1 00:00:21,960 --> 00:00:24,990 there is a small planet so near the Sun 2 00:00:24,990 --> 00:00:25,000 there is a small planet so near the Sun 3 00:00:25,000 --> 00:00:27,300 there is a small planet so near the Sun that it is scarcely visited in the 4 00:00:27,300 --> 00:00:27,310 that it is scarcely visited in the 5 00:00:27,310 --> 00:00:31,410 that it is scarcely visited in the bright glare of our star like an elusive 6 00:00:31,410 --> 00:00:31,420 bright glare of our star like an elusive 7 00:00:31,420 --> 00:00:33,990 bright glare of our star like an elusive ghost it is best observed from Earth in 8 00:00:33,990 --> 00:00:34,000 ghost it is best observed from Earth in 9 00:00:34,000 --> 00:00:36,420 ghost it is best observed from Earth in the Twilight hours when the Sun is gone 10 00:00:36,420 --> 00:00:36,430 the Twilight hours when the Sun is gone 11 00:00:36,430 --> 00:00:37,460 the Twilight hours when the Sun is gone from the sky 12 00:00:37,460 --> 00:00:37,470 from the sky 13 00:00:37,470 --> 00:00:44,760 from the sky the ancient Romans gave it its name so 14 00:00:44,760 --> 00:00:44,770 the ancient Romans gave it its name so 15 00:00:44,770 --> 00:00:46,920 the ancient Romans gave it its name so little was known about the planet but 16 00:00:46,920 --> 00:00:46,930 little was known about the planet but 17 00:00:46,930 --> 00:00:48,840 little was known about the planet but scientists could only guess at its 18 00:00:48,840 --> 00:00:48,850 scientists could only guess at its 19 00:00:48,850 --> 00:00:54,689 scientists could only guess at its origin and evolution like the planet 20 00:00:54,689 --> 00:00:54,699 origin and evolution like the planet 21 00:00:54,699 --> 00:01:00,500 origin and evolution like the planet Mars it could have had violent volcanoes 22 00:01:00,500 --> 00:01:00,510 23 00:01:00,510 --> 00:01:07,130 deep canyons scarred by violent winds 24 00:01:07,130 --> 00:01:07,140 25 00:01:07,140 --> 00:01:10,289 more like our own moon its surface might 26 00:01:10,289 --> 00:01:10,299 more like our own moon its surface might 27 00:01:10,299 --> 00:01:12,960 more like our own moon its surface might be pitted with craters a record of 28 00:01:12,960 --> 00:01:12,970 be pitted with craters a record of 29 00:01:12,970 --> 00:01:14,789 be pitted with craters a record of ancient events written on a planet's 30 00:01:14,789 --> 00:01:14,799 ancient events written on a planet's 31 00:01:14,799 --> 00:01:19,469 ancient events written on a planet's surface the best photographs of mercury 32 00:01:19,469 --> 00:01:19,479 surface the best photographs of mercury 33 00:01:19,479 --> 00:01:22,920 surface the best photographs of mercury added little to our knowledge but when 34 00:01:22,920 --> 00:01:22,930 added little to our knowledge but when 35 00:01:22,930 --> 00:01:25,350 added little to our knowledge but when man learned to travel in space the 36 00:01:25,350 --> 00:01:25,360 man learned to travel in space the 37 00:01:25,360 --> 00:01:27,209 man learned to travel in space the electronic cameras of a spacecraft 38 00:01:27,209 --> 00:01:27,219 electronic cameras of a spacecraft 39 00:01:27,219 --> 00:01:30,840 electronic cameras of a spacecraft called Mariner 10 revealed the planet in 40 00:01:30,840 --> 00:01:30,850 called Mariner 10 revealed the planet in 41 00:01:30,850 --> 00:01:49,709 called Mariner 10 revealed the planet in startling detail 42 00:01:49,709 --> 00:01:49,719 43 00:01:49,719 --> 00:01:54,010 in June of 1975 scientists from five 44 00:01:54,010 --> 00:01:54,020 in June of 1975 scientists from five 45 00:01:54,020 --> 00:01:55,959 in June of 1975 scientists from five nations assembled at the California 46 00:01:55,959 --> 00:01:55,969 nations assembled at the California 47 00:01:55,969 --> 00:01:58,870 nations assembled at the California Institute of Technology to exchange the 48 00:01:58,870 --> 00:01:58,880 Institute of Technology to exchange the 49 00:01:58,880 --> 00:02:00,459 Institute of Technology to exchange the information they had gained from the 50 00:02:00,459 --> 00:02:00,469 information they had gained from the 51 00:02:00,469 --> 00:02:02,649 information they had gained from the exploration of the planet Mercury by the 52 00:02:02,649 --> 00:02:02,659 exploration of the planet Mercury by the 53 00:02:02,659 --> 00:02:06,819 exploration of the planet Mercury by the spacecraft Mariner 10 included in the 54 00:02:06,819 --> 00:02:06,829 spacecraft Mariner 10 included in the 55 00:02:06,829 --> 00:02:08,770 spacecraft Mariner 10 included in the group for scientists representing many 56 00:02:08,770 --> 00:02:08,780 group for scientists representing many 57 00:02:08,780 --> 00:02:11,559 group for scientists representing many techniques of exploration including the 58 00:02:11,559 --> 00:02:11,569 techniques of exploration including the 59 00:02:11,569 --> 00:02:13,420 techniques of exploration including the detection of various forms of radiation 60 00:02:13,420 --> 00:02:13,430 detection of various forms of radiation 61 00:02:13,430 --> 00:02:16,089 detection of various forms of radiation a study of gases in a planet's 62 00:02:16,089 --> 00:02:16,099 a study of gases in a planet's 63 00:02:16,099 --> 00:02:18,789 a study of gases in a planet's atmosphere and the powerful scientific 64 00:02:18,789 --> 00:02:18,799 atmosphere and the powerful scientific 65 00:02:18,799 --> 00:02:21,940 atmosphere and the powerful scientific tool photography of the surface of a 66 00:02:21,940 --> 00:02:21,950 tool photography of the surface of a 67 00:02:21,950 --> 00:02:25,490 tool photography of the surface of a planet 68 00:02:25,490 --> 00:02:25,500 69 00:02:25,500 --> 00:02:32,369 welcome to Pasadena we are convened the 70 00:02:32,369 --> 00:02:32,379 welcome to Pasadena we are convened the 71 00:02:32,379 --> 00:02:34,559 welcome to Pasadena we are convened the photographic exploration of mercury was 72 00:02:34,559 --> 00:02:34,569 photographic exploration of mercury was 73 00:02:34,569 --> 00:02:36,540 photographic exploration of mercury was led by dr. Bruce Murray of the 74 00:02:36,540 --> 00:02:36,550 led by dr. Bruce Murray of the 75 00:02:36,550 --> 00:02:40,910 led by dr. Bruce Murray of the California Institute of Technology the 76 00:02:40,910 --> 00:02:40,920 California Institute of Technology the 77 00:02:40,920 --> 00:02:44,210 California Institute of Technology the objective I have is to present a 78 00:02:44,210 --> 00:02:44,220 objective I have is to present a 79 00:02:44,220 --> 00:02:46,949 objective I have is to present a relatively simple interpretation of 80 00:02:46,949 --> 00:02:46,959 relatively simple interpretation of 81 00:02:46,959 --> 00:02:49,650 relatively simple interpretation of history of mercury and to draw some 82 00:02:49,650 --> 00:02:49,660 history of mercury and to draw some 83 00:02:49,660 --> 00:02:51,539 history of mercury and to draw some conclusions about the other terrestrial 84 00:02:51,539 --> 00:02:51,549 conclusions about the other terrestrial 85 00:02:51,549 --> 00:02:55,020 conclusions about the other terrestrial planets the work that dr. Murray and his 86 00:02:55,020 --> 00:02:55,030 planets the work that dr. Murray and his 87 00:02:55,030 --> 00:02:57,360 planets the work that dr. Murray and his colleagues are engrossed in goes beyond 88 00:02:57,360 --> 00:02:57,370 colleagues are engrossed in goes beyond 89 00:02:57,370 --> 00:02:59,160 colleagues are engrossed in goes beyond the exploration of a single planet 90 00:02:59,160 --> 00:02:59,170 the exploration of a single planet 91 00:02:59,170 --> 00:03:03,630 the exploration of a single planet mercury they are seeking insights into 92 00:03:03,630 --> 00:03:03,640 mercury they are seeking insights into 93 00:03:03,640 --> 00:03:05,759 mercury they are seeking insights into the history of our entire inner solar 94 00:03:05,759 --> 00:03:05,769 the history of our entire inner solar 95 00:03:05,769 --> 00:03:09,900 the history of our entire inner solar system the search for new information 96 00:03:09,900 --> 00:03:09,910 system the search for new information 97 00:03:09,910 --> 00:03:26,010 system the search for new information began with the launch of Mary Murphy 98 00:03:26,010 --> 00:03:26,020 99 00:03:26,020 --> 00:03:29,200 these photographs appear were taken to 100 00:03:29,200 --> 00:03:29,210 these photographs appear were taken to 101 00:03:29,210 --> 00:03:31,090 these photographs appear were taken to test the cameras that were to photograph 102 00:03:31,090 --> 00:03:31,100 test the cameras that were to