“Lunar Leapfrog with Jupiter and Saturn!”
JAMES: WELCOME TO STAR GAZERS.
I'M JAMES ALBURY, DIRECTOR OF THE KIKA SILVA PLA PLANETARIUM IN GAINESVILLE FLORIDA.
DEAN: AND I'M DEAN REGAS, ASTRONOMER FROM THE CINCINNATI OBSERVATORY.
WE’RE HERE TO HELP YOU FIND YOUR WAY AROUND THE SKY!
JAMES: IF YOUR FAVORITE PLANETS ARE JUPITER AND SATURN, HAVE WE GOT A SHOW FOR YOU!
DEAN: THAT'S RIGHT, JAMES!
JUPITER AND SATURN WILL PLAY LEAPFROG WITH THE MOON NEXT WEEK.
JAMES: AND WE’RE GOING TO SHOW IT TO YOU HERE FIRST.
LET’S GO!
JAMES: OK, WE HAVE OUR SKIES SET FOR AN HOUR BEFORE SUNRISE, SUNDAY MORNING, APRIL 21ST.
IF YOU LOOK TOWARD THE SOUTH, YOU'LL SEE THREE BRIGHT OBJECTS IN THE SKY.
THE BRIGHTEST OF COURSE IS THE MOON.
DEAN: ON APRIL 21ST, THE MOON WILL BE IN THE WANING GIBBOUS PHASE IN THE CONSTELLATION
SCORPIUS THE SCORPION.
JAMES: THE NEXT BRIGHTEST OBJECT IN THE SKY IS JUPITER.
IT WILL BE TO THE LEFT OF THE MOON, AND IT WILL SHINE WITH A BRIGHT, STEADY WHITE LIGHT.
DEAN: JUPITER IS THE LARGEST PLANET IN OUR SOLAR SYSTEM, AND MAKES UP OVER 75% OF THE
SOLAR SYSTEM’S PLANETARY MASS.
JAMES: JUPITER HAS BEEN OBSERVED IN THE SKY SINCE ANTIQUITY.
THE ANCIENT ROMANS NAMED IT AFTER THE KING OF THEIR GODS, WHOM THE GREEKS REFERED TO
AS ZEUS.
DEAN: BABYLONIAN ASTRONOMERS HAVE RECORDS OF JUPITER DATING BACK TO THE 7TH CENTURY
B.C. IN HIS BOOK THE ALMAGEST, GREEK ASTRONOMER CLAUDIUS PTOLEMY USED JUPITER'S MOTION WITH
RESPECT TO THE EARTH TO REFINE HIS EARTH-CENTERED MODEL OF THE SOLAR SYSTEM.
JAMES: BY DOING THIS, PTOLEMY SHOWED THAT JUPITER TOOK ALMOST 12 YEARS TO MAKE A COMPLETE
CIRCUIT OF THE SKY, WHICH WE NOW KNOW AS THE AMOUNT OF TIME IT TAKES JUPITER TO ORBIT THE
SUN.
DEAN: IN 1610, ITALIAN ASTRONOMER GALILEO GALILEI STUDIED JUPITER USING A TELESCOPE
AND IS CREDITED WITH DISCOVERING THE FOUR LARGEST MOONS OF JUPITER; IO, EUROPA, GANYMEDE
AND CALLISTO.
THE MOTIONS OF THESE MOONS AROUND JUPITER PROVIDED GALILEO WITH AN EXAMPLE SUPPORTING
NICHOLAS COPERNICUS' VIEW OF A SUN-CENTERED SOLAR SYSTEM
DEAN: THE THIRD BRIGHT OBJECT IN THE SOUTHERN SKY WILL BE SATURN.
SATURN WAS NAMED AFTER JUPITER’S FATHER; THE ROMAN GOD OF AGRICULTURE.
BEING THE SECOND LARGEST PLANET IN OUR SOLAR SYSTEM, SATURN IS SO LARGE, YOU COULD PUT
750 EARTHS INSIDE IT, IF IT WERE HOLLOW.
JAMES: SATURN IS AN AMAZING PLANET.
