is the definition of space relative ?

genphis

I have just finished reading stuart clark's book 'The Universe' and i find myself pondering the question of space its possible infinite size,shape, and its relation to our universe.
a) if space did not exist before our universe's expansion. What are we expanding into and what are we pushing back to make room for our universe?
b) it seems to me inevitable that there are a multitude of universes which are separated from ours via vast incomprehensible distances.
c) And do these universes and ours reside in a megaverse?

d) i am troubled that we accept that we are falling through space.but is the space we fall through the same space our universe exist in ?

sorry to ramble

mfb

What are we expanding into and what are we pushing back to make room for our universe?

Nothing. We don't need to "make room", and there is no "outside" to push back / expand into.

it seems to me inevitable that there are a multitude of universes which are separated from ours via vast incomprehensible distances.

This cannot work with the usual definitions of "universe" - there is no distance without space, and there is no space without universe.

And do these universes and ours reside in a megaverse?

Pure speculation and/or depends on the definition.

i am troubled that we accept that we are falling through space

What do you mean with "falling through space"? I am standing on earth.

but is the space we fall through the same space our universe exist in ?

Our universe does not exist in some space, our universe IS space (plus objects in that space).

genphis

thanks for reply, it was my understanding that the earth was hurtling in orbit approximately 66,000 mph around the sun, which in turn is orbiting with among many celestial objects the centre of our galaxy possibly a super massive black hole, in addition to this our galaxy is also in an orbiting spiral. i meant falling in a universal sense not localised to my position on the earth. if we use our own experience of space and time as a measure we will not learn much about the universe. we fall around the curvatures in space created by matter warping the fabric of space-time.
if something expands, there must be room for the expansion,if not pressure will build and hey presto big bang

d3mm

Quote by genphis

if something expands, there must be room for the expansion,if not pressure will build and hey presto big bang

Intuition is holding you back, you have to understand it terms of solutions to equations and not in everyday concepts like 3 dimensions. They don't really apply here.

EDIT: in fact, you said it yourself:

if we use our own experience of space and time as a measure we will not learn much about the universe

genphis

point taken d3mm thanks..... i struggle with the fact that if we were in a box we would be free to move around within that space. but if our box was in another box, our box would be the only space we experience. yet that experience would limit our ability to understand the processes really at work in the scheme of things.......

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genphis	point taken d3mm thanks..... i struggle with the fact that if we were in a box we would be free to move around within that space. but if our box was in another box, our box would be the only space we experience. yet that experience would limit our ability to understand the processes really at work in the scheme of things.......