WEBVTT FILE 1 00:00:00.020 --> 00:00:04.030 [slate] 2 00:00:04.050 --> 00:00:08.070 [slate] 3 00:00:08.090 --> 00:00:12.130 Well this is something that 4 00:00:12.150 --> 00:00:16.230 really is a once-in-a-lifetime event for so many people. The Earth, the moon and the sun 5 00:00:16.250 --> 00:00:20.340 are going to line up perfectly so that the moon actually blocks out the sun 6 00:00:20.360 --> 00:00:24.520 that casts a shadow down on the Earth. And there's about a 70 mile path 7 00:00:24.540 --> 00:00:28.590 that's going to go all the way across the United States. It's going to start in Portland, Oregon and actually end 8 00:00:28.610 --> 00:00:32.660 in Charleston, South Carolina. And in that one little strip the sky 9 00:00:32.680 --> 00:00:36.790 will go entirely dark. The moon will entirely cover up the sun. 10 00:00:36.810 --> 00:00:40.980 But even if you're not in that strip you're going to see something called a partial solar eclipse. 11 00:00:41.000 --> 00:00:45.040 So different levels of the sun will be blocked depending on where you are in the United States. 12 00:00:45.060 --> 00:00:49.120 But everyone in the United States has a chance to view this and participate 13 00:00:49.140 --> 00:00:53.140 in this wonderful natural event. 14 00:00:53.160 --> 00:00:57.270 [slate] 15 00:00:57.290 --> 00:01:01.360 Well if you're lucky enough to actually be in the path of totality, it's something that changes 16 00:01:01.380 --> 00:01:05.520 your life. I've seen two total eclipses of the sun. And 17 00:01:05.540 --> 00:01:09.720 the dark goes entirely dark, the moon covers up the sun and you're able to see 18 00:01:09.740 --> 00:01:13.810 something called the solar corona which is the atmosphere of the sun. So you see these streaming 19 00:01:13.830 --> 00:01:17.930 streamers of light coming away from the covered up sun. And that you can actually 20 00:01:17.950 --> 00:01:22.080 see with your unaided eye. You can take off any sort of eye projection when it's totally 21 00:01:22.100 --> 00:01:26.130 dark and look up at the sky. You see the stars come out. You see the planets Mercury 22 00:01:26.150 --> 00:01:30.230 and Venus near the sun. And you actually see a 360 degree 23 00:01:30.250 --> 00:01:34.350 sunset all the way around you. If you're not in the path of totality, 24 00:01:34.370 --> 00:01:38.510 there really important thing is to get some good eye projection. So there are eclipse 25 00:01:38.530 --> 00:01:42.570 glasses and you can actually find out where to get these and how to use them properly 26 00:01:42.590 --> 00:01:46.650 on our website. NASA's put together a big website called eclipse2017.nasa.gov 27 00:01:46.670 --> 00:01:50.750 And you can go there to find out how much 28 00:01:50.770 --> 00:01:54.880 of the sun is going to be blocked out in your area. Where to get eclipse glasses 29 00:01:54.900 --> 00:01:58.890 and also other ways to view the eclipse safely. 30 00:01:58.910 --> 00:02:02.930 [slate] 31 00:02:02.950 --> 00:02:07.010 Well the main thing that I really can't iterate enough is that 32 00:02:07.030 --> 00:02:11.120 even a tiny little bit of the sun is still visible it can damage your eyes. 33 00:02:11.140 --> 00:02:15.300 So unless the moon is entirely covering up the sun you either need 34 00:02:15.320 --> 00:02:19.360 eclipse viewing glasses or you can do something relatively simple called a pinhole 35 00:02:19.380 --> 00:02:23.440 camera. And with a pinhole camera all you need to do is punch a little hole 36 00:02:23.460 --> 00:02:27.560 in a piece of cardboard or you can actually use something like a colander. You know a kitchen 37 00:02:27.580 --> 00:02:31.730 implement that has little holes in it. You let the sunlight shine through that 38 00:02:31.750 --> 00:02:35.800 and then you look down on the ground at the image that's being projected 39 00:02:35.820 --> 00:02:39.890 Those little holes will actually focus the sunlight and you'll be able to see 40 00:02:39.910 --> 00:02:44.010 a crescent shape. You'll be able to see the moon blocking out a good portion of the sun. 41 00:02:44.030 --> 00:02:48.170 But do not ever look at the sun even if a little bit of the surface is uncovered. 42 00:02:48.190 --> 00:02:52.190 [slate] 43 00:02:52.210 --> 00:02:56.300 If even a little bit of the sun is not 44 00:02:56.320 --> 00:03:00.490 blocked then the sky will be mainly bright, but you'll notice changes 45 00:03:00.510 --> 00:03:04.540 There will be changes in the temperature. You'll be able to actually want animals change. 46 00:03:04.560 --> 00:03:08.620 Birds will go back to their nests if it gets quite dark. You know one of the amazing 47 00:03:08.640 --> 00:03:12.760 things is you can help us take information about this. NASA is going taking information 48 00:03:12.780 --> 00:03:16.950 about changes in temperature, changes in cloud shapes. We have an app 49 00:03:16.970 --> 00:03:21.000 called the GLOBE Observer. And if you just have a simple cheap thermometer 50 00:03:21.020 --> 00:03:25.090 If you download this app, you can enter data about how the temperature is changing 51 00:03:25.110 --> 00:03:29.210 and how clouds are changing and we're going to use that to do original science 52 00:03:29.230 --> 00:03:33.400 research about how sunlight and the Earth's atmosphere interact. 53 00:03:33.420 --> 00:03:37.430 [slate] 54 00:03:37.450 --> 00:03:41.500 All of the energy that we use on this planet originally comes from the sun 55 00:03:41.520 --> 00:03:45.600 and it may surprise you to know that something as simple as sunlight 56 00:03:45.620 --> 00:03:49.770 is not perfectly understood. Our atmosphere absorbs sunlight 57 00:03:49.790 --> 00:03:53.820 it reflects some. There are different levels of the atmosphere, different colors that are used. 58 00:03:53.840 --> 00:03:57.900 So we actually have experiments set up to figure out how much sunlight actually reaches 59 00:03:57.920 --> 00:04:02.000 the surface of the Earth. And we have an experiment going to the space station later this year 60 00:04:02.020 --> 00:04:06.393 called TSIS which is going to measure the total amount of sunlight that the Earth receives.