1 00:00:00,010 --> 00:00:04,010 [no sound] 2 00:00:04,030 --> 00:00:08,050 [no sound] >>Interviewer: Mars is facing a close call 3 00:00:08,070 --> 00:00:12,070 on Sunday, October 19th when a rare comet will pass by at 4 00:00:12,090 --> 00:00:16,100 an extremely close distance, and here to tell us more about Comet 5 00:00:16,120 --> 00:00:20,130 Siding Spring is NASA scientist Dr. Jared Espley. Thank you for joining us. 6 00:00:20,150 --> 00:00:24,150 >>JARED: Good morning. >>INTERVIEWER: So what is a comet and why do we study them? 7 00:00:24,170 --> 00:00:28,200 >>JARED: Most people when they think of comets, think of these objects that they can 8 00:00:28,220 --> 00:00:32,240 look up into the night sky, these beautiful objects that have these long, arching 9 00:00:32,260 --> 00:00:36,270 tails that come out behind them. From our modern observations, we actually 10 00:00:36,290 --> 00:00:40,300 know that these are chunks of ice and rock, dirty snowballs, 11 00:00:40,320 --> 00:00:44,350 that are the leftovers of the beginnings of the solar system. They are 12 00:00:44,370 --> 00:00:48,360 ancient relics of the beginnings of the planets, and potentially the beginnings of life. 13 00:00:48,380 --> 00:00:52,390 So generally, they reside in the outer reaches of the solar system, and occasionally something 14 00:00:52,410 --> 00:00:56,450 nudges them into the inner solar system, where they start to heat up, and they get this cloud of 15 00:00:56,470 --> 00:01:00,470 gas that is around the comet, and that's what you can see when you 16 00:01:00,490 --> 00:01:04,490 look up at the night sky. >>INTERVIEWER: What makes Comet Siding Spring 17 00:01:04,510 --> 00:01:08,510 so special, and will we be able to see it? >>JARED: Comet 18 00:01:08,530 --> 00:01:12,520 Siding Spring, like most of its siblings, resided in the outer reaches 19 00:01:12,540 --> 00:01:16,550 of the solar system. But about a million years ago, it started to drift slowly 20 00:01:16,570 --> 00:01:20,610 and invisibly, at first, into the inner solar system. 21 00:01:20,630 --> 00:01:24,650 When we humans first noticed it about a year ago, we realized it was on a near direct collision course 22 00:01:24,670 --> 00:01:28,680 with Mars. And so that nucleus, that central chunk of ice and rock 23 00:01:28,700 --> 00:01:32,730 would just barely miss the planet. But the gas cloud will in fact envelop 24 00:01:32,750 --> 00:01:36,750 the planet. And so that will give us a fantastic opportunity to do science when 25 00:01:36,770 --> 00:01:40,770 the comet comes by, and swallows Mars on Sunday for a few 26 00:01:40,790 --> 00:01:44,820 hours. >>INTERVIEWER: How will NASA study Comet Siding Spring from Mars? 27 00:01:44,840 --> 00:01:48,840 >>JARED: NASA's going to use a variety of telescopes on 28 00:01:48,860 --> 00:01:52,870 the ground observatories to look up, and also telescopes in orbit at Earth 29 00:01:52,890 --> 00:01:56,890 like Hubble, but most especially are going to use the spacecraft at Mars. 30 00:01:56,910 --> 00:02:00,920 The rovers that are on the surface to look up at the night sky, the Martian night sky, 31 00:02:00,940 --> 00:02:04,960 and also the spacecraft that are in orbit around the planet. And in particular 32 00:02:04,980 --> 00:02:09,030 I'm really excited about a mission called MAVEN that by really good luck is 33 00:02:09,050 --> 00:02:13,050 going to arrive at Mars, just, has just arrived, and so it is there 34 00:02:13,070 --> 00:02:17,090 in perfect opportunity to be able to study the comet and how it 35 00:02:17,110 --> 00:02:21,150 will be potentially heating up and potentially temporarily blowing away the Martian 36 00:02:21,170 --> 00:02:25,160 atmosphere, which is what MAVEN is designed to do, so it's a fantastic opportunity for science. 37 00:02:25,180 --> 00:02:29,180 >>INTERVIEWER: Is the comet dangerous, and will the satellites orbiting 38 00:02:29,200 --> 00:02:33,190 Mars be damaged? >>JARED: So the dust, which is 39 00:02:33,210 --> 00:02:37,210 distinct from the gas cloud that I mentioned before, the dust is moving at about a hundred thousand 40 00:02:37,230 --> 00:02:41,250 miles per hour. And so yes, if that were to hit a spacecraft 41 00:02:41,270 --> 00:02:45,260 at Mars, that would be a really sad day for that spacecraft. However, we 42 00:02:45,280 --> 00:02:49,290 very carefully modeled the dust, and we think that it's going to just barely miss the planet, 43 00:02:49,310 --> 00:02:53,330 and therefore the satellites that are in orbit around the planet. Nonetheless, we're 44 00:02:53,350 --> 00:02:57,340 going to try to time the orbit of our spacecraft so that we're hiding behind the planet 45 00:02:57,360 --> 00:03:01,360 when the dust tail comes by, so that we'll be protected by the planet 46 00:03:01,380 --> 00:03:05,400 from the dust. And so, we'll be able to avoid all the danger, and be able to do all 47 00:03:05,420 --> 00:03:09,420 the awesome science that are a result. >>INTERVIEWER: Sounds good, where can we 48 00:03:09,440 --> 00:03:13,450 learn more? >>JARED: You can learn more at mars.nasa.gov, 49 00:03:13,470 --> 00:03:17,500 there you can learn about all the Mars program missions there, and also 50 00:03:17,520 --> 00:03:21,520 about the Comet Siding Spring encounter specifically. 51 00:03:21,540 --> 00:03:25,560 >>INTERVIEWER: Dr. Jared Espley from NASA Goddard Space Flight Center, thank you very much. 52 00:03:25,580 --> 00:03:29,570 >>JARED: Thank you. [beep beep...] 53 00:03:29,590 --> 00:03:33,580 [beep beep... beep beep... beep beep...] 54 00:03:33,600 --> 00:03:37,590 55 00:03:37,610 --> 00:03:41,535