A Heavenly Merry-Go-Round
Our Solar System is only a small part of the great Universe. Solar means “ of the sun.” A system is a plan to be followed. As we know that, The sun is the most powerful ruler of our Solar System. It is the center of our heavenly merry-go round. Old “‘ Sol ” is the ring-master of our skies. Around him the planets go like circus horses in a ring. He is the policeman who keeps this bit of sky traffic moving in an orderly fashion.
Our Solar System is made up of the sun, the planets, and their moons. Then, there are very small planets, called . asteroids. Swarms of meteors are streak through the sky. We call these balls of fire, shooting stars.
The Planets and a Train Trip
We know that there are nine planets. They’re Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. Jupiter is the largest; Mercury is the smallest and the closest to the sun. Pluto is the farthest away. Some planets move faster than others. ‘Our Earth is quite near to the sun. Near, that is, as distance is measured in the sky.
In the huge Universe a few million miles mean nothing. How far is our planet Earth from the sun? Is it one thousand, ten thousand, or a million miles away? No, our earth is much farther off than that. This is 93 million miles from the earth to the sun. Just suppose that a train could start from the earth and travel toward the sun at 50 miles an hour.
It would take that train 200 years to make the trip! That is almost three times as long as most people live. No one who began such a ride would ever live long enough to reach the sun! All of the planets are very small compared to the sun. Thousands of them could be dumped into the sun, and there would still be room for more.
Our moon’s surface is covered with high mountains and deep pits, or craters. There is no life upon our moon. It is too cold. All of the heavenly bodies in our Solar System get their light from the sun. Without the sun’s heat and light our world would be a cold, dreary place, for it has no light of its own. We should have to keep our fires going and our lights burning all of the time. Our earth is the only planet where people are known to live. All of the others are too hot or too cold or too something.
The Power of Gravity
Tis said Sir Isaac Newton once,
A man both good and wise,
Sat down beneath an apple tree
To rest and closed his eyes
For forty winks, when suddenly,
An apple from a bough
Fell toward the earth and landed on
Sir Isaac’s learned brow.
From such a simple thing this man
Discovered gravity,
And since that day his name and fame
Ring down through history.
What is it which holds the planets to their path around the sun? It is a strange thing called gravity. Gravity is like a magnet. It is the force which keeps everything from flying off into space and never coming back. It is the power which most objects have to pull upon ether objects. The sun has this pulling power. The planets have it; our earth has it. You and I have only a tiny bit of this power; we must use our hands to pull things to us.
When you throw a ball into the air, why does it come down? . Why does an apple or a leaf always fall toward the earth? Because gravity is on the job. You cannot fall off the earth because gravity keeps your feet on the ground. You cannot jump away up into the air because gravity pulls you back. Everything that goes up must come down. That is the law of gravity, and it cannot be broken. Without this law eve
rything would be all mixed up. There is always the tug of gravity between the sun and the planets. ; They all pull against one another; so each is kept in its proper place in our Solar System.
