Is the universe expanding?
In the 1990s, Australian and British astronomers compiled the largest map of the universe by plotting the positions of more than 30,000 galaxies. Most of these galaxies are moving away from us here on Earth. Most astronomers believe that the universe is expanding that all points in the universe are getting farther apart all the time. It's not that stars and galaxies are getting bigger, but rather the space between all objects is expanding with time.
We never notice the expansion on planet Earth because it happens over such a large scale. In fact, it was only in 1929 that the expansion of the universe was discovered, when American astronomer Edwin Hubble brought together many scientists' work. He studied the sky and created “Hubble's diagram,” which showed that the redness of a galaxy's light, and thus the speed with which the galaxy moved away from Earth, increased with its distance from Earth, and that the increase graphed into a straight line. The farther away a galaxy is, the faster it moves away from us.