1 00:00:10,070 --> 00:00:06,630 what we're talking about is several 2 00:00:12,789 --> 00:00:10,080 visualizations of the path of the moon's 3 00:00:14,709 --> 00:00:12,799 shadow during the eclipse in 2017. 4 00:00:17,349 --> 00:00:14,719 everything in it is driven by the data 5 00:00:19,990 --> 00:00:17,359 so the color of the ground the position 6 00:00:22,150 --> 00:00:20,000 of the path of totality the lighting 7 00:00:22,950 --> 00:00:22,160 from the sun the sun angle all of those 8 00:00:26,790 --> 00:00:22,960 are 9 00:00:28,950 --> 00:00:26,800 nasa products were used to create this 10 00:00:30,870 --> 00:00:28,960 visualization i used the lunar 11 00:00:33,910 --> 00:00:30,880 reconnaissance orbiter the laser 12 00:00:35,990 --> 00:00:33,920 altimetry data from that which gives us 13 00:00:37,990 --> 00:00:36,000 a digital map of the elevations on the 14 00:00:40,069 --> 00:00:38,000 moon for the earth i used something 15 00:00:41,750 --> 00:00:40,079 called srtm this was a radar that was 16 00:00:43,510 --> 00:00:41,760 flown on the space shuttle for the 17 00:00:46,229 --> 00:00:43,520 positions of the 18 00:00:48,950 --> 00:00:46,239 the earth the moon and the sun i used a 19 00:00:50,709 --> 00:00:48,960 jpl ephemeris and a femoris is just a 20 00:00:52,790 --> 00:00:50,719 list of positions 21 00:00:54,630 --> 00:00:52,800 but it's the most it's the most accurate 22 00:00:56,470 --> 00:00:54,640 tabulation of those positions this 23 00:00:58,549 --> 00:00:56,480 visualization is unique because it shows 24 00:01:00,310 --> 00:00:58,559 the effect of both 25 00:01:02,069 --> 00:01:00,320 the irregular 26 00:01:03,750 --> 00:01:02,079 edge of the moon the limb of the moon we 27 00:01:06,550 --> 00:01:03,760 call it and the elevation of the 28 00:01:08,550 --> 00:01:06,560 observer now we've known for a long time 29 00:01:10,550 --> 00:01:08,560 that the elevation of the observer 30 00:01:12,390 --> 00:01:10,560 affects where the shadow is 31 00:01:14,870 --> 00:01:12,400 we've also known that the 32 00:01:17,510 --> 00:01:14,880 mountains and the valleys along the edge 33 00:01:19,670 --> 00:01:17,520 of the moon affect the shadow so you may 34 00:01:22,630 --> 00:01:19,680 have seen on on eclipse maps in the past 35 00:01:24,550 --> 00:01:22,640 that the image of the umbra 36 00:01:26,950 --> 00:01:24,560 that shape of the shadow on the earth is 37 00:01:28,789 --> 00:01:26,960 drawn as a smooth oval but we know that 38 00:01:31,190 --> 00:01:28,799 the moon isn't smooth around the edge of 39 00:01:33,910 --> 00:01:31,200 the moon we have these sort of jagged 40 00:01:35,590 --> 00:01:33,920 peaks and valleys and a peak can block 41 00:01:37,910 --> 00:01:35,600 the sun a little bit earlier than you 42 00:01:39,910 --> 00:01:37,920 thought and a valley can let the sun in 43 00:01:41,910 --> 00:01:39,920 a few seconds longer than you thought 44 00:01:44,469 --> 00:01:41,920 the combined effect of these peaks and 45 00:01:47,109 --> 00:01:44,479 valleys is to create a shape that's not 46 00:01:49,190 --> 00:01:47,119 really an oval it's more like a polygon 47 00:01:51,830 --> 00:01:49,200 but it hasn't actually been seen in 48 00:01:54,069 --> 00:01:51,840 exactly this way before where 49 00:01:56,709 --> 00:01:54,079 we calculate those circumstances for 50 00:01:57,590 --> 00:01:56,719 every point on the map and draw that 51 00:02:00,069 --> 00:01:57,600 shape 52 00:02:02,469 --> 00:02:00,079 totality is that is that two minutes 53 00:02:05,030 --> 00:02:02,479 when the or two and a half minutes when 54 00:02:07,030 --> 00:02:05,040 the moon completely covers the sun the 55 00:02:09,029 --> 00:02:07,040 sudden darkness of totality is just 56 00:02:10,869 --> 00:02:09,039 something that a lot of people can't 57 00:02:13,030 --> 00:02:10,879 compare to anything else 58 00:02:15,190 --> 00:02:13,040 i love the idea that i'm giving this 59 00:02:17,350 --> 00:02:15,200 kind of map to other people and 60 00:02:19,510 --> 00:02:17,360 especially that it's more detailed and