How big is the Universe? Many astronomers think it has no end, so its real size cannot be measured. But it is possible to measure the diameter of the observable Universe by calculating the distance between the farthest known objects in all directions.
The light from the most distant galaxies has travelled 15 to 20 million galaxies light years before it reaches the Earth. So the diameter of the Universe, as far as we can see, is as much as 40 million million light years, or 378 million million million million kilometres.
Picture Credit : Google