"From Out Of This World" - читать интересную книгу автора (Morrison William)

FROM OUT OF THIS WORLD

THE campfire had died down, and as a song came to an end, John looked up. Far
overhead, the stars twinkled through the clean air. And then, suddenly, there
was a flash of light.
"Look!" cried Johnny. "A star just fell down!"
"There's another one!" shouted the boy next to him.
"And another! Gosh, soon there won't be any left in the sky!”
But you don't have to worry about that. What Johnny and his friends had seen
falling were not real stars, but "shooting stars,” also known as "meteors."
A real star is like our sun, only so far away that it looks very small. There
are trillions of miles between us and the nearest star, and even light takes
many years to travel that distance.
But a shooting star is very much closer. Actually, it's usually very little. It
may be no bigger than a lump of sugar, and is sometimes even smaller. It travels
many miles a second, but not nearly as fast as light.
How, you ask, can we see a tiny thing that moves so fast? Because, when it
enters the earth's atmosphere—that's the layer of air around the earth—it warms
up. In fact, as it rushes through the air, it gets very hot, and that's why we
can see the streak of light which looks like a star falling.
The earth's atmosphere not only lets us see the meteors, it protects us from
them. Tens of thousands of meteors enter the earth's atmosphere every day.
Imagine what it would be like if all of them landed around us! It would be like
being in a battle that never ends.
But the air slows the meteors down, heats them up, and in a few seconds most of
them vanish. They just change into gas and dust and we don't even realize that
most of them have existed. For instance, you don't see shooting stars during the
day, and yet as many hit the earth's atmosphere in the day as at night.

WHAT SHOOTING STARS ARE

How do we know what shooting stars are made of? Well, for one thing, not all of
than vanish in the air. Some are so large that they get through the atmosphere
and hit the ground. When that happens, people usually see a great streak of
light, and hear a boom similar to a shell exploding.
A meteor is like a shell in other ways too. Either before it lands, or just
after, the meteor may explode with pieces flying in every direction. If it
doesn't explode, it may bury itself deep in the ground, burning up the trees and
grass all around it.
About forty years ago, a great meteor landed in Siberia with a tremendous roar
that could be heard miles away. In fact, people who were a long distance off saw
a great ball of fire rushing through the sky. This meteor roasted everything
within miles, and must have weighed thousands of tons. It did as much damage as
an atomic bomb, although by good luck it landed in an unpopulated wasteland.
When a shooting star actually lands, and we see the pieces, they are not called
meteors any longer, but "meteorites." Most of these meteorites are smaller than
the one that hit Siberia, some weighing only a few pounds, others a good part of
a ton. At any rate, they're big enough to be examined.