WPBT2's Star Gazers

Episode #13-46 "I See, Icy Comet Ison"
Air Dates November 18, 2013 - November 24, 2013



FIVE MINUTE EPISODE SCRIPT
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.

JAMES:  NEXT WEEK IS THE MOMENT WE’VE ALL BEEN WAITING FOR!

DEAN:  THANKSGIVING?!

JAMES:  WELL… YES, BUT THAT’S NOT WHY WE’RE EXCITED.

DEAN:  OH!  COMET ISON REACHES ITS CLOSEST POINT TO THE SUN!

JAMES: EXACTLY!  AND THIS CAN MEAN ONE OF TWO THINGS.  ONE, THAT THIS COMET COULD BE ONE OF THE BRIGHTEST COMETS WE’VE SEEN IN A VERY LONG TIME, OR TWO…

DEAN:  IT COULD TOTALLY FALL APART AS IT SWINGS AROUND THE SUN.

JAMES:  SO WHICH WILL IT DO, AND WHAT IS A COMET ANYWAY?  LET’S SHOW YOU!

DEAN:  FIRST, LET’S TALK ABOUT WHAT A COMET ACTUALLY IS.  FROM THE BEGINNING OF ASTRONOMY, PEOPLE HAVE STUDIED THE SKY AND WERE AWESTRUCK BY ITS BEAUTY.  THE SUN, THE MOON AND THE STARS ALL HAD PREDICTABLE MOTIONS, APPEARING AND REAPPEARING AT REGULAR INTERVALS.  EVEN THE PLANETS, WHOSE MOTIONS AT FIRST SEEMED STRANGE AND UNKNOWABLE, ACTUALLY SHOWED PATTERNS AS WELL AND THEY TOO BECAME PREDICTABLE.

JAMES: EVERY ONCE IN A WHILE, HOWEVER, THERE WOULD BE STRANGE VISITORS TO THE HEAVENS; UNLIKE THE STARS AND PLANETS.  THEY WOULD TAKE ON A STRANGE, ALMOST GHOSTLY FORM.  THEY WOULD APPEAR TO HANG IN THE SKY FOR WEEKS, AND THEN DISAPPEAR ALMOST AS QUICKLY AS THEY APPEARED.  THE CHINESE REFERRED TO THEM AS “BROOM STARS”.  THE GREEKS REFERRED TO THEM AS “HAIRY STARS”.  THE TERM THEY USED WAS “COMETES ASTERES”.  “COMETES” MEANING “HAIRY” AND “ASTERES” MEANING “STARS”.

DEAN:  SO, LIKE THE WORD “PLANET”, WE HAVE SHORTENED THE WORD “COMETES” TO “COMET”.  THE APPEARANCE OF A COMET, ESPECIALLY A BRIGHT ONE, IS A VERY RARE EVENT.  EVEN COMET HALLEY, THE MOST POPULAR COMET IN HISTORY, VISITS OUR SKIES ONLY ONCE EVERY 76 YEARS.

DEAN: COMETS WERE ONCE THOUGHT TO BE ATMOSPHERIC PHENOMENA THAT FORETOLD THE DEATH OF PRINCES AND THE FALL OF KINGDOMS. HOWEVER, WE NOW KNOW THAT COMETS ARE ACTUALLY LARGE COLLECTIONS OF ICE AND ROCK FROM THE OUTER SOLAR SYSTEM, WHICH OCCASSIONALLY FALL INWARD TOWARD THE SUN.

JAMES:  COMETS ARE BELIEVED TO BE ICY REMNANTS FROM THE FORMATION OF THE SOLAR SYSTEM.  IT’S SO COLD IN THE OUTER PART OF THE SOLAR SYSTEM, THAT THE NUCLEUS OF THE COMET HAS LARGE QUANTITIES OF FROZEN WATER, AND MANY FROZEN GASES, SUCH AS METHANE, AMMONIA AND CARBON DIOXIDE.  

DEAN: AS THE COMET FALLS TOWARD THE SUN, THE HEAT FROM THE SUN MELTS THE ICES FORMING A CLOUD OF GAS AROUND THE COMET’S NUCLEUS.  WE CALL THIS THE COMET’S “HEAD” OR “COMA” AND THIS PROCESS IS CALLED “OUTGASSING”.

JAMES:  AS THE COMET NEARS THE ORBIT OF SATURN, THE AMMONIA AND METHANE ICES BEGIN TO THAW AND AS THE COMET NEARS THE ORBITS OF JUPITER AND MARS, THE WATER ICE AND FROZEN CARBON DIOXIDE BEGIN TO THAW.  THIS IS WHERE ASTRONOMERS GET EXCITED ABOUT COMETS.