photograph 103 00:03:31,100 --> 00:03:33,220 test the cameras that were to photograph both venus and mercury for the first 104 00:03:33,220 --> 00:03:33,230 both venus and mercury for the first 105 00:03:33,230 --> 00:03:40,210 both venus and mercury for the first time after leaving the gravitational 106 00:03:40,210 --> 00:03:40,220 time after leaving the gravitational 107 00:03:40,220 --> 00:03:43,090 time after leaving the gravitational field of Earth Mariner 10 began its long 108 00:03:43,090 --> 00:03:43,100 field of Earth Mariner 10 began its long 109 00:03:43,100 --> 00:03:47,230 field of Earth Mariner 10 began its long voyage to mercury the spacecraft's 110 00:03:47,230 --> 00:03:47,240 voyage to mercury the spacecraft's 111 00:03:47,240 --> 00:03:49,750 voyage to mercury the spacecraft's flight path was carefully chosen to skim 112 00:03:49,750 --> 00:03:49,760 flight path was carefully chosen to skim 113 00:03:49,760 --> 00:03:51,940 flight path was carefully chosen to skim past the planet orbiting between Earth 114 00:03:51,940 --> 00:03:51,950 past the planet orbiting between Earth 115 00:03:51,950 --> 00:03:55,990 past the planet orbiting between Earth and Mercury cloud-covered Venus the 116 00:03:55,990 --> 00:03:56,000 and Mercury cloud-covered Venus the 117 00:03:56,000 --> 00:03:58,330 and Mercury cloud-covered Venus the Mariner 10 cameras at close range 118 00:03:58,330 --> 00:03:58,340 Mariner 10 cameras at close range 119 00:03:58,340 --> 00:04:01,320 Mariner 10 cameras at close range were to show us a startling new Venus a 120 00:04:01,320 --> 00:04:01,330 were to show us a startling new Venus a 121 00:04:01,330 --> 00:04:05,680 were to show us a startling new Venus a Venus we couldn't see from Earth Venus 122 00:04:05,680 --> 00:04:05,690 Venus we couldn't see from Earth Venus 123 00:04:05,690 --> 00:04:07,990 Venus we couldn't see from Earth Venus has been a real frustration to 124 00:04:07,990 --> 00:04:08,000 has been a real frustration to 125 00:04:08,000 --> 00:04:10,690 has been a real frustration to photograph from the ground because in 126 00:04:10,690 --> 00:04:10,700 photograph from the ground because in 127 00:04:10,700 --> 00:04:12,360 photograph from the ground because in the visible it's perfectly featureless 128 00:04:12,360 --> 00:04:12,370 the visible it's perfectly featureless 129 00:04:12,370 --> 00:04:14,830 the visible it's perfectly featureless there is occasionally a little bit of 130 00:04:14,830 --> 00:04:14,840 there is occasionally a little bit of 131 00:04:14,840 --> 00:04:17,220 there is occasionally a little bit of indentation along the Terminator and 132 00:04:17,220 --> 00:04:17,230 indentation along the Terminator and 133 00:04:17,230 --> 00:04:20,229 indentation along the Terminator and occasionally one can see a little 134 00:04:20,229 --> 00:04:20,239 occasionally one can see a little 135 00:04:20,239 --> 00:04:22,660 occasionally one can see a little structure around the limb but basically 136 00:04:22,660 --> 00:04:22,670 structure around the limb but basically 137 00:04:22,670 --> 00:04:25,450 structure around the limb but basically appears from the earth to be obscured by 138 00:04:25,450 --> 00:04:25,460 appears from the earth to be obscured by 139 00:04:25,460 --> 00:04:29,500 appears from the earth to be obscured by an incredible haze and the ultraviolet 140 00:04:29,500 --> 00:04:29,510 an incredible haze and the ultraviolet 141 00:04:29,510 --> 00:04:32,050 an incredible haze and the ultraviolet however that's the wavelengths beyond 142 00:04:32,050 --> 00:04:32,060 however that's the wavelengths beyond 143 00:04:32,060 --> 00:04:34,780 however that's the wavelengths beyond the blue that the eye cannot see but 144 00:04:34,780 --> 00:04:34,790 the blue that the eye cannot see but 145 00:04:34,790 --> 00:04:37,990 the blue that the eye cannot see but photographic film can respond to very 146 00:04:37,990 --> 00:04:38,000 photographic film can respond to very 147 00:04:38,000 --> 00:04:41,440 photographic film can respond to very faint markings have been observed and it 148 00:04:41,440 --> 00:04:41,450 faint markings have been observed and it 149 00:04:41,450 --> 00:04:42,760 faint markings have been observed and it was those faint markings in the 150 00:04:42,760 --> 00:04:42,770 was those faint markings in the 151 00:04:42,770 --> 00:04:45,130 was those faint markings in the ultraviolet that persuaded us to make a 152 00:04:45,130 --> 00:04:45,140 ultraviolet that persuaded us to make a 153 00:04:45,140 --> 00:04:47,320 ultraviolet that persuaded us to make a maximum effort to photograph Venus in 154 00:04:47,320 --> 00:04:47,330 maximum effort to photograph Venus in 155 00:04:47,330 --> 00:04:50,790 maximum effort to photograph Venus in the ultraviolet up close 156 00:04:50,790 --> 00:04:50,800 the ultraviolet up close 157 00:04:50,800 --> 00:04:53,249 the ultraviolet up close the Mariner 10 cameras photographed 158 00:04:53,249 --> 00:04:53,259 the Mariner 10 cameras photographed 159 00:04:53,259 --> 00:04:56,810 the Mariner 10 cameras photographed Venus in high-resolution sections 160 00:04:56,810 --> 00:04:56,820 Venus in high-resolution sections 161 00:04:56,820 --> 00:04:59,270 Venus in high-resolution sections each photograph covering only a small 162 00:04:59,270 --> 00:04:59,280 each photograph covering only a small 163 00:04:59,280 --> 00:05:04,700 each photograph covering only a small portion of the planet the frames were 164 00:05:04,700 --> 00:05:04,710 portion of the planet the frames were 165 00:05:04,710 --> 00:05:06,890 portion of the planet the frames were then pieced together into mosaics to 166 00:05:06,890 --> 00:05:06,900 then pieced together into mosaics to 167 00:05:06,900 --> 00:05:09,020 then pieced together into mosaics to give a detailed picture of the entire 168 00:05:09,020 --> 00:05:09,030 give a detailed picture of the entire 169 00:05:09,030 --> 00:05:19,100 give a detailed picture of the entire planet the results of the Mariner 10 170 00:05:19,100 --> 00:05:19,110 planet the results of the Mariner 10 171 00:05:19,110 --> 00:05:21,500 planet the results of the Mariner 10 photography in the ultraviolet are 172 00:05:21,500 --> 00:05:21,510 photography in the ultraviolet are 173 00:05:21,510 --> 00:05:23,270 photography in the ultraviolet are really good in fact much much better 174 00:05:23,270 --> 00:05:23,280 really good in fact much much better 175 00:05:23,280 --> 00:05:26,390 really good in fact much much better than we had hoped because as you can see 176 00:05:26,390 --> 00:05:26,400 than we had hoped because as you can see 177 00:05:26,400 --> 00:05:28,940 than we had hoped because as you can see looking at first a picture of Venus in 178 00:05:28,940 --> 00:05:28,950 looking at first a picture of Venus in 179 00:05:28,950 --> 00:05:31,600 looking at first a picture of Venus in the visible that was taken by Mariner 10 180 00:05:31,600 --> 00:05:31,610 the visible that was taken by Mariner 10 181 00:05:31,610 --> 00:05:34,310 the visible that was taken by Mariner 10 and then when we switched to one that 182 00:05:34,310 --> 00:05:34,320 and then when we switched to one that 183 00:05:34,320 --> 00:05:36,560 and then when we switched to one that was taken in the ultraviolet and has 184 00:05:36,560 --> 00:05:36,570 was taken in the ultraviolet and has 185 00:05:36,570 --> 00:05:38,600 was taken in the ultraviolet and has been enhanced for the computer to bring 186 00:05:38,600 --> 00:05:38,610 been enhanced for the computer to bring 187 00:05:38,610 --> 00:05:41,300 been enhanced for the computer to bring up the details there's a tremendous 188 00:05:41,300 --> 00:05:41,310 up the details there's a tremendous 189 00:05:41,310 --> 00:05:43,510 up the details there's a tremendous pattern of organization of markings 190 00:05:43,510 --> 00:05:43,520 pattern of organization of markings 191 00:05:43,520 --> 00:05:45,530 pattern of organization of markings let's take a look at what's in these 192 00:05:45,530 --> 00:05:45,540 let's take a look at what's in these 193 00:05:45,540 --> 00:05:50,120 let's take a look at what's in these pictures the most prominent thing that 194 00:05:50,120 --> 00:05:50,130 pictures the most prominent thing that 195 00:05:50,130 --> 00:05:53,690 pictures the most prominent thing that one can see is a very bright south polar 196 00:05:53,690 --> 00:05:53,700 one can see is a very bright south polar 197 00:05:53,700 --> 00:05:57,980 one can see is a very bright south polar cap probably a great vortex almost like 198 00:05:57,980 --> 