WEBVTT FILE 1 00:00:00.900 --> 00:00:04.466 On April 8th, 2024, portions of the United States 2 00:00:04.466 --> 00:00:07.733 will get to enjoy the sight of a total solar eclipse. 3 00:00:07.733 --> 00:00:11.633 The last time this took place was back in August of 2017. 4 00:00:11.633 --> 00:00:15.233 So, this is a good time to refresh our memory as to what's going to happen, 5 00:00:15.233 --> 00:00:16.433 why it occurs, 6 00:00:16.433 --> 00:00:19.733 and let you know where you can watch the show in the sky. 7 00:00:19.733 --> 00:00:23.366 A solar eclipse occurs when the Moon moves between the Earth and the Sun, 8 00:00:23.366 --> 00:00:26.566 blocks the Sun's light and casts a shadow on the Earth. 9 00:00:26.566 --> 00:00:27.866 When the Moon completely covers 10 00:00:27.866 --> 00:00:31.800 the bright disk of the Sun, that's a total solar eclipse. 11 00:00:31.800 --> 00:00:35.566 This differs from a lunar eclipse, where the Moon moves behind the Earth, 12 00:00:35.566 --> 00:00:38.633 so it's now the Earth blocking the Sun's light on the Moon, 13 00:00:38.633 --> 00:00:41.100 creating a shadow on it with a red tint. 14 00:00:41.100 --> 00:00:42.333 To remember the difference, 15 00:00:42.333 --> 00:00:44.733 just remember what object gets darker. 16 00:00:44.733 --> 00:00:46.866 With a solar eclipse, it's the Sun, 17 00:00:46.866 --> 00:00:49.566 and during a lunar eclipse, it's the Moon. 18 00:00:49.566 --> 00:00:51.933 Because the Moon's shadow is relatively small, 19 00:00:51.933 --> 00:00:55.200 a total solar eclipse is a pretty rare event to see. 20 00:00:55.200 --> 00:00:57.766 In order to do so, you have to be on the sunny side 21 00:00:57.766 --> 00:01:00.800 of the planet and within the path of the Moon's shadow. 22 00:01:00.800 --> 00:01:04.533 And that path is affected by the Earth's rotation, Moon's orbit 23 00:01:04.533 --> 00:01:07.333 and where they are in their orbit around the Sun. 24 00:01:07.333 --> 00:01:11.700 There are a lot of moving parts that go into creating this incredible sight. 25 00:01:11.700 --> 00:01:16.533 And speaking of parts, during a solar eclipse, the Moon is actually casting a shadow 26 00:01:16.533 --> 00:01:20.033 consisting of two parts: The umbra and penumbra. 27 00:01:20.033 --> 00:01:22.266 The Moon's umbra is the part of the Moon's shadow 28 00:01:22.266 --> 00:01:25.033 where the entire sun is blocked by the Moon. 29 00:01:25.033 --> 00:01:30.166 In space, it's a cone extending about 232.000 miles behind the Moon. 30 00:01:30.166 --> 00:01:32.700 It's when the small end of this cone hits the Earth 31 00:01:32.700 --> 00:01:35.666 that a total solar eclipse can be seen. 32 00:01:35.666 --> 00:01:39.200 Those factors are why only a limited number of locations on Earth 33 00:01:39.200 --> 00:01:40.800 get to actually see it. 34 00:01:40.800 --> 00:01:45.833 So, if you find your area in the path of totality this year, treasure the sight - 35 00:01:45.833 --> 00:01:49.533 because on average, that same spot on Earth won't see another 36 00:01:49.533 --> 00:01:53.366 total solar eclipse for 375 years. 37 00:01:53.366 --> 00:01:57.533 The area around Carbondale, Illinois, however, has hit the cosmic jackpot - 38 00:01:57.533 --> 00:02:02.166 getting to experience this year's eclipse, as well as the one from 2017. 39 00:02:02.166 --> 00:02:05.366 But their next view of a total solar eclipse 40 00:02:05.366 --> 00:02:09.733 won't happen until the year 2343. 41 00:02:09.733 --> 00:02:13.166 When you check out an eclipse map that depicts the path of totality, 42 00:02:13.166 --> 00:02:14.600 keep this in mind: 43 00:02:14.600 --> 00:02:17.833 While many maps will show a circle representing the Moon's shadow, 44 00:02:17.833 --> 00:02:19.266 the true shape of the umbra 45 00:02:19.266 --> 00:02:23.333 is more like an irregular polygon with slightly curved edges. 46 00:02:23.333 --> 00:02:26.700 This is due to the fact that the Moon isn't a smooth sphere. 47 00:02:26.700 --> 00:02:30.133 It has mountains, valleys and craters on its surface - 48 00:02:30.133 --> 00:02:34.533 all of which affect the passing sunlight and shape of the resulting shadow. 49 00:02:34.533 --> 00:02:37.233 NASA's Lunar Reconnaissance Orbiter spacecraft, 50 00:02:37.233 --> 00:02:41.066 which has been orbiting the Moon since 2009, has provided scientists 51 00:02:41.066 --> 00:02:45.300 with incredibly detailed photographs, terrain maps, and other sets of data 52 00:02:45.300 --> 00:02:48.933 that have allowed us to better understand the shape of the Moon's surface. 53 00:02:48.933 --> 00:02:53.700 This, in turn, has given us the ability to create more finely detailed maps 54 00:02:53.700 --> 00:02:59.166 depicting which specific areas on Earth lie within the solar eclipse’s path of totality. 55 00:03:00.266 --> 00:03:02.366 Regions outside the narrow path, 56 00:03:02.366 --> 00:03:03.800 depending on their distance from it, 57 00:03:03.800 --> 00:03:07.433 will get to witness a partial eclipse to varying degrees. 58 00:03:07.433 --> 00:03:12.866 As you can see, the penumbra shadow passes over almost all of North and Central America, 59 00:03:12.866 --> 00:03:16.900 as well as Greenland, Iceland and the Western British Isles. 60 00:03:16.900 --> 00:03:21.400 This 2024 total solar eclipse is therefore giving millions of people 61 00:03:21.400 --> 00:03:24.833 the opportunity to share in this rare and dynamic interaction 62 00:03:24.833 --> 00:03:27.766 between our Earth, Sun and Moon.