(MUSIC)
JOAN CARTAN-HANSEN, HOST: IS
THE MOON SHRINKING?
SCIENTISTS THOUGHT SO, BUT NEW
RESEARCH SAYS THE MOON IS ALSO
EXPANDING A LITTLE BIT.
AND THAT'S CAUSING MOONQUAKES.
WHEN THE APOLLO ASTRONAUTS
LANDED ON THE MOON, THEY LEFT
BEHIND SOME SEISMOMETERS TO
KEEP TRACK OF LUNAR
MOONQUAKES.
SCIENTISTS THOUGHT SOME
MOONQUAKES WERE CAUSED BY
IMPACTS FROM METEORITES
AND OTHERS WERE CAUSED BY THE
MOON'S SURFACE BEING WARMED
AND COOLED BY THE SUN EVERY
TWO WEEKS.
BUT THERE WERE MOONQUAKES THAT
THEY JUST COULDN'T EXPLAIN.
NOW THEY THINK THESE
MYSTERIOUS MOONQUAKES ARE
CAUSED BY A COMBINATION OF
ESCAPING INTERNAL HEAT AND THE
EARTH'S GRAVITATIONAL PULL.
THE MOON HAS A CORE, MANTLE
AND CRUST LIKE THE EARTH.
BUT PLANETARY GEOLOGISTS
THOUGHT THE MOON'S CORE HAD
ALREADY COOLED DOWN,
APPARENTLY NOT.
ITS STILL RUNNING HOT ENOUGH
TO SHAKE THINGS UP.
FOR MORE INFORMATION ABOUT THE
MOON, CHECK OUT THE SCIENCE
TREK WEBSITE.
YOU'LL FIND IT AT
IDAHOPTV.ORG/SCIENCE TREK