1 00:00:20,020 --> 00:00:21,788 ASTRONOMICAL DISTANCES 2 00:00:21,888 --> 00:00:23,823 DEAN: HEY THERE STAR GAZERS. 3 00:00:23,923 --> 00:00:26,693 I'M DEAN REGAS, ASTRONOMER FOR THE CINCINNATI OBSERVATORY. 4 00:00:26,793 --> 00:00:28,962 JAMES: AND I'M JAMES ALBURY, DIRECTOR OF THE KIKA 5 00:00:29,062 --> 00:00:31,297 SILVA PLA PLANETARIUM IN GAINESVILLE, FLORIDA. 6 00:00:31,398 --> 00:00:34,567 WE RE HERE TO HELP YOU FIND YOUR WAY AROUND THE SKY TONIGHT. 7 00:00:34,667 --> 00:00:36,770 HEY DEAN, HUMOR ME. 8 00:00:36,870 --> 00:00:39,706 IF YOU WANT TO DESCRIBE YOUR HEIGHT, WHAT UNITS OF MEASURE WOULD 9 00:00:39,806 --> 00:00:40,707 YOU USE? 10 00:00:40,807 --> 00:00:41,908 DEAN: I'D USE FEET AND INCHES. 11 00:00:42,008 --> 00:00:43,610 JAMES: AND IF WE WANT TO MEASURE THE DISTANCE TO 12 00:00:43,710 --> 00:00:44,844 THE MOON WHAT DO WE USE? 13 00:00:44,944 --> 00:00:47,547 DEAN: I COULD USE FEET AND INCHES, BUT USING MILES 14 00:00:47,647 --> 00:00:48,548 MAKES MORE SENSE. 15 00:00:48,648 --> 00:00:50,283 JAMES: HOW ABOUT THE DISTANCE TO STARS? 16 00:00:50,383 --> 00:00:53,520 DEAN: AH, WE USE LIGHT YEARS. 17 00:00:53,620 --> 00:00:55,055 DISTANCES IN SPACE ARE SO 18 00:00:55,155 --> 00:00:56,423 WELL 19 00:00:56,523 --> 00:00:58,958 ASTRONOMICAL THAT IT S HARD TO WRAP OUR BRAINS AROUND THEM. 20 00:00:59,059 --> 00:01:03,530 SO WE CREATED NEW UNITS OF MEASUREMENT TO TAKE US AROUND THE SOLAR SYSTEM AND THROUGH 21 00:01:03,630 --> 00:01:04,764 INTERSTELLAR SPACE. 22 00:01:04,864 --> 00:01:07,567 JAMES: SO, LET'S TAKE YOU TO THE MOON,JUPITER , AND 23 00:01:07,667 --> 00:01:08,802 BEYOND! 24 00:01:08,902 --> 00:01:11,071 JAMES: OKAY, WE HAVE OUR SKY SET UP FOR THE EVENING 25 00:01:11,171 --> 00:01:15,341 OF MAY 26TH, ABOUT 10:30PM AND WE RE FACING SOUTHEAST. 26 00:01:15,442 --> 00:01:17,911 DEAN: EVERY NIGHT THIS WEEK YOU WILL SEE THE WAXING 27 00:01:18,011 --> 00:01:22,949 MOON IN THE NIGHT SKY BUT ON THIS NIGHT, THE MOON WILL BE A WAXING GIBBOUS AND APPEAR AT 28 00:01:23,049 --> 00:01:25,585 THE FEET OF THE CONSTELLATION VIRGO. 29 00:01:25,685 --> 00:01:28,321 LET'S ZOOM IN ON THE MOON AND GET OUT OUR TAPE-MEASURE. 30 00:01:28,421 --> 00:01:32,459 DEAN: ON AVERAGE, THE MOON IS ABOUT 239,000 MILES 31 00:01:32,559 --> 00:01:34,461 FROM THE EARTH. 32 00:01:34,561 --> 00:01:39,032 WE CAN FIND OUT THE PRECISE DISTANCE TO THE MOON ANY TIME BY BOUNCING LASERS OFF THE REFLECTORS 33 00:01:39,132 --> 00:01:40,633 SET UP BY THE APOLLO ASTRONAUTS. 