1 00:00:01,530 --> 00:00:05,820 A balloon mission from NASA observed rare electric blue clouds. 2 00:00:05,840 --> 00:00:10,220 These are polar mesospheric clouds, or PMCs. 3 00:00:10,240 --> 00:00:12,380 They are only visible during twilight 4 00:00:12,400 --> 00:00:17,210 and form above Earth’s polar regions at the upper reaches of the atmosphere. 5 00:00:17,230 --> 00:00:20,550 As Earth’s uppermost clouds at around 50 miles high, 6 00:00:20,570 --> 00:00:27,170 PMCs are composed of ice crystals that glow a bright blue or white when reflecting sunlight. 7 00:00:27,190 --> 00:00:32,670 They are extremely sensitive to environmental factors like water vapor and temperature. 8 00:00:32,690 --> 00:00:36,350 Atmospheric motions like airflow over mountains or thunderstorms 9 00:00:36,370 --> 00:00:42,130 can disturb the atmosphere and cause waves that can propagate to very high altitudes. 10 00:00:42,150 --> 00:00:44,730 These waves are known as gravity waves 11 00:00:44,750 --> 00:00:50,360 and although they are invisible, they can be seen as they move through PMCs. 12 00:00:50,380 --> 00:00:52,480 Gravity waves lead to turbulence 13 00:00:52,500 --> 00:00:54,250 - chaotic movement in the atmosphere 14 00:00:54,270 --> 00:00:58,090 that can influence weather and climate, and their predictions. 15 00:00:58,110 --> 00:01:02,830 But the exact causes and effects of turbulence are not well understood. 16 00:01:02,850 --> 00:01:04,630 To better understand this complex process, 17 00:01:04,650 --> 00:01:12,010 scientists sent a giant balloon to observe gravity waves in PMCs. 18 00:01:12,030 --> 00:01:14,650 See you in Canada. 19 00:01:14,670 --> 00:01:17,120 The crewless balloon traveled to 50 miles high 20 00:01:17,140 --> 00:01:22,360 and floated from Sweden to Canada over 5 days, in July 2018. 21 00:01:22,380 --> 00:01:25,820 A laser radar on the balloon measured the PMC altitudes 22 00:01:25,840 --> 00:01:29,790 and the atmospheric temperature that affects their formation and brightness. 23 00:01:29,810 --> 00:01:33,480 And from six million camera images captured from the balloon, 24 00:01:33,500 --> 00:01:38,610 scientists could see both large and small ripples caused by gravity waves. 25 00:01:38,630 --> 00:01:42,980 A better understanding of turbulence can help improve weather forecast models 26 00:01:43,000 --> 00:01:46,170 and our understanding of processes around Earth, 27 00:01:46,190 --> 00:01:50,590 which affect our satellites and assets in space. 28 00:01:50,610 --> 00:01:57,631