How Old is The Universe?
The night sky with twinkling stars is a fascinating sight. Although it looks very big with millions of stars, what we are able to see is a very small part of the universe. According to scientists there may be as many as 10,000,000,000,000,000,000,000 stars in the universe!
It is difficult to find out how old the universe is, but scientists have found a way to calculate it, or at least to estimate how long it has been here in its present form.
Many scientists believe that the universe began with a big explosion that sent all matter flying out into space. This theory is called the ‘big bang’ theory.
One of the reason to believe in the big bang theory is that the universe seems to be expanding. All stars and galaxies are flying away from each other (may be due to the first big explosion).
Scientists can measure the speed of stars and by comparing the speed of the nearer and the distant stars they can figure out when the stars began to move through space. And they say that the universe is at least ten billion years old!