34 00:01:40,733 --> 00:01:43,803 JAMES: NEIL ARMSTRONG, BUZZ ALDRIN AND COMPANY TOOK 35 00:01:43,903 --> 00:01:49,776 THREE DAYS TO FLY THE 239,000 MILES TO THE MOON - AND THREE DAYS TO FLY BACK. 36 00:01:49,876 --> 00:01:51,077 JAMES: OUR NEXT STOP 37 00:01:51,177 --> 00:01:52,545 IS JUPITER. 38 00:01:52,645 --> 00:01:56,149 THE LARGEST PLANET IS EASY TO FIND IN THE NIGHT SKY ALL THIS WEEK. 39 00:01:56,249 --> 00:01:58,952 LOOK SOUTHEAST AFTER DARK AND YOU CAN T MISS IT. 40 00:01:59,052 --> 00:02:01,087 JUPITER IS SOUP-IT-TER BRIGHT! 41 00:02:01,187 --> 00:02:02,122 DEAN: SOUP-IT-TER? 42 00:02:02,222 --> 00:02:03,656 I LIKE IT! 43 00:02:03,756 --> 00:02:07,026 ANYWAY, JUPITER IS BRIGHTER THAN ANY OTHER STAR IN THE NIGHTTIME SKY. 44 00:02:07,127 --> 00:02:10,330 ONLY THE PLANET VENUS (AND ON RARE OCCASIONS, MARS) 45 00:02:10,430 --> 00:02:11,531 CAN BE MORE DAZZLING. 46 00:02:11,631 --> 00:02:13,833 JAMES: THIS IS A GOOD WEEK TO AIM A TELESCOPE AT 47 00:02:13,933 --> 00:02:18,438 JUPITER WHERE YOU CAN SEE SEVERAL MOONS AROUND IT, SOME STRIPES ON IT, AND MAYBE THE GREAT 48 00:02:18,538 --> 00:02:20,940 RED SPOT: THE GIANT HURRICANE ON THE PLANET. 49 00:02:21,040 --> 00:02:24,611 JAMES: THIS WEEK JUPITER IS ABOUT 410 MILLION MILES 50 00:02:24,711 --> 00:02:26,246 AWAY. 51 00:02:26,346 --> 00:02:29,015 NOW, THAT NUMBER IS HARD TO PICTURE, SO WHEN WE'RE TALKING ABOUT DISTANCES IN 52 00:02:29,115 --> 00:02:32,418 THE SOLAR SYSTEM ASTRONOMERS USE A DIFFERENT UNIT OF MEASURE - 53 00:02:32,519 --> 00:02:34,621 THE ASTRONOMICAL UNIT OR A.U... 54 00:02:34,721 --> 00:02:38,825 ONE A.U. IS THE AVERAGE DISTANCE BETWEEN THE SUN AND EARTH, 55 00:02:38,925 --> 00:02:40,326 SO WE'RE ABOUT 1 A.U. 56 00:02:40,426 --> 00:02:41,327 FROM THE SUN. 57 00:02:41,427 --> 00:02:43,596 IN MILES, THAT'S 93,000,000 MILES. 58 00:02:43,696 --> 00:02:47,300 DEAN: SO SINCE JUPITER IS 410 MILLION MILES AWAY 59 00:02:47,400 --> 00:02:51,104 IT IS ALSO ABOUT 4.4 A.U.S FROM US. 60 00:02:51,204 --> 00:02:53,706 A.U.'S WORK GREAT WITHIN THE SOLAR SYSTEM. 61 00:02:53,806 --> 00:02:58,878 FOR EXAMPLE, WE COULD SAY SATURN IS ABOUT 10 A.U.'S FROM THE SUN, NEPTUNE IS ABOUT 30 62 00:02:58,978 --> 00:03:03,049 A.U.'S FROM THE SUN AND VOYAGER 1 -- OUR FARTHEST FLUNG SPACECRAFT -- 63 00:03:03,149 --> 00:03:06,686 IS A WHOPPING 140 A.U.'S FROM THE SUN! 64 00:03:06,786 --> 00:03:10,156 JAMES: YOU MAY NOTICE A LITTLE STAR NEXT TO JUPITER. 