,000 --> 00:04:17,000 This is Dr. J signing off for the Hubblecast. 43 00:04:17,000 --> 00:04:21,000 Once again, nature has surprised us beyond our wildest imagination...