1 00:00:03,766 --> 00:00:07,766 - IN THE PAST, COMETS HAVE SOMETIMES GOTTEN A BAD RAP. 2 00:00:07,766 --> 00:00:09,800 A LOT OF PEOPLE TEND TO BE SUPERSTITIOUS ABOUT THEM, 3 00:00:09,800 --> 00:00:11,400 BLAMING UNFORTUNATE EVENTS 4 00:00:11,400 --> 00:00:14,033 AND NATURAL DISASTERS ON THEIR PRESENCE. 5 00:00:14,033 --> 00:00:16,733 HOWEVER, NASA SAYS THERE IS NOTHING TO FEAR. 6 00:00:16,733 --> 00:00:18,800 AS A MATTER OF FACT, NASA IS QUITE EXCITED 7 00:00:18,800 --> 00:00:21,200 ABOUT COMETS AND WHAT THEY CAN TEACH US. 8 00:00:21,200 --> 00:00:24,700 FIND OUT ABOUT THESE FROZEN MYSTERIES NEXT ON "REAL WORLD." 9 00:00:31,466 --> 00:00:34,833 COMETS ARE COSMIC SNOWBALLS MADE UP OF FROZEN GASES, 10 00:00:34,833 --> 00:00:37,500 ROCK, AND DUST, AND WHEN THEY GET CLOSE ENOUGH TO THE SUN, 11 00:00:37,500 --> 00:00:40,833 ALL THOSE ICES BEGIN TO SUBLIMATE, OR BURN OFF, 12 00:00:40,833 --> 00:00:43,033 AS A DUSTY GAS AND CAN EVEN CREATE 13 00:00:43,033 --> 00:00:46,533 A TEMPORARY ATMOSPHERE AROUND THE COMET CALLED A COMA. 14 00:00:46,533 --> 00:00:49,066 SOLAR WINDS BLOW THOSE GASES AWAY FROM THE SUN, 15 00:00:49,066 --> 00:00:51,200 CREATING THOSE FAMOUS COMET TAILS, 16 00:00:51,200 --> 00:00:53,733 BUT WHAT'S SO INTERESTING ABOUT A BIG CHUNK OF ICE 17 00:00:53,733 --> 00:00:55,400 AND ROCK HURTLING THROUGH SPACE? 18 00:00:55,400 --> 00:00:58,533 - COMETS ARE THE LEFTOVERS OF THOSE ICY CHUNKS, 19 00:00:58,533 --> 00:01:01,666 THOSE ICY BITS THAT WENT INTO MAKING UP THE PLANETS, 20 00:01:01,666 --> 00:01:04,000 SO ONE OF THE GREAT REASONS TO STUDY THEM 21 00:01:04,000 --> 00:01:07,666 IS THAT WE WOULD REALLY LIKE TO KNOW HOW MUCH 22 00:01:07,666 --> 00:01:10,500 OF THE VARIOUS PARTS OF WHAT WENT INTO 23 00:01:10,500 --> 00:01:12,133 MAKING PLANETS ENDED UP ON THE EARTH, 24 00:01:12,133 --> 00:01:13,433 HOW MUCH ENDED UP ON MARS, 25 00:01:13,433 --> 00:01:14,600 HOW MUCH ENDED UP ON VENUS, 26 00:01:14,600 --> 00:01:16,166 AND DOES THAT HELP EXPLAIN 27 00:01:16,166 --> 00:01:18,000 WHY THE DIFFERENT PLANETS ARE SO DIFFERENT? 28 00:01:18,000 --> 00:01:20,433 - JUST AS NO TWO PLANETS ARE EXACTLY ALIKE, 29 00:01:20,433 --> 00:01:23,166 NO TWO COMETS ARE ALIKE EITHER. 30 00:01:23,166 --> 00:01:24,833 COMETS COME IN DIFFERENT SIZES 31 00:01:24,833 --> 00:01:26,766 AND ARE MADE UP OF DIFFERENT MATERIALS. 