Space
Rotation and Revolution of Planets
 
 
What causes day and night?

Day and night are caused by the earth rotating on its axis.  An axis is an imaginary line through the earth from the north pole to the south pole.  As you see in the picture, the earth spins on this pole. As it spins half of the earth is facing the sun and having daytime and the other half is facing away from the sun having nighttime.

 
These pictures were taken from different satelites in space at about 7:00 pm St. Louis time (Central Standard Time) just as it is starting to get dark.   Notice how the eastern United States is dark and the restr is still light.  South America and Africa are in total darkness.  Asia and Australia (on the opposite side of the earth than us) are having day light.
 
Use the Satelite viewer to see what the earth looks like at the present time.

Shadow approaching Mid- Western United States.

South America is further east so it is already under the shadow of night.

Atlantic Ocean is completes dark as is Africa.

Africa is still having night but morning is not far away.

Dawn or Day break is over the Indian Ocan opposite of what is happening in North Amerca

Asia, and Australia are having daytime.

All the Pacific Ocean is Daylight

Night Shadow can be seen over North America again.
Here is a flat map of the earth showing what part of the earth is having day and night.  Compare this picture taken at 7:00 pm Central Standard Time to what it is like at the present time.

Image of the Earth from Satalite
 
What is the difference between a rotation and revolution?
A rotation is when the earth spins one complete turn on its axis.  This takes 24 hours or one day.  When the earth rotates it spins on its axis.  It always spins from east to west.  That is why the sun rises in the east and sets in the west.  Although the sun really is not moving the earth is.

    A revolution is when the earth makes a complete orbit around the sun.  An orbit is a circular path.
  Although it is not a perfect circle more
like an egg shape.  It takes 365 days or
one year for the earth to make one
revolution.  The earth, as well as the other
planets, revolves around the sun. 
The sun does not move. 
    It is the revolving around the sun that causes the changes of seasons on the earth.  Find out more about the seasons by visiting the NASA site.  Take a seasons quiz
 
What is the difference between a moon and a planet?
          A moon and a planet are similar.  They both are objects in space made of rock, they both reflect light, and they both rotate on an axis.
          The difference is that a moon (natural satellite) revolves around a planet and a planet revolves around a star or sun. Many planets in our solar system have more than one moon.  Find out how many moons each planet has at Astro for Kids.
   As the moon revolves around the earth, it reflects light from the sun.  Have you ever noticed that moon looks like it is different shapes.  These are called phases of the moon.
 
 
What is a solar system?

    A solar system is a group of planets that revolve around a star.  Our solar system consists of 9 planets that revolve around our star which we call the sun.  Can you name the planets.  Remember this sentence to help you remember the names of the nine planets in order from the sun:

My Very Educated Mother Just Served Us Nine Pickles.

Become a Planet expert by joining an expedition to one of the nine planets.  Follow the directions of this Planet Web Quest.

 
Is the Sun really a star?

   Yes the sun is really a star like any other star.  It just looks so big because it is so close compared to other stars. The sun, like any other star, is not a solid object like a planet.  It is a ball of burning gases.  It produces or makes light.

Have more questions about outer space, our solar system, or the sun?

The following sites are great places to learn more information about space, the planets and the sun.