What are meteors?
Dust, ice, and gas are left around the orbits of comets. Well, the Earth comes near some of these orbits quite often. When this
happens, some of the dust and ice hit the Earth’s atmosphere. The ice melts
away, while the dust and bits of gravel enter the atmosphere so fast that they
glow from the friction. These glowing bits of dust and gravel are called
meteors, which are sometimes called shooting stars.
Every November 27, Earth comes near the orbit of Biela’s Comet, and there
is a meteor shower. A meteor shower is when more than one meteor is seen in the
same area at the same time. Once in a while, Earth passes through the part of a
comet’s orbit where the main part of the comet once was. When this happens,
there is a huge meteor shower.
This happened on November 12, 1833. It was the largest meteor shower ever
described. There were so many meteors that some people thought all the
stars were falling!
Billions of meteors enter Earth’s atmosphere every day. We can’t see them
all because some enter the atmosphere in daytime, and others are so small and
dim that you would only be able to see them through a powerful telescope. Most
of the meteors that enter the atmosphere are dust. They usually burn up before
they are even 50 miles from Earth’s surface!
What are meteorites?
Every once in a while, a large piece of matter enters the atmosphere. It is so
large it doesn’t burn up. It becomes brighter and hotter and turns into a
fireball. Fireballs shoot off sparks and make noises like thunder. They can even
explode!
The outside of the fireball melts and flakes away, but before it can
completely melt it hits the ground. What is left of the fireball is called a
meteorite. They are different from stones because their surfaces are glassy and
smooth from melting. What didn’t melt is mostly metal. It is 90% iron and 10%
nickel.
Most meteorites only weigh a few pounds, but some have been known to weigh a
few tons! That is like the weight of three or four elephants put together!
Meteorites can cause a lot of damage. In 1908, a large meteorite crashed into
a forest in northern Siberia. It killed 1,500 reindeer and knocked a man
unconscious who was 50 miles away! Large meteorites are very rare though.
Thousands of years ago when there were a lot more large pieces of matter in
space, there were more meteorites. The moon is covered with craters from
meteorites hitting it. Some of the craters on it are hundreds of miles across!
In Arizona a meteorite hit about 10,000 years ago. It left a crater that is
now ¾ of a mile across! Some even larger meteorites hit Earth in the past, but
wind and water have erased most of the damage over thousands of years.