00:05:57,990 cap probably a great vortex almost like 199 00:05:57,990 --> 00:06:01,490 cap probably a great vortex almost like a huge cyclone and there are dark 200 00:06:01,490 --> 00:06:01,500 a huge cyclone and there are dark 201 00:06:01,500 --> 00:06:03,740 a huge cyclone and there are dark streaks that come into this as though 202 00:06:03,740 --> 00:06:03,750 streaks that come into this as though 203 00:06:03,750 --> 00:06:07,550 streaks that come into this as though they're winding up like taffy so the 204 00:06:07,550 --> 00:06:07,560 they're winding up like taffy so the 205 00:06:07,560 --> 00:06:10,640 they're winding up like taffy so the whole series of mosaics is like a series 206 00:06:10,640 --> 00:06:10,650 whole series of mosaics is like a series 207 00:06:10,650 --> 00:06:14,030 whole series of mosaics is like a series of snapshots of Venus in time and from 208 00:06:14,030 --> 00:06:14,040 of snapshots of Venus in time and from 209 00:06:14,040 --> 00:06:17,270 of snapshots of Venus in time and from those mosaics it was possible to create 210 00:06:17,270 --> 00:06:17,280 those mosaics it was possible to create 211 00:06:17,280 --> 00:06:20,660 those mosaics it was possible to create a time-lapse movie of the rotation of 212 00:06:20,660 --> 00:06:20,670 a time-lapse movie of the rotation of 213 00:06:20,670 --> 00:06:23,150 a time-lapse movie of the rotation of the Venus atmosphere during the period 214 00:06:23,150 --> 00:06:23,160 the Venus atmosphere during the period 215 00:06:23,160 --> 00:06:26,180 the Venus atmosphere during the period of time mirror ten flew by and flew away 216 00:06:26,180 --> 00:06:26,190 of time mirror ten flew by and flew away 217 00:06:26,190 --> 00:06:29,780 of time mirror ten flew by and flew away from the front so the pattern of 218 00:06:29,780 --> 00:06:29,790 from the front so the pattern of 219 00:06:29,790 --> 00:06:32,120 from the front so the pattern of rotation of features on Venus and the 220 00:06:32,120 --> 00:06:32,130 rotation of features on Venus and the 221 00:06:32,130 --> 00:06:34,190 rotation of features on Venus and the upper atmosphere way up high by our 222 00:06:34,190 --> 00:06:34,200 upper atmosphere way up high by our 223 00:06:34,200 --> 00:06:38,750 upper atmosphere way up high by our standards is remarkable in that the 224 00:06:38,750 --> 00:06:38,760 standards is remarkable in that the 225 00:06:38,760 --> 00:06:42,710 standards is remarkable in that the atmosphere on Venus rotates faster than 226 00:06:42,710 --> 00:06:42,720 atmosphere on Venus rotates faster than 227 00:06:42,720 --> 00:06:45,470 atmosphere on Venus rotates faster than the surface in the case of the earth the 228 00:06:45,470 --> 00:06:45,480 the surface in the case of the earth the 229 00:06:45,480 --> 00:06:47,090 the surface in the case of the earth the atmosphere tends to drag behind a little 230 00:06:47,090 --> 00:06:47,100 atmosphere tends to drag behind a little 231 00:06:47,100 --> 00:06:49,490 atmosphere tends to drag behind a little bit as one might imagine case of Venus 232 00:06:49,490 --> 00:06:49,500 bit as one might imagine case of Venus 233 00:06:49,500 --> 00:06:51,470 bit as one might imagine case of Venus the atmosphere rotates all the way 234 00:06:51,470 --> 00:06:51,480 the atmosphere rotates all the way 235 00:06:51,480 --> 00:06:53,950 the atmosphere rotates all the way around the planet once every four days 236 00:06:53,950 --> 00:06:53,960 around the planet once every four days 237 00:06:53,960 --> 00:06:58,780 around the planet once every four days the surface rotates once every 243 days 238 00:06:58,780 --> 00:06:58,790 the surface rotates once every 243 days 239 00:06:58,790 --> 00:07:01,940 the surface rotates once every 243 days so the atmosphere is rotating almost 60 240 00:07:01,940 --> 00:07:01,950 so the atmosphere is rotating almost 60 241 00:07:01,950 --> 00:07:05,240 so the atmosphere is rotating almost 60 times as fast at the top anyway as a 242 00:07:05,240 --> 00:07:05,250 times as fast at the top anyway as a 243 00:07:05,250 --> 00:07:10,030 times as fast at the top anyway as a planet itself 244 00:07:10,030 --> 00:07:10,040 245 00:07:10,040 --> 00:07:12,950 the gravitational field of Venus was 246 00:07:12,950 --> 00:07:12,960 the gravitational field of Venus was 247 00:07:12,960 --> 00:07:14,990 the gravitational field of Venus was used to bend the flight path of Mariner 248 00:07:14,990 --> 00:07:15,000 used to bend the flight path of Mariner 249 00:07:15,000 --> 00:07:18,260 used to bend the flight path of Mariner 10 inwards towards mercury then the 250 00:07:18,260 --> 00:07:18,270 10 inwards towards mercury then the 251 00:07:18,270 --> 00:07:20,120 10 inwards towards mercury then the gravity of the Sun pulled Mariner 252 00:07:20,120 --> 00:07:20,130 gravity of the Sun pulled Mariner 253 00:07:20,130 --> 00:07:21,740 gravity of the Sun pulled Mariner towards its first encounter with the 254 00:07:21,740 --> 00:07:21,750 towards its first encounter with the 255 00:07:21,750 --> 00:07:25,250 towards its first encounter with the planet 256 00:07:25,250 --> 00:07:25,260 257 00:07:25,260 --> 00:07:29,210 in March of 1974 Mariner 10 flew past 258 00:07:29,210 --> 00:07:29,220 in March of 1974 Mariner 10 flew past 259 00:07:29,220 --> 00:07:32,810 in March of 1974 Mariner 10 flew past mercury during the next year it would 260 00:07:32,810 --> 00:07:32,820 mercury during the next year it would 261 00:07:32,820 --> 00:07:36,380 mercury during the next year it would perform two more flyby Mariner 10 262 00:07:36,380 --> 00:07:36,390 perform two more flyby Mariner 10 263 00:07:36,390 --> 00:07:38,900 perform two more flyby Mariner 10 returned almost 3,000 pictures of the 264 00:07:38,900 --> 00:07:38,910 returned almost 3,000 pictures of the 265 00:07:38,910 --> 00:07:43,790 returned almost 3,000 pictures of the surface of mercury these pictures reveal 266 00:07:43,790 --> 00:07:43,800 surface of mercury these pictures reveal 267 00:07:43,800 --> 00:07:46,700 surface of mercury these pictures reveal craters and other features which were 268 00:07:46,700 --> 00:07:46,710 craters and other features which were 269 00:07:46,710 --> 00:07:49,010 craters and other features which were formed very early in the history of 270 00:07:49,010 --> 00:07:49,020 formed very early in the history of 271 00:07:49,020 --> 00:07:51,830 formed very early in the history of mercury and may refer to events that 272 00:07:51,830 --> 00:07:51,840 mercury and may refer to events that 273 00:07:51,840 --> 00:07:53,900 mercury and may refer to events that affected the entire inner solar system 274 00:07:53,900 --> 00:07:53,910 affected the entire inner solar system 275 00:07:53,910 --> 00:07:57,860 affected the entire inner solar system Mars Earth Moon and Venus as well as 276 00:07:57,860 --> 00:07:57,870 Mars Earth Moon and Venus as well as 277 00:07:57,870 --> 00:08:06,500 Mars Earth Moon and Venus as well as mercury the pictures of mercury revealed 278 00:08:06,500 --> 00:08:06,510 mercury the pictures of mercury revealed 279 00:08:06,510 --> 00:08:09,650 mercury the pictures of mercury revealed craters and many other features and to 280 00:08:09,650 --> 00:08:09,660 craters and many other features and to 281 00:08:09,660 --> 00:08:12,410 craters and many other features and to the geologist these features and these 282 00:08:12,410 --> 00:08:12,420 the geologist these features and these 283 00:08:12,420 --> 00:08:14,960 the geologist these features and these pictures are like the pages of a history 284 00:08:14,960 --> 00:08:14,970 pictures are like the pages of a history 285 00:08:14,970 --> 00:08:19,550 pictures are like the pages of a history book and the entry book for mercury may 286 00:08:19,550 --> 00:08:19,560 book and the entry book for mercury may 287 00:08:19,560 --> 00:08:23,600 book and the entry book for mercury may go back almost to the formation of the 288 00:08:23,600 --> 00:08:23,610 go back almost to the formation of the 289 00:08:23,610 --> 00:08:30,310 go back almost to the formation of the solar system itself 290 00:08:30,310 --> 00:08:30,320 291 00:08:30,320 --> 00:08:34,460 five million years ago a vast cloud of 292 00:08:34,460 --> 00:08:34,470 five million years ago a vast cloud of 293 00:08:34,470 --> 00:08:37,310 five million years ago a vast cloud of gas and dust floated through the galaxy 294 00:08:37,310 --> 00:08:37,320 gas and dust floated through the galaxy 295 00:08:37,320 --> 00:08:40,640 gas and dust floated through the galaxy we call the Milky Way the