It is quite possible and amazing to grasp that the whole universe could contain many more observable universes. People want to know what is out there past the earths universe. They want to know how big exactly the whole universe is. For all anyone knows, it could be infinite.
The observable universe is simply the space around the earth that can be observed. It is only a small fraction, possibly, of the whole universe. To picture this, draw a small circle. That is the earth. Then draw a larger circle around it. In between those two circles is the observable universe. Everything outside of that larger circle is the whole universe. The biggest circle drawn representing the rest of space could be undecipherable, for it is unknown how big the whole universe is.
The observable universe is massive and since the whole universe could be infinite, then that must be extremely massive. The earths universe travels within the wide open space. It takes an entire year for the earth to rotate around the sun. It takes 250 years for the entire solar system to orbit the Milky Way. The outer space could be so much bigger and may possibly contain hundreds, thousands, millions, billions, or trillions of other milky ways. Within the earths universe, the closest star is 40 light years away. If a voyager was sent to that star at 17 kilometers per second, it would take 74,817 years to get there. The observable universe is currently 46 billion light years away. That means the entire diameter is around 93 billion light years away.
It is amazing to know that the observable universe gets bigger, and that could mean the whole universe either becomes bigger or smaller. The edge is determined by the light reflecting off of the furthest stars. Light takes time to travel, so when the light from the furthest star reaches the earth, it is basically seeing into the past. Say the light from a planet from millions of years ago finally reached the earth and then it blew up. The fact that it had exploded would not be known for millions of years. Eventually light from other galaxies will reach the earth and expand our observable universe. Therefore, the view of the cosmos is getting bigger as older light reaches the earth.
There is an edge to the observable universe and it is unknown if the whole universe has an edge. For all anyone knows, the outer space is infinite. Many wonder if there is a ledge to the outer edge.
Every edge diameter must have a center. The observable universe has a center. It is the earth. Everything has a center of its own universe. People have their own center of their own observable universe. If a person was on the tippy top of a tower, that person could see as far as the horizon. Anywhere inside the diameter of the horizon would be considered their own personal universe. But they could not see past that horizon, like one cannot see past the observable universe.
By Brittany Varner-Miller