WEBVTT FILE 1 00:00:01.000 --> 00:00:07.180 Isolated and icy, Antarctica is among the most challenging natural laboratories to access. 2 00:00:07.180 --> 00:00:12.160 Getting to Antarctica isn't easy, and landing a plane on McMurdo Station's Sea Ice Runway 3 00:00:12.160 --> 00:00:16.830 can give even the most seasoned researcher an adventurous arrival. 4 00:00:16.830 --> 00:00:21.778 Each year researchers from around the globe brave the frigid conditions in order to obtain critical 5 00:00:21.779 --> 00:00:24.779 field measurements on the ice sheet. 6 00:00:25.460 --> 00:00:30.820 Luckily, remote-sensing scientists have dedicated time to developing detailed, accurate imagery 7 00:00:30.820 --> 00:00:34.940 of this frozen land from a far more hospitable vantage point. 8 00:00:35.140 --> 00:00:40.500 This new image mosaic, seen here, is known as the Landsat Image Mosaic of Antarctica, 9 00:00:40.510 --> 00:00:41.870 or LIMA. 10 00:00:41.870 --> 00:00:46.669 The spatial resolution of this satellite image you are seeing is 15 meters per pixel, the 11 00:00:46.670 --> 00:00:52.329 most detailed satellite mosaic of the rugged continent ever created. 12 00:00:52.329 --> 00:00:57.060 A hearty few have ventured here, but as you can see, this new image mosaic makes it possible 13 00:00:57.060 --> 00:01:05.390 for anyone to explore this remarkable region without ice axes, crampons, or risk of frostbite. 14 00:01:05.390 --> 00:01:10.310 Throughout history, this mysterious land has captivated researchers, adventurers, and those 15 00:01:10.310 --> 00:01:13.050 drawn to the most remote corners of the Earth. 16 00:01:13.280 --> 00:01:19.880 Antarctica is a land of extremes: the highest, driest, coldest, windiest, and brightest of 17 00:01:19.880 --> 00:01:21.280 the seven continents. 18 00:01:25.100 --> 00:01:29.880 As we approach the mainland of Antarctica, you can see how far the ice shelf extends 19 00:01:29.880 --> 00:01:31.880 off the coast of the continent. 20 00:01:31.880 --> 00:01:36.789 Roughly the size of the United States and Mexico combined, Antarctica is almost completely 21 00:01:36.790 --> 00:01:38.909 covered by a thick layer of ice. 22 00:01:38.909 --> 00:01:44.590 The virtual journey of Antarctica, provided by LIMA, is due to the compilation of more 23 00:01:44.590 --> 00:01:50.549 than a thousand Landsat images acquired between 1999 and 2001. 24 00:01:50.549 --> 00:01:56.500 To create the images, data visualizers combine actual field data measurements and LIMA satellite 25 00:01:56.500 --> 00:02:01.140 imagery over a digital elevation model to give a three-dimensional effect. 26 00:02:02.000 --> 00:02:06.659 As we move further inland you can begin to see that Antarctica is much more than an endless 27 00:02:06.659 --> 00:02:07.979 plain of snow. 28 00:02:07.979 --> 00:02:13.470 You might be surprised to learn how diverse the terrain actually is. 29 00:02:13.470 --> 00:02:17.920 The ground beneath the Antarctic ice sheet is a mixture of mountains, plains, and ocean 30 00:02:17.920 --> 00:02:24.059 basins, and the tallest mountains raise their rocky faces above the vast ice sheet. 31 00:02:30.200 --> 00:02:36.000 Among Antarctica's most prominent features are its mighty glaciers, like those seen here. 32 00:02:36.000 --> 00:02:41.360 As we move over the Ferrar glacier, we notice that LIMA reveals some areas of bare ground, 33 00:02:41.360 --> 00:02:45.810 where blistering winds have swept valleys clean of their snow cover. 34 00:02:45.810 --> 00:02:51.459 Glaciers are essentially slow-moving rivers of ice, and they gradually deform over time. 35 00:02:51.459 --> 00:02:56.900 These masses of ice form when snow accumulates on a stretch of land over thousands of years. 36 00:02:56.900 --> 00:03:01.459 The snow eventually compresses enough to form dense glacial ice. 37 00:03:01.459 --> 00:03:07.129 As the thickness of glacial ice increases, it slowly succumbs to gravity and flows downhill 38 00:03:07.129 --> 00:03:10.448 or spreads out across flat lands. 39 00:03:10.700 --> 00:03:15.839 Moving glaciers, forced by gravity, sculpt the land as they erode the underlying rock. 40 00:03:17.880 --> 00:03:23.720 Antarctica is a glacial hub: 90 percent of the world's 33 million cubic kilometers of 41 00:03:23.730 --> 00:03:27.350 glacial ice is found in the Antarctic ice sheet. 42 00:03:31.780 --> 00:03:36.460 The telltale signs of glaciers are their flow stripes, which you can see in the many smaller 43 00:03:36.460 --> 00:03:41.650 glaciers feeding into the large Ferrar glacier. 44 00:03:41.650 --> 00:03:46.180 Few people have the chance to experience a glacier firsthand in their lifetime, and even 45 00:03:46.180 --> 00:03:49.960 fewer can access a bird's eye view of these icy giants. 46 00:03:49.960 --> 00:03:55.560 LIMA gives us an opportunity to soar above this unique landscape, and experience a mesmerizing 47 00:03:55.560 --> 00:03:59.100 view of Antarctica's extraordinary glaciers. 48 00:04:03.420 --> 00:04:08.738 This region's relentless and powerful winds are responsible for one of Antarctica's most 49 00:04:08.739 --> 00:04:11.359 fascinating features: blue ice. 50 00:04:11.980 --> 00:04:16.940 Ice absorbs a small amount of red light, but snow crystals are too small to show this 51 00:04:16.940 --> 00:04:18.579 light-absorption effect. 52 00:04:18.579 --> 00:04:23.000 However, blue ice is comprised of larger ice crystals, which makes the red light 53 00:04:23.000 --> 00:04:24.980 absorption more obvious. 54 00:04:25.440 --> 00:04:30.620 Antarctica is a fascinating natural laboratory, but the continent's frigid temperatures and 55 00:04:30.620 --> 00:04:34.759 inaccessibility have historically made it a difficult place to study. 56 00:04:34.759 --> 00:04:39.410 Now armed with the Landsat Image Mosaic of Antarctica, researchers hope to get a better 57 00:04:39.410 --> 00:04:43.970 view of Antarctica and to increase their understanding of this fascinating part of our planet.