ghostly 296 00:08:40,640 --> 00:08:40,650 we call the Milky Way the ghostly 297 00:08:40,650 --> 00:08:43,040 we call the Milky Way the ghostly remains of a great star that had died in 298 00:08:43,040 --> 00:08:43,050 remains of a great star that had died in 299 00:08:43,050 --> 00:08:47,810 remains of a great star that had died in a gigantic explosion the gas and dust is 300 00:08:47,810 --> 00:08:47,820 a gigantic explosion the gas and dust is 301 00:08:47,820 --> 00:08:50,410 a gigantic explosion the gas and dust is twisted and shaped by magnetic forces 302 00:08:50,410 --> 00:08:50,420 twisted and shaped by magnetic forces 303 00:08:50,420 --> 00:08:53,210 twisted and shaped by magnetic forces electrical currents and the subtle pull 304 00:08:53,210 --> 00:08:53,220 electrical currents and the subtle pull 305 00:08:53,220 --> 00:08:58,430 electrical currents and the subtle pull of gravity as it swirls around a 306 00:08:58,430 --> 00:08:58,440 of gravity as it swirls around a 307 00:08:58,440 --> 00:09:01,700 of gravity as it swirls around a thickening core the huge cloud gradually 308 00:09:01,700 --> 00:09:01,710 thickening core the huge cloud gradually 309 00:09:01,710 --> 00:09:08,000 thickening core the huge cloud gradually flattens into a disk dust and gas 310 00:09:08,000 --> 00:09:08,010 flattens into a disk dust and gas 311 00:09:08,010 --> 00:09:11,210 flattens into a disk dust and gas gravitates slowly inwards and Eddie's 312 00:09:11,210 --> 00:09:11,220 gravitates slowly inwards and Eddie's 313 00:09:11,220 --> 00:09:20,080 gravitates slowly inwards and Eddie's begin to form in the cloud 314 00:09:20,080 --> 00:09:20,090 315 00:09:20,090 --> 00:09:22,570 particles of matter clustering two solid 316 00:09:22,570 --> 00:09:22,580 particles of matter clustering two solid 317 00:09:22,580 --> 00:09:38,579 particles of matter clustering two solid bodies 318 00:09:38,579 --> 00:09:38,589 319 00:09:38,589 --> 00:09:41,259 the larger bodies continue to grow 320 00:09:41,259 --> 00:09:41,269 the larger bodies continue to grow 321 00:09:41,269 --> 00:09:43,840 the larger bodies continue to grow sweeping up particles and dust as they 322 00:09:43,840 --> 00:09:43,850 sweeping up particles and dust as they 323 00:09:43,850 --> 00:09:45,790 sweeping up particles and dust as they orbit the condensing core of the disk 324 00:09:45,790 --> 00:09:45,800 orbit the condensing core of the disk 325 00:09:45,800 --> 00:09:48,460 orbit the condensing core of the disk and begin to heat under the increasing 326 00:09:48,460 --> 00:09:48,470 and begin to heat under the increasing 327 00:09:48,470 --> 00:09:54,639 and begin to heat under the increasing gravitational pressures in the central 328 00:09:54,639 --> 00:09:54,649 gravitational pressures in the central 329 00:09:54,649 --> 00:09:57,280 gravitational pressures in the central core of the disk incredible heat is 330 00:09:57,280 --> 00:09:57,290 core of the disk incredible heat is 331 00:09:57,290 --> 00:09:59,949 core of the disk incredible heat is being generated hotter and hotter until 332 00:09:59,949 --> 00:09:59,959 being generated hotter and hotter until 333 00:09:59,959 --> 00:10:03,310 being generated hotter and hotter until it reaches critical temperatures and 334 00:10:03,310 --> 00:10:03,320 it reaches critical temperatures and 335 00:10:03,320 --> 00:10:07,210 it reaches critical temperatures and then billions of years ago a nuclear 336 00:10:07,210 --> 00:10:07,220 then billions of years ago a nuclear 337 00:10:07,220 --> 00:10:09,730 then billions of years ago a nuclear reaction occurred and our Sun was 338 00:10:09,730 --> 00:10:09,740 reaction occurred and our Sun was 339 00:10:09,740 --> 00:10:17,690 reaction occurred and our Sun was ignited 340 00:10:17,690 --> 00:10:17,700 341 00:10:17,700 --> 00:10:20,150 it's intense radiation repels the 342 00:10:20,150 --> 00:10:20,160 it's intense radiation repels the 343 00:10:20,160 --> 00:10:24,410 it's intense radiation repels the surrounding gas and dust the increasing 344 00:10:24,410 --> 00:10:24,420 surrounding gas and dust the increasing 345 00:10:24,420 --> 00:10:26,570 surrounding gas and dust the increasing heat of the inner planets has formed 346 00:10:26,570 --> 00:10:26,580 heat of the inner planets has formed 347 00:10:26,580 --> 00:10:30,440 heat of the inner planets has formed them into molten spheres mercury like 348 00:10:30,440 --> 00:10:30,450 them into molten spheres mercury like 349 00:10:30,450 --> 00:10:33,230 them into molten spheres mercury like the other inner planets is continuously 350 00:10:33,230 --> 00:10:33,240 the other inner planets is continuously 351 00:10:33,240 --> 00:10:36,260 the other inner planets is continuously bombarded by debris that form craters on 352 00:10:36,260 --> 00:10:36,270 bombarded by debris that form craters on 353 00:10:36,270 --> 00:10:40,970 bombarded by debris that form craters on its surface in the final stages of its 354 00:10:40,970 --> 00:10:40,980 its surface in the final stages of its 355 00:10:40,980 --> 00:10:44,180 its surface in the final stages of its formation mercury flowed from internal 356 00:10:44,180 --> 00:10:44,190 formation mercury flowed from internal 357 00:10:44,190 --> 00:10:48,620 formation mercury flowed from internal heat hot lava was forced to a surface 358 00:10:48,620 --> 00:10:48,630 heat hot lava was forced to a surface 359 00:10:48,630 --> 00:10:51,440 heat hot lava was forced to a surface being torn by collisions with masses of 360 00:10:51,440 --> 00:10:51,450 being torn by collisions with masses of 361 00:10:51,450 --> 00:10:56,000 being torn by collisions with masses of rock that were shaping the planet the 362 00:10:56,000 --> 00:10:56,010 rock that were shaping the planet the 363 00:10:56,010 --> 00:10:58,030 rock that were shaping the planet the same heat that triggered the lava flows 364 00:10:58,030 --> 00:10:58,040 same heat that triggered the lava flows 365 00:10:58,040 --> 00:11:00,800 same heat that triggered the lava flows also melted rock and metals in the 366 00:11:00,800 --> 00:11:00,810 also melted rock and metals in the 367 00:11:00,810 --> 00:11:05,560 also melted rock and metals in the interior of Mercury heavy iron 368 00:11:05,560 --> 00:11:05,570 interior of Mercury heavy iron 369 00:11:05,570 --> 00:11:07,970 interior of Mercury heavy iron concentrated at Mercury's center to form 370 00:11:07,970 --> 00:11:07,980 concentrated at Mercury's center to form 371 00:11:07,980 --> 00:11:10,880 concentrated at Mercury's center to form a dense core which was overlain by a 372 00:11:10,880 --> 00:11:10,890 a dense core which was overlain by a 373 00:11:10,890 --> 00:11:13,130 a dense core which was overlain by a thin shell of lighter material brought 374 00:11:13,130 --> 00:11:13,140 thin shell of lighter material brought 375 00:11:13,140 --> 00:11:17,870 thin shell of lighter material brought to the surface by lava flows again the 376 00:11:17,870 --> 00:11:17,880 to the surface by lava flows again the 377 00:11:17,880 --> 00:11:20,150 to the surface by lava flows again the surface was gouged and pitted by a great 378 00:11:20,150 --> 00:11:20,160 surface was gouged and pitted by a great 379 00:11:20,160 --> 00:11:23,120 surface was gouged and pitted by a great series of impacts leaving huge craters 380 00:11:23,120 --> 00:11:23,130 series of impacts leaving huge craters 381 00:11:23,130 --> 00:11:27,140 series of impacts leaving huge craters on the surface the Mariner 10 382 00:11:27,140 --> 00:11:27,150 on the surface the Mariner 10 383 00:11:27,150 --> 00:11:29,480 on the surface the Mariner 10 photographs have revealed these early 384 00:11:29,480 --> 00:11:29,490 photographs have revealed these early 385 00:11:29,490 --> 00:11:46,310 photographs have revealed these early craters to scientists for the first time 386 00:11:46,310 --> 00:11:46,320 387 00:11:46,320 --> 00:11:49,170 one of these craters was formed by a 388 00:11:49,170 --> 00:11:49,180 one of these craters was formed by a 389 00:11:49,180 --> 00:11:52,170 one of these craters was formed by a massive rock perhaps a small planet that 390 00:11:52,170 --> 00:11:52,180 massive rock perhaps a small planet that 391 00:11:52,180 --> 00:11:56,730 massive rock perhaps a small planet that crashed into mercury in the Mariner 10 392 00:11:56,730 --> 00:11:56,740 crashed into mercury in the Mariner 10 393 00:11:56,740 --> 00:11:59,430 crashed into mercury in the Mariner 10 photographs half of this huge crater was 394 00:11:59,430 --> 00:11:59,440 photographs half of this huge crater was 