Earth and Space

“http://creativestockphoto.com/wp-content/uploads/2014/09/images-of-earth-in-space.jpg” 

Author: Belinda Gallagher 

Book Title: Encyclopedia of questions and answers 

What is the Universe made of?

According to the book of Ms. Belinda Gallagher

“The Universe is made up almost entirely of hydrogen and helium. these are the two lightest elements. all the rest of the matter in the universe is very rare. elements such as silicon, carbon and others are concentrated into clouds, stars and planets. the universe is held together by four invisible forces. Gravity and electromagnetism are the two familiar forces. The other two kinds are strong and weak nuclear forces. These operate only inside the incredibly tiny nucleus of atoms, holding the tiny particles together.”

How Old is the Universe?

“It is possible to calculate the approximate age of the Universe by looking at how fast the distant galaxies are moving away from us. However, it is not possible for us to make this calculation accurately. Scientist have estimated that the Universe is between 13,000 and 18,000 million years old.”

What was the Big Bang?

“The Big Bang is the most popular theory about the creation of the universe. According to it, the whole Universe was created in a split second in one huge explosion. All matter was squeezed together into a tiny, super-hot, dense ball that was smaller than an atom. The ball gradually expanded as it cooled, Then exploded, releasing energy and matter in all directions. We cannot see the Big Bang because it would have happened billions of years ago. But we can see that the Universe is growing steadily bigger. All galaxies are speeding away from each other as the Universe Expands”

 

Why is the Earth round?

Gravity pulled the earth and the other planets into a sphere when they were being formed. The Earth is not truly round, but is slightly flattened making it bulge out at the equator. This effect is due to the speed with which the Earth spins, causing the Equator to try to fly out from the Axis of the spinning Earth. It is rather like a heavy object whirling round on the end of a piece of string. The shape of some of the other planets is Distorted in the same way.

all credits to Ms. Belinda Gallagher(except the photo)