1 00:00:11,277 --> 00:00:11,711 HIS. 2 00:00:11,711 --> 00:00:13,813 >>> HI, I'M JOAN CARTAN-HANSEN, AND WELCOME TO SCIENCE TREK THE 3 00:00:13,813 --> 00:00:16,082 WEB SHOW, AND JOINING ME TODAY TO ANSWER YOUR QUESTIONS ABOUT 4 00:00:16,082 --> 00:00:18,818 THE EARTH, ARE VIRGINIA GILLERMAN AND JEFFERY JOHNSON. 5 00:00:18,818 --> 00:00:20,120 THANK YOU BOTH FOR BEING HERE. 6 00:00:20,120 --> 00:00:21,888 I APPRECIATE YOU TAKING THE TIME. 7 00:00:21,888 --> 00:00:23,089 >> THANKS FOR INVITING US. 8 00:00:23,089 --> 00:00:23,723 >> THANK YOU. 9 00:00:23,723 --> 00:00:24,290 >> OK. 10 00:00:24,290 --> 00:00:32,399 LET'S GO TO YOUR QUESTIONS. 11 00:00:32,399 --> 00:00:34,668 >> SHILA WOULD LIKE TO KNOW WHY IS THE EARTH ROUND? 12 00:00:34,668 --> 00:00:39,105 >> WHEN THE EARTH FORMED, IT WAS A HOT GLOB OF MATERIAL. 13 00:00:39,105 --> 00:00:44,110 AND GRAVITY PULLED IT TOGETHER IN THE FORM THAT WAS MOST 14 00:00:44,110 --> 00:00:44,644 CONVENIENT. 15 00:00:44,644 --> 00:00:48,114 THEY COULD NOT PULL IT TOGETHER IN THE FORM OF A CUBE BECAUSE 16 00:00:48,114 --> 00:00:50,583 THAT WOULD BE UNNATURAL FOR THE GRAVITATIONAL FIELD. 17 00:00:50,583 --> 00:00:55,488 IT PULLED IT TOGETHER IN THE SHAPE OF A SPHERE, A SLIGHTLY 18 00:00:55,488 --> 00:01:00,527 DISTORTED SPHERE, BUT FOR, FOR MOST PURPOSES, A PERFECT SPHERE, 19 00:01:00,527 --> 00:01:06,700 THAT IS THE EASIEST SHAPE FOR GRAVITY TO PULL AN OBJECT INTO. 20 00:01:06,700 --> 00:01:12,238 >> I AM PURDUE, AND MY QUESTION IS -- HOW DO EARTHQUAKES WORK? 21 00:01:12,238 --> 00:01:16,976 >> EARTHQUAKES ARE WHEN ROCKS MOVE PAST EACH OTHER, AND THEY 22 00:01:16,976 --> 00:01:22,082 WILL FRACTURE, RELEASE ENERGY BY FRACTURING QUICKLY, AND JEFF 23 00:01:22,082 --> 00:01:23,016 WILL TELL US MORE. 24 00:01:23,016 --> 00:01:24,451 >> EARTHQUAKES HAPPEN WHEN ROCKS BREAK. 25 00:01:24,451 --> 00:01:27,554 ROCKS CAN BREAK ON VERY SMALL SCALES. 26 00:01:27,554 --> 00:01:30,724 IF YOU HAD, LET'S SAY, A ROCK THAT WAS THE SIZE OF A 27 00:01:30,724 --> 00:01:34,627 REFRIGERATOR, THAT ALL OF A SUDDEN BROKE, YOU WOULD HAVE A 28 00:01:34,627 --> 00:01:36,629 MAGNITUDE OF ONE EARTHQUAKE. 29 00:01:36,629 --> 00:01:40,734 NOW, IMAGINE YOU HAVE ROCK THAT EXTENDS FOR HUNDREDS OF MILES 30 00:01:40,734 --> 00:01:45,105 THAT BREAKS, YOU WOULD ALSO HAVE A VERY SIMILAR EARTHQUAKE, BUT 31 00:01:45,105 --> 00:01:47,273 IT WOULD BE MUCH, MUCH LARGER. 32 00:01:47,273 --> 00:01:52,212 IN BOTH CASES, SMALL AND LARGE, THE EARTH'S ROCKS ARE BREAKING. 