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: VALENTINES DAY IS THIS WEEK AND IF YOU WANT TO GIVE YOUR SWEETHEART SOMETHING
SPECIAL AND OUT OF THIS WORLD, WE HAVE A TRIO OF EXQUISITELY BEAUTIFUL CELESTIAL OBJECTS,
GIFT WRAPPED AND READY TO PRESENT.
DEAN: WHAT ARE WE TALKING ABOUT?
LETS SHOW YOU!
DEAN: OK, WE HAVE OUR SKY SET UP FOR ANY NIGHT THIS WEEK, ABOUT AN HOUR AFTER SUNSET, FACING
WEST.
JUST ABOVE THE WESTERN HORIZON, YOULL SEE TWO BRIGHT NON-TWINKLING LIGHTS IN THE CONSTELLATION
OF PISCES THE FISH.
THE BRIGHTER OF THE TWO IS VENUS (REPRESENTING THE GODDESS
OF LOVE).
JAMES: AND THE DIMMER AND REDDER OF THE TWO IS MARS (THE GOD OF WAR).
BOTH PLANETS HAVE BEEN GETTING CLOSER AND CLOSER TO EACH OTHER IN THE SKY SINCE THE
END OF 2016.
THIS WEEK, THEY BEGIN TO GET FURTHER AND FURTHER APART.
DEAN: IF YOU LOOK AT VENUS THROUGH A TELESCOPE, IT WILL LOOK LIKE A WAXING CRESCENT MOON.
IN THIS CASE HOWEVER, VENUS IS WANING AND IT WILL BE BETWEEN US AND THE SUN IN A LITTLE
OVER A MONTH FROM NOW.
JAMES: VENUS' PHASING IS CAUSED BY SUNLIGHT BOUNCING OFF THE DAYTIME SIDE OF THE PLANET,
WHEREAS THE DARK PART THAT WE CAN'T SEE IS THE NIGHTTIME SIDE.
AS VENUS COMPLETES ITS ORBIT OF THE SUN, WE'LL SEE LESS AND LESS OF THE DAYTIME SIDE, AND
MORE AND MORE OF THE NIGHT TIME SIDE.
DEAN: YOU'LL ALSO NOTICE THAT VENUS IS GETTING A LITTLE LARGER EACH DAY.
WHEN ITALIAN ASTRONOMER GALILEO GALILEI RECORDED THESE OBSERVATIONS IN 1610, HE CAME TO THE
CONCLUSION THAT VENUS WAS ORBITING THE SUN, CONFIRMING THE HELIOCENTRIC MODEL OF THE SOLAR
SYSTEM
JAMES: UP AND TO THE LEFT OF VENUS IS THE RED PLANET MARS.
MARS IS MORE THAN 4 TIMES AS FAR AWAY FROM US RIGHT NOW AS VENUS IS.
, AND WITH MARS ONLY BEING HALF THE DIAMETER OF VENUS, IT'S GOING TO LOOK QUITE TINY; EVEN
THROUGH A TELESCOPE.
DEAN: THE REDDISH COLOR OF MARS IS CAUSED BY IRON OXIDE, BETTER KNOWN AS RUST, WHICH
COVERS THE ROCKS ON THE MARTIAN SURFACE.
IT WAS THE RED COLOR OF MARS THAT PROMPTED MANY ANCIENT PEOPLE TO ASSOCIATE THIS PLANET
WITH THEIR GODS OF WAR AND VIOLENCE.
JAMES: SPEAKING OF THINGS THAT ARE RED, LET'S CHECK OUT OUR VALENTINES DAY STAR!
JAMES: LOOK DUE SOUTH BETWEEN THE HOURS OF 8 AND 9 P.M.
AND YOU'LL SEE A VERY BRIGHT RED STAR SHINING ABOVE THE HORIZON.
IT MARKS THE SHOULDER STAR OF THE GREAT SKY-GIANT ORION THE HUNTER.
DEAN: IT'S NAME IS BETELGEUSE WHICH MOST PEOPLE PRONOUNCE BEETLE JUICE (DON'T WORRY, I WON'T
SAY IT A THIRD TIME).
AND IF YOU'VE EVER WANTED TO GIVE YOUR LOVED ONE A REALLY BIG VALENTINE, WELL THIS IS ABOUT
AS BIG AS IT GETS.
JAMES: IF WE COMPARE BETELGEUSE THE VALENTINE'S STAR, WITH OUR OWN STAR, THE SUN, AND OUR
OWN PLANET THE EARTH, YOU'LL UNDERSTAND JUST HOW BIG.
OUR EARTH IS 8,000 MILES WIDE, WHICH MEANS IT IS PRETTY DINKY COMPARED TO OUR SUN, WHICH
IS 865,000 MILES WIDE.
IN FACT, WE COULD FIT OVER ONE MILLION EARTH'S INSIDE OUR SUN.
BETELGEUSE HOWEVER, IS SO HUGE WE COULD FIT OVER 160 MILLION OF OUR SUNS INSIDE IT.
AND THAT'S JUST WHEN BETELGEUSE IS AT ITS SMALLEST SIZE.
DEAN: WE SAY SMALLEST SIZE BECAUSE BETELGEUSE CHANGES ITS SIZE REGULARLY LIKE A GIGANTIC
SLOWLY PULSATING HEART, ONE THAT BEATS ONLY ONCE EVERY 6 YEARS.
JAMES: WHEN BETELGEUSE IS FULLY CONTRACTED AND AT ITS SMALLEST SIZE IT IS STILL ABOUT
500 TIMES THE WIDTH OF OUR SUN.
BUT WHEN IT EXPANDS TO ITS BIGGEST SIZE IT IS ALMOST 900 TIMES AS WIDE.
DEAN: OR IF YOU CARE TO THINK OF IT THIS WAY, IF WE COULD PLACE BETELGEUSE WHERE OUR SUN
IS, WHEN BETELGEUSE IS AT ITS SMALLEST, IT WOULD STRETCH OUT PAST THE ORBITS OF MERCURY,
VENUS, EARTH, AND ALL THE WAY TO MARS.
BUT WHEN IT'S AT ITS LARGEST IT WILL REACH ALL THE WAY TO JUPITER.
WOW!
DEAN: SO, CELEBRATE THIS VALENTINE'S DAY BY FIRST SHOWING YOUR LOVED ONE THE PAIRING OF
THE RED PLANET MARS WITH THE SUPER BRIGHT PLANET VENUS.
JAMES: AND TO THE SOUTH, THE GIANT RED STAR BETELGEUSE, SLOWLY BEATING LIKE A HEAVENLY
HEART FOR YOUR SWEETHEART; COURTESY OF OUR LOCAL GALAXY.
DEAN: IS THIS A ROMANTIC UNIVERSE OR WHAT?
BOTH: KEEP LOOKING UP!