WPBT2's Star Gazers

Episode #14-52 "Don't Worry About Winter, it's the Shortest Day of the Year"
Air Dates December 29, 2014 - January 4, 2015



FIVE MINUTE EPISODE SCRIPT

JAMES: HEY THERE STAR GAZERS. I'M JAMES ALBURY, DIRECTOR OF THE KIKA SILVA PLA PLANETARIUM IN GAINESVILLE, FLORIDA.

DEAN: AND I'M DEAN REGAS, ASTRONOMER FOR THE CINCINNATI OBSERVATORY. WE'RE HERE TO TALK ABOUT WINTER, THE SHORTEST SEASON.

JAMES: IF WE COULD FLY OUT INTO SPACE THIS WEEK WE WOULD SEE THAT OUR EARTH IS AT PERIHELION, WHICH MEANS THAT IT'S AT ITS CLOSEST TO THE SUN FOR THE ENTIRE YEAR. PERIHELION OCCURS ON SUNDAY, JANUARY 4TH THIS YEAR AT 2 A.M. EASTERN TIME WHEN THE EARTH WILL BE ONLY 91.4 MILLION MILES AWAY FROM THE SUN.

DEAN: THAT'S 3 MILLION MILES CLOSER THAN AT APHELION, ITS FARTHEST POINT FROM THE SUN, WHICH WILL OCCUR ON JULY 6TH. WE ARE SO CLOSE TO THE SUN THIS WEEK IT WILL APPEAR 7% BRIGHTER THAN IT WILL IN JULY.

JAMES: SO WHY IS IT COLDER OUT IN JANUARY THAN JULY? SIMPLE, BECAUSE OUR EARTH IS TILTED, THE SUN'S RAYS OF LIGHT APPEAR LESS DIRECT AND ARE MORE SPREAD OUT OVER THE NORTHERN HEMISPHERE IN JANUARY THAN IN JULY.

DEAN: THE OPPOSITE IS TRUE FOR THE SOUTHERN HEMISPHERE WHERE THE RAYS OF SUNLIGHT ARE MORE DIRECT IN JANUARY THAN JULY. IT'S A GOOD THING WINTER IS THE SHORTEST SEASON, I'M NOT SURE I COULD TAKE IT IF IT WAS AS LONG AS SUMMER.

JAMES: YES YOU HEARD RIGHT. WINTER FOR THE NORTHERN HEMISPHERE IS THE SHORTEST SEASON OF THE ENTIRE YEAR. AND NOT ONLY ARE THE FOUR SEASONS NOT EQUAL IN LENGTH, NO TWO OF THEM ARE THE SAME LENGTH. AND NOT ONLY IS WINTER SHORTEST, IT IS GETTING EVEN SHORTER. WHY? LET'S SHOW YOU.

DEAN: NOW EVERYONE KNOWS THAT OUR EARTH MAKES ONE TRIP AROUND THE SUN ONCE A YEAR. IN FACT, ASTRONOMICALLY SPEAKING, THAT IS EXACTLY WHAT A YEAR IS - ONE ORBIT OF A PLANET AROUND THE SUN. NOW FOR OUR PLANET EARTH THAT IS 365 1/4 EARTH DAYS. AND ACCORDING TO KEPLER'S LAWS OF MOTION THE CLOSER AN OBJECT IS TO THE SUN THE FASTER IT WILL TRAVEL. ANY PLANET CLOSER TO THE SUN THAN OUR EARTH SHOULD TRAVEL FASTER AND HAVE A SHORTER YEAR.

JAMES: THE CLOSEST PLANET TO THE SUN, MERCURY, ZIPS AROUND THE SUN ONCE EVERY 88 EARTH DAYS; ONE YEAR ON MERCURY IS 88 EARTH DAYS LONG. AT THE OTHER EXTREME, THE MOST DISTANT PLANET PLUTO,

DEAN: COUGH, COUGH!!

JAMES: WHOOPS! I MEAN DWARF PLANET, PLUTO TAKES 249 EARTH YEARS TO MAKE ONE TRIP AROUND THE SUN, SO ONE PLUTO YEAR IS 249 EARTH YEARS. THE RULE: THE CLOSER AN OBJECT IS TO THE SUN THE FASTER IT TRAVELS AND THE FARTHER IT IS FROM THE SUN THE SLOWER IT TRAVELS. AND THIS APPLIES TO OUR EARTH AS IT TRAVELS IN ITS ORBIT.