33 00:01:52,212 --> 00:01:54,381 AND BREAKING FAST. 34 00:01:54,381 --> 00:01:58,418 >> DEBRA WOULD LIKE TO KNOW, IS THE EARTH THE ONLY PLANET WITH 35 00:01:58,418 --> 00:01:58,885 WATER? 36 00:01:58,885 --> 00:02:03,323 >> IT'S NOT THE ONLY PLANET WITH WATER, IT'S THE ONLY ONE THAT, 37 00:02:03,323 --> 00:02:06,860 THAT WE KNOW OF THAT, THAT HAS A, HAS ABUNDANT WATER, FOR 38 00:02:06,860 --> 00:02:10,697 EXAMPLE, ABOUT THREE QUARTERS OF OUR SURFACE IS COVERED WITH 39 00:02:10,697 --> 00:02:11,064 WATER. 40 00:02:11,064 --> 00:02:14,434 WE HAVE SOME EVIDENCE THAT ON A PLANET LIKE MARS, THERE WAS 41 00:02:14,434 --> 00:02:17,804 WATER IN THE PAST, OR THERE MIGHT BE WATER THAT'S BOUND UP 42 00:02:17,804 --> 00:02:23,076 WITH THE ROCKS OR FROZEN CARBON DIOXIDE. 43 00:02:23,076 --> 00:02:27,180 BUT, I DON'T THINK WE KNOW OF ANY OTHER PLANETS WITH ROTS OF 44 00:02:27,180 --> 00:02:30,283 LIQUID WATER ON THE SURFACE LIKE, LIKE THE EARTH HAS. 45 00:02:30,283 --> 00:02:31,351 BUT, WE'RE STILL LOOKING. 46 00:02:31,351 --> 00:02:35,288 THERE IS A LOT OF PLANETS, WE JUST DON'T KNOW THAT MUCH ABOUT. 47 00:02:35,288 --> 00:02:39,526 >> AND ONE EXCEPTION THAT I CAN THINK OF, IS UROPA, WHICH IS A 48 00:02:39,526 --> 00:02:43,730 MOON OF JUPITER, WHICH DOES HAVE PLENTY OF WATER ICE, AND MAYBE 49 00:02:43,730 --> 00:02:46,933 EVEN AN OCEAN BENEATH THAT WATER ICE. 50 00:02:46,933 --> 00:02:50,737 MOST OF MARS' WATER IS PROBABLY TIED UP RIGHT NOW IN ICE. 51 00:02:50,737 --> 00:02:54,274 NOT VERY USABLE FOR, FOR ANY SORTS OF LIFE THAT MAY, THAT MAY 52 00:02:54,274 --> 00:02:57,110 LIVE THERE. 53 00:02:57,110 --> 00:02:59,713 >> HI, I AM MIA. 54 00:02:59,713 --> 00:03:03,616 AND MY QUESTION IS, WHICH PART OF THE EARTH IS THE MOST 55 00:03:03,616 --> 00:03:06,319 IMPORTANT TO LIVE? 56 00:03:06,319 --> 00:03:08,988 >> I WOULD SAY THE SURFACE OF THE EARTH, THAT INCLUDES THE 57 00:03:08,988 --> 00:03:10,156 ROCKS THAT WE STAND ON. 58 00:03:10,156 --> 00:03:14,227 THE SOIL THAT'S PRODUCED FROM THOSE ROCKS, AND THE OCEANS, AND 59 00:03:14,227 --> 00:03:16,229 THE SPHERE THAT WE BREATHE. 60 00:03:16,229 --> 00:03:23,269 WE, ESSENTIALLY, LIVE AT, AT THE JUNCTION OF ALL OF THOSE VERY 61 00:03:23,269 --> 00:03:28,008 COMPLEX GEOCHEMICAL AND GEO LOGIC SYSTEMS. 62 00:03:28,008 --> 00:03:31,811 IT MIGHT BE THE DIVERSITY THAT HAS HELPED TO CREATE LIFE AND 63 00:03:31,811 --> 00:03:37,717 CREATED THE DELICATE BALANCE THAT WE USE IN OUR DAILY LIVES. 