Our Universe: Expanding, Evolving, and Massive in Scale
So….what is the Universe? The Universe is, well, everything! It is everything that we know exists and everything else – things we don’t even know, let alone understand. The Universe contains all the physical things that we can see and touch like matter as well as all the space in between. It contains all the laws that govern how the things we know behave – like gravity and time. It encompasses dimensions like height, width and length. It is everything!
The Universe is old and BIG. Scientists speculate that the age of our Universe is between 13 and 20 billion years and that it is about 93 billion light years in diameter (we’ll talk about light years some other time). By comparison, our galaxy – The Milky Way Galaxy is only about 30,000 light years in diameter. There are billions of galaxies in The Universe. Our solar system is roughly about 1 light year in diameter if you include the Oort Cloud. It is commonly believed that there are billions of planetary systems like our solar system in each galaxy. So…if you do the math – billions of planetary systems in billions of galaxies in The Universe, you start to get a sense of the enormity of it all.
Here’s the thing – the current thinking (including the Big Bang Theory) is that The Universe started as an incredibly small (subatomic), infinitely dense ball or singularity that exploded into the space we live in today. I would venture to guess that there are other universes as well. We just haven’t figured out how to detect them – they may be beyond the walls of our universe or they may exist in parallel to ours. What caused all of this to start? What happens when our universe stops?