395 00:11:59,440 --> 00:12:03,410 photographs half of this huge crater was hidden on the night side of the planet 396 00:12:03,410 --> 00:12:03,420 397 00:12:03,420 --> 00:12:09,250 today this huge crater is called Caloris 398 00:12:09,250 --> 00:12:09,260 today this huge crater is called Caloris 399 00:12:09,260 --> 00:12:11,830 today this huge crater is called Caloris the impact spewed millions of tons of 400 00:12:11,830 --> 00:12:11,840 the impact spewed millions of tons of 401 00:12:11,840 --> 00:12:13,620 the impact spewed millions of tons of debris across the surface of mercury 402 00:12:13,620 --> 00:12:13,630 debris across the surface of mercury 403 00:12:13,630 --> 00:12:16,180 debris across the surface of mercury creating a ring of mountain ranges over 404 00:12:16,180 --> 00:12:16,190 creating a ring of mountain ranges over 405 00:12:16,190 --> 00:12:21,460 creating a ring of mountain ranges over a mile high the floor of this basement 406 00:12:21,460 --> 00:12:21,470 a mile high the floor of this basement 407 00:12:21,470 --> 00:12:25,450 a mile high the floor of this basement was split by great surface cracks wide 408 00:12:25,450 --> 00:12:25,460 was split by great surface cracks wide 409 00:12:25,460 --> 00:12:31,120 was split by great surface cracks wide and deep as the surface continued to 410 00:12:31,120 --> 00:12:31,130 and deep as the surface continued to 411 00:12:31,130 --> 00:12:34,690 and deep as the surface continued to form deep inside mercury it's heavy iron 412 00:12:34,690 --> 00:12:34,700 form deep inside mercury it's heavy iron 413 00:12:34,700 --> 00:12:38,950 form deep inside mercury it's heavy iron core began to contract the surface 414 00:12:38,950 --> 00:12:38,960 core began to contract the surface 415 00:12:38,960 --> 00:12:42,580 core began to contract the surface buckled cracked and great sections 416 00:12:42,580 --> 00:12:42,590 buckled cracked and great sections 417 00:12:42,590 --> 00:12:45,120 buckled cracked and great sections hundreds of miles wide were split open 418 00:12:45,120 --> 00:12:45,130 hundreds of miles wide were split open 419 00:12:45,130 --> 00:12:48,310 hundreds of miles wide were split open leaving immense mile-high walls of rock 420 00:12:48,310 --> 00:12:48,320 leaving immense mile-high walls of rock 421 00:12:48,320 --> 00:12:55,990 leaving immense mile-high walls of rock called scarps again there was a great 422 00:12:55,990 --> 00:12:56,000 called scarps again there was a great 423 00:12:56,000 --> 00:12:58,330 called scarps again there was a great flow of lava covering many of the large 424 00:12:58,330 --> 00:12:58,340 flow of lava covering many of the large 425 00:12:58,340 --> 00:13:04,230 flow of lava covering many of the large craters and leaving smooth flat plains 426 00:13:04,230 --> 00:13:04,240 craters and leaving smooth flat plains 427 00:13:04,240 --> 00:13:07,060 craters and leaving smooth flat plains this set the stage for the final episode 428 00:13:07,060 --> 00:13:07,070 this set the stage for the final episode 429 00:13:07,070 --> 00:13:10,120 this set the stage for the final episode in the history of mercury a period of 430 00:13:10,120 --> 00:13:10,130 in the history of mercury a period of 431 00:13:10,130 --> 00:13:16,590 in the history of mercury a period of light cratering of the Great Plains 432 00:13:16,590 --> 00:13:16,600 433 00:13:16,600 --> 00:13:23,009 in this time mercury died the internal 434 00:13:23,009 --> 00:13:23,019 in this time mercury died the internal 435 00:13:23,019 --> 00:13:24,809 in this time mercury died the internal heat that triggered many of the events 436 00:13:24,809 --> 00:13:24,819 heat that triggered many of the events 437 00:13:24,819 --> 00:13:29,999 heat that triggered many of the events in the planet's history turned off and 438 00:13:29,999 --> 00:13:30,009 in the planet's history turned off and 439 00:13:30,009 --> 00:13:32,389 in the planet's history turned off and for three and a half billion years 440 00:13:32,389 --> 00:13:32,399 for three and a half billion years 441 00:13:32,399 --> 00:13:46,020 for three and a half billion years mercury has remained as we see it today 442 00:13:46,020 --> 00:13:46,030 443 00:13:46,030 --> 00:13:49,600 before Mariner 10 there were a multitude 444 00:13:49,600 --> 00:13:49,610 before Mariner 10 there were a multitude 445 00:13:49,610 --> 00:13:52,300 before Mariner 10 there were a multitude of possible Mercury's now there's only 446 00:13:52,300 --> 00:13:52,310 of possible Mercury's now there's only 447 00:13:52,310 --> 00:13:55,240 of possible Mercury's now there's only one the mercury of craters and basins 448 00:13:55,240 --> 00:13:55,250 one the mercury of craters and basins 449 00:13:55,250 --> 00:13:58,330 one the mercury of craters and basins and planes this illustrates how 450 00:13:58,330 --> 00:13:58,340 and planes this illustrates how 451 00:13:58,340 --> 00:14:01,150 and planes this illustrates how photography can be an exploratory tool 452 00:14:01,150 --> 00:14:01,160 photography can be an exploratory tool 453 00:14:01,160 --> 00:14:04,870 photography can be an exploratory tool it displays features which were perhaps 454 00:14:04,870 --> 00:14:04,880 it displays features which were perhaps 455 00:14:04,880 --> 00:14:07,270 it displays features which were perhaps never even anticipated and and sometimes 456 00:14:07,270 --> 00:14:07,280 never even anticipated and and sometimes 457 00:14:07,280 --> 00:14:10,210 never even anticipated and and sometimes could not even be imagined before the 458 00:14:10,210 --> 00:14:10,220 could not even be imagined before the 459 00:14:10,220 --> 00:14:12,790 could not even be imagined before the experiment was flown in a sense it 460 00:14:12,790 --> 00:14:12,800 experiment was flown in a sense it 461 00:14:12,800 --> 00:14:14,590 experiment was flown in a sense it provides answers to questions that were 462 00:14:14,590 --> 00:14:14,600 provides answers to questions that were 463 00:14:14,600 --> 00:14:18,220 provides answers to questions that were not even asked this was true at Mars 464 00:14:18,220 --> 00:14:18,230 not even asked this was true at Mars 465 00:14:18,230 --> 00:14:20,620 not even asked this was true at Mars when Mariner 4 returned pictures of what 466 00:14:20,620 --> 00:14:20,630 when Mariner 4 returned pictures of what 467 00:14:20,630 --> 00:14:23,770 when Mariner 4 returned pictures of what appeared to be a a moon like surface it 468 00:14:23,770 --> 00:14:23,780 appeared to be a a moon like surface it 469 00:14:23,780 --> 00:14:25,420 appeared to be a a moon like surface it had been expected that Mars might be 470 00:14:25,420 --> 00:14:25,430 had been expected that Mars might be 471 00:14:25,430 --> 00:14:27,520 had been expected that Mars might be very much like the earth the folded 472 00:14:27,520 --> 00:14:27,530 very much like the earth the folded 473 00:14:27,530 --> 00:14:29,320 very much like the earth the folded mountain ranges and many other 474 00:14:29,320 --> 00:14:29,330 mountain ranges and many other 475 00:14:29,330 --> 00:14:31,750 mountain ranges and many other earth-like features instead it looked 476 00:14:31,750 --> 00:14:31,760 earth-like features instead it looked 477 00:14:31,760 --> 00:14:34,950 earth-like features instead it looked like the moon and that was a big shock 478 00:14:34,950 --> 00:14:34,960 like the moon and that was a big shock 479 00:14:34,960 --> 00:14:37,210 like the moon and that was a big shock and it was even bigger shock when 480 00:14:37,210 --> 00:14:37,220 and it was even bigger shock when 481 00:14:37,220 --> 00:14:41,410 and it was even bigger shock when Mariner 9 in 1971 visited Mars again and 482 00:14:41,410 --> 00:14:41,420 Mariner 9 in 1971 visited Mars again and 483 00:14:41,420 --> 00:14:44,890 Mariner 9 in 1971 visited Mars again and found huge volcanoes and even some 484 00:14:44,890 --> 00:14:44,900 found huge volcanoes and even some 485 00:14:44,900 --> 00:14:48,130 found huge volcanoes and even some peculiar sinuous channels that looked 486 00:14:48,130 --> 00:14:48,140 peculiar sinuous channels that looked 487 00:14:48,140 --> 00:14:49,360 peculiar sinuous channels that looked like they might have been formed by 488 00:14:49,360 --> 00:14:49,370 like they might have been formed by 489 00:14:49,370 --> 00:14:51,040 like they might have been formed by flowing water at some point in Mars 490 00:14:51,040 --> 00:14:51,050 flowing water at some point in Mars 491 00:14:51,050 --> 00:14:55,720 flowing water at some point in Mars history now Viking has transported