64 00:03:37,717 --> 00:03:44,357 >> SAM ASKS, WHERE DOES THE AIR COME FROM TO SUPPORT LIFE? 65 00:03:44,357 --> 00:03:48,528 >> SAM, THE AIR COMES FROM THE OXYGEN IN OUR AIR COMES FROM 66 00:03:48,528 --> 00:03:52,732 PHOTO SYNTHETIC PROCESSES, AND MOST OF THE OXYGEN THAT WE NEED 67 00:03:52,732 --> 00:03:58,004 AS HUMANS TO SURVIVE ON COMES AS A BY-PRODUCT, OR A POLLUTION 68 00:03:58,004 --> 00:04:00,140 FROM PLANT MATTER. 69 00:04:00,140 --> 00:04:05,078 SO, OXYGEN ORIGINALLY CAME FROM WATER AND CARBON DIOXIDE, WHICH 70 00:04:05,078 --> 00:04:10,684 WAS SPEWED OUT BY VOLCANOES OVER MANY, MANY EONS, AND PLANTS, 71 00:04:10,684 --> 00:04:13,720 TREES, BLUE-GREEN ALGAE AND OTHER VEGETATION TURNED THOSE 72 00:04:13,720 --> 00:04:17,424 RAW MATERIALS INTO THE OXYGEN THAT WE NEED. 73 00:04:17,424 --> 00:04:23,630 >> I AM SABRINA FROM HILLCRUST ELEMENTARY. 74 00:04:23,630 --> 00:04:27,000 HOW ARE DINOSAUR FOSSILS STILL UNDERI DON'T YOU UNDERSTAND? 75 00:04:27,000 --> 00:04:30,704 >> THEY ARE BECAUSE 24E6 NOT BEEN EROIDED OR WASHED DOWN FROM 76 00:04:30,704 --> 00:04:34,641 THE MOUNTAINTOPS OR WHEREVER THEY ARE FOUND YET. 77 00:04:34,641 --> 00:04:38,178 FOSSILS FORM UNDERGROUND, AND BACK WHEN THE DINOSAURS WERE 78 00:04:38,178 --> 00:04:40,714 STILL LIVING, AND THEY WOULD DIE. 79 00:04:40,714 --> 00:04:43,550 THEIR BONES WOULD FALL TO THE BOTTOM OF THE OCEAN. 80 00:04:43,550 --> 00:04:48,521 OR THE RIVER BOTTOM, WHEREVER THEY WERE LIVING. 81 00:04:48,521 --> 00:04:53,660 OVER TIME, THOSE BONES WOULD GET COVERED WITH DIRT, MUD, SAND, 82 00:04:53,660 --> 00:04:58,231 ETC., AND THOSE SEDIMENTS WOULD LIQUIFY, OR TURN INTO ROCK. 83 00:04:58,231 --> 00:05:03,303 AS THEY DO SO, ANY WATER THAT MIGHT HAVE SAY DISSOLVED SILICA 84 00:05:03,303 --> 00:05:10,477 IN IT, IE QUARTS, CAN PERCOLATE THROUGH THOSE, AND INTERACT WITH 85 00:05:10,477 --> 00:05:14,681 THOSE BONES, AND REPLACE THEM WITH FOSSILIZING MATERIAL. 86 00:05:14,681 --> 00:05:21,888 SO, THOSE FOSSILS ARE, ACTUALLY, FORMED UNDERGROUND. 87 00:05:21,888 --> 00:05:27,527 UNTIL THEY ARE EITHER FOUND BY A PALEONTOLOGIST OR A SCIENCE KID 88 00:05:27,527 --> 00:05:33,700 OUT FOR A NATURE HIKE, OR ERODED OFF, THEN THEY WILL REMAIN 89 00:05:33,700 --> 00:05:34,100 UNDERGROUND. 90 00:05:34,100 --> 00:05:39,072 >> I AM RYLEE, AND HOW DOES, HOW DO THE LAYERS OF THE SPHERE ALL 91 00:05:39,072 --> 00:05:39,539 CONNECT? 