LETS LOOK AT LYRA!
DEAN:
WELCOME TO
STAR GAZERS.
I'M DEAN REGAS, ASTRONOMER FROM THE CINCINNATI
OBSERVATORY.
JAMES:
AND I'M JAMES ALBURY, DIRECTOR OF THE KIKA
SILVA PLA PLANETAR-IUM IN GAINESVILLE FLORIDA.
THE SUMMER TRIANGLE
IS RIDING HIGH AT SUNSET THIS WEEK,
SO WE'RE GOING TO
TALK ABOUT ONE OF THE CONSTELLATIONS THAT
MAKES UP THIS VERY
POPULAR GROUPING OF STARS.
DEAN:
THAT'S RIGHT, JAMES.
WE'RE GOING TO GIVE YOU A GUIDED TOUR OF
THE CONSTELLATION LYRA
THE HARP.
IT'S TINY AND CUTE,
BUT REALLY FUN TO FIND IN THE SUMMER SKY.
LET'S SHOW YOU!
DEAN:
OK, WE'VE SET UP OUR SKIES FOR ANY NIGHT
THIS WEEK,
ABOUT AN HOUR AFTER SUNSET.
IF YOU LOOK DIRECTLY OVERHEAD,
YOU WILL SEE A GROUPING OF STARS WE CALL THE
SUMMER TRIANGLE.
THE BRIGHTEST STAR IN THE TRIANGLE IS ACTUALLY
THE FIFTH BRIGHTEST STAR WE CAN SEE FROM EARTH
AND
ITS NAME IS VEGA.
JAMES:
ONCE YOU HAVE FOUND VEGA, YOU'VE FOUND LYRA
THE HARP.
THE NEXT BRIGHTEST STAR IN THE SUMMER TRIANGLE
IS ALTAIR IN AQUILA THE EAGLE AND THE THIRD
BRIGHTEST
IS DENEB IN CYGNUS
THE SWAN.
DEAN:
LYRA IS OFTEN SAID TO BE THE SMALL HARP THAT
BELONGED TO APOLLO AND WAS SUBSEQUENTLY GIVEN
TO ORPHEUS.
ORPHEUS WAS SO SKILLED AT PLAYING THE HARP,
THAT THE MUSIC WAS SAID TO CHARM ANY-ONE WHO
HEARD IT; EVEN ANIMALS.
JAMES:
INDEED, WHEN ORPHEUS PLAYED THE HARP,
HE COULD EVEN CHARM INANIMATE OBJECTS LIKE
TREES AND ROCKS.
FURTHERMORE,
WHEN OR-PHEUS JOINED JASON AND THE ARGONAUTS,
HIS MUSIC WAS ABLE TO MUFFLE THE SONGS OF
THE DREADED SIRENS WHO'S VOICES TRIED TO LEAD
THE ARGONAUTS
TO THEIR DOOM!
DEAN:
QUITE A FEW CULTURES SAW THIS GROUPING OF
STARS AS A HARP.
IN WALES, THEY REFER TO IT AS KING ARTHURS
HARP AND IN PERSIA THEY CALLED IT THE LYRE
OF ZURAH.
JAMES:
LYRA IS ALSO KNOWN AS PRAESEPE SALVATORIS
(THE MANGER OF THE INFANT SAVIOR) AND TO THE
INCAS,
THEY SAW IT AS URCUCHILLAY,
A GOD IN THE FORM OF A LLAMA WHO WATCHED OVER
ANIMALS.
JAMES:
OF THE 25 STARS THAT ARE WITHIN THE INTERNATIONAL
ASTRONOMICAL UNIONS BOUNDARY FOR THE CONSTELLATION
LYRA, FIVE OF THOSE STARS ARE BRIGHT ENOUGH
TO BE VISIBLE WITH THE NAKED EYE FROM MOST
CITIES.
DEAN:
THE BRIGHTEST ONE IS OF COURSE VEGA.
VEGAS BLUE-WHITE COLOR TELLS US THAT IT IS
MUCH HOTTER THAN OUR OWN YELLOW-ORANGE SUN.
IN FACT, COMPARED TO OUR SUN'S TEMPERATURE
OF 10 THOUSAND DEGREES FAHRENHEIT, VEGA BLAZES
AWAY AT
A FIERCE 17 THOUSAND DEGREES FAHRENHEIT!
JAMES:
VEGA IS ALSO CONSIDERABLY LARGER, FOR WHILE
OUR SUN IS A LIT-TLE UNDER A MILLION MILES
WIDE,
VEGA IS ALMOST THREE MILLION MILES IN DIAMETER,
WHICH MAKES IT EASY TO UNDERSTAND THAT IF
WE COULD PLACE OUR SUN AND VEGA SIDE BY SIDE,
VEGA WOULD SHINE 58 TIMES BRIGHTER
THAN THE SUN.
JAMES:
NEAR VEGA,
THERE ARE FOUR STARS THAT MAKE A
PARALLELOGRAM.
TRAVELING
COUNTER- CLOCKWISE FROM VEGA,
WE HAVE ZETA LYRAE, DELTA LYRAE AND THE TWO
ON THE FAR END ARE, SULAFAT AND SHELIAK.
DEAN:
AS FAR AS STATISTICS GO, THE STARS IN LYRA
ARE QUITE IMPRESSIVE.
ZETA LYRAE AND DELTA LYRAE ARE BOTH BINARY
STAR SYSTEMS.
ZETA LYRAE IS 156 LIGHT YEARS AWAY AND DELTA
LYRAE IS A WHOPPING 1,100 LIGHT YEARS
FROM US!
COMPARE THAT TO
VEGA WHICH IS ONLY
25 LIGHT YEARS AWAY.
JAMES:
MY TWO FAVORITE STARS IN THE PARALLELOGRAM
ARE SULAFAT AND SHELIAK.
SULAFAT IS 2400 TIMES AS BRIGHT AS OUR SUN
AND IS ABOUT 620 LIGHT YEARS AWAY.
MEANWHILE,
SHELIAK IS OVER 26,000 TIMES AS BRIGHT AS
OUR SUN, HAS A SURFACE TEMPERATURE OF OVER
54,000 DEGREES FAHRENHEIT AND IS
960 LIGHT YEARS AWAY.
SHELIAK WAS ALSO MENTIONED IN AN EPISODE OF
STAR TREK THE NEXT GENERATION,
SO I'M REALLY HAPPY ABOUT THAT.
JAMES:
ONE LAST THING ABOUT LYRA.
DID YOU KNOW THAT THE SUN AND ALL THE PLANETS
IN OUR SOLAR SYSTEM ARE HEADING TOWARDS VEGA?
DEAN:
THATS RIGHT, JAMES!
OUR SOLAR SYSTEM IS RACING TOWARDS VEGA AT
THE INCREDIBLE SPEED OF 12 MILES PER SECOND,
AND EVEN THOUGH
VEGA IS ONLY 25
LIGHT YEARS AWAY,
AT THIS SPEED IT WOULD STILL TAKE OUR SUN
ALMOST 500 MILLION YEARS TO REACH VEGA.
JAMES:
WELL THAT'S GOOD.
I'D HATE FOR US TO GET AN INTERGALACTIC SPEEDING
TICKET.
DEAN:
RIGHT?!
SO GET OUTSIDE AND CHECK OUT LYRA
THE HARP AND SEE IF THE STARS PLAY SWEET MUSIC!
JAMES:
IT'S EASY TO DO WHEN YOU
BOTH:
KEEP LOOKING UP!.