1 00:00:11,000 --> 00:00:13,000 I find it very 2 00:00:14,000 --> 00:00:15,000 Fascinating 3 00:00:15,000 --> 00:00:18,000 Yeah, very good, very well done 4 00:00:18,000 --> 00:00:22,000 It touches, I was also laughing at some parts 5 00:00:41,000 --> 00:00:43,000 Episode 74: Hubble and Heaven's Carousel 6 00:00:47,000 --> 00:00:50,000 Presented by DR J aka Dr Joe Liske 7 00:00:53,000 --> 00:00:54,000 Over its lifetime 8 00:00:55,000 --> 00:00:58,000 Hubble has inspired new thinking about the Universe 9 00:00:58,000 --> 00:01:05,000 and contributed to more fields within physics and astronomy than we could ever have imagined. 10 00:01:06,000 --> 00:01:10,000 But, Hubble has also become an icon of discovery, 11 00:01:11,000 --> 00:01:14,000 of human achievement, and of culture. 12 00:01:15,000 --> 00:01:20,000 And, has been the inspiration for artistic work that goes beyond the science. 13 00:01:30,000 --> 00:01:32,000 Creations of art and sound. 14 00:01:33,000 --> 00:01:36,000 Creations like Tim Otto Roth's Heaven's Carousel, 15 00:01:37,000 --> 00:01:45,000 premiered in March 2014 at the fourth Hubble Space Telescope Conference at the Accademia dei Lincei in Rome. 16 00:01:47,000 --> 00:01:48,000 What's the point? 17 00:01:48,000 --> 00:01:54,000 Well, you see it glowing but finally you will see, or will hear, that there are sounds coming out. 18 00:01:55,000 --> 00:01:58,000 So, what I am doing, I am translating light physics 19 00:01:58,000 --> 00:02:00,000 into acoustics. 20 00:02:04,000 --> 00:02:07,000 So imagine, that's the simple experiment of the Heaven's Carousel, 21 00:02:08,000 --> 00:02:11,000 you hear the stars, the galaxies, up on there. 22 00:02:13,000 --> 00:02:21,000 Tim Otto Roth has used sound to interpret the light that Hubble collects when it looks at the stars. 23 00:02:22,000 --> 00:02:27,000 This allows us to explore the physics of light with our ears, 24 00:02:27,000 --> 00:02:31,000 and follows an ancient tradition of linking music to astronomy. 25 00:02:33,000 --> 00:02:35,000 Two and a half thousand years ago 26 00:02:36,000 --> 00:02:41,000 the Pythagorean speculated about a connection between planetary motions, 27 00:02:41,000 --> 00:02:46,000 and the small numbered ratios that describe musical harmonies. 28 00:02:47,000 --> 00:02:51,000 These ratios form the foundation of Western music, 29 00:02:51,000 --> 00:02:55,000 and the mathematics of this Harmony of the Spheres 30 00:02:55,000 --> 00:03:00,000 was even used by the renowned astronomer Johannes Kepler. 31 00:03:01,000 --> 00:03:04,000 More recently, in the 1800's, 32 00:03:04,000 --> 00:03:09,000 Christian Doppler wondered whether the effect that he observed in stars, 33 00:03:09,000 --> 00:03:12,000 and which would later bare his name, 34 00:03:12,000 --> 00:03:15,000 could be demonstrated with sound. 35 00:03:15,000 --> 00:03:16,000 And so it was. 36 00:03:17,000 --> 00:03:21,000 First, using a brass band on an open railway wagon. 37 00:03:21,000 --> 00:03:24,000 And then, later, by the Heaven's Carousel. 38 00:03:27,000 --> 00:03:28,000 The Doppler Effect 39 00:03:28,000 --> 00:03:31,000 causes a shift in the observed wavelength of radiation 40 00:03:31,000 --> 00:03:35,000 if the source of the radiation and the observer are in motion, 41 00:03:35,000 --> 00:03:37,000 relative to each another. 42 00:03:38,000 --> 00:03:41,000 Now, in this simulation we have a light source moving to the right. 43 00:03:41,000 --> 00:03:45,000 So, to Alice, sitting on the right, the source appears bluer 44 00:03:45,000 --> 00:03:47,000 because the wavelengths are compressed 45 00:03:48,000 --> 00:03:53,000 but Bob, on the left, sees redder light because the wavelengths are stretched. 46 00:03:53,000 --> 00:03:56,000 The light is blue- or red-shifted 47 00:03:56,000 --> 00:03:58,000 The same thing happens to sound. 48 00:03:59,000 --> 00:04:04,000 As the train with the brass band passed the audience, they would have heard the pitch changing, 49 00:04:04,000 --> 00:04:06,000 from higher, to lower. 50 00:04:08,000 --> 00:04:16,000 Just because I could not afford a whole brass band sitting for days or weeks on a carousel and turning around, 51 00:04:16,000 --> 00:04:19,000 I just took loudspeakers playing sine waves. 52 00:04:21,000 --> 00:04:24,000 At the centre of the Heaven's Carousel 53 00:04:24,000 --> 00:04:28,000 the pitch of the tones is constant and no Doppler Effect is heard. 54 00:04:30,000 --> 00:04:33,000 The thirty six speakers circle overhead, 55 00:04:33,000 --> 00:04:36,000 and neither approach, nor recede from your ears. 56 00:04:44,000 --> 00:04:49,000 As you move out from the centre the effect becomes steadily stronger. 57 00:04:49,000 --> 00:04:53,000 Each new position brings a new perspective, 58 00:04:53,000 --> 00:04:56,000 and a different set of pitches can be heard, 59 00:04:56,000 --> 00:04:59,000 changing with the changes in direction of the speakers. 