1 00:00:00,000 --> 00:00:06,000 A spectacular new image of an unusual spiral galaxy in the Coma Galaxy Cluster has been created 2 00:00:06,000 --> 00:00:12,000 from data taken by the Advanced Camera for Surveys on the NASA/ESA Hubble Space Telescope. 3 00:00:12,000 --> 00:00:17,000 It reveals lots of new details in the galaxy, NGC 4921, 4 00:00:17,000 --> 00:00:23,000 as well as an extraordinary rich background of more remote galaxies stretching back to the early Universe. 5 00:00:41,000 --> 00:00:42,000 This is the Hubblecast! 6 00:00:42,000 --> 00:00:46,000 News and images from the NASA/ESA Hubble Space Telescope. 7 00:00:46,000 --> 00:00:52,000 Travelling through time and space with our host, Dr. J. a.k.a. Dr. Joe Liske. 8 00:00:52,000 --> 00:00:55,000 Hello, and welcome to another episode of the Hubblecast. 9 00:00:55,000 --> 00:00:57,000 I am Richard Hook from ESO. 10 00:00:57,000 --> 00:01:02,000 Our usual host, Dr J, has just had a baby daughter and will be on paternity leave for a while. 11 00:01:02,000 --> 00:01:06,000 So I am here at short notice to tell you about the latest image from Hubble — 12 00:01:06,000 --> 00:01:09,000 a rather strange and ghostly galaxy. 13 00:01:10,000 --> 00:01:12,000 The Coma Galaxy Cluster, 14 00:01:12,000 --> 00:01:16,000 in the northern constellation of Coma Berenices, the hair of Queen Berenice, 15 00:01:16,000 --> 00:01:20,000 is one of the closest very rich collections of galaxies in the nearby Universe 16 00:01:20,000 --> 00:01:23,000 and contains more than 1000 members. 17 00:01:23,000 --> 00:01:28,000 The brightest galaxies, including the one called NGC 4921, 18 00:01:28,000 --> 00:01:35,000 which we are going to talk about today, were discovered back in the late 18th century by the great astronomer William Herschel. 19 00:01:35,000 --> 00:01:38,000 Rich clusters like Coma are pretty crowded places 20 00:01:38,000 --> 00:01:42,000 and galaxies undergo many interactions and mergers. 21 00:01:42,000 --> 00:01:45,000 This constant slow activity gradually turns spiral galaxies, 22 00:01:45,000 --> 00:01:51,000 which are rich in dust and gas, into cleaner elliptical systems without much active star formation. 23 00:01:51,000 --> 00:01:58,000 As a result there are far more ellipticals and fewer spirals in the Coma Cluster than are found in quieter corners of the Universe. 24 00:02:01,000 --> 00:02:08,000 The new Hubble pictures shows NGC 4921, which is one of the rare spirals in Coma, and a rather unusual one — 25 00:02:08,000 --> 00:02:18,000 it is an example of an "anaemic spiral" where the normal lively star formation that creates a spiral galaxy’s familiar bright arms is much less intense. 26 00:02:18,000 --> 00:02:23,000 Because of this we can just see a delicate swirl of dust in a ring around the galaxy, 27 00:02:23,000 --> 00:02:30,000 accompanied by some bright young blue stars in clusters that are clearly separated out by Hubble’s sharp vision. 28 00:02:30,000 --> 00:02:35,000 Much of the pale spiral structure in the outer parts of the galaxy is unusually smooth 29 00:02:35,000 --> 00:02:39,000 and gives the whole galaxy the ghostly look of a vast translucent jellyfish. 30 00:02:41,000 --> 00:02:47,000 This very long-exposure Hubble picture shows us lots of fine detail of the galaxy and the Universe beyond. 31 00:02:47,000 --> 00:02:55,000 If we look more closely in the middle we can see that this galaxy has a bright nucleus with a straight bar extending to each side. 32 00:02:56,000 --> 00:03:01,000 Further out we can see a ring of dust and lots of hot young blue stars in clusters. 33 00:03:01,000 --> 00:03:08,000 Galaxies are quite transparent and we can see right through to much more remote galaxies far beyond. 34 00:03:11,000 --> 00:03:14,000 Further out we can see lots of dots that look a little like stars. 35 00:03:14,000 --> 00:03:17,000 These are actually very faint globular star clusters – 36 00:03:17,000 --> 00:03:21,000 huge balls of stars slowly orbiting the galaxies in the cluster. 37 00:03:25,000 --> 00:03:30,000 The image is filled with thousands of fainter and more distant galaxies of all shapes and sizes. 38 00:03:30,000 --> 00:03:37,000 Some are normal but many of the fainter ones are blobby and chaotic star-forming clumps back in the early Universe, 39 00:03:37,000 --> 00:03:40,000 far, far beyond the huge galaxy in the foreground. 40 00:03:43,000 --> 00:03:46,000 Also seen are foreground stars in our own Milky Way. 41 00:03:46,000 --> 00:03:52,000 Many galaxies have companions and NGC 4921 seems to be no exception. 42 00:03:52,000 --> 00:04:00,000 We can see several faint patches that are most likely to be smaller satellite systems orbiting their huge parent. 43 00:04:00,000 --> 00:04:04,000 Thanks for joining me for a quick tour of this stunning view of NGC 4921 – 44 00:04:04,000 --> 00:04:08,000 a vast translucent jellyfish of a galaxy. 45 00:04:08,000 --> 00:04:12,000 This is Richard Hook, signing off for the Hubblecast. 46 00:04:12,000 --> 00:04:15,000 Once again, nature has surprised us beyond our wildest imagination.