92 00:05:39,539 --> 00:05:42,008 >> HOW DO THE SPHERES OF THE EARTH CONNECT? 93 00:05:42,008 --> 00:05:44,544 THERE ARE A LOT OF SPHERE WORDS. 94 00:05:44,544 --> 00:05:47,814 THERE IS THE ATMOSPHERE, WHICH COMPRISES THE EARTH'S GASES, 95 00:05:47,814 --> 00:05:51,351 THERE IS THE HYDROSPHERE, WHICH IS THE EARTH'S OCEANS, THERE IS 96 00:05:51,351 --> 00:05:54,387 THE CRYOSPHERE, WHICH IS THE ICE CAPS. 97 00:05:54,387 --> 00:05:59,292 AND THEN BENEATH WE HAVE THE LITHOSPHERE, WHICH IS THE ROCKY 98 00:05:59,292 --> 00:06:02,762 OR RIGID PORTION OF THE EARTH THAT COMPRISES OUR TECTONIC 99 00:06:02,762 --> 00:06:03,129 PLATES. 100 00:06:03,129 --> 00:06:07,400 BEFORE THIS WE HAVE THE ESTHENOSPHERE, WHICH IS THE 101 00:06:07,400 --> 00:06:11,404 REGION ON TOP OF WHICH OUR TECTONIC PLATES FLOAT. 102 00:06:11,404 --> 00:06:16,976 >> AND UNDER THAT, YOU CONTINUE WITH THE MANTLE AND THE CORE, 103 00:06:16,976 --> 00:06:21,314 WHICH ARE OTHER SPHERICAL-SHAPED ROCKY OR MOLTEN ROCK REGIONS 104 00:06:21,314 --> 00:06:22,215 WITHIN THE EARTH. 105 00:06:22,215 --> 00:06:26,252 THEY JUST DON'T HAVE THE WORDS SPHERE IN THEM FOR SOME REASON. 106 00:06:26,252 --> 00:06:30,056 >> ALYSON WOULD LIKE TO KNOW, HOW DOES THE EARTH ROTATE? 107 00:06:30,056 --> 00:06:33,360 >> NOW, THE EARTH ROTATES BECAUSE IT'S ALWAYS ROTATED. 108 00:06:33,360 --> 00:06:36,162 THIS IS NOT A VERY SATISFACTORY ANSWER. 109 00:06:36,162 --> 00:06:40,166 BUT, WHEN THE EARTH WAS FORMED SOME 4.6 BILLION YEARS AGO, IT 110 00:06:40,166 --> 00:06:43,737 HAD SOMETHING WE CALL ANGULAR MOMENTUM ASSOCIATED WITH IT. 111 00:06:43,737 --> 00:06:47,907 THAT MEANS A TENDENCY TO SPIN, AND NOW, AS ALL OF THE PARTICLES 112 00:06:47,907 --> 00:06:52,078 IN OUR SOLAR SYSTEM ARE CREATED TO FORM PLANETS, IT ALL SORT OF 113 00:06:52,078 --> 00:06:55,648 CAME CLOSER TO THE SUN AND BEGAN TO SPIN FASTER. 114 00:06:55,648 --> 00:06:59,386 THINK OF AN ICE SKATER WITH HIS OR HER ARMS EXTENDED OUTWARD, 115 00:06:59,386 --> 00:07:02,956 AND AS THOSE ARMS COME IN CLOSER, THE ROTATION OR THE 116 00:07:02,956 --> 00:07:06,693 ANGULAR MOMENTUM IS CONSERVED BUT THE SPIN BECOMES FASTER. 117 00:07:06,693 --> 00:07:11,331 AND WE ARE SEEING THE RESULT OF THAT INITIAL ROTATION IN TODAY'S 118 00:07:11,331 --> 00:07:12,866 EARTH ROTATION. 119 00:07:12,866 --> 00:07:16,036 THE EARTH WILL CONTINUE TO ROTATE FOR A LONG, LONG TIME, 120 00:07:16,036 --> 00:07:20,340 UNLESS IT COLLIDES WITH SOME OTHER BODIES. 