man's 492 00:14:55,720 --> 00:14:55,730 history now Viking has transported man's 493 00:14:55,730 --> 00:14:59,800 history now Viking has transported man's vision to the actual surface the fantasy 494 00:14:59,800 --> 00:14:59,810 vision to the actual surface the fantasy 495 00:14:59,810 --> 00:15:02,200 vision to the actual surface the fantasy of science fiction has been replaced by 496 00:15:02,200 --> 00:15:02,210 of science fiction has been replaced by 497 00:15:02,210 --> 00:15:04,930 of science fiction has been replaced by the strange lonely reality of the 498 00:15:04,930 --> 00:15:04,940 the strange lonely reality of the 499 00:15:04,940 --> 00:15:09,730 the strange lonely reality of the Martian landscape when Mariner 10 flew 500 00:15:09,730 --> 00:15:09,740 Martian landscape when Mariner 10 flew 501 00:15:09,740 --> 00:15:13,420 Martian landscape when Mariner 10 flew by Venus it discovered an unexpectedly 502 00:15:13,420 --> 00:15:13,430 by Venus it discovered an unexpectedly 503 00:15:13,430 --> 00:15:17,980 by Venus it discovered an unexpectedly well-organized set of cloud motions and 504 00:15:17,980 --> 00:15:17,990 well-organized set of cloud motions and 505 00:15:17,990 --> 00:15:20,470 well-organized set of cloud motions and the unexpected was certainly encountered 506 00:15:20,470 --> 00:15:20,480 the unexpected was certainly encountered 507 00:15:20,480 --> 00:15:23,410 the unexpected was certainly encountered in case of mercury which turned out to 508 00:15:23,410 --> 00:15:23,420 in case of mercury which turned out to 509 00:15:23,420 --> 00:15:25,870 in case of mercury which turned out to exhibit not only moonlight features on 510 00:15:25,870 --> 00:15:25,880 exhibit not only moonlight features on 511 00:15:25,880 --> 00:15:28,390 exhibit not only moonlight features on its surface but a sequence of events 512 00:15:28,390 --> 00:15:28,400 its surface but a sequence of events 513 00:15:28,400 --> 00:15:30,820 its surface but a sequence of events there that seemed to be very similar to 514 00:15:30,820 --> 00:15:30,830 there that seemed to be very similar to 515 00:15:30,830 --> 00:15:33,550 there that seemed to be very similar to those of the moon and that's 516 00:15:33,550 --> 00:15:33,560 those of the moon and that's 517 00:15:33,560 --> 00:15:34,390 those of the moon and that's extraordinary 518 00:15:34,390 --> 00:15:34,400 extraordinary 519 00:15:34,400 --> 00:15:37,720 extraordinary because mercury is very different inside 520 00:15:37,720 --> 00:15:37,730 because mercury is very different inside 521 00:15:37,730 --> 00:15:40,840 because mercury is very different inside compared to the moon and that means it 522 00:15:40,840 --> 00:15:40,850 compared to the moon and that means it 523 00:15:40,850 --> 00:15:43,350 compared to the moon and that means it must have had a different history of 524 00:15:43,350 --> 00:15:43,360 must have had a different history of 525 00:15:43,360 --> 00:15:46,510 must have had a different history of heating and modification the surface 526 00:15:46,510 --> 00:15:46,520 heating and modification the surface 527 00:15:46,520 --> 00:15:49,960 heating and modification the surface from the inside and furthermore it lives 528 00:15:49,960 --> 00:15:49,970 from the inside and furthermore it lives 529 00:15:49,970 --> 00:15:51,160 from the inside and furthermore it lives in a very different part of the solar 530 00:15:51,160 --> 00:15:51,170 in a very different part of the solar 531 00:15:51,170 --> 00:15:52,950 in a very different part of the solar system much closer to the Sun and 532 00:15:52,950 --> 00:15:52,960 system much closer to the Sun and 533 00:15:52,960 --> 00:15:55,510 system much closer to the Sun and therefore it must have experienced a 534 00:15:55,510 --> 00:15:55,520 therefore it must have experienced a 535 00:15:55,520 --> 00:15:59,370 therefore it must have experienced a for exterior history as well and yet a 536 00:15:59,370 --> 00:15:59,380 for exterior history as well and yet a 537 00:15:59,380 --> 00:16:01,810 for exterior history as well and yet a picture show that we're Creek has a 538 00:16:01,810 --> 00:16:01,820 picture show that we're Creek has a 539 00:16:01,820 --> 00:16:04,390 picture show that we're Creek has a surface history very similar to that of 540 00:16:04,390 --> 00:16:04,400 surface history very similar to that of 541 00:16:04,400 --> 00:16:06,460 surface history very similar to that of the moon and to me that's extraordinary 542 00:16:06,460 --> 00:16:06,470 the moon and to me that's extraordinary 543 00:16:06,470 --> 00:16:10,740 the moon and to me that's extraordinary a comparison of the craters on the moon 544 00:16:10,740 --> 00:16:10,750 a comparison of the craters on the moon 545 00:16:10,750 --> 00:16:14,110 a comparison of the craters on the moon Mercury and Mars shows that these inner 546 00:16:14,110 --> 00:16:14,120 Mercury and Mars shows that these inner 547 00:16:14,120 --> 00:16:16,150 Mercury and Mars shows that these inner planets were subjected to cratering at 548 00:16:16,150 --> 00:16:16,160 planets were subjected to cratering at 549 00:16:16,160 --> 00:16:20,080 planets were subjected to cratering at the same time before Mariner 10 it was 550 00:16:20,080 --> 00:16:20,090 the same time before Mariner 10 it was 551 00:16:20,090 --> 00:16:21,820 the same time before Mariner 10 it was believed that the source of cratering of 552 00:16:21,820 --> 00:16:21,830 believed that the source of cratering of 553 00:16:21,830 --> 00:16:24,460 believed that the source of cratering of the inner solar system was the asteroid 554 00:16:24,460 --> 00:16:24,470 the inner solar system was the asteroid 555 00:16:24,470 --> 00:16:28,510 the inner solar system was the asteroid belt orbiting beyond Mars because of the 556 00:16:28,510 --> 00:16:28,520 belt orbiting beyond Mars because of the 557 00:16:28,520 --> 00:16:30,670 belt orbiting beyond Mars because of the difference in distance from the belt it 558 00:16:30,670 --> 00:16:30,680 difference in distance from the belt it 559 00:16:30,680 --> 00:16:32,740 difference in distance from the belt it was assumed that no two planets would be 560 00:16:32,740 --> 00:16:32,750 was assumed that no two planets would be 561 00:16:32,750 --> 00:16:36,520 was assumed that no two planets would be cratered the same those planets farther 562 00:16:36,520 --> 00:16:36,530 cratered the same those planets farther 563 00:16:36,530 --> 00:16:38,500 cratered the same those planets farther from the asteroid belt like mercury 564 00:16:38,500 --> 00:16:38,510 from the asteroid belt like mercury 565 00:16:38,510 --> 00:16:42,580 from the asteroid belt like mercury would have fewer craters but a careful 566 00:16:42,580 --> 00:16:42,590 would have fewer craters but a careful 567 00:16:42,590 --> 00:16:44,950 would have fewer craters but a careful count of the craters on mercury and a 568 00:16:44,950 --> 00:16:44,960 count of the craters on mercury and a 569 00:16:44,960 --> 00:16:46,420 count of the craters on mercury and a comparison with those on the Moon and 570 00:16:46,420 --> 00:16:46,430 comparison with those on the Moon and 571 00:16:46,430 --> 00:16:50,700 comparison with those on the Moon and Mars showed them all to be roughly equal 572 00:16:50,700 --> 00:16:50,710 Mars showed them all to be roughly equal 573 00:16:50,710 --> 00:16:53,920 Mars showed them all to be roughly equal if the crater count is equal then the 574 00:16:53,920 --> 00:16:53,930 if the crater count is equal then the 575 00:16:53,930 --> 00:16:55,720 if the crater count is equal then the source could not be the asteroid belt 576 00:16:55,720 --> 00:16:55,730 source could not be the asteroid belt 577 00:16:55,730 --> 00:16:58,150 source could not be the asteroid belt but must have come from elsewhere in the 578 00:16:58,150 --> 00:16:58,160 but must have come from elsewhere in the 579 00:16:58,160 --> 00:17:00,090 but must have come from elsewhere in the solar system 580 00:17:00,090 --> 00:17:00,100 solar system 581 00:17:00,100 --> 00:17:03,070 solar system one strong possibility is the planet 582 00:17:03,070 --> 00:17:03,080 one strong possibility is the planet 583 00:17:03,080 --> 00:17:04,960 one strong possibility is the planet Jupiter with a gravitational attraction 584 00:17:04,960 --> 00:17:04,970 Jupiter with a gravitational attraction 585 00:17:04,970 --> 00:17:09,010 Jupiter with a gravitational attraction second only to the Sun it is possible 586 00:17:09,010 --> 00:17:09,020 second only to the Sun it is possible 587 00:17:09,020 --> 00:17:11,949 