Transcript Solar Movements

MOVEMENT IN THE SOLAR
SYSTEM
The sun is a huge ball of glowing gases
at the center of the solar system. This star
supplies light energy for the earth and for
the other planets that move around it.
Without this light energy, the earth would
be a cold, dark planet.
Many years ago, people watched the sun rise,
move across the sky, and then set. They believed
that the earth was still and that the sun was
moving around the earth. We now know that
the sun only appears to rise and set. It is the
turning of the earth that causes sunrise and sunset.
T earth is like a ball that is spinning on someone’s finger. The
The
earth spins on an imaginary line called an axis. Each time the
earth goes around it is called a rotation.
The rotation makes day and night. As the earth turns, the part
that faces the sun has day and the part away from the sun has night.
The length of time for the earth to rotate is one full day. It takes 24
hours for the earth to rotate.
REVOLVING AROUND THE SUN
As it spins, the earth also moves around the sun. This movement
is called revolving. The path that the earth takes around the sun is
called the orbit. When the earth completes one complete path
around the sun it is called one revolution. It takes the earth one
year to complete this trip. So a revolution takes about 365 days.
If the earth was straight up and down on its axis, sunlight would
always hit the earth at the same angle. However, the earth is tilted
and as it makes its revolution around the sun different parts of the
earth get more sunlight than others.
WHAT DOES THE MOON’S MOVEMENT CAUSE?
You have seen the brightness of a full moon on a dark night.
However, the moon does not make its own light. Moonlight is
actually sunlight reflected from the moon.
Even though the moon is shaped like a ball, its shape seems
to change from day to day. Those different shapes are the
moon’s phases. Sometimes it appears that the moon is a full
circle. This is a full moon.
As the moon revolves around the earth, a part of the dark side
of the moon faces the earth. As the days pass, people see more of
the dark side and less of the moon. The moon slowly changes to a
half circle. When the moon is a half circle, half of the moon is lit,
and half is dark. This is called a half moon.
As time passes, only the dark side of the moon faces the earth.
The moon does not appear in the sky. This is called a new moon,
though it is really not new. The moon is beginning a new set of
phases or stages. The new moon takes place a little more than two
weeks after a full moon.
The moon slowly changes from the new moon back to a
full moon. The changes from a full moon, to a new moon, and
back to a full moon take 29 1/3 days. The moon takes this long
to revolve around the earth once.
June 12
June 15
June 30
July 2
June 18
July 5
June 21
June 24
July 7
July 8
June 27
ECLIPSES OF THE MOON :
As the moon revolves around the earth, the earth usually
does not come between the sun and the moon. When the
earth does come between the sun and moon the moon will pass
through the earth’s shadow, which causes a lunar eclipse.
The moon usually does not come between the earth and
the sun. When it does, the moon blocks some sunlight from
the earth, and a solar eclipse takes place. The moon makes a
small shadow on the earth. From this shadow, the sun appears to
get covered slowly.
HOW DO THE PLANETS OF THE SOLAR SYSTEM MOVE ?
For thousands of years, people have watched the stars at
night. The stars appear to rise and set slowly as the night
goes on. The stars and sun make their own light.
From night to night, some points of light seem to move
among the stars. These are the planets. Planets, like the earth
and moon do not make light. They get light from the sun.
It has been known for more than 500 years that planets are
satellites of the sun. That means that they go around the sun.
This model represents the scale size of the nine planets as they are in
orbit around the sun.
THE PLANETS
Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto
MERCURY
Time for orbit - 88 days
Time for rotation-176 days
Moons - 0
This picture represents the hills on Mercury.
Mercury
Mercury is covered with large holes called craters. These
craters were formed when Mercury was hit by huge rocks from
space.
Because Mercury is closest to the sun, it is very hot. The
temperature on Mercury can reach 425 degrees Celsius.
Mercury is less than half the size of Earth and has no moons.
VENUS
Gula Mons - a volcano
Time for orbit - 8 months
Time for rotation - 127 days
Moons - 0
Eistla - A Rift Valley
This is a picture of the Arachnoids, one
of the most interesting things about Venus.
Notice how the land is spiral-shaped.
This picture was taken using
special equipment so that the
different elevations of Venus
would show up.
Venus is about the same size as Earth. It is always covered
with clouds. These clouds are made from drops of acid. The
air is mostly carbon dioxide.
Venus has giant volcanoes.
EARTH
Time for orbit - 1 year
Time for rotation - 1 day
Moons - 1
MARS
As you look at the pictures
you will notice that Mars is
much like Earth.
Time for orbit - 1.9 years
Time for rotation-25 hours
Moons - 2
Mars
Mars is covered in reddish dust and rocks. Winds blow the
dust into the air and make the sky pink.
Mars has giant volcanoes. It also has a giant canyon much
larger than the Grand Canyon on Earth.
The temperature on Mars is usually lower than on Earth.
JUPITER
Time for 1 orbit - 12 years
Time for rotation -10 hours
Moons - 16
Notice the large red spot on Jupiter.
It is a large storm that is larger than Earth.
Jupiter
Jupiter is the largest planet. Some of its moons are bigger
than some of the planets. One of its moons even has volcanoes.
Unlike the other planets, Jupiter gives off energy that heats the
gas above it.
These are the rings of
Jupiter.
This is the Giant Red Spot on
Jupiter. It is a storm that is
larger than the Earth.
SATURN
Time for 1 orbit - 29.5 hours
Time for rotation - 10 hours
Moons - 17
Saturn is the 2nd largest
planet. It has many moons.
Saturn has storms and
gives off energy that heats
the air above it. Saturn has
bands that are harder to see
than Jupiter’s bands. It has
Here is a close up of the rings.
beautiful rings that are made
of thousands of thinner rings.
URANUS
Time for 1 orbit - 84 years
Time for 1 rotation - 17 hours
Moons -15
Uranus is 4 times larger than Earth.
It is so far away that it is very cold.
Uranus is a blue-green color because
of a gas that is around it. Uranus has
at least 10 narrow rings.
NEPTUNE
Time for 1 orbit - 165 years
Time for rotation - 18 hours
Moons -2
Not much is known about Neptune and Pluto. Neptune
is a large planet that looks greenish. Scientists hope to learn
more about Neptune in the future.
PLUTO
Time for 1 orbit - 250 years
Time for 1 rotation -6 days
Moons -1
Pluto is the smallest planet.
It is about the size of Earth’s moon.
Meteors and Asteroids
A meteor is a piece of rock or dust from space that burns up
in the earth’s air. People see meteors as flashes of light crossing the
sky. Some people call them shooting stars, but they aren’t stars at
all.
Meteorites are any part of the meteor that reaches the Earth.
Asteroids are rocky objects that orbit the sun between the planets.
The largest asteroid is about the same size as the state of Texas.
Comets
Large chunks of ice and dust orbit the sun. These
are called comets. Comets have orbits that are much longer
and flatter than the planets. Comets can not be seen from the
earth when they are far away in their orbit.
When comets are far away from the sun, they do not get
much heat. As comets move closer to the sun, the sun’s
energy begins to heat them. Some of the ice becomes a gas.
The sun pushes the gas and dust into a long tail. The tail goes
from the bright part of the comet known as the head. A
comet’s tail can be millions of kilometers long.