DEAN: YOU SEE, OUR EARTH'S ORBIT IS NOT A PERFECT CIRCLE BUT A SLIGHTLY STRETCHED OUT ONE CALLED AN ELLIPSE. AND THE SUN IS NOT AT THE CENTER OF THIS ELLIPSE. SO THE EARTH VARIES ITS DISTANCE FROM THE SUN DURING THE YEAR. AND THE EARTH IS CLOSEST TO THE SUN THE FIRST WEEK OF EVERY JANUARY AND FARTHEST FROM THE SUN THE FIRST WEEK OF EVERY JULY.

JAMES: SO OUR EARTH TRAVELS MUCH FASTER WHEN IT'S WINTER IN THE NORTHERN HEMISPHERE AND MUCH SLOWER DURING THE SUMMER. INDEED, ON THE FIRST DAY OF SPRING, THE VERNAL EQUINOX, THE EARTH IS TRAVELLING 66,900 MPH AND TAKES 93 DAYS TO GO FROM THE FIRST DAY OF SPRING TO THE FIRST DAY OF SUMMER. THEREAFTER THE EARTH CONTINUES TO SLOW DOWN 'TIL IT'S AT ITS FARTHEST POINT FROM THE SUN THE FIRST WEEK OF JULY WHEN IT REACHES ITS SLOWEST SPEED OF 65,500 MPH. BUT THEREAFTER IT SLOWLY STARTS TO SPEED UP. EVEN SO, IT TAKES 94 DAYS FOR THE EARTH TO TRAVEL FROM THE FIRST DAY OF SUMMER TO THE FIRST DAY OF AUTUMN MAKING SUMMER THE LONGEST SEASON OF ALL.

DEAN: AND THEN, PICKING UP MORE SPEED DAY BY DAY, IT TAKES ONLY 90 DAYS FOR OUR EARTH TO TRAVEL FROM THE FIRST DAY OF AUTUMN TO THE FIRST DAY OF WINTER. BUT IT CONTINUES TO SPEED UP UNTIL IT REACHES ITS CLOSEST POINT TO THE SUN THE FIRST WEEK OF JANUARY WHEN IT'S ZIPPING ALONG AT 67,700 MILES AN HOUR. THAT'S 2,200 MILES PER HOUR FASTER THAN IT TRAVELLED IN JULY. SO THE EARTH WHIPS THROUGH WINTER IN ONLY 89 DAYS.

JAMES: SO IF ANYONE TELLS YOU WINTERS ARE GETTING LONGER, THEY'RE WRONG. WINTER IS A FULL FIVE DAYS SHORTER THAN SUMMER. WHICH WOULD MEAN YOU'D REALLY HAVE TO BUNDLE UP AS YOU

BOTH: KEEP LOOKING UP!

 

Episode #14-52 "Don't Worry About Winter, it's the Shortest Day of the Year"
Air Dates December 29, 2014 - January 4, 2015



ONE MINUTE EPISODE SCRIPT

JAMES: ON SUNDAY MORNING JANUARY 4TH THE EARTH IS CLOSEST TO THE SUN.

DEAN: BUT THE EARTH'S DISTANCE FROM THE SUN IS NOT WHY WE HAVE SEASONS.

DEAN: HAVE YOU EVER WONDERED WHICH SEASON IS THE LONGEST OR SHORTEST? WELL, I'LL BET MOST SCHOOL KIDS WOULD SAY SUMMER IS THE SHORTEST BECAUSE IT JUST FLIES BY. BUT IS THAT SIMPLY A MATTER OF HUMAN PERCEPTION?

JAMES: YOU SEE, OUR EARTH'S ORBIT IS NOT A PERFECT CIRCLE, BUT IS ACTUALLY AN ELLIPSE SO OUR EARTH VARIES ITS DISTANCE FROM THE SUN DURING THE YEAR. WHEN IT'S CLOSER TO THE SUN IT TRAVELS FASTER, WHEN ITS FARTHER AWAY IT TRAVELS SLOWER.

DEAN: AND BELIEVE IT OR NOT THE EARTH IS CLOSER IN WINTER AND TRAVELS OVER 2,200 MILES PER HOUR FASTER THAN IT DOES IN SUMMER.

JAMES: SO FAST IN FACT THAT WINTER, WHICH IS 89 DAYS LONG, IS 5 DAYS SHORTER THAN SUMMER, WHICH IS 94 DAYS LONG, FOR THE NORTHERN HEMISPHERE.

BOTH: KEEP LOOKING UP!

 

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