second only to the Sun it is possible that on two occasions Jupiter literally 588 00:17:11,949 --> 00:17:11,959 that on two occasions Jupiter literally 589 00:17:11,959 --> 00:17:14,199 that on two occasions Jupiter literally hurled millions of tons of rock inwards 590 00:17:14,199 --> 00:17:14,209 hurled millions of tons of rock inwards 591 00:17:14,209 --> 00:17:17,110 hurled millions of tons of rock inwards towards the Sun to impact the planets of 592 00:17:17,110 --> 00:17:17,120 towards the Sun to impact the planets of 593 00:17:17,120 --> 00:17:20,310 towards the Sun to impact the planets of the inner solar system including mercury 594 00:17:20,310 --> 00:17:20,320 the inner solar system including mercury 595 00:17:20,320 --> 00:17:23,530 the inner solar system including mercury this cratered record on Mercury was read 596 00:17:23,530 --> 00:17:23,540 this cratered record on Mercury was read 597 00:17:23,540 --> 00:17:25,600 this cratered record on Mercury was read three times because of a fortunate 598 00:17:25,600 --> 00:17:25,610 three times because of a fortunate 599 00:17:25,610 --> 00:17:29,140 three times because of a fortunate coincidence Mercury's orbit around the 600 00:17:29,140 --> 00:17:29,150 coincidence Mercury's orbit around the 601 00:17:29,150 --> 00:17:33,790 coincidence Mercury's orbit around the Sun is 88 Earth days Mariner tens orbit 602 00:17:33,790 --> 00:17:33,800 Sun is 88 Earth days Mariner tens orbit 603 00:17:33,800 --> 00:17:35,440 Sun is 88 Earth days Mariner tens orbit was twice as long or a hundred 604 00:17:35,440 --> 00:17:35,450 was twice as long or a hundred 605 00:17:35,450 --> 00:17:38,740 was twice as long or a hundred seventy-six days these synchronous 606 00:17:38,740 --> 00:17:38,750 seventy-six days these synchronous 607 00:17:38,750 --> 00:17:41,680 seventy-six days these synchronous orbits allowed Mariner 10 to fly past 608 00:17:41,680 --> 00:17:41,690 orbits allowed Mariner 10 to fly past 609 00:17:41,690 --> 00:17:48,890 orbits allowed Mariner 10 to fly past mercury a second and third time 610 00:17:48,890 --> 00:17:48,900 611 00:17:48,900 --> 00:17:52,020 the path of the first flyby was on the 612 00:17:52,020 --> 00:17:52,030 the path of the first flyby was on the 613 00:17:52,030 --> 00:17:59,340 the path of the first flyby was on the dark side of mercury the second 614 00:17:59,340 --> 00:17:59,350 dark side of mercury the second 615 00:17:59,350 --> 00:18:01,770 dark side of mercury the second encounter sent the spacecraft past the 616 00:18:01,770 --> 00:18:01,780 encounter sent the spacecraft past the 617 00:18:01,780 --> 00:18:03,690 encounter sent the spacecraft past the light side of the planet specifically 618 00:18:03,690 --> 00:18:03,700 light side of the planet specifically 619 00:18:03,700 --> 00:18:08,520 light side of the planet specifically for photography after another six-month 620 00:18:08,520 --> 00:18:08,530 for photography after another six-month 621 00:18:08,530 --> 00:18:11,130 for photography after another six-month journey around the Sun Mariner 10 made 622 00:18:11,130 --> 00:18:11,140 journey around the Sun Mariner 10 made 623 00:18:11,140 --> 00:18:13,470 journey around the Sun Mariner 10 made its third and final encounter to look 624 00:18:13,470 --> 00:18:13,480 its third and final encounter to look 625 00:18:13,480 --> 00:18:15,480 its third and final encounter to look again at a major discovery made during 626 00:18:15,480 --> 00:18:15,490 again at a major discovery made during 627 00:18:15,490 --> 00:18:18,330 again at a major discovery made during the first flyby the presence of a 628 00:18:18,330 --> 00:18:18,340 the first flyby the presence of a 629 00:18:18,340 --> 00:18:21,030 the first flyby the presence of a magnetic field around mercury similar to 630 00:18:21,030 --> 00:18:21,040 magnetic field around mercury similar to 631 00:18:21,040 --> 00:18:26,490 magnetic field around mercury similar to earth a bow shock wave blocks the solar 632 00:18:26,490 --> 00:18:26,500 earth a bow shock wave blocks the solar 633 00:18:26,500 --> 00:18:30,900 earth a bow shock wave blocks the solar wind from the Sun and deflects it around 634 00:18:30,900 --> 00:18:30,910 wind from the Sun and deflects it around 635 00:18:30,910 --> 00:18:32,910 wind from the Sun and deflects it around the planet creating an environment 636 00:18:32,910 --> 00:18:32,920 the planet creating an environment 637 00:18:32,920 --> 00:18:34,530 the planet creating an environment similar to the magnetic field around 638 00:18:34,530 --> 00:18:34,540 similar to the magnetic field around 639 00:18:34,540 --> 00:18:38,490 similar to the magnetic field around Earth this discovery was a surprise 640 00:18:38,490 --> 00:18:38,500 Earth this discovery was a surprise 641 00:18:38,500 --> 00:18:41,820 Earth this discovery was a surprise because mercury slow rotation about once 642 00:18:41,820 --> 00:18:41,830 because mercury slow rotation about once 643 00:18:41,830 --> 00:18:45,060 because mercury slow rotation about once every 57 Earth days had led scientists 644 00:18:45,060 --> 00:18:45,070 every 57 Earth days had led scientists 645 00:18:45,070 --> 00:18:46,560 every 57 Earth days had led scientists to believe that the planet could not 646 00:18:46,560 --> 00:18:46,570 to believe that the planet could not 647 00:18:46,570 --> 00:18:50,310 to believe that the planet could not generate a magnetic field it is believed 648 00:18:50,310 --> 00:18:50,320 generate a magnetic field it is believed 649 00:18:50,320 --> 00:18:52,290 generate a magnetic field it is believed that Earth's magnetic field is generated 650 00:18:52,290 --> 00:18:52,300 that Earth's magnetic field is generated 651 00:18:52,300 --> 00:18:54,870 that Earth's magnetic field is generated by an interaction between the planets 652 00:18:54,870 --> 00:18:54,880 by an interaction between the planets 653 00:18:54,880 --> 00:18:59,270 by an interaction between the planets faster rotation and its molten core 654 00:18:59,270 --> 00:18:59,280 faster rotation and its molten core 655 00:18:59,280 --> 00:19:02,040 faster rotation and its molten core mariner tens discovery may change 656 00:19:02,040 --> 00:19:02,050 mariner tens discovery may change 657 00:19:02,050 --> 00:19:04,440 mariner tens discovery may change theories on how these fields are formed 658 00:19:04,440 --> 00:19:04,450 theories on how these fields are formed 659 00:19:04,450 --> 00:19:07,470 theories on how these fields are formed and has given scientists their first 660 00:19:07,470 --> 00:19:07,480 and has given scientists their first 661 00:19:07,480 --> 00:19:09,960 and has given scientists their first opportunity to compare two magnetic 662 00:19:09,960 --> 00:19:09,970 opportunity to compare two magnetic 663 00:19:09,970 --> 00:19:15,090 opportunity to compare two magnetic fields in the inner solar system there 664 00:19:15,090 --> 00:19:15,100 fields in the inner solar system there 665 00:19:15,100 --> 00:19:16,919 fields in the inner solar system there were other measurements made at Mercury 666 00:19:16,919 --> 00:19:16,929 were other measurements made at Mercury 667 00:19:16,929 --> 00:19:21,540 were other measurements made at Mercury by Mariner 10 infrared showed that 668 00:19:21,540 --> 00:19:21,550 by Mariner 10 infrared showed that 669 00:19:21,550 --> 00:19:24,120 by Mariner 10 infrared showed that mercury surface ranges in temperature 670 00:19:24,120 --> 00:19:24,130 mercury surface ranges in temperature 671 00:19:24,130 --> 00:19:27,000 mercury surface ranges in temperature from 700 degrees Fahrenheit to 300 672 00:19:27,000 --> 00:19:27,010 from 700 degrees Fahrenheit to 300 673 00:19:27,010 --> 00:19:29,310 from 700 degrees Fahrenheit to 300 degrees below zero the widest 674 00:19:29,310 --> 00:19:29,320 degrees below zero the widest 675 00:19:29,320 --> 00:19:33,330 degrees below zero the widest temperature range of any planet the 676 00:19:33,330 --> 00:19:33,340 temperature range of any planet the 677 00:19:33,340 --> 00:19:35,700 temperature range of any planet the ultraviolet experiment revealed that 678 00:19:35,700 --> 00:19:35,710 ultraviolet experiment revealed that 679 00:19:35,710 --> 00:19:37,890 ultraviolet experiment revealed that mercury has a very thin atmosphere of 680 00:19:37,890 --> 00:19:37,900 mercury has a very thin atmosphere of 681 00:19:37,900 --> 00:19:42,870 mercury has a very thin atmosphere of helium sensors measured the invisible 682 00:19:42,870 --> 00:19:42,880 helium sensors measured the invisible 683 00:19:42,880 --> 00:19:45,270 