32 00:01:26,766 --> 00:01:29,566 ALTHOUGH THE COMET'S COMA AND TAIL ARE FASCINATING TO SEE, 33 00:01:29,566 --> 00:01:31,566 SCIENTISTS DETERMINE THE SIZE OF A COMET 34 00:01:31,566 --> 00:01:34,066 BY MEASURING THE DIAMETER OF ITS NUCLEUS. 35 00:01:34,066 --> 00:01:36,733 THE DIAMETER IS THE DISTANCE ACROSS 36 00:01:36,733 --> 00:01:38,466 A SPHERE RIGHT THROUGH THE MIDDLE. 37 00:01:38,466 --> 00:01:39,966 BECAUSE OF SOLAR RADIATION, 38 00:01:39,966 --> 00:01:42,766 COMETS LOSE MASS AS THEY ORBIT THE SUN. 39 00:01:42,766 --> 00:01:45,800 THIS MASS LOSS CAN TELL US A LOT ABOUT THE LIFE OF A COMET 40 00:01:45,800 --> 00:01:47,366 AND WHERE IT MIGHT HAVE COME FROM. 41 00:01:47,366 --> 00:01:49,000 - EVERY TIME A COMET COMES IN NEAR THE SUN, 42 00:01:49,000 --> 00:01:50,300 IT'S GONNA LOSE SOME MASS. 43 00:01:50,300 --> 00:01:53,100 SO THE LIFETIME OF A COMET, 44 00:01:53,100 --> 00:01:56,600 HOW LONG IT'S ACTUALLY GONNA SURVIVE AS AN ENTITY 45 00:01:56,600 --> 00:01:58,133 IN THE SOLAR SYSTEM DEPENDS ENTIRELY 46 00:01:58,133 --> 00:02:00,700 ON HOW MUCH MASS IT LOSES EVERY TIME IT COMES AROUND THE SUN. 47 00:02:00,700 --> 00:02:03,700 SOME COMETS COME IN SO CLOSE TO THE SUN, 48 00:02:03,700 --> 00:02:06,000 THEY LOSE SO MUCH MASS THAT THEY DON'T EVEN SURVIVE 49 00:02:06,000 --> 00:02:07,566 THE TRIP AROUND THE SUN. 50 00:02:07,566 --> 00:02:11,000 WHEREAS OTHERS, LIKE THE FAMOUS HALLEY'S COMET, 51 00:02:11,000 --> 00:02:13,466 CAN SURVIVE MANY, MANY TRIPS AROUND THE SUN 52 00:02:13,466 --> 00:02:15,733 BECAUSE THEY DON'T LOSE NEARLY AS MUCH MASS. 53 00:02:15,733 --> 00:02:17,966 - FROM TIME TO TIME, A COMET IS IN JUST THE RIGHT PLACE 54 00:02:17,966 --> 00:02:20,066 IN OUR SOLAR SYSTEM THAT HUMANS CAN LOOK UP 55 00:02:20,066 --> 00:02:22,766 AND SEE A BRIGHT OBJECT IN THE SKY. 56 00:02:22,766 --> 00:02:26,500 ONE COMET THAT HAS NASA LOOKING TO THE SKY IS COMET ISON. 57 00:02:26,500 --> 00:02:28,800 - AND THIS IS PROBABLY COMET ISON'S FIRST TRIP PAST THE SUN. 58 00:02:28,800 --> 00:02:31,433 IT'S A YOUNG COMET. 59 00:02:31,433 --> 00:02:34,300 WE SPEAK OF THEM AS BEING YOUNG BECAUSE THEY'VE ONLY BEEN 60 00:02:34,300 --> 00:02:36,666 PAST THE SUN ONCE OR MAYBE A COUPLE OF TIMES. 61 00:02:36,666 --> 00:02:39,300 THIS IS PROBABLY COMET ISON'S ONLY TRIP PAST THE SUN. 62 00:02:39,300 --> 00:02:41,400 IT'S ON WHAT WE CALL A HYPERBOLIC TRAJECTORY, 63 00:02:41,400 --> 00:02:43,733 WHICH MEANS THAT AFTER IT GOES AROUND THE SUN, 64 00:02:43,733 --> 00:02:46,200 WE'RE ACTUALLY GONNA LOSE IT FROM THE SOLAR SYSTEM. 