1 00:00:00,020 --> 00:00:08,700 [ music ] 2 00:00:08,720 --> 00:00:18,290 On February 15, asteroid 2012 DA14 will pass within 22,000 miles of Earth: less than a tenth of the distance to the Moon. 3 00:00:18,310 --> 00:00:22,300 Although this 45-meter rock has a zero percent chance of hitting us, 4 00:00:22,320 --> 00:00:27,180 near-earth asteroids in general raise a number of interesting scientific questions. 5 00:00:27,200 --> 00:00:30,760 What makes the difference between a near-miss and an impact? 6 00:00:30,780 --> 00:00:34,380 How would we navigate a spacecraft around an asteroid in the future? 7 00:00:34,400 --> 00:00:37,580 And what can we learn from the asteroids themselves? 8 00:00:37,600 --> 00:00:47,580 To answer these questions, NASA is sending the OSIRIS-REx spacecraft to another near-earth asteroid designated 1999 RQ36. 9 00:00:47,600 --> 00:00:53,400 When it arrives in the year 2018, OSIRIS-REx will study a property called the Yarkovsky Effect, 10 00:00:53,420 --> 00:00:58,680 where the Sun's illumination of a rotating asteroid can change its direction over time. 11 00:00:58,700 --> 00:01:02,530 As the asteroid rotates, the sun heats one side of the surface. 12 00:01:02,550 --> 00:01:07,980 Once that side rotates away from the sun, however, it radiates the heat into space. 13 00:01:08,000 --> 00:01:12,780 This can act as a sort of mini-thruster that slowly changes the asteroid's direction, 14 00:01:12,800 --> 00:01:17,360 potentially making the difference between a near-miss and an impact. 15 00:01:17,380 --> 00:01:24,530 OSIRIS-REx will also study the gravitational properties of asteroids, providing useful insights for follow-up visits. 16 00:01:24,550 --> 00:01:28,580 Because asteroids have a small and variable gravitational pull, 17 00:01:28,600 --> 00:01:33,240 new techniques will need to be developed to help spacecraft approach and fly around them. 18 00:01:33,260 --> 00:01:38,500 Finally, OSIRIS-REx will take a direct sample of the asteroid and return it to Earth. 19 00:01:38,520 --> 00:01:41,580 This could perhaps yield the most interesting results of all, 20 00:01:41,600 --> 00:01:47,780 as 1999 RQ36 is thought to be a leftover from the formation of our solar system. 21 00:01:47,800 --> 00:01:52,580 By studying its composition, scientists will be looking at a snapshot of the solar system 22 00:01:52,600 --> 00:01:59,200 taken four-and-a-half billion years ago, one that may even hold clues to understanding our own origins. 23 00:01:59,220 --> 00:02:03,910 So although 2012 DA14 will miss us when it flies by in February, 24 00:02:03,930 --> 00:02:08,080 NASA isn't missing an opportunity to study near-earth objects, 25 00:02:08,100 --> 00:02:15,510 and OSIRIS-REx will provide the best results yet when it visits 1999 RQ36. 26 00:02:15,530 --> 00:02:26,260 [ music, sound effects ]