1 00:00:00,010 --> 00:00:04,020 [no sound] 2 00:00:04,040 --> 00:00:08,050 [no sound] >>INTERVIEWER: Mars is facing a 3 00:00:08,070 --> 00:00:12,070 close call on Sunday, October 19th, when a rare comet will pass by 4 00:00:12,090 --> 00:00:16,110 at an extremely close distance. And here to tell us more about Comet 5 00:00:16,130 --> 00:00:20,150 Siding Spring, out of NASA's Goddard Space Flight Center in Greenbelt, 6 00:00:20,170 --> 00:00:24,160 Maryland, is Planetary Science Division Director Dr. Jim Green. 7 00:00:24,180 --> 00:00:28,180 Thank you for joining us. >>JIM: Thank you. >>INTERVIEWER: What is a comet and why 8 00:00:28,200 --> 00:00:32,220 do we study them? >>JIM: Well comets have been looked at for 9 00:00:32,240 --> 00:00:36,240 millions of years here on Earth by humans and they're just beautiful 10 00:00:36,260 --> 00:00:40,270 objects. They're bright with long tails. And 11 00:00:40,290 --> 00:00:44,320 when we look inside them, we see that the nucleus is a dirty snowball, 12 00:00:44,340 --> 00:00:48,330 made up of ices and rock, that as it gets close to the Sun, 13 00:00:48,350 --> 00:00:52,380 produces these long, beautiful tails. These comets were 14 00:00:52,400 --> 00:00:56,420 actually born in the early part of our solar system. They're 15 00:00:56,440 --> 00:01:00,440 older than the planet Earth. And interactions with the Earth, 16 00:01:00,460 --> 00:01:04,470 they're throwing these comets out for millions of miles, and now 17 00:01:04,490 --> 00:01:08,510 we have a wonderful opportunity to see Siding Spring come by 18 00:01:08,530 --> 00:01:12,520 into the inner solar system. >>INTERVIEWER: So what makes Comet Siding 19 00:01:12,540 --> 00:01:16,560 Spring so special, and will we be able to see it here from Earth? 20 00:01:16,580 --> 00:01:20,570 >>JIM: Well Siding Spring is very special because it's coming in from 21 00:01:20,590 --> 00:01:24,590 the far reaches of our solar system. It's going to pass right 22 00:01:24,610 --> 00:01:28,640 in front of Mars. Mars will be bathed 23 00:01:28,660 --> 00:01:32,690 in cometary material. Now what's really great about 24 00:01:32,710 --> 00:01:36,720 the comet is we'll have assets like Opportunity 25 00:01:36,740 --> 00:01:40,760 and Curiosity on the surface observing the comet. 26 00:01:40,780 --> 00:01:44,770 In addition to that, we're going to have our spacecraft, like MAVEN, 27 00:01:44,790 --> 00:01:48,800 and Mars Reconnaissance Orbiter, and Mars Odyssey, making 28 00:01:48,820 --> 00:01:52,830 observations of the comet as it flies by. 29 00:01:52,850 --> 00:01:56,900 >>INTERVIEWER: Is this comet dangerous, and will the satellites orbiting Mars 30 00:01:56,920 --> 00:02:00,920 be damaged? >>JIM: The comet is not dangerous, in the sense 31 00:02:00,940 --> 00:02:04,950 that our spacecraft will be on the other side of the 32 00:02:04,970 --> 00:02:09,000 planet Mars when the dust tail goes by. So we've 33 00:02:09,020 --> 00:02:13,020 phased them just right so that they're out of danger. And this 34 00:02:13,040 --> 00:02:17,060 is very important because it also enables them to observe the comet 35 00:02:17,080 --> 00:02:21,110 before, during, and after this fabulous encounter. 36 00:02:21,130 --> 00:02:25,140 [no sound] 37 00:02:25,160 --> 00:02:29,170 [no sound] 38 00:02:29,190 --> 00:02:33,180 >>INTERVIEWER: Sounds great. Where can we learn more? >>JIM: For more 39 00:02:33,200 --> 00:02:37,200 information, please go to mars.nasa.gov. 40 00:02:37,220 --> 00:02:41,210 [no sound] 41 00:02:41,230 --> 00:02:45,220 >>INTERVIEWER: Great, thank you very much, Dr. Jim Green. >>JIM: You're welcome, thank you. 42 00:02:45,240 --> 00:02:49,280 [beep beep... beep beep... beep beep...] 43 00:02:49,300 --> 00:02:53,310 [beep beep... beep beep... beep beep...] 44 00:02:53,330 --> 00:02:57,350 45 00:02:57,370 --> 00:02:59,426