65 00:02:46,200 --> 00:02:48,433 IT'S GONNA BE COMPLETELY EJECTED FROM THE SOLAR SYSTEM 66 00:02:48,433 --> 00:02:50,900 AND GO WANDERING AROUND THROUGH INTERSTELLAR SPACE. 67 00:02:50,900 --> 00:02:54,000 SO COMET ISON CAME FROM VERY FAR OUT 68 00:02:54,000 --> 00:02:57,400 IN THE OUTER, OUTERMOST REGIONS OF THE SOLAR SYSTEM. 69 00:02:57,400 --> 00:02:58,400 IT'S COME IN. 70 00:02:58,400 --> 00:03:01,300 THIS IS ITS 15 SECONDS OF FAME, 71 00:03:01,300 --> 00:03:03,066 AND THEN IT'S GONNA BE GONE FOREVER, 72 00:03:03,066 --> 00:03:06,433 SO IT'S VERY INTERESTING TO STUDY THESE OBJECTS, 73 00:03:06,433 --> 00:03:08,266 BECAUSE WE DON'T GET VERY MANY OPPORTUNITIES. 74 00:03:08,266 --> 00:03:11,000 - THIS COMET HAS SPENT THE LAST FEW MILLION YEARS 75 00:03:11,000 --> 00:03:13,866 COMING TO US FROM THE FAR REACHES OF THE OORT CLOUD, 76 00:03:13,866 --> 00:03:17,200 WHERE IT HAS BEEN IN DEEP FREEZE FOR BILLIONS OF YEARS. 77 00:03:17,200 --> 00:03:19,233 BUT AS THE COMET GETS CLOSER TO THE SUN, 78 00:03:19,233 --> 00:03:22,233 IT WILL BOIL AND EVAPORATE AND LOSE MUCH OF ITS MASS 79 00:03:22,233 --> 00:03:24,333 AS THE MATERIAL FROM THE BEGINNING OF TIME 80 00:03:24,333 --> 00:03:26,233 STREAMS ACROSS THE SOLAR SYSTEM. 81 00:03:26,233 --> 00:03:29,000 NASA HAS USED SEVERAL OF THE TOOLS IN ITS BAG 82 00:03:29,000 --> 00:03:32,033 TO GET A BETTER LOOK AT THE HEAVENLY PHENOMENON. 83 00:03:32,033 --> 00:03:34,766 SPACECRAFT LIKE DEEP IMPACT, SPITZER, SWIFT, 84 00:03:34,766 --> 00:03:36,333 AND EVEN THE HUBBLE SPACE TELESCOPE 85 00:03:36,333 --> 00:03:39,666 HAVE OBSERVED COMET ISON AND HAVE GIVEN US 86 00:03:39,666 --> 00:03:42,533 SOME PRETTY INTERESTING PICTURES OF THIS UNIQUE COMET. 87 00:03:42,533 --> 00:03:43,700 BUT THAT'S NOT ALL. 88 00:03:43,700 --> 00:03:45,833 NASA INTENDS TO OBSERVE COMET ISON 89 00:03:45,833 --> 00:03:48,666 WITH ALL AVAILABLE TOOLS AT THEIR DISPOSAL, 90 00:03:48,666 --> 00:03:50,600 INCLUDING SOHO, STEREO, 91 00:03:50,600 --> 00:03:53,066 SDO, CHANDRA SPACE TELESCOPE, 92 00:03:53,066 --> 00:03:55,933 MESSENGER, THE INTERNATIONAL SPACE STATION, 93 00:03:55,933 --> 00:03:57,766 MARS RECONNAISSANCE ORBITER, 94 00:03:57,766 --> 00:03:59,566 AND EVEN THE MARS CURIOSITY ROVER. 95 00:03:59,566 --> 00:04:02,000 COMET ISON WILL HELP SCIENTISTS GATHER 96 00:04:02,000 --> 00:04:04,266 THE MOST COMPREHENSIVE PACKAGE OF DATA 97 00:04:04,266 --> 00:04:06,400 EVER COLLECTED ABOUT A SINGLE COMET. 