DEAN:  YEP! THE CLOSER THE COMET GETS TO THE SUN, THE MORE THE ICE MELTS AND THE SOLAR WIND BEGINS TO PUSH THIS GAS AWAY FROM THE NUCLEUS, CREATING THE CHARACTERISTIC TAIL OF THE COMET.  THE BRIGHTNESS OF A COMET IS DEPENDENT ON HOW MUCH ICE IT HAS, AND ESPECIALLY THE TYPE OF ICE.

JAMES: COMET ISON SHOWED A LOT OF OUTGASSING EARLY IN ITS DISCOVERY, LEADING ASTRONOMERS TO BELIEVE THAT THIS COMET WILL BE QUITE BRIGHT.  HOWEVER, COMET ISON HAS A VERY UNCERTAIN FUTURE.

DEAN: THAT’S RIGHT, JAMES.  UNLIKE HALLEY’S COMET, WHICH DOESN’T GET CLOSER TO THE SUN THAN THE ORBIT OF MERCURY, COMET ISON IS WHAT SOME ARE CALLING A “SUN GRAZER”.  SUN GRAZING COMETS ARE ONES WHOSE ORBIT TAKES THEM SO CLOSE TO THE SUN THAT THEY ACTUALLY ENTER THE SUN’S CORONA; THE UPPER ATMOSPHERE OF THE SUN MADE OF HIGHLY ENERGETIC HYDROGEN, MILLIONS OF DEGREES FAHRENHEIT.

JAMES:  IF YOU’VE EVER EATEN AN ICE CREAM CONE ON A HOT SUMMER DAY, YOU KNOW THAT HEAT AND ICE DON’T MIX. SINCE COMET ISON IS MOSTLY MADE OF ICE, THIS EXTREMELY CLOSE PASSAGE TO THE SUN CAN PRODUCE TREMENDOUS OUTGASSING. IF THE NUCLEUS IS STRUCTURALLY STRONG ENOUGH TO WITHSTAND THE GRAVITATIONAL STRESS OF BEING WHIPPED AROUND THE SUN AT OVER 150,000 MPH, AND IT STILL HAS ICE LEFT, IT COULD BE A SPECTACULARLY BRIGHT COMET VISIBLE IN THE PREDAWN SKY.

DEAN: HOWEVER, IF IT LOSES MOST OF ITS ICE BEFORE IT GETS TO THE SUN, AND THE NUCLEUS BREAKS APART AS IT GOES AROUND THE SUN, IT WILL GO THE WAY OF COMET ELENIN.  A ROCKY PILE OF ICELESS RUBBLE.

JAMES: SO… HERE’S TO A SAFE PERHELION PASSAGE FOR COMET ISON. 

ALL:  KEEP LOOKING UP!

 

Episode #13-46 "I See, Icy Comet Ison"
Air Dates November 18, 2013 - November 24, 2013



ONE MINUTE EPISODE SCRIPT
JAMES: HEY DEAN!  NEXT WEEK IS THE MOMENT WE’VE ALL BEEN WAITING FOR!

DEAN:  THANKSGIVING?!

JAMES:  WELL... YES, BUT THAT’S NOT WHY WE’RE EXCITED.

DEAN:  OH!  COMET ISON REACHES ITS CLOSEST POINT TO THE SUN!

JAMES: EXACTLY!  AND THIS CAN MEAN TWO THINGS.  ONE, THAT THIS COMET COULD BE ONE OF THE BRIGHTEST COMETS WE’VE SEEN IN A VERY LONG TIME, OR TWO IT COULD TOTALLY FALL APART AS IT SWINGS AROUND THE SUN.

DEAN:  SO WHICH WILL IT DO?  LET’S SHOW YOU!

DEAN:  COMETS ARE ACTUALLY LARGE COLLECTIONS OF ICE AND ROCK FROM THE OUTER SOLAR SYSTEM, WHICH OCCASIONALLY FALL INWARD TOWARD THE SUN.  COMET ISON IS WHAT SOME ARE CALLING A “SUN GAZER” AND ITS ORBIT IS GOING TO TAKE IT SO CLOSE TO THE SUN THAT IT ACTUALLY ENTER THE SUN’S CORONA.

JAMES: THIS EXTREMELY CLOSE PASSAGE TO THE SUN CAN PRODUCE TREMENDOUS OUTGASSING AND MAKE THIS AN INCREDIBLY BRIGHT COMET IN THE PREDAWN SKY IN EARLY DECEMBER.

DEAN:  OR, IT COULD BE COMPLETELY DESTROYED BY THE INTENSE HEAT. SO HERE’S TO A SAFE PERHELION PASSAGE FOR COMET ISON! 

BOTH:  KEEP LOOKING UP!

 

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