1 00:00:00,040 --> 00:00:04,030 [slate] Well this is a really exciting 2 00:00:04,050 --> 00:00:08,030 event for us because the transit of Mercury only happens rarely once every 3 00:00:08,050 --> 00:00:12,040 the last one was 10 years ago. And it happens when Mercury passes 4 00:00:12,060 --> 00:00:16,040 between us and the sun. It blocks out part of the light from the sun 5 00:00:16,060 --> 00:00:20,040 Now today this transit is starting at 7:12 a.m. 6 00:00:20,060 --> 00:00:24,140 East coast time and will end at 2:30 p.m. Again East coast time. 7 00:00:24,160 --> 00:00:28,190 And you can observe it from the ground if you have the right equipment particularly 8 00:00:28,210 --> 00:00:32,190 safety equipment. But really the best place to observe it by going to 9 00:00:32,210 --> 00:00:36,200 the NASA website and watching the live stream data coming from the Solar Dynamics Observatory 10 00:00:36,220 --> 00:00:40,210 [slate] 11 00:00:40,230 --> 00:00:44,250 Well astronomers have been using transit data to understand our solar system 12 00:00:44,270 --> 00:00:48,250 and beyond for literally hundreds of years. 13 00:00:48,270 --> 00:00:52,260 Originally those transits were used to establish a yard stick 14 00:00:52,280 --> 00:00:56,260 to measure the sizes of things in our own solar system. But since then 15 00:00:56,280 --> 00:01:00,270 we've also used transits to understand the atmospheres of the planets in our solar system. 16 00:01:00,290 --> 00:01:04,320 We've used the transit of Mercury in fact as the first 17 00:01:04,340 --> 00:01:08,320 test of general relativity. And now we're using transits 18 00:01:08,340 --> 00:01:12,330 to learn for planets around distant stars. To look for exoplanets. 19 00:01:12,350 --> 00:01:16,350 [slate] 20 00:01:16,370 --> 00:01:20,390 Well the sun is fascinating. It's obviously very important to us. And one of the things 21 00:01:20,410 --> 00:01:24,400 we've discovered over years and years of study is that every time you look at the sun 22 00:01:24,420 --> 00:01:28,400 in more detail, you find more structure. And in fact 23 00:01:28,420 --> 00:01:32,400 now the Solar Dynamics Observatory is looking at the sun with 24 00:01:32,420 --> 00:01:36,410 the best resolution ever. And we're learning more than ever before about 25 00:01:36,430 --> 00:01:40,420 the magnetic fields of the sun. About flares, about spots 26 00:01:40,440 --> 00:01:44,430 about the activity that's going on in our own sun. And 27 00:01:44,450 --> 00:01:48,440 by understanding that we start to understand how the sun can actually 28 00:01:48,460 --> 00:01:52,440 have an effect on us here on Earth. [slate] 29 00:01:52,460 --> 00:01:56,440 Well astronomers have been using the transit method 30 00:01:56,460 --> 00:02:01,720 to find exoplanets for a number of years now. And in fact we've found literally thousands 31 00:02:01,740 --> 00:02:05,720 of exoplanets so far. But the upcoming TESS mission -the 32 00:02:05,740 --> 00:02:09,730 Transiting Exoplanet Survey Satellite - is going to survey the entire sky looking for 33 00:02:09,750 --> 00:02:13,730 transiting planets around bright, nearby stars 34 00:02:13,750 --> 00:02:17,740 Now these exoplanets, this list of targets 35 00:02:17,760 --> 00:02:21,740 is going to be the perfect list of targets for follow up observations 36 00:02:21,760 --> 00:02:25,750 using telescopes such as the James Webb Space Telescope or other facilities 37 00:02:25,770 --> 00:02:29,760 to try to get the follow up data to help us understand these planets. 38 00:02:29,780 --> 00:02:33,760 And that means understanding what they're made out of. Understanding 39 00:02:33,780 --> 00:02:37,760 what they're atmospheres are like and maybe even finding signs of habitability. 40 00:02:37,780 --> 00:02:41,760 [slate] 41 00:02:41,780 --> 00:02:45,770 Well go to www.nasa.gov/transit 42 00:02:45,790 --> 00:02:49,770 And if you go to that website you will find an array of 43 00:02:49,790 --> 00:02:53,770 stunning images of the sun and of the transit. And importantly you'll find a link 44 00:02:53,790 --> 00:02:57,780 to the live stream data coming from the Solar Dynamics Observatory 45 00:02:57,800 --> 00:02:59,926 as it happens.