According to scientists the universe expanded at the big bang from a size of less than a single atom to a billion times.Currently they found out that the universe does not become static but is still expanding . They donot know will the universe would stop to expand , will it come to a stand still, will there be a end of universe or a beginning of a new universe. Some scientists beleive that the force of gravity would not remain so strong and the universe would continue to expand further.The proof for the expanding universe is the red shift, all the galaxies are moving away from us. It was also found that the farther away is the galaxy from us , the faster it is moving away from us.We cannot predict the center of universe , Friedmann assumed that the universe is similar in all directions.The red shift can be explained easily , the scientists observed the frequency of radiations coming from a galaxy , the frequency decreases with time which means the number of waves coming to us is decreasing , because the galaxy is continously moving away from us. As the frequency decrease the wavelength increases that is why they called it as red shift (red light has maximum wavelength).
Newton and other scientists thought that the universe would come to stand still and from there would start to contract.But that is not happening.
Shristi uniyal 