1 00:00:00,000 --> 00:00:03,380 Let's head to NASA Langley Research Center in Hampton, Virginia and meet up with some 2 00:00:03,380 --> 00:00:05,580 George Washington University graduate students. 3 00:00:05,580 --> 00:00:10,580 They are using pictures from the Mars Global Surveyor and geometry to survey Mars. 4 00:00:10,580 --> 00:00:18,580 How are shadows measured on Mars? 5 00:00:18,580 --> 00:00:23,780 How is geometry used to determine the height of land formation on Mars? 6 00:00:23,780 --> 00:00:27,860 Hey guys, I want you to meet Corey Hernandez and Brooke Anderson. 7 00:00:27,860 --> 00:00:30,660 They are graduate students at George Washington University. 8 00:00:30,660 --> 00:00:33,060 Guys, what are you studying over there? 9 00:00:33,060 --> 00:00:37,780 Well, with simple geometry and shadows, we are able to determine the elevation on Mars 10 00:00:37,780 --> 00:00:43,180 surface such as a mountain, Olympus Mons, that's three times the size of Mount Everest, 11 00:00:43,180 --> 00:00:46,940 or a valley, Valles Marineris, which is the size of the United States. 12 00:00:46,940 --> 00:00:49,580 Wow, those are some pretty large land formations. 13 00:00:49,580 --> 00:00:53,420 So let me get this right, what you are telling me is that geometry is used to determine the 14 00:00:53,420 --> 00:00:55,340 elevation of land formations on Mars? 15 00:00:55,340 --> 00:00:59,580 Yes, and we set up an example here for you to demonstrate this. 16 00:00:59,580 --> 00:01:04,500 If this is a mountain on the surface of Mars, this is a protractor to measure the angle 17 00:01:04,500 --> 00:01:09,060 of the sun, this is a metric ruler to measure the length of a shadow. 18 00:01:09,060 --> 00:01:14,140 If this flashlight represents the sun, we know that like here on Earth, the sun is directly 19 00:01:14,140 --> 00:01:18,580 overhead at 90 degrees at high noon, and as the day goes on, it goes down to zero degrees 20 00:01:18,580 --> 00:01:19,580 at sunset. 21 00:01:19,580 --> 00:01:24,340 So, Corey, what you are telling me is this model here creates a right triangle? 22 00:01:24,340 --> 00:01:28,500 The bottom leg can be represented by the length of the shadow, which we can get from 23 00:01:28,500 --> 00:01:30,900 taking a picture with the Mars Global Surveyor. 24 00:01:30,900 --> 00:01:34,840 Now the sun makes an angle between the hypotenuse and the bottom leg. 25 00:01:34,840 --> 00:01:37,660 So let's pretend it's mid-afternoon on Mars. 26 00:01:37,660 --> 00:01:43,780 The sun would be at about an angle of 45 degrees, which broke how long is our shadow? 27 00:01:43,780 --> 00:01:45,260 It gives us about 17 centimeters. 28 00:01:45,260 --> 00:01:47,660 Wow, so you got your angle there. 29 00:01:47,660 --> 00:01:53,500 Yes, so using our formula, remembering the tangent of 45 degrees is equal to one, which 30 00:01:53,500 --> 00:01:57,980 we can find from our scientific calculators or our tangent tables, we can find the height 31 00:01:57,980 --> 00:02:00,820 of our mountain to be 17 centimeters. 32 00:02:00,820 --> 00:02:08,260 So to double-check our answer, we can see that the height of our mountain is 17 centimeters. 33 00:02:08,260 --> 00:02:09,580 That's about what you calculated. 34 00:02:09,580 --> 00:02:10,820 That's pretty cool, Corey. 35 00:02:10,820 --> 00:02:14,740 Well, I looked at Mars through the telescope, and it is definitely red. 36 00:02:14,740 --> 00:02:18,180 But could green slime have once existed on the red planet? 37 00:02:18,180 --> 00:02:23,220 That's one of the many reasons NASA Ames Research Center in Moffett Field, California, is studying 38 00:02:23,220 --> 00:02:24,220 Mars. 39 00:02:24,220 --> 00:02:30,180 So now let's join researcher Chris McKay with the latest on green slime. 40 00:02:30,180 --> 00:02:33,500 I'm interested in Mars, and in particular, life on Mars. 41 00:02:33,500 --> 00:02:36,500 We know that early in Mars' history, it had water, lots of water. 42 00:02:36,500 --> 00:02:39,980 We can see the rivers and lakes that were formed by that water. 43 00:02:39,980 --> 00:02:42,620 The question is, when it had water, did it have life? 44 00:02:42,620 --> 00:02:47,220 To understand how life might have survived on a cold planet like Mars and where to look 45 00:02:47,220 --> 00:02:52,460 for it, we go to places on Earth where life is surviving in very cold, dry conditions, 46 00:02:52,460 --> 00:02:53,820 Mars-like conditions. 47 00:02:53,820 --> 00:02:58,100 This is a rock from the Antarctic, the dry valleys of Antarctica, the most Mars-like 48 00:02:58,100 --> 00:02:59,640 place on Earth. 49 00:02:59,640 --> 00:03:03,140 In this rock, there's life, but it's hidden inside the rock. 50 00:03:03,140 --> 00:03:05,980 Just below the surface, there's a layer of green. 51 00:03:05,980 --> 00:03:09,900 These are algae and lichen, and they're growing inside the rock because the rock provides 52 00:03:09,900 --> 00:03:14,380 them a source of moisture while at the same time allowing enough light to come through. 53 00:03:14,380 --> 00:03:19,420 By studying life forms in these environments, we learn about the strategies that life can 54 00:03:19,420 --> 00:03:21,260 use in a cold, dry place. 55 00:03:21,260 --> 00:03:25,500 We might apply those strategies to the search for life on Mars, and maybe we'll find evidence 56 00:03:25,500 --> 00:03:30,860 that there was life there when Mars was not too much colder than the dry valleys of Antarctica. 57 00:03:30,860 --> 00:03:36,180 Well, it looks like the sun has shifted, and that's about all we have time for today. 58 00:03:36,180 --> 00:03:40,140 But before we go, Jennifer and I would love to hear from you with your comments and ideas. 59 00:03:40,140 --> 00:03:49,020 So why don't you drop us a line at NASA Connect, NASA LARC MS400, Hampton, Virginia 23681. 60 00:03:49,020 --> 00:03:55,740 Or if you're on the web, email us at connect at edu.larc.nasa.gov.