1 00:00:03,000 --> 00:00:06,000 Space is a hostile environment. 2 00:00:07,000 --> 00:00:10,000 Our planet shields us from the harshness of the cosmos, 3 00:00:10,000 --> 00:00:17,000 but space telescopes like Hubble spend their lives beyond Earth’s shielding atmosphere. 4 00:00:18,000 --> 00:00:23,000 Such telescopes are carefully engineered to survive the hostility of space — 5 00:00:23,000 --> 00:00:29,000 but there is a danger zone, where observations become almost impossible. 6 00:00:47,000 --> 00:00:49,000 Episode 77: Hubble and the Bermuda Triangle of space. 7 00:00:52,000 --> 00:01:00,000 Above the Earth’s atmosphere, along Hubble’s path, is a mysterious region known as the South Atlantic Anomaly. 8 00:01:01,000 --> 00:01:08,000 When satellites pass through this area they are bombarded with swarms of intensely high energy particles. 9 00:01:09,000 --> 00:01:12,000 This can produce “glitches” in astronomical data, 10 00:01:14,000 --> 00:01:17,000 malfunctioning of on-board electronics, 11 00:01:17,000 --> 00:01:21,000 and has even shut down unprepared spacecraft for weeks! 12 00:01:22,000 --> 00:01:25,000 And it doesn’t just affect machinery — 13 00:01:27,000 --> 00:01:30,000 when taking space walks in the anomaly region, 14 00:01:30,000 --> 00:01:37,000 astronauts have reported peculiar “shooting stars” as streaks of light flicker across their field of view. 15 00:01:43,000 --> 00:01:47,000 The reason for the anomaly lies in the Van Allen radiation belts. 16 00:01:47,000 --> 00:01:56,000 These two doughnut-shaped clouds surround the Earth and trap the charged particles streaming from the Sun, 17 00:01:56,000 --> 00:02:00,000 and hurtling towards Earth from the depths of space as cosmic rays. 18 00:02:02,000 --> 00:02:06,000 This is part of our cosmic shield against potentially harmful particles. 19 00:02:10,000 --> 00:02:16,000 But just off the coast of Brazil, spanning an area larger than the USA, 20 00:02:16,000 --> 00:02:20,000 the Earth’s magnetic field is at its weakest 21 00:02:20,000 --> 00:02:28,000 and the inner doughnut dips below Hubble’s orbit to just 200 kilometres above the Earth’s surface. 22 00:02:29,000 --> 00:02:35,000 This belt contains high energy electrons, protons and atomic nuclei. 23 00:02:35,000 --> 00:02:38,000 All trapped like fireflies in a bottle. 24 00:02:41,000 --> 00:02:50,000 These particles are so densely packed that in one second there can be 3000 “hits” in an area the size of a fingertip. 25 00:02:52,000 --> 00:03:02,000 One of these energetic stray particles can easily hurtle through Hubble, change the meaning of an electronic message, and cause havoc. 26 00:03:04,000 --> 00:03:06,000 So, for its own protection, 27 00:03:06,000 --> 00:03:13,000 some of Hubble’s interior electronics must be shut down when transiting through this cosmic Bermuda Triangle. 28 00:03:16,000 --> 00:03:20,000 Hubble’s detectors are designed to be super-sensitive to light. 29 00:03:21,000 --> 00:03:26,000 Without this feature, Hubble could not delve into the Universe in the way it does. 30 00:03:33,000 --> 00:03:36,000 But this sensitivity has consequences. 31 00:03:37,000 --> 00:03:45,000 The detectors are also very sensitive to high energy particles and would not survive the bombardment in the anomaly. 32 00:03:46,000 --> 00:03:50,000 So for the 15% of its life that Hubble spends there, 33 00:03:50,000 --> 00:03:52,000 the detectors must be shut down. 34 00:03:56,000 --> 00:04:04,000 Only one of Hubble’s cameras, the WFC3, can still be used in this electronic deadzone. 35 00:04:04,000 --> 00:04:08,000 But the images produced are somewhat unusual. 36 00:04:08,000 --> 00:04:10,000 They are speckled with blemishes. 37 00:04:14,000 --> 00:04:22,000 Artifacts of hard-hitting cosmic rays and a reminder of the dangers that lurk above our atmosphere. 38 00:04:25,000 --> 00:04:30,000 Despite its many passages through the perilous South Atlantic Anomaly, 39 00:04:30,000 --> 00:04:35,000 Hubble has survived for almost 25 years in orbit, 40 00:04:35,000 --> 00:04:44,000 and continues to send us stunning astronomical images and observations that help to unravel the mysteries of the Universe. 41 00:04:56,000 --> 00:05:04,000 Did you send a question to Hubble? In the next Hubblecast Dr J will start to answer some of the many questions asked. Watch this space! 42 00:05:14,000 --> 00:05:17,000 Hubblecast is produced by ESA/Hubble at the European Southern Observatory in Germany. 43 00:05:17,000 --> 00:05:22,000 The Hubble mission is a project of international cooperation between NASA and the European Space Agency.