AWESOME ALTAIR
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 FOR
THE CINCINNATI OBSERVATORY.
WE'RE HERE TO HELP YOU FIND YOUR WAY AROUND THE SKY.
JAMES: ONE OF THE MAIN STAR PATTERNS OF SUMMER
IS THE SUMMER TRIANGLE THAT RISES IN THE EAST AFTER DARK THIS MONTH.
IT INCLUDES THE STARS VEGA, ALTAIR, AND DENEB.
WHENEVER WE TALK ABOUT THE SUMMER TRIANGLE, WE OFTEN TALK ABOUT ITS BRIGHTEST STAR, VEGA.
DEAN: VEGA MAY BE BEAUTIFUL AND BRILLIANT,
BUT IT CAN'T BEAT THE SECOND BRIGHTEST STAR OF THE SUMMER TRIANGLE,
ALTAIR, WHEN IT COMES TO BEING WONDERFUL AND WEIRD.
WONDERING WHAT WE'RE TALKING ABOUT?
LET'S SHOW YOU
DEAN: O.K., WE HAVE OUR SKIES SET UP FOR ABOUT
11PM FACING EAST.
THERE YOU'LL SEE THE THREE BRIGHT STARS THAT MAKE UP THE POINTS OF THE SUMMER TRIANGLE,
THE BRIGHTEST BEING VEGA IN LYRA THE HARP, THE SECOND BRIGHTEST ALTAIR IN AQUILA THE
EAGLE AND THE THIRD BRIGHTEST, DENEB MARKING THE TAIL OF CYGNUS THE SWAN.
JAMES: NOW ALTHOUGH THERE ARE MANY STRANGE STARS
IN THE HEAVENS, ALTAIR IS ONE OF THE STRANGEST.
LOCATED ONLY 17 LIGHT YEARS AWAY FROM US, (WHICH IS PRETTY CLOSE STAR-WISE),
ALTAIR IS THE 12TH BRIGHTEST STAR WE CAN SEE FROM EARTH.
AND IF WE COMPARE IT TO OUR ALMOST MILLION MILE WIDE SUN,
ALTAIR IS NOT ONLY 1 1/2 TIMES ITS SIZE,
BUT SINCE ITS A HOT WHITE STAR, ALTAIR IS ACTUALLY
9 TIMES BRIGHTER THAN OUR COOLER YELLOW SUN.
DEAN: BUT THE REALLY PECULIAR THING ABOUT ALTAIR
HAS TO DO WITH THE LENGTH OF ITS DAY.
YOU SEE, A DAY FOR ANY STAR OR PLANET IS DEFINED AS
THE AMOUNT OF TIME IT TAKES FOR IT TO MAKE ONE COMPLETE ROTATION
ON ITS AXIS.
NOW WE ALL KNOW THAT OUR EARTH MAKES ONE TURN ON ITS AXIS
EVERY 24 HOURS.
SO AN EARTH DAY IS 24 HOURS LONG.
JAMES: OUR SUN HOWEVER,
HAS A MUCH LONGER DAY BECAUSE IT MAKES ONE COMPLETE ROTATION
EVERY 25 1/2 EARTH DAYS.
SO ONE DAY ON THE SUN IS THE EQUIVALENT OF 25 1/2 EARTH DAYS.
DEAN: SINCE OUR SUN IS WAY BIGGER THAN THE EARTH
AND SPINS MUCH MORE SLOWLY,
YOU MIGHT THINK THAT ALTAIR,
WHICH IS WAY BIGGER THAN THE SUN SHOULD TAKE LIKE A YEAR TO SPIN.
AH, YOU BETTER THINK AGAIN!
ALTAIR IS FULL OF SURPRISES!
JAMES: ALTAIR DOES NOT TURN SLOWER THAN OUR SUN.
IN FACT, IT IS ONE OF THE FASTEST ROTATING STARS WE
KNOW IN THE GALAXY.
INDEED, ALTAIR'S ROTATIONAL SPEED AT IT'S EQUATOR IS 150 MILES PER SECOND -
WHICH MEANS THAT ALTAIR ROTATES ONCE EVERY 9 HOURS!
SO ONE ALTAIR DAY IS LESS THAN HALF AN EARTH DAY LONG.
PLUS ITS INCREDIBLY FAST ROTATIONAL SPEED PRODUCES ONE VERY WEIRD EFFECT.
DEAN: THATS RIGHT, JAMES.
ALTAIR SPINS SO RAPIDLY THAT IT BULGES AROUND ITS EQUATOR...
SO MUCH SO THAT ALTAIR IS TWICE AS WIDE FROM SIDE TO SIDE AS IT IS FROM TOP TO BOTTOM.
THIS GIVES ALTAIR THE DISTINCTION OF LOOKING LIKE A BLUE-WHITE M&M.
JAMES: HAVE I MENTIONED HOW MUCH I LIKE M&MS?
DEAN: I KNOW.
I KNOW.
HERE, CATCH!
JAMES: NICE THROW!
DEAN: NOW THAT JAMES IS FED, LETS SEE WHAT THE PLANETS
ARE DOING THIS WEEK.
JAMES: OK, NOW WE'RE FACING TOWARD THE SOUTH-- SOUTHEAST
AFTER IT GETS GOOD AND DARK OUTSIDE.
THERE ARE TWO PLANETS HANGING OUT HERE - ONE IS EASY TO SPOT
AND THE OTHER IS A LITTLE TRICKIER.
DEAN: THE EASY PLANET IS
SO INCREDIBLY BRIGHT YOU WONT BE ABLE TO MISS IT.
THAT, MY FRIENDS, IS JUPITER THE LARGEST PLANET IN THE
SOLAR SYSTEM.
THIS MONTH YOU'LL ALSO NOTICE A LITTLE STAR BELOW IT.
THATS MY FAVORITE STAR NAME TO SAY IN ALL ASTRONOMY.
ITS ZUBENELGENUBI AND IT IS THE WESTERNMOST STAR IN THE CONSTELLATION LIBRA THE SCALES.
JAMES: THE MORE CHALLENGING PLANET TO IDENTIFY IS
THE BRIGHT YELLOW STAR CLOSER TO ME.
IT IS NO STAR AT ALL BUT IS,
IN FACT, THE SECOND LARGEST PLANET IN THE SOLAR SYSTEM -
SATURN.
SATURN IS NESTLED AMONG THE STARS OF SAGITTARIUS HOWEVER YOURE MORE LIKELY
TO PICTURE THESE STARS LOOKING LIKE A TEA POT.
DEAN: SO GET OUTSIDE TO
SEE ALTAIR, THE TOTALLY OUT-OF-SHAPE STAR OF THE SUMMER
TRIANGLE…
JAMES: AND LOOK TOWARD THE SOUTH TO FIND THE LARGEST
PLANETS IN OUR SOLAR SYSTEM - REALLY BRIGHT JUPITER TO THE RIGHT AND DIMMER
SATURN TO THE LEFT.
ALL: KEEP LOOKING UP!