121 00:07:20,340 --> 00:07:24,611 >> LEXI WOULD LIKE TO KNOW, DO ALL PLANETS HAVE MOONS? 122 00:07:24,611 --> 00:07:27,947 >> NO, NOT ALL PLANETS HAVE MOONS. 123 00:07:27,947 --> 00:07:28,848 VENUS DOESN'T HAVE ANY. 124 00:07:28,848 --> 00:07:33,987 AND EARTH HAS ONE AND, AND SOME PLANETS, LIKE JUPITER AND SATURN 125 00:07:33,987 --> 00:07:36,056 HAVE MANY MOONS. 126 00:07:36,056 --> 00:07:38,358 SO, IT VARIES. 127 00:07:38,358 --> 00:07:41,261 >> BETSY WOULD LIKE TO KNOW, WHY IS THE EARTH NOT BEING STUCK 128 00:07:41,261 --> 00:07:43,329 INTO THE SUN? 129 00:07:43,329 --> 00:07:46,800 >> BETSY, THE EARTH IS ALWAYS FALLING TOWARDS THE SUN. 130 00:07:46,800 --> 00:07:50,870 BELIEVE IT OR NOT, THE SUN'S PULL OF GRAVITY CAUSES THE EARTH 131 00:07:50,870 --> 00:07:54,074 TO MOVE TOWARDS IT ALL THE TIME. 132 00:07:54,074 --> 00:07:57,377 BUT, I WOULD NOT LOSE ANY SLEEP OVER IT BECAUSE AT THE SAME 133 00:07:57,377 --> 00:08:00,213 TIME, THE EARTH HAS SOMETHING CALLED INERTIA. 134 00:08:00,213 --> 00:08:04,050 IT IS MOVING IT IN A DIRECTION THAT IS AWAY FROM THE SUN. 135 00:08:04,050 --> 00:08:07,654 SO, EVEN THOUGH THE EARTH IS CONTINUOUSLY FALLING TOWARDS THE 136 00:08:07,654 --> 00:08:12,459 SUN, IT IS MOVING AROUND THE SUN, AND ULTIMATELY, IT IS 137 00:08:12,459 --> 00:08:15,295 ORBITING IN A CIRCLE AROUND THE SUN. 138 00:08:15,295 --> 00:08:16,963 >> I'M SORRY BUT WE HAVE RUN OUT OF TIME. 139 00:08:16,963 --> 00:08:20,500 MY THANKS TO JEFF AND VIRGINIA FOR ANSWERING QUESTIONS TODAY. 140 00:08:20,500 --> 00:08:22,035 >> THANKS VERY MUCH FOR HAVING US. 141 00:08:22,035 --> 00:08:25,238 >> THANK YOU, AND THANK YOU TO THE STUDENTS WHO SUBMITTED GREAT 142 00:08:25,238 --> 00:08:26,673 QUESTIONS. 143 00:08:26,673 --> 00:08:29,709 THANKS, ALSO, TO THE FOLKS HERE AT BOISE STATE UNIVERSITY'S 144 00:08:29,709 --> 00:08:32,312 EARTH, SCIENCE, RESEARCH LAB FOR HOSTING US. 145 00:08:32,312 --> 00:08:35,682 IF YOU WANT TO LEARN MORE, CHECK OUT THE EARTH AREA ON THE 146 00:08:35,682 --> 00:08:36,316 SCIENCE TREK WEBSITE. 147 00:08:36,316 --> 00:08:40,053 YOU WILL FIND LINKS, GAMES, AND EARTH BROADCAST SHOWS, AND LOTS 148 00:08:40,053 --> 00:08:40,620 MORE. 149 00:08:40,620 --> 00:08:43,523 EVERY WEEK, CHECK OUT MY BLOG FOR THE LATEST SCIENCE NEWS FOR 150 00:08:43,523 --> 00:08:45,992 KIDS. 151 00:08:45,992 --> 00:08:46,860 ALL AT IDAHOPTV.ORG. 152 00:08:46,860 --> 00:08:52,699 THANKS FOR JOINING US FOR SCIENCE TREK, THE WEB SHOW.