Put simply, nothing is defined as "the absence of something."
Think of the number zero. For the purposes of this article, we'll take it to mean nothing. The absence of something – the absence of numbers.
There's a lot to be said about a number that represents nothing. The entire number system is riding on zero – is riding on nothing. It defines place values, defines the significance of digits. This one closed loop that has no value of its own.
You can't convert zero into something unless you think additively. Zero can be converted to one easily enough – 0+1=1. Simple math. But that's not how everyday objects work, and we attempt to describe everyday objects. The trouble is, the simplest everyday object can carry a world of abstract ideas within itself.
Think of it like this – A balloon can be filled to occupy a large space, assuming it doesn't burst. It'll grow to twice its size, three times its size, and so on. In fact, that's usually how we compare quantities. This isn't anything new. But this is one of the most notable differences between something and nothing. You can't do this with nothing.
To convert something into more of something, you can multiply it. Mathematically speaking, 5*2=10. If you have five apples and you add five more, you have twice as many apples. But...
0*1=0
0*2=0
0*3=0, and so on.
x*0=0, not x.
Neither can you distribute something amongst nothing. Every schoolchild knows – division by zero, by nothing, is undefined.
But for all that we have set up around this number, this entity, our knowledge is incomplete, because it is next to impossible to conceive of nothingness.
All our lives we have been surrounded by something – air, space, anything. Usually when we speak of nothing, we mean "nothing of consequence" or "nothing that pertains to this conversation." In daily use, "nothing" has become a shorthand for this specific kind of nothingness.
But there's a principle in science – there's no such thing as empty space. Essentially, there's no such thing as nothing. Even in the vacuum of of space, there's at least one particle per some thousands of units of volume. And even here on Earth, nothing is not a concrete concept. We have always described nothing in terms of something. So, we may have turned nothing into a function of something. There's something that can be said about that.
In many ways, our language explains our psychological tendencies. I don't have to define a pen in terms of a pencil. I don't have to define heart in terms of the amount of blood it pumps. I could, but it won't be necessary. These objects don't rely on each other for their definitions, the way nothing depends on something. And even this dependence is one-way, because something doesn't have to rely on nothing to define it.
Our trouble with conceptualizing nothing is an explanation for why the Big Bang is not an easy concept to grasp. The math checks out, sure. But if you sit down to think about it long enough, a question does rise – "How can something be created out of nothing?"
Indeed, because here are some ideas the Big Bang model puts forth:
1. There was no space or time when there was a singularity, and one could not come into existence without the other.
2. The singularity itself was infinitely hot and dense, and all that would become our universe was packed into an extremely tiny volume.
You need space to describe where something is, and you need time to tell when something happened. But how do you explain where the Big Bang occurred, when space was nothing? How do you explain what came before the Bang, when you couldn't invoke an idea of time, since time was also nothing?
Space and time are part of something. They are the most fundamental somethings anyone can think of. Their absence creates the most fundamental nothing, the kind of nothing no one can ever dream of. Because we've never experienced or come close to experiencing such a thing.
And the hot and dense part. This is where we know of something coming from nothing.
The "primordial soup" we call the singularity had an immense amount of energy. Energy equates to heat, hence we say the singularity was hot. But the thing is, space wasn't defined; it didn't exist. So all that energy was packed into...well, nothing. Conditions were getting divided by zero, because that was all that did exist. And anything divided by zero not only is undefined, but it is also infinite. All that energy, packed into nothing...it became everything.
There are few places and conditions where our definitions of the everyday world just crumble, become meaningless. The origin of the universe is one of them.
We've done so much with the concepts of zero and nothingness, it is nearly impossible to imagine where we'd be without them. But at the same time, we can't think of them in the same way that we think about everything else, either. What a concept nothing is!
