1027 meters = 1000 yottameters

I have spent a lot of time thinking about how to present this image. There is more than one way to approach the issue. The image at the left represents the size of the known universe -- a sphere with a radius of 13.7 billion light years. The rest of the image is black because if anything is there, it is fundamentally unknowable to us on Earth because of the speed of light. (This comes from Einstein's general relativity that nothing can travel faster than the speed of light.)

Our universe is 13.7 billion years old and so any light from objects further away than 13.7 billion light years has not had time to reach us. Gravitation is also limited to the speed of light. Any object beyond 13.7 light years can only affect us in the future.

There are some conceptual difficulties with this image. It makes it appear that the Earth is at the center of the universe and we have no reason to think our place is unique. The universe should look the same from any viewpoint at any place in the universe.