WHAT IS THE UNIVERSE?

People in the past thought that the universe consisted of their own region and distant places, which they had heard of along with the sun, the moon, the planets and stars. As for the heavenly bodies, they believed them to be gods and spirits. It was during the 1400's and 1500's that astronomers like Nicolaus Copernicus made new discoveries.

Later on, the invention of Galileo's telescope shattered all the previous wrong beliefs about the universe and its behavior. Today, it is rightly believed that the universe is the whole of space and time and everything in them-matter, light and all other forms of radiation and energy.

Thus the universe includes the entire solar system-along with our earth and everything on it. All the stars (our sun is one of these stars) are part of the universe too. The bodies in the universe are big as well as small.

BIGGER BODIES

Billions of stars have formed large groups that are almost circular in shape. Our most powerful telescopes have located at least 10,000 million such stars-groups, which are generally called star-systems or galaxies. The galaxies in the universe tend to form even bigger groups that are called clusters. These huge clusters are also spherical in shape.

That is not all indeed. The clusters of galaxies in their turn appear to be grouped into still larger groups which we call super-clusters. These giant super-clusters are also circular in form.

SMALLER BODIES

The super-clusters are the largest coherent (united) bodies discovered in the universe so far.

Besides the stars, galaxies, clusters and super-clusters, there are other objects (bodies) too in the universe. They include planets, satellites, asteroids, comets, meteors and meteorites. All these bodies are scattered through the emptiness of the space.

Are there any other universes outside our own? This question still awaits an answer. So, we can say that no other universe has come to be known so far except the universe of which we are a part.