60 00:05:07,000 --> 00:05:11,000 Wavelengths are stretched as the speakers recede, 61 00:05:11,000 --> 00:05:14,000 and compressed as they approach. 62 00:05:16,000 --> 00:05:21,000 The Doppler Shift explains what we see in the local Universe, 63 00:05:21,000 --> 00:05:24,000 when objects are moving away from or towards us. 64 00:05:25,000 --> 00:05:31,000 This is one way that astronomers have detected exoplanets orbiting nearby stars. 65 00:05:32,000 --> 00:05:37,000 But, this effect also has a cosmological cousin. 66 00:05:37,000 --> 00:05:41,000 A form of redshift that allowed Hubble's namesake, 67 00:05:41,000 --> 00:05:42,000 Edwin Hubble, 68 00:05:42,000 --> 00:05:47,000 to discover, in the 1920's, that the Universe is expanding. 69 00:05:48,000 --> 00:05:52,000 A discovery that revolutionised our thinking about the cosmos. 70 00:05:54,000 --> 00:05:58,000 Space itself is stretched as the Universe expands. 71 00:05:58,000 --> 00:06:01,000 And, stretched with it, are the wavelengths of light from distant galaxies. 72 00:06:02,000 --> 00:06:04,000 The more distant a galaxy, 73 00:06:04,000 --> 00:06:08,000 the more its light waves are stretched as they travel across the Universe, 74 00:06:08,000 --> 00:06:10,000 and the redder its light appears. 75 00:06:10,000 --> 00:06:13,000 This is the cosmological redshift. 76 00:06:13,000 --> 00:06:18,000 Now clearly the cosmological redshift is somehow connected with distance. 77 00:06:18,000 --> 00:06:23,000 But the exact relation between the two depends on how the Universe expanded in the past. 78 00:06:24,000 --> 00:06:29,000 Astronomers have studied this relationship using far away exploding stars, 79 00:06:29,000 --> 00:06:31,000 called supernovae. 80 00:06:31,000 --> 00:06:35,000 By comparing their redshifts with Hubble's observations of their actual distances, 81 00:06:35,000 --> 00:06:42,000 they discovered that the Universe began accelerating round about six billion years ago. 82 00:06:42,000 --> 00:06:44,000 Now, this came as quite a shock, 83 00:06:44,000 --> 00:06:50,000 because, after all, the combined gravitational pull of all the matter in the Universe 84 00:06:50,000 --> 00:06:54,000 should in fact slow down the expansion of the Universe. 85 00:06:54,000 --> 00:06:56,000 Why it is instead speeding up, 86 00:06:56,000 --> 00:07:00,000 is one of the biggest mysteries in contemporary physics. 87 00:07:02,000 --> 00:07:06,000 To the cosmologist acceleration offers insight into the age and fate of the Universe 88 00:07:06,000 --> 00:07:09,000 and perhaps an echo of the prior growth spurt called inflation. 89 00:07:10,000 --> 00:07:16,000 But it seems only natural that new knowledge evokes feelings and feelings are communicated better by art than by science. 90 00:07:18,000 --> 00:07:21,000 This incredible dynamic sculpture created by Tim Otto Roth 91 00:07:22,000 --> 00:07:26,000 channels some of those feelings about the accelerating Universe. 92 00:07:26,000 --> 00:07:29,000 Important themes are related to the discovery are echoed in the piece. 93 00:07:30,000 --> 00:07:32,000 Blue shifts and red shifts. 94 00:07:32,000 --> 00:07:34,000 Isotropy and Homogeneity. 95 00:07:34,000 --> 00:07:38,000 Our inability to see the strings directing the action. 96 00:07:38,000 --> 00:07:41,000 The struggle to perceive depth in the Universe. Are just a few. 97 00:07:41,000 --> 00:07:44,000 And I'm sure you will have and will find many more. 98 00:07:49,000 --> 00:07:51,000 Hubble has shown us the Universe 99 00:07:51,000 --> 00:07:56,000 and the Heaven's Carousel has transformed these red and blue shifts 100 00:07:56,000 --> 00:08:00,000 into a moving fabric of speakers and sound. 101 00:08:00,000 --> 00:08:03,000 The expansion of the Universe 102 00:08:03,000 --> 00:08:06,000 played out in a concert of sound and light. 103 00:08:07,000 --> 00:08:14,000 At times, these sources of sound are telling us through their pitch that they are moving away from us. 104 00:08:14,000 --> 00:08:19,000 Leaving the same clues that planets around distant stars leave 105 00:08:19,000 --> 00:08:21,000 for today's astronomers. 106 00:08:22,000 --> 00:08:24,000 And at other times, 107 00:08:24,000 --> 00:08:27,000 A high pitch and dazzling ice blue 108 00:08:27,000 --> 00:08:29,000 transitions to a deep red 109 00:08:29,000 --> 00:08:32,000 and a pitch almost too low to hear. 110 00:08:33,000 --> 00:08:36,000 Making us feel like an observer of cosmic time. 111 00:08:37,000 --> 00:08:40,000 Listening as the Universe expands, 112 00:08:40,000 --> 00:08:44,000 and its contents accelerate away from us. 113 00:08:50,000 --> 00:08:54,000 Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany. 114 00:08:54,000 --> 00:08:59,000 The Hubble mission is a project of international cooperation between NASA and the European Space Agency. 115 00:09:07,000 --> 00:09:10,000 Transcription by ESO; translation by —