The curiosity of people has always been piqued by the cosmos, as for thousands of people have turned their eyes towards the sky in a state of amazement. People’s understanding of the universe was incredibly limited until the birth of the telescope in the early 17th century, a technological innovation that completely expanded the common perception of the universe. By the 20th century, astronomy had become sophisticated enough to begin recognizing other galaxies in the universe and understanding just how small the Earth was in the universe.
Astronomy and it’s technologies have progressed far enough today for astronomers to see the very limit of what is possible to have seen in the universe, thus creating the boundaries for our known universe. Astronomers state that the universe is about 93 billion light-years across, meaning Earth is 46.5 billion light years away from the edge of the known universe at any given time.
To put that in a more understandable scale, imagine that the distance between the Earth and the Sun, about 93 million miles, is represented by the thickness of one sheet of paper. Using this measurement to put things into scale:
- Representing the distance between Earth and Alpha Centauri, the nearest star to Earth, would require a stack of paper 70 feet high.
- The diameter of the Milky Way would be the equivalent of a stack of paper 310 miles high.
- Covering the distance between the Earth and the edge of the known universe would require a stack of paper reaching 31 million miles into the air.
- Depicting the size of the known universe would require a stack of paper that was 62 million miles tall!
Most references to the size of the universe are actually about the size of the known universe. This is due to the fact that astronomers and scientists do not actually understand much about the universe beyond the observable boundaries. What is visible to astronomers on Earth are objects that are close enough for light to have traveled the distance to Earth since the birth of the universe. Beyond those limits, scientists have little to no understanding and can only postulate, even suggesting that the universe may be an infinite, open structure outside of our visible perception of it.
Most people would assume that since our visibility limitations are based on the amount of time light has traveled since the birth of the universe that more of the universe would become visible to people on Earth as time progressed. In spite of this logic, recent astronomical observations have shown that the boundaries of the known universe are quite definite. Astronomical observations have actually captured evidence that galaxies appear to be moving, an indication that space is expanding. Based on the images retrieved by astronomers, space not only is expanding but is doing so at an accelerated pace. The expansion of space make it highly unlikely that light from objects beyond the edge of the known universe would ever be able to move faster than the rapid expansion of space.
In conclusion, although the universe as people on Earth know it is absolutely massive and the rapid expansion of space is only increasing the size of our universe, there is little known about what exists beyond the limits of our observations and there exists a great chance that the known universe that is perceived on Earth is only a tiny fraction of the entire mass of our universe and cuold perhaps be only one of many universes existing simultaneously.
Here are a couple of cool animations to help visualize the scale of the universe: