(MUSIC)
JOAN CARTAN-HANSEN, HOST:
SCIENTISTS HAVE SPECIAL TERMS
FOR MEASURING VERY SMALL AND
VERY BIG DISTANCES.
A MICRON IS ONE MILLIONTH OF A
METER.
SOME BACTERIA ARE A FEW
MICRONS ACROSS.
A NANOMETER IS ONE BILLIONTH
OF A METER.
THE DNA INSIDE THE CELLS OF
YOUR BODY ARE ABOUT TWO
NANOMETERS ACROSS.
A PICOMETER IS ONE TRILLIONTH
OF A METER.
A HYDROGEN ATOM IS ABOUT 25
PICOMETERS ACROSS.
IN SPACE, DISTANCES ARE SO
VAST THAT WE MEASURE THEM IN
ASTRONOMICAL UNITS AND LIGHT
YEARS.
ONE ASTRONOMICAL UNIT OR A-U
EQUAL 93 MILLION MILES, THE
DISTANCE FROM THE EARTH TO THE
SUN.
SO, MARS, FOR EXAMPLE IS 1
POINT 5-2 ASTRONOMICAL UNITS
FROM THE SUN.
A LIGHT YEAR IS HOW FAR LIGHT
TRAVELS IN ONE YEAR.
A LIGHT YEAR IS 60 THOUSAND
ASTRONOMICAL UNITS.
THE SUN'S CLOSEST STAR IS
ALPHA CENTAURI AND IT'S 4
POINT 4 LIGHT YEARS AWAY.
FOR MORE INFORMATION ABOUT
MEASUREMENT, CHECK OUT THE
SCIENCE TREK WEBSITE.
YOU'LL FIND IT AT SCIENCE TREK
DOT ORG.