This is "Science
in the News" in VOA Special English. I'm Steve Ember. This week our
program is about a mystery as
old as time. Bob Doughty and Sarah Long tell about the mystery of
as old as:
tan antiguo como;
If you can read a clock, you can know the time of day. But
no one knows what time
itself is. We cannot see it. We cannot touch it. We cannot hear it. We
know it only by the way
we mark its passing.
nadie; by the way: por la forma (que);
For all our success in measuring
the smallest parts of time, time
remains one of the great
mysteries of the universe.
parts: las partes más pequeñas; remains: sigue siendo;
One way to think about time is to imagine a world
There could be no movement,
because time and movement cannot be separated.
sin; There could be no movement: no podría faltar el movimiento;
A world without time could exist
only as long as there were no changes.
For time and change are
linked. We know that time
has passed when something changes.
only as long
as: solamente mientras que; for: pues; linked:
In the real world – the world with time – changes never stop. Some
changes happen only once in a
while, like an eclipse of the moon. Others happen repeatedly,
like the rising and setting of
the sun. Humans always have noted natural events that repeat
themselves. When people began to count
such events, they began
to measure time.
once in a
while: de vez en cuando; rising and setting of the sun:
salida y puesta del sol; such events: tales acontecimientos;
to measure: para medir;
In early human history,
the only changes that seemed
to repeat themselves evenly
were the movements of objects in the sky. The most
easily seen result of
these movements was the difference between light and
human history: en la historia humana primitiva; seemed:
parecían; evenly: con uniformidad; easily seen; fácilmente
apreciable; darkness: la oscuridad;
The sun rises in the eastern
sky, producing light. It moves
across the sky and sinks
in the west, causing darkness. The appearance and disappearance of the
sun was even and
unfailing. The periods of
light and darkness it created were the first accepted periods of time.
We have named each period
of light and darkness – one day.
el Este (oriental); moves across: se desplaza a través (del);
sinks: cae, se hunde; even: regular, uniforme; unfailing:
infalible; each: cada;
People saw the sun rise
higher in the sky during the summer than in winter. They counted the
days that passed from the sun's highest position
until it returned to that
position. They counted three hundred sixty-five days. We now know that
is the time Earth takes
to move once around the
sun. We call this period of time a year.
observó (que); until: hasta (que); takes: le lleva;
once: una vez;
Early humans also noted changes in the
As it moved across the
night sky, they must have
wondered. Why did it look
different every night? Why did it disappear? Where did it go?
luna; as: a medida que; must have wondered: deben haberse
preguntado; did it look: se veía, parecía;
Even before they learned
the answers to these questions, they
developed a way to use
the changing faces of the
moon to tell time.
aún antes de (que); developed: desarrollaron; changing:
The moon was "full" when
its face was bright and
round. The early humans counted the number of
times the sun appeared
between full moons. They learned that this number always remained
the same – about twenty-nine
suns. Twenty-nine suns equaled
one moon. We now know this period of time as one month.
llena; bright: brillante, resplandeciente; times: veces;
the same: inalterable; equaled: equivalían a;
Early humans hunted
animals and gathered
wild plants. They moved
in groups or tribes from
place to place in search of
food. Then, people learned to plant
seeds and grow
crops. They learned to
use animals to help them work, and for food.
cazaban; gathered: recogían; wild plants: plantas
silvestres; tribes: tribus; in search of: en busca de;
seeds: semillas; crops: cultivos;
They found they no longer needed
to move from one place to another to survive.
needed: ya no necesitaban;
As hunters, people did not need a way to measure time. As farmers,
however, they had to
plant crops in time to harvest
them before winter. They had to know when the
seasons would change. So,
they developed calendars.
no obstante; to harvest: para cosechar; seasons:
No one knows when the first calendar was developed. But it seems
possible that it was based on moons, or lunar months.
When people started farming, the
wise men of the tribes
became very important. They studied the sky. They gathered
enough information so
they could know when the seasons would change. They announced when it
was time to plant crops.
sabios; became: resultaron; enough: suficiente;
The divisions of time we use today were developed in ancient Babylonia
four thousand years ago. Babylonian astronomers believed the sun moved
around the Earth every
365 days. They divided the trip
into twelve equal parts, or months. Each month was thirty days. Then,
they divided each day into twenty-four equal parts, or hours. They
divided each hour into sixty minutes, and each minute into sixty seconds.
Tierra (planeta); trip: viaje.