Space and time are big and complicated. Like, really big, and really complicated. The enormous sizes that we use when talking about space and the incomprehensible timescales of the universe truly boggle my mind. It is hard to understand just what it means for a star to be 150 light years away from earth, or for the earth to be about 4.5 billion years old, and for the universe itself to be almost 14 billion years old. But even more challenging to understand than the incredible time and size proportions that go so far beyond what human experience can comprehend is our current understanding of how it all started.
In her book Trespassing on Einstein’s Lawn, Amanda Gefter walks us through her journey to try to understand the Universe and the Big Bang. At the start of the Universe, 13.75 billion years ago, everything in the universe existed as nothing. Everything was everywhere around us, as Gefter and her father would come to call and undifferentiated homogenous state. And then something changed, and the Universe as we can see and measure it today began to take shape. That event has been called the Big Bang, and since that event the universe has been expanding and changing. The origin of the Big Bang is called a singularity in physics, and Gefter explains a little about that starting point of the universe:
“It was tempting to think of a singularity as small, but, as my father and I quickly learned, that’s a rookie mistake. It only seems small because you picture it as a point in space, as if you’re looking at it from the outside. But the singularity has no outside. It’s not a point in space because it is space. It’s the universe, it’s everything. We’re in the point. Besides, a point isn’t small—it’s sizeless. I had learned that in geometry class, in spite of my protests. You can just as well think of a point as infinitely big. The Big Bang happened everywhere, I scribbled in my notebook. Even in the suburbs.”
Thinking about space, time, and universe requires that we change what we understand nature and reality to be. The way that physics and nature work on planet Earth appear to be different from the way reality and physics operate in other parts of the universe, but the reality is that the physics is working the same and we are observing the same reality, just at different scales and with different things experiencing different forces. If we force everything to be understood as we experience reality with our limited set of senses and limited time scales here on Earth, we won’t fully understand what is happening throughout space and time. What Gefter explains throughout her book, and what must be accepted for all the physics of the universe to work, is that there is no gods-eye-view of the universe. You cannot take a viewpoint from outside the universe, because everything is within the universe. Whether the universe is a single dense point of all matter, or an ever expanding infinite expanse of galaxies, planets, and dust, every view point is within the universe. The Big Bang happened everywhere because it was everything. We cannot be a god and stand outside the Big Bang and watch it happen. We are inside the universe, and must look at the Big Bang from the inside.