98 00:04:06,400 --> 00:04:08,800 WHO KNOWS WHAT WE'LL LEARN, BUT JUST WATCHING A COMET 99 00:04:08,800 --> 00:04:13,266 ISN'T ENOUGH FOR NASA OR OUR INTERNATIONAL PARTNERS IN SPACE. 100 00:04:13,266 --> 00:04:17,333 THE EUROPEAN SPACE AGENCY HAS LAUNCHED A COMETARY FIRST. 101 00:04:17,333 --> 00:04:19,533 THE ROSETTA SPACECRAFT WILL RENDEZVOUS WITH A COMET 102 00:04:19,533 --> 00:04:22,366 AND LAND ROBOTIC INSTRUMENTS ON THE SURFACE. 103 00:04:22,366 --> 00:04:24,966 NASA HAS SEVERAL INSTRUMENTS ABOARD ROSETTA, 104 00:04:24,966 --> 00:04:26,800 INSTRUMENTS THAT WILL HELP US UNDERSTAND 105 00:04:26,800 --> 00:04:29,500 HOW A COMET DEVELOPS ITS COMA AND TAILS, 106 00:04:29,500 --> 00:04:31,833 HOW A COMET'S CHEMICALS INTERACT WITH EACH OTHER 107 00:04:31,833 --> 00:04:33,266 AND WITH THE SUN, 108 00:04:33,266 --> 00:04:35,733 AND HOW THE COMET WAS FORMED IN THE FIRST PLACE. 109 00:04:35,733 --> 00:04:39,166 - WE HAVE VISITED COMETS WITH LITTLE FLYBY KINDS OF PROBES, 110 00:04:39,166 --> 00:04:40,600 BUT THIS IS THE FIRST ATTEMPT 111 00:04:40,600 --> 00:04:44,266 TO ACTUALLY NOT ONLY GO INTO ORBIT AROUND THE COMET NUCLEUS 112 00:04:44,266 --> 00:04:48,166 AND OBSERVE IT VERY CLOSELY, BUT ALSO TO LAND ON THE SURFACE, 113 00:04:48,166 --> 00:04:50,800 AND SO IT'S GONNA PROVIDE US, REALLY, 114 00:04:50,800 --> 00:04:54,466 THE MOST IN-DEPTH UNDERSTANDING OF WHAT COMETS ARE MADE OF 115 00:04:54,466 --> 00:04:57,633 AND HOW THEY BEHAVE AND WHAT THEIR DYNAMICS ARE 116 00:04:57,633 --> 00:04:59,000 AND HOW THEY EVOLVE OVER TIME. 117 00:04:59,000 --> 00:05:00,666 ONE OF THE BIGGEST CHALLENGES, ACTUALLY, 118 00:05:00,666 --> 00:05:02,766 HAS BEEN THE DURATION OF THIS MISSION. 119 00:05:02,766 --> 00:05:05,800 BECAUSE WE'RE TRYING TO CATCH UP WITH A COMET, 120 00:05:05,800 --> 00:05:07,033 IT'S NOT JUST STRAIGHTFORWARD. 121 00:05:07,033 --> 00:05:08,366 YOU CAN'T JUST DRIVE TO THE COMET. 122 00:05:08,366 --> 00:05:10,866 YOU'VE GOT TO SYNC UP YOUR ORBIT WITH THE COMET 123 00:05:10,866 --> 00:05:14,233 SO AS IT'S GOING AROUND THE SUN, YOU JOIN UP WITH IT-- 124 00:05:14,233 --> 00:05:16,733 SMOOTHLY, BECAUSE WE DON'T WANT TO FLY PAST IT REAL FAST. 125 00:05:16,733 --> 00:05:18,500 WE ACTUALLY WANT TO GO INTO ORBIT AROUND IT, 126 00:05:18,500 --> 00:05:20,766 SO WE HAVE TO SMOOTHLY CATCH UP WITH IT. 127 00:05:20,766 --> 00:05:22,766 AND THAT'S NOT EASY. 128 00:05:22,766 --> 00:05:25,600 COMETS TEND TO BE GOING PRETTY QUICKLY. 