The Big Bang didn't happen *in* space, it happened *with* space. The universe didn't expand *into* an already existing space; space itself expanded. Think of it like this: Imagine drawing dots on a balloon. As you inflate the balloon, the dots move further apart. The dots themselves aren't moving across the balloon, the balloon's surface is expanding, and the dots are just along for the ride.
So, while all galaxies are moving away from each other, it's not because they're all rushing away from a single point. Instead, space itself is stretching and pulling them apart.
This means:
* No center: There isn't a single point in the universe that is the origin of the Big Bang. Every point in the universe can be considered the "center" because the expansion is happening everywhere at once.
* Relative motion: Galaxies are moving away from each other because of the expanding space between them. This means that galaxies far away from us are moving away faster than galaxies that are closer.
Analogy: Imagine a grid of dots on a sheet of rubber. If you stretch the rubber, the dots will move further apart. The dots themselves aren't moving, but the rubber is stretching, which causes them to appear to move away from each other. The Big Bang is similar: the rubber is space, and the dots are galaxies.
It's important to note:
* The Big Bang is not an explosion in the traditional sense, where things move outwards into a pre-existing space.
* The expansion is not accelerating in all directions from a central point; it's a uniform expansion of space itself.
Hopefully, this clears up some of the confusion!
