What is space?
Does space only exist when there's stuff in it?
Does space only have a meaning when it's enclosed by walls?

Think of the distance between two objects.
Does that gap still exist if you take the objects away?
What meaning can we give to distance if it doesn't have a start and end point?

Ultimately the question is this:
Does space in itself have form?
Does it have structure or shape?
or Is it just the place where things happen?

Since Newton's time,
gravity was thought to be a force that pulls all objects together.
But Einstein's general theory of relativity gives us a completely different picture and a totally
new perspective.
Although gravity appears to be a force ---
it's nothing more than the curvature of space itself.
When an object falls it isn't really being pulled by gravity ---
it's just following the simplest path through bent space.
The equations of general relativity revealed that
it was the presence of mass that caused space to curve and distort.
The reason we have gravity on earth is because the earth is actually bending the space around it.

In Einsteinium theory of the universe,
space becomes a dynamic entity that reacts to its contents.
Space knows about the presence of gravitating bodies,
and responds to their presence by changing its geometry.

observable universe

cosmic web
it shows massive clusters of galaxies linked together in vast filaments,
each one containing trillions of stars;
its scale is sometimes difficult to appreciate,
but it would take light almost ten billion years to across the distance in this image.

Far into the future, some hundred billion years from now,
if intelligent life form still exists in our galaxy,
they'll look out into space and see only the stars in our own milky way.
All the other galaxies will have disappeared,
and we'll be alone in a vast dark empty expanse.

To Aristotle, the concept of nothingness was deeply disturbing ---
it seemed to present all sorts of problems and paradoxes.
He came to believe that nature would forever fight against the creation of true nothingness ---
as he put it, 'Nature abhors a vacuum'.

'We live at the bottom of an ocean of air.'
The earth is cocooned in an atmosphere that rapidly thins out the higher you go ---
eventually becoming the cold silent expanse of space.

They believed there had to be a medium carrying the lightwaves.
'luminiferous aether'

This is the classical world.
Action and reaction.
Cause and effect.
It's sensible, certain, and knowable.

Heisenberg's uncertainty principal：
The more I know about where something is,
the less I know about how it's moving.

In truly tiny amounts of time and space,
something could come from nothing.
You could borrow energy from nothing,
so long as you pay it back quickly enough.
(the vacuum is alive)

the Dirac equation
If things and anti-things ever met each other,
they would instantly annihilate,
turning all their mass into energy.
Disappear completely.

Whenever you try to remove everything you can from empty space,
it's still always awash with all these fluctuations.
Within nothingness there's a kind of fizzing,
a dynamic dance as pairs of particles and anti-particles borrowing energy from the vacuum
for brief moments before annihilating and paying it back again.
The vacuum goes from being nothing
to being a place absolutely teeming with matter, anti-matter creation.
Nothingness is a seething mass of virtual particles appearing and disappearing
trillions of times in the blink of an eye.

Nothing really has shaped everything.
(embryonic universe)

We are simply the debris of huge annihilation of matter and anti-matter at the beginning of time.

There's a profound connection between
the nothingness from which we originated,
and the infinite in which we are engulfed.