How big is the universe?

Most of the times we are stuck in our own life problems. Whenever I encounter some problem I try to think something big on the scale of universe and cosmos. Try to think on this scale is not less then a revolution for me.


Have you ever thought exactly how big is the UNIVERSE? As we all know the universe is constantly expanding in all directions, therefore its size cannot be stated. Scientists think it contains approximately 100 billion galaxies with each galaxy containing between 100 and 200 billion star systems. Our own galaxy, the Milky Way, is average when compared with other galaxies. It is a disk-shaped spiral galaxy of about 100,000 light-years in diameter.


If the age of universe is only 13.7 billion years, how can we see objects that are 30 billion light-years away?


This question is essentially answered by Special Relativity. When talking about the distance of a moving object, we mean the spatial separation now, with the positions of us and the object specified at the current time. In an expanding universe, this distance is now larger than the speed of light times the light travel time due to the increase of separations between objects, as the universe expands. It does not mean that any object in the universe travels faster than light.


I hope with this post you also might be getting some feel like me by forgetting your life affairs.


Image Source: SCIENCE@NASA