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!