65 00:03:10,256 --> 00:03:13,092 THAT IS ONE OF MY FAVORITE STARS TO SAY OUT LOUD AND FAST. 66 00:03:13,193 --> 00:03:17,363 IT S CALLED ZUBENELGENUBI AND IT S THE SECOND BRIGHTEST STAR IN THE CONSTELLATION 67 00:03:17,463 --> 00:03:18,565 LIBRA THE SCALES. 68 00:03:18,665 --> 00:03:22,502 DEAN: ZUBENELGENUBI IS ABOUT 447 TRILLION MILES 69 00:03:22,602 --> 00:03:25,872 FROM EARTH, OR ALMOST 5 MILLION A.U.'S. 70 00:03:25,972 --> 00:03:30,343 WE COULD MEASURE THE DISTANCE TO ZUBENELGENUBI IN MILLIMETERS IF WE WANTED TO, BUT THOSE 71 00:03:30,443 --> 00:03:32,178 NUMBERS LOSE ALL MEANING. 72 00:03:32,278 --> 00:03:34,514 JAMES: ASTRONOMERS USE LIGHT YEARS AS THEIR UNIT 73 00:03:34,614 --> 00:03:37,584 OF CHOICE FOR MEASURING INTERSTELLAR DISTANCES. 74 00:03:37,684 --> 00:03:43,856 A LIGHT YEAR IS THE DISTANCE LIGHT TRAVELS IN A YEAR -- ROUGHLY 5.8 TRILLION MILES. 75 00:03:43,957 --> 00:03:46,993 SO A LIGHT YEAR IS A DISTANCE LIKE A MILE OR AN A.U.. 76 00:03:47,093 --> 00:03:51,064 DEAN: AND ZUBENELGENUBI IS A WHOPPING 77 LIGHT YEARS 77 00:03:51,164 --> 00:03:52,532 FROM EARTH. 78 00:03:52,632 --> 00:03:55,401 IT'S BY NO MEANS THE FARTHEST STAR YOU CAN SEE WITH THE NAKED EYE. 79 00:03:55,501 --> 00:04:00,373 THAT HONOR MOST LIKELY GOES TO DENEB - THE TAIL STAR OF CYGNUS THE SWAN - WHO YOU'LL 80 00:04:00,473 --> 00:04:02,175 BE LEARNING MORE ABOUT THIS SUMMER. 81 00:04:02,275 --> 00:04:05,245 DENEB IS OVER 3000 LIGHT YEARS AWAY. 82 00:04:05,345 --> 00:04:10,283 THAT MEANS THE LIGHT YOU SEE FROM DENEB LEFT IT AROUND 1000 BC AND IS ONLY NOW GETTING 83 00:04:10,383 --> 00:04:11,517 TO YOUR EYES. 84 00:04:11,618 --> 00:04:14,487 DEAN: SO THIS WEEK GET OUTSIDE TO SEE THE MOON AT 85 00:04:14,587 --> 00:04:16,589 239,000 MILES AWAY. 86 00:04:16,689 --> 00:04:19,359 JAMES: JUPITER FROM 4.4 A.U.'S AWAY. 87 00:04:19,459 --> 00:04:23,596 DEAN: AND ZUBENELGENUBI AT 77 LIGHT YEARS AWAY. 88 00:04:23,696 --> 00:04:24,597 AND THERE IS ONE MORE THING 89 00:04:24,697 --> 00:04:25,732 JAMES: YESSSS? 90 00:04:25,832 --> 00:04:27,700 DEAN: I KNOW YOU LL LIKE THIS JAMES BUT ON THE 91 00:04:27,800 --> 00:04:33,506 NIGHT OF MAY 27TH, THE MOON WILL COZY UP TO JUPITER AND ZUBENELGENUBI AND MAKE A COOL 92 00:04:33,606 --> 00:04:34,540 JAMES: CONJUNCTION! 93 00:04:34,641 --> 00:04:36,676 DEAN: IT S ALL THERE WHEN YOU 94 00:04:36,776 --> 00:04:40,776 ALL: KEEP LOOKING UP!