1 00:00:00,150 --> 00:00:02,993 Over the last 25 years, 2 00:00:02,993 --> 00:00:10,354 the NASA/ESA Hubble Space Telescope has revealed the distant Universe with ever-increasing depth 3 00:00:10,354 --> 00:00:13,372 through the Deep and Ultra Deep fields. 4 00:00:13,372 --> 00:00:17,482 Hubble has embarked on an ambitious new programme 5 00:00:17,482 --> 00:00:22,822 to push even further towards the Universe’s furthest frontiers. 6 00:00:40,000 --> 00:00:43,209 Hello, and welcome to another episode of the Hubblecast! 7 00:00:43,209 --> 00:00:46,050 In 2013, Hubble began a campaign 8 00:00:46,052 --> 00:00:48,040 to capture very deep images 9 00:00:48,456 --> 00:00:51,405 of some of the most massive structures in the Universe 10 00:00:52,868 --> 00:00:54,795 — galaxy clusters. 11 00:00:55,200 --> 00:00:57,066 The Frontier Fields campaign 12 00:00:57,066 --> 00:00:58,738 is using six of these giants 13 00:00:58,738 --> 00:01:01,454 to peer into the farthest reaches of the Universe. 14 00:01:02,500 --> 00:01:06,655 The enormous amount of mass in a galaxy cluster means 15 00:01:06,656 --> 00:01:09,006 that it bends the space around it 16 00:01:09,200 --> 00:01:12,654 and acts like a gigantic magnifying glass. 17 00:01:14,750 --> 00:01:18,056 This process is known as gravitational lensing 18 00:01:18,056 --> 00:01:21,055 and it allows astronomers to study objects behind the cluster 19 00:01:21,056 --> 00:01:23,900 in the very distant Universe 20 00:01:23,950 --> 00:01:25,055 that would normally be too faint to see 21 00:01:25,700 --> 00:01:27,413 even for Hubble. 22 00:01:29,000 --> 00:01:31,685 Abell 2744. 23 00:01:31,685 --> 00:01:37,351 One of the first and most captivating targets of the Frontier Fields campaign. 24 00:01:39,700 --> 00:01:42,645 Like all large galaxy clusters, 25 00:01:42,645 --> 00:01:48,194 Abell 2744’s mammoth mass is warping the space around it 26 00:01:48,194 --> 00:01:52,164 and magnifying the light from distant galaxies behind it. 27 00:01:53,200 --> 00:01:57,412 This produces weird and wonderful arrangements of warped light 28 00:01:57,412 --> 00:02:00,410 in the form of arcs and distorted shapes. 29 00:02:00,412 --> 00:02:04,169 Magnified by Abell 2744, 30 00:02:04,172 --> 00:02:09,509 some of the most distant galaxies ever found became visible. 31 00:02:10,500 --> 00:02:14,060 These galaxies are so distant 32 00:02:14,060 --> 00:02:16,661 that the light Hubble has captured from them 33 00:02:16,661 --> 00:02:21,885 was emitted when the Universe was just 500 million years old. 34 00:02:22,100 --> 00:02:24,005 These distant galaxies 35 00:02:24,500 --> 00:02:26,970 — some of the first to form in the Universe — 36 00:02:26,970 --> 00:02:31,799 offer astronomers a glimpse of the conditions in the early Universe. 37 00:02:37,600 --> 00:02:40,321 One of the most distant clusters studied 38 00:02:40,321 --> 00:02:46,451 is MACS J1149.5+2223 39 00:02:46,900 --> 00:02:52,116 — so distant that it takes the light five billion years to reach us! 40 00:02:53,600 --> 00:02:55,367 Using this cluster 41 00:02:55,380 --> 00:02:59,500 Hubble has captured a rare event for the first time: 42 00:02:59,580 --> 00:03:03,656 the gravitationally lensed image of a supernova, 43 00:03:03,656 --> 00:03:07,510 arranged four times in a galaxy in the cluster. 44 00:03:09,900 --> 00:03:11,852 The light from the dying star 45 00:03:11,852 --> 00:03:14,011 was magnified by the mass of the cluster. 46 00:03:14,011 --> 00:03:18,446 And as it is perfectly aligned with one of the galaxies in the cluster, 47 00:03:18,446 --> 00:03:21,999 its light has been split into four images. 48 00:03:25,000 --> 00:03:27,023 By studying gravitational lensing, 49 00:03:27,023 --> 00:03:31,481 astronomers are able to map out the total amount of matter in galaxy clusters. 50 00:03:31,481 --> 00:03:34,639 Now, this mapping is a very valuable tool 51 00:03:34,639 --> 00:03:37,639 in the search for one of the most elusive components of the Universe 52 00:03:39,400 --> 00:03:40,885 — dark matter. 53 00:03:41,850 --> 00:03:43,486 If the galaxy cluster 54 00:03:43,486 --> 00:03:46,415 contained only the matter that we can see directly, 55 00:03:46,416 --> 00:03:51,360 it would never have the gravitational power to distort the light as we observe it. 56 00:03:51,800 --> 00:03:55,400 So there must be additional dark matter present, 57 00:03:55,400 --> 00:03:58,400 and gravitational lensing tells us how this dark matter is distributed 58 00:03:58,650 --> 00:04:00,276 within the cluster. 59 00:04:03,000 --> 00:04:05,384 In the case of MACSJ1149, 60 00:04:05,384 --> 00:04:09,680 our understanding of the distribution of dark matter is in fact so good 61 00:04:09,800 --> 00:04:14,184 that it allowed us to predict the appearance of a fifth image of the lensed supernova 62 00:04:14,184 --> 00:04:16,088 in December 2015, 63 00:04:16,088 --> 00:04:18,178 and, lo and behold, 64 00:04:18,178 --> 00:04:21,475 this appearance has in fact been observed as predicted. 65 00:04:26,900 --> 00:04:29,068 As well as observing the clusters, 66 00:04:29,068 --> 00:04:33,874 Hubble puts its multiple cameras to use during the cluster observations 67 00:04:33,874 --> 00:04:37,400 by also observing six parallel fields 68 00:04:37,403 --> 00:04:39,911 — regions near the galaxy clusters. 69 00:04:40,100 --> 00:04:45,530 While these adjacent images cannot be used for gravitational lensing, 70 00:04:45,530 --> 00:04:49,640 Hubble uses them to perform deep-field observations 71 00:04:49,640 --> 00:04:51,892 and therefore to give astronomers 72 00:04:51,892 --> 00:04:55,839 an even larger window on the early Universe. 73 00:04:57,488 --> 00:04:58,230 So far, 74 00:04:58,231 --> 00:05:02,457 Hubble has completed the observations for three of the six Frontier Fields clusters 75 00:05:02,457 --> 00:05:04,198 and their parallel fields. 76 00:05:04,198 --> 00:05:09,000 These data are already teaching us a lot about the very early Universe 77 00:05:09,001 --> 00:05:13,000 and they are paving the way for the James Webb Space Telescope 78 00:05:13,001 --> 00:05:16,342 in its quest for the very first generation of galaxies. 79 00:05:17,245 --> 00:05:19,799 This is Dr J, signing off for the Hubblecast. 80 00:05:19,799 --> 00:05:20,519 Once again, 81 00:05:20,519 --> 00:05:22,097 nature has surprised us 82 00:05:23,000 --> 00:05:25,097 beyond our wildest imagination. 83 00:05:30,338 --> 00:05:43,108 Transcription by ESO; translated by —