129 00:05:25,600 --> 00:05:27,366 THEY'RE ON RATHER ODD ORBITS 130 00:05:27,366 --> 00:05:29,233 COMPARED TO THINGS LIKE THE EARTH, 131 00:05:29,233 --> 00:05:33,466 AND SO ROSETTA'S TRAJECTORY HAS TAKEN IT PAST THE EARTH 132 00:05:33,466 --> 00:05:34,733 A COUPLE OF TIMES. 133 00:05:34,733 --> 00:05:38,000 IT'S TAKEN A ZING PAST-- A SLING PAST MARS, 134 00:05:38,000 --> 00:05:40,666 AND WE'VE BEEN USING THESE PLANETARY ENCOUNTERS 135 00:05:40,666 --> 00:05:43,666 TO SYNC UP THE ORBIT WITH THE COMET. 136 00:05:43,666 --> 00:05:46,033 - SO WHILE YOU'RE WAITING FOR NEWS ABOUT THE COMET ISON 137 00:05:46,033 --> 00:05:48,466 OR THAT NEXT EXCITING COMET MISSION, 138 00:05:48,466 --> 00:05:53,100 CHECK OUT COMET QUEST, A GAME CREATED BY NASA'S SPACE TEAM. 139 00:05:53,100 --> 00:05:54,866 JUST LIKE THE REAL ROSETTA MISSION, 140 00:05:54,866 --> 00:05:58,300 YOU CAN HITCH A RIDE ON A COMET AS IT JOURNEYS TOWARDS THE SUN, 141 00:05:58,300 --> 00:06:00,666 AND JUST LIKE NASA, YOU MAY HAVE TO USE 142 00:06:00,666 --> 00:06:03,100 A LITTLE BIT OF MATH TO MEET THE CHALLENGE. 143 00:06:03,100 --> 00:06:06,300 I'M DIEGO, AND SEE YOU NEXT TIME ON "REAL WORLD." 144 00:06:06,300 --> 00:06:08,566 - AND NOW FOR AN UPDATE ABOUT COMET ISON. 145 00:06:08,566 --> 00:06:11,366 AS NASA DETERMINES THE FINAL STATUS OF ISON, 146 00:06:11,366 --> 00:06:13,500 MOST AGREE THAT THE COMET WAS DESTROYED 147 00:06:13,500 --> 00:06:15,500 AS IT ROUNDED THE SUN, LEAVING BEHIND 148 00:06:15,500 --> 00:06:16,833 ONLY PIECES OF RUBBLE, 149 00:06:16,833 --> 00:06:19,333 BUT EVEN THOSE DUSTY FRAGMENTS HAVE A STORY TO TELL. 150 00:06:19,333 --> 00:06:21,933 COMET ISON, WHICH BEGAN ITS JOURNEY FROM THE OORT CLOUD 151 00:06:21,933 --> 00:06:23,533 SOME 3 MILLION YEARS AGO, 152 00:06:23,533 --> 00:06:27,200 MADE ITS CLOSEST APPROACH TO THE SUN ON NOVEMBER 28, 2013. 153 00:06:27,200 --> 00:06:28,433 REGARDLESS OF ITS FATE, 154 00:06:28,433 --> 00:06:30,466 COMET ISON DID NOT DISAPPOINT RESEARCHERS. 155 00:06:30,466 --> 00:06:32,600 OBSERVATORIES AROUND THE WORLD AND IN SPACE 156 00:06:32,600 --> 00:06:35,733 GATHERED THE LARGEST SET OF COMET OBSERVATIONS OF ALL TIME, 157 00:06:35,733 --> 00:06:37,966 WHICH SHOULD PROVIDE ENOUGH DATA FOR PROFESSIONAL 158 00:06:37,966 --> 00:06:40,766 AND AMATEUR ASTRONOMERS TO STUDY FOR YEARS TO COME.