is this endlessness?

[Eddi]

The plane between any 2 lines is flat.

But how does that make the universe flat?

 

[ChristineM]

But how does that make the universe flat?

You are still thinking in 2 dimensions. You need to drop that idea. Its flat (to at least 6 decimal places) in any direction you measure.

Take a large stiff card, cut it into a triangle. Lift one end of the card leaving the one point on the ground. You can move it any direction in 3 dimensions by leaving the one point fixed on the ground.

 

[Eddi]

You are still thinking in 2 dimensions. You need to drop that idea. Its flat (to at least 6 decimal places) in any direction you measure.

Take a large stiff card, cut it into a triangle. Lift one end of the card leaving the one point on the ground. You can move it any direction in 3 dimensions by leaving the one point fixed on the ground.

So it's flat but flat in all dimensions, not just in one? Basically, it is flat because you can always draw flat lines through it? In all directions?

 

[ChristineM]

So it's flat but flat in all dimensions, not just in one? Basically, it is flat because you can always draw flat lines through it? In all directions?

I think you've got it

 

[Eddi]

I think you've got it

But that's obvious

Why is the universe being flat but flat in all possible directions such a big deal?

Is that a new idea? Did people ever think differently?

 

[ChristineM]

But that's obvious

Why is the universe being flat but flat in all possible directions such a big deal?

Is that a new idea? Did people ever think differently?

If it's not flat it would curl back on itself. Like your chessboard.

It's only quite recently (10 years or so) that science has worked put how to measure it.

I think it weird that it's 13.8 billion years old, inflating but infinit. My only solution to this conundrum is that it's potentially infinite

 

[RestlessSoul]

I don't understand the difference to a triangle that