helium sensors measured the invisible cosmic rays which flood our solar system 684 00:19:45,270 --> 00:19:45,280 cosmic rays which flood our solar system 685 00:19:45,280 --> 00:19:47,790 cosmic rays which flood our solar system at tremendous speeds penetrate any 686 00:19:47,790 --> 00:19:47,800 at tremendous speeds penetrate any 687 00:19:47,800 --> 00:19:50,100 at tremendous speeds penetrate any surface and are unaffected by 688 00:19:50,100 --> 00:19:50,110 surface and are unaffected by 689 00:19:50,110 --> 00:19:53,190 surface and are unaffected by gravitational forces their source is 690 00:19:53,190 --> 00:19:53,200 gravitational forces their source is 691 00:19:53,200 --> 00:19:58,290 gravitational forces their source is unknown exploration is an adaptive 692 00:19:58,290 --> 00:19:58,300 unknown exploration is an adaptive 693 00:19:58,300 --> 00:20:00,650 unknown exploration is an adaptive process each new piece of information 694 00:20:00,650 --> 00:20:00,660 process each new piece of information 695 00:20:00,660 --> 00:20:03,270 process each new piece of information adds the value of others that were 696 00:20:03,270 --> 00:20:03,280 adds the value of others that were 697 00:20:03,280 --> 00:20:06,810 adds the value of others that were accumulated earlier we had the results 698 00:20:06,810 --> 00:20:06,820 accumulated earlier we had the results 699 00:20:06,820 --> 00:20:08,970 accumulated earlier we had the results of the Apollo program on the moon to 700 00:20:08,970 --> 00:20:08,980 of the Apollo program on the moon to 701 00:20:08,980 --> 00:20:11,760 of the Apollo program on the moon to help us understand the timescales and a 702 00:20:11,760 --> 00:20:11,770 help us understand the timescales and a 703 00:20:11,770 --> 00:20:13,680 help us understand the timescales and a some extent the processes we were seeing 704 00:20:13,680 --> 00:20:13,690 some extent the processes we were seeing 705 00:20:13,690 --> 00:20:19,340 some extent the processes we were seeing when we looked at Mars than Mariner 9 706 00:20:19,340 --> 00:20:19,350 707 00:20:19,350 --> 00:20:21,600 now that Mariner 10 has looked at 708 00:20:21,600 --> 00:20:21,610 now that Mariner 10 has looked at 709 00:20:21,610 --> 00:20:24,060 now that Mariner 10 has looked at mercury we can begin to compare it with 710 00:20:24,060 --> 00:20:24,070 mercury we can begin to compare it with 711 00:20:24,070 --> 00:20:27,090 mercury we can begin to compare it with the Moon and Mars and begin to realize 712 00:20:27,090 --> 00:20:27,100 the Moon and Mars and begin to realize 713 00:20:27,100 --> 00:20:29,010 the Moon and Mars and begin to realize that there is a common solar system 714 00:20:29,010 --> 00:20:29,020 that there is a common solar system 715 00:20:29,020 --> 00:20:31,320 that there is a common solar system history which has been recorded on these 716 00:20:31,320 --> 00:20:31,330 history which has been recorded on these 717 00:20:31,330 --> 00:20:33,960 history which has been recorded on these planets whose early services have not 718 00:20:33,960 --> 00:20:33,970 planets whose early services have not 719 00:20:33,970 --> 00:20:35,850 planets whose early services have not been erased by erosion and other 720 00:20:35,850 --> 00:20:35,860 been erased by erosion and other 721 00:20:35,860 --> 00:20:40,710 been erased by erosion and other atmospheric processes that same common 722 00:20:40,710 --> 00:20:40,720 atmospheric processes that same common 723 00:20:40,720 --> 00:20:43,620 atmospheric processes that same common history affected the earth too and so by 724 00:20:43,620 --> 00:20:43,630 history affected the earth too and so by 725 00:20:43,630 --> 00:20:46,500 history affected the earth too and so by looking at these services reading those 726 00:20:46,500 --> 00:20:46,510 looking at these services reading those 727 00:20:46,510 --> 00:20:49,200 looking at these services reading those records we're in fact looking back into 728 00:20:49,200 --> 00:20:49,210 records we're in fact looking back into 729 00:20:49,210 --> 00:20:51,470 records we're in fact looking back into the Earth's history into a heretofore 730 00:20:51,470 --> 00:20:51,480 the Earth's history into a heretofore 731 00:20:51,480 --> 00:20:54,630 the Earth's history into a heretofore unexplored domain of time our own 732 00:20:54,630 --> 00:20:54,640 unexplored domain of time our own 733 00:20:54,640 --> 00:20:57,750 unexplored domain of time our own history on the earth now we can begin to 734 00:20:57,750 --> 00:20:57,760 history on the earth now we can begin to 735 00:20:57,760 --> 00:21:00,510 history on the earth now we can begin to compare and contrast to look for 736 00:21:00,510 --> 00:21:00,520 compare and contrast to look for 737 00:21:00,520 --> 00:21:04,020 compare and contrast to look for similarities and differences and try to 738 00:21:04,020 --> 00:21:04,030 similarities and differences and try to 739 00:21:04,030 --> 00:21:07,500 similarities and differences and try to recognize our family relationships among 740 00:21:07,500 --> 00:21:07,510 recognize our family relationships among 741 00:21:07,510 --> 00:21:10,770 recognize our family relationships among the terrestrial planets are we cousins 742 00:21:10,770 --> 00:21:10,780 the terrestrial planets are we cousins 743 00:21:10,780 --> 00:21:14,340 the terrestrial planets are we cousins or brothers or all of us bizarre 744 00:21:14,340 --> 00:21:14,350 or brothers or all of us bizarre 745 00:21:14,350 --> 00:21:16,350 or brothers or all of us bizarre strangers it happened inhabit the same 746 00:21:16,350 --> 00:21:16,360 strangers it happened inhabit the same 747 00:21:16,360 --> 00:21:20,100 strangers it happened inhabit the same portion of the solar system that's the 748 00:21:20,100 --> 00:21:20,110 portion of the solar system that's the 749 00:21:20,110 --> 00:21:22,470 portion of the solar system that's the task of comparative planetology 750 00:21:22,470 --> 00:21:22,480 task of comparative planetology 751 00:21:22,480 --> 00:21:29,090 task of comparative planetology that's where we go from here 752 00:21:29,090 --> 00:21:29,100 753 00:21:29,100 --> 00:21:32,730 in future planetary flights Venus will 754 00:21:32,730 --> 00:21:32,740 in future planetary flights Venus will 755 00:21:32,740 --> 00:21:38,139 in future planetary flights Venus will be explored once again 756 00:21:38,139 --> 00:21:38,149 757 00:21:38,149 --> 00:21:40,959 the probes of one pioneer spacecraft 758 00:21:40,959 --> 00:21:40,969 the probes of one pioneer spacecraft 759 00:21:40,969 --> 00:21:43,139 the probes of one pioneer spacecraft will penetrate its thick atmosphere 760 00:21:43,139 --> 00:21:43,149 will penetrate its thick atmosphere 761 00:21:43,149 --> 00:21:53,909 will penetrate its thick atmosphere while a second pioneer orbits the planet 762 00:21:53,909 --> 00:21:53,919 763 00:21:53,919 --> 00:21:57,130 - Mariner class spacecraft will explore 764 00:21:57,130 --> 00:21:57,140 - Mariner class spacecraft will explore 765 00:21:57,140 --> 00:22:03,880 - Mariner class spacecraft will explore the planet Jupiter and then fly upward 766 00:22:03,880 --> 00:22:03,890 the planet Jupiter and then fly upward 767 00:22:03,890 --> 00:22:08,710 the planet Jupiter and then fly upward to reach Saturn one of the Mariners may 768 00:22:08,710 --> 00:22:08,720 to reach Saturn one of the Mariners may 769 00:22:08,720 --> 00:22:11,409 to reach Saturn one of the Mariners may be sent on to the planet Uranus over a 770 00:22:11,409 --> 00:22:11,419 be sent on to the planet Uranus over a 771 00:22:11,419 --> 00:22:14,789 be sent on to the planet Uranus over a billion and a half miles from the Sun 772 00:22:14,789 --> 00:22:14,799 billion and a half miles from the Sun 773 00:22:14,799 --> 00:22:19,570 billion and a half miles from the Sun and someday in our future we will send 774 00:22:19,570 --> 00:22:19,580 and someday in our future we will send 775 00:22:19,580 --> 00:22:23,260 and someday in our future we will send intelligent machines robots to explore 776 00:22:23,260 --> 00:22:23,270 intelligent machines robots to explore 777 00:22:23,270 --> 00:22:27,240 intelligent machines robots to explore the hostile surface of Mars and perhaps 778 00:22:27,240 --> 00:22:27,250 the hostile surface of Mars and perhaps 779 00:22:27,250 --> 00:22:30,539 the hostile surface of Mars and perhaps even the ancient moons of Jupiter and 780 00:22:30,539 --> 00:22:30,549 even the ancient moons of Jupiter and 781 00:22:30,549 --> 00:22:33,549 even the ancient moons of Jupiter and Saturn