The coastland times with which is combined the pilot and herald of Belhaven and Swan Quarter. [volume] (Manteo, N.C.) 1959-1973, 1960-12-23
ATOMIC CLOCKS MAY
LOSE ONLY SECOND
IN MILLIONS OF YEARS

| WASHINGTON. - Science i.
starting to tell time with clock.
so accurate they may lose only
one second in millions of years.
The fantastic precision is made
possible by the absolutely steady
vibration of atoms, acting as pen.
dulums in timepieces as revolu-
tionary as the sundial of 140(
BE-, the National Geographic So.
ciety says.
A clock tells time by recording
the regular recurrence of an event
such as the swing of a pendulum
or a cycle of alternating electric
current. A clock counts the recur.
'rences and translates the infor.
nation in terms of hours and min.
utes.
Earth Runs Slow
But neither the swing of a pen
dulum nor the current cycle in an
electric clock is regular enough
for present-day scientific work.
Even the great pendulum" Of
nature-the earth itself-does not
always take the same time to ro-
tate around its axis. The globe,
now slowing down, takes about
one-thousandth of a second long
er to turn than it did three years
ago. The rotation is uneven due
to a slight wobble.
To make a really accurate
clock, scientists needed a phenom-
enon that occurs with extreme
regularity. They found it in the
minute vibrations of the atom.
Each type of atom has its own
particular frequency of incredibly
constant vibration.
In 1913 the National Bureau Of
Standards built a clock using as
its pendulum the nitrogen atom
in ammonia. The nitrogen atom
swings back and forth at the rate
of 24,000,000 times a second.
Three years later Charles H.
Townes of Columbia University,
was sitting in a Washington park
with slime on my hands," when
he suddenly conceived an even
more accurate ammonia clock.
With his colleagues, he devised a
new timekeeper called a maser,
an abbreviation for "microwave
application by stimulated ennis
sion of radiation"
The first maser worked by
picking up the radio wave which
an ammonia molecule emits each
time it's nitrogen atom vibrates.
The wave receiver is adjusted to
vibrate at precisely the same
frequency as the nitrogen atom.
This very, very steady movement
controls the motor of an electric
clock.
In 1860 Harvard University
scientists announced the develop
ment of a still more accurtae mas
er, using high-energy hydrogen
atoms trapped in quartz bulb.
The oscillating atoms give off a
|21-centimeter radiation chorus
which is so steady that the clock
is reported to have an accuracy
of one part in a quadrillion. This
means, theoretically, that it could
measure time with an error Of
only one second in 100000
years.
May Check on Einstein
Such superaccuracy will enable
scientists to study the minute TO-
tations of atoms and molecules.
1t also may help determine wheth-
er Albert Einstein's theories of
RELATIVELY are correct.
DR.. Einstein's special theory of
relatively holds that the hands
of a clock turn more. slowly if it
is moving. Thus a clock placed in
vehicle travelling at the speed
of light would come to a stop.
According to the general theory,
the rate at which a clock runs
also depends on the strength Of
the gravitational field it is in. A
clock ticks more slowly as it is
moved closer to a large body.
These theories may be tested
eventually by placing an atomic
colck in a satellite and comparing
it's record of time with that of
identical atomic clocks on the
clock in a satellite and comparing
at $4,000 miles an hour; they are
far less affected by gravity than
objects on the earth's surface.