many of the threads which discuss theories of space/gravity etc. use the phrase "space-time". can anyone please give me a simplish definition of this for it is a concept i havent come across at all before.

 

grateful for any response

Space is everything around us, and time is ...time.

 

Think of a graph with time on the x-axis, and space on the y axis. We exist on the line y=x

What exists around x=y? What lies not on our line?

Space is x y z, space-time is x y z today.

Just aman

starting to understand. am i right in saying that at the beginning of the y=x line, that was the start of the universe? and as time increases space also increases or expands?

We're not sure if the universe will always be expanding, the point of the graph is just to illustrate how one cannot exist without the other.

Imagine us traveling infinitly forward with the equation y=x. Now, say we start traveling through space faster and faster. This means our equation has to change to say x=1/2y. The faster we travel through space, the slower we travel through time.

 

"What exists around x=y? What lies not on our line?"

 

Beats me :l

Originally posted by fafalone

Space is everything around us, and time is ...time.

 

Think of a graph with time on the x-axis, and space on the y axis. We exist on the line y=x

 

how about relativity?

What about it?

Time is relative to a reference point. Since the big bang we are surrounded by reference points and even 50 billion light years away in the void, it may seem like only space but there is still time relative to us.

Maybe outside x=y is warped space-time

Just aman

All space-time is warped, just by a degree effected by proximity to massive objects; if you look at gravitation equations the influence of gravity only approaches 0 as the distance approaches infinity; so it's never 0.

All space-time is warped, just by a degree effected by proximity to massive objects

 

the above quote gives me visuals of a black background with green square grid over it, kinda bulging and tunelling in2 a black hole (ne1 seen that 3D episode of the simpsons?) am i thinking of the right thing here? i understand what everyone has said so far but i cant visulise "space-time"

 

has ne1 got links to a site with graphical info on it?...i always find tat much easier

 

tnx for everything so far thou

Assuming you have a functional visual system, you see space-time.

oh. i see

Space-time is the universe around us.

Originally posted by *Marmite*

(ne1 seen that 3D episode of the simpsons?) am i thinking of the right thing here?

 

hehe, I've seen that too; but that's more like a black hole kinda thing, except black holes should be much stronger.

 

Originally posted by *Marmite*

i understand what everyone has said so far but i cant visulise "space-time"

 

Well, in math, we assign different variables to describe different things that change.

 

In our world, we can go forward, sideways, and up. These variables make up space. Another way to show where we are is through time. ie. if there were only three dimensions, we would just be frozen. So time can be used to show where we are.

there many more than 4 dimensions...

Originally posted by fafalone

there many more than 4 dimensions...

 

There are an infinite number of theoreticals, but only empirically 4.

Isn't the theoretical number 26?

Originally posted by fafalone

Isn't the theoretical number 26?

 

Mathematically, there are infinite dimensions.

 

You can't use M-Theory as an example of a physical theory, as it's nowhere near complete. Empirically there are 4.

Originally posted by MrL_JaKiri

 

Mathematically, there are infinite dimensions.

 

You can't use M-Theory as an example of a physical theory, as it's nowhere near complete. Empirically there are 4.

 

M-Theory?

What are the other 26 dimensions?

lol

 

But I remember reading about 9 dimensions in Temporal Mechanics;

 

Or what about the 11 dimension string theory?

Historical note: we use the phrase "space-time" because in Einstein's relativity theories, both space (3 dimensions) and time (1 dimension) get treated in an analogous way, mathematically. Therefore, it was convenient to have a phrase with which to refer to both space and time dimensions at once. Hence, Space-Time.

Historical note: we use the phrase "space-time" because in Einstein's relativity theories, both space (3 dimensions) and time (1 dimension) get treated in an analogous way, mathematically. Therefore, it was convenient to have a phrase with which to refer to both space and time dimensions at once. Hence, Space-Time.

 

true

 

but this is what is happening and this is pervasive , throughout all of physics and astronomy for this is not the first time that I have persented this argument which is ;

 

that space has some substance asscociated with it and that time has some sort of energy associated with it

 

both associations are entirely error simply put

 

you can't grasp space

 

and time , no matter how much is entered into an equation will NEVER change the situation between two or more objects EVER

 

but what will change the situation between objects is the energy which is inherent within the objects and the energy which is from the object and projected out beyond the object its self

 

hence a movement and therefore hence a measure of " time " that this happens because of the objects themselves nothing more nothing less

There are an infinite number of theoreticals, but only empirically 4.

 

Would you believe there is a fifth dimension? That space-time could be the surface of a five-dimensional balloon?

 

Gravity and Space-Time: Related to Each Other