1 00:00:05,000 --> 00:00:10,000 A new ALMA image has revealed extraordinarily fine detail 2 00:00:10,000 --> 00:00:15,000 that has never been seen before in the planet-forming disc around a young star. 3 00:00:16,000 --> 00:00:23,000 These are the first observations that have used ALMA with its antennas at almost their maximum extent. 4 00:00:23,000 --> 00:00:30,000 This has resulted in the sharpest picture ever made at submillimetre wavelengths. 5 00:00:31,000 --> 00:00:40,000 The new results are a huge step forward in the observation of how protoplanetary discs develop and how planets form. 6 00:00:45,000 --> 00:00:47,000 This is the ESOcast! 7 00:00:47,000 --> 00:00:52,000 Cutting-edge science and life behind the scenes at ESO, 8 00:00:52,000 --> 00:00:55,000 the European Southern Observatory. 9 00:01:04,000 --> 00:01:08,000 ALMA, the Atacama Large Millimeter/submillimeter Array 10 00:01:08,000 --> 00:01:14,000 is the world’s most powerful telescope for observing the cold Universe. 11 00:01:14,000 --> 00:01:22,000 It consists of 66 high-precision antennas that can be placed in different configurations. 12 00:01:24,000 --> 00:01:32,000 For the first time, the ALMA array has now been configured with the antennas up to 15 kilometres apart. 13 00:01:32,000 --> 00:01:37,000 This is close to the maximum possible baseline of 16 kilometres 14 00:01:37,000 --> 00:01:45,000 and allows ALMA to discern much finer detail than has ever been possible up to now. 15 00:01:49,000 --> 00:01:56,000 For ALMA’s first observations in this powerful new mode, researchers pointed the antennas at HL Tauri — 16 00:01:56,000 --> 00:02:04,000 a young star about 450 light-years away, which is surrounded by a dusty disc. 17 00:02:04,000 --> 00:02:08,000 The resulting image exceeds all expectations 18 00:02:08,000 --> 00:02:15,000 and is sharper than images routinely obtained by the NASA/ESA Hubble Space Telescope. 19 00:02:19,000 --> 00:02:25,000 It reveals unexpected fine detail in the HL Tauri protoplanetary disc, 20 00:02:25,000 --> 00:02:29,000 which consists of material leftover from the birth of the star. 21 00:02:34,000 --> 00:02:40,000 The image shows a series of concentric bright rings with enigmatic dark patches. 22 00:02:42,000 --> 00:02:47,000 These structures are clear signs of the presence of multiple planets, 23 00:02:47,000 --> 00:02:50,000 as they sweep up material from the disc. 24 00:02:54,000 --> 00:03:02,000 HL Tauri’s disc appears to be a lot more developed than would be expected from the age of the system. 25 00:03:02,000 --> 00:03:09,000 This suggests that the process of planet formation may be faster than previously thought. 26 00:03:11,000 --> 00:03:16,000 Young stars like HL Tauri are born in clouds of gas and fine dust, 27 00:03:16,000 --> 00:03:21,000 in regions which have collapsed under the effects of gravity. 28 00:03:21,000 --> 00:03:27,000 Dense hot cores form and eventually ignite to become young stars. 29 00:03:27,000 --> 00:03:38,000 These baby stars are initially cocooned in the remaining gas and dust, which eventually settles into a protoplanetary disc. 30 00:03:41,000 --> 00:03:49,000 Through many collisions the dust particles will stick together, growing into clumps the size of sand grains and pebbles. 31 00:03:49,000 --> 00:03:57,000 And ultimately, asteroids, comets and even planets can form in the disc. 32 00:03:57,000 --> 00:04:07,000 The young planets will then disrupt the disc and create rings, gaps and holes such as those structures now observed by ALMA. 33 00:04:10,000 --> 00:04:18,000 The investigation of these protoplanetary discs is essential to our understanding of how Earth formed in the Solar System. 34 00:04:18,000 --> 00:04:24,000 Observing the first stages of planet formation around HL Tauri may show us 35 00:04:24,000 --> 00:04:32,000 how our own planetary system may have looked during its formation more than four billion years ago. 36 00:04:34,000 --> 00:04:43,000 By operating in its close to final configuration, ALMA has demonstrated its enormous observational potential. 37 00:04:43,000 --> 00:04:51,000 This starts a new era in our exploration of how stars and planets form. 38 00:05:11,000 --> 00:05:15,000 Transcription by ESO; translation by —