Astronomy - Entertainment - http://maxpages.com/gravity/Astronomy

How Big Is Big?

The Universe

What is the universee? It may be defined simply as aeverything that exists. The idea behind the definition certainly is not simple. Imagine that everyhing that exists, from the smallest atomic particle to the largest groups of stars, is part of the universe.

If we believe that definition is true, then the universe must be amazingly huge! Scientists are not sure about the size of the univers. Some scientists believe that the universe has no boundaries, no edgies, no limits. This is an idea that is difficult for most of us to understand. Perhaps as scientists continue to make new discoveries, they will be able to better help pus understand just exactly what the size of the universe is.

What are some of the things that amke up the universe? Astronomers (scientist who specialize in studying plantes, stars, and all other objects in space) have identified a number of space objects that are included in the vast area known as the universe. Among them are galaxies, groups of millions to hundreds of billions of stars. Between these stars are planets, comets, astroids, and black holes -- not to mention a whole lot of empty space. Just where do we fit in all this vastness?

Our small, blue planet, Earth is the third planet from the Sun. The Sun and its nine planets make up out solar system. It is believed that there are other solar systems in space. When we have our discussions about the Sun and the solar system we will be referring to the solar system which we are part of. Our Sun is a star, just like any other. Our Sun, along with other stars , belongs to a group of stars (a galaxy) called the Milky Way. The Milky Way is a spiral shaped galaxy. There is more than one galaxy in space. Not all galaxies (groups of billions of stars) are the same shape as the Milky Way. Earth also belongs to the Milky Way galaxy because the Earth circles the star called the Sun.

Groups of galaxies form clusters. The Milky Way, our galaxy is only a tiny part of a grouping of galaxies called a super cluster.

Secret's Poem:

Space keeps its secrets hidden.
It does not tell.
Are black holes time machines?
Where do lost comets go?
How many, how vast unknown galaxies beyond us?
Do other creatures dwell
on distant spheres?
Will we ever know?
Space is silent.
It seldom answers.

But we ask.

Galaxy

A galaxy is a gigantic mass of stars and other heavenly bodies. They are bound together by gravity and whirl through space at tremendous speeds. The galaxy we live in is callled the Milkay Way but there are billions of other galaxies in space.

Galaxies have different shapes. Many are sprial shaped. They look like slowly turning giant pinwheels.

Other galaxies are shaped like a football. The scientific name for this shape is "Ellipse". The stars in the center of an ellipse are packed closely together.

Still other galaxies have irregular shapes with random groupings of stars. This means they do not have a definite shape.

The Milky Way Galaxy

The Milky Way is the galaxy in which we live. It contains billioins of stars and is shaped like a spiral. All the stars we see when we look up in the night sky belong to the Milky Way Galaxy which is also the home of our solar system.

If you step out during the early evening on a clear, moonless winter night, you willl see a faint milky band of light stretching across the sky directly overhead. That is a band of stars known as the Milky Way, and it is part of the Milky Way Galaxy. How did our galaxy get its name? The ancients imagined it was a trail of milk. the Greeks derived the term 'galaxy' from their word 'gala' which means milk.

The stars in the Milky Way appear to be close together, but they are really separated by billions of miles of mostly empty space. Seymour Simon, a well known author who is considered an expert on space, writes, "If a dozen tennis balls were spread out across the United States, they would be more crowded than most of the stars in the Milky Way Galaxy.

Spiral galaxies have a center of gravity or nucleus and spiral arms that rotate around the nucleus. The Milky Way galaxy has three spiral arms. Our solar system is located on one of those arms.

Here are some amazing facts about our galaxy. The Milky Way is so huge it would take the light shining from a star on one side 100, 000 years to reach the other side. Also, the Milky Way is not standing still. We are moving ins pace at the speed of a million miles every two hours!!!

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Page Updated Tue Feb 22, 2000 5:39pm EST