ASIDE FROM IT’S BEAUTIFUL RINGS, ASTRONOMERS DISCOVERED SOMETHING ELSE INTERESTING THING
ABOUT IT.
WHEN THE CASSINI SPACE PROBE VISITED SATURN IN 2006, IT CONFIRMED A DISCOVERY THAT VOYAGER
1 MADE BACK IN 1981 - A LARGE HEXAGON AT SATURN’S NORTH POLE.
DEAN: LIKE SATURN ITSELF, THIS HEXAGON IS ENORMOUS.
EACH SIDE OF SATURN’S HEXAGON IS 9,000 MILES IN LENGTH AND THE CLOUDS ARE ESTIMATED TO
BE OVER 190 MILES HIGH.
JAMES: MANY ASTRONOMERS BELIEVE THAT THIS BIZARRE FEATURE IS THE RESULT OF AN ATMOSPHERIC
WAVE PATTERN CAUSED BY DIFFERENCES IN THE DENSITIES AND SPEEDS OF THE ATMOSPHERE NEAR
SATURN’S NORTH POLE.
DEAN: THE CASSINI MISSION DETERMINED THE ROTATION RATE FOR THE HEXAGON TO BE A LITTLE OVER 10
HOURS AND 40 MINUTES.
THIS IS THE SAME PERIOD OF ROTATION OF SATURN’S INTERNAL RADIO EMISSIONS.
JAMES: NOW THAT YOU KNOW A LITTLE MORE ABOUT JUPITER AND SATURN, LET’S CHECK OUT THAT
CELESTIAL GAME OF LUNAR LEAPFROG.
(STOP - SET TIME TO 5:30 AM, MONDAY, APRIL 22ND, 2019 TO START)
JAMES: OK, WE HAVE OUR SKIES SET UP FOR AN HOUR BEFORE SUNRISE ON MONDAY MORNING, APRIL
22ND.
THE WANING GIBBOUS MOON IS JUST TO THE RIGHT OF JUPITER AND DIRECTLY NORTH OF ANTARES;
THE HEART OF SCORPIUS THE SCORPION.
DEAN: THE FUN BEGINS THE FOLLOWING MORNING, ON APRIL 23RD.
MAN!
CHECK OUT HOW CLOSE THE MOON IS TO JUPITER NOW!
JAMES: ON APRIL 23RD, THE MOON WILL BE A LITTLE OVER ONE DEGREE (OR TWO FULL MOON WIDTHS)
AWAY FROM JUPITER.
LET’S CHECK OUT IT OUT ON THE 24TH.
DEAN: NOW THE MOON IS ALMOST EXACTLY HALFWAY BETWEEN JUPITER AND SATURN; AND RIGHT ABOVE
THE STAR KAUS BOREALIS IN THE TEAPOT OF SAGITTARIUS.
LET’S ADVANCE TIME ONE MORE DAY TO THE 25TH.
JAMES: BOOM!
OUR SECOND CONJUNCTION OF THE WEEK!
JUST BEFORE SUNRISE, SATURN AND THE MOON WILL BE JUST OVER 2 DEGREES (OR FOUR FULL MOON
WIDTHS) APART.
DEFINITELY WORTH WAKING UP EARLY FOR.
DEAN: SO, TO RECAP…
LET’S CHECK OUT THAT LUNAR LEAPFROG AGAIN.
HERE’S THE SKY ON THE 21ST…, 22ND…, 23RD…, 24TH…
AND 25TH!
WOW!
DEAN: SO, GET OUTSIDE AND GAZE UPON OUR NEAREST NEIGHBOR IN SPACE PLAYING LEAP FROG WITH KING
OF THE ROMAN GODS AND HIS FATHER, THE ROMAN GOD OF AGRICULTURE.
JAMES: IT'S EASY TO DO WHEN YOU…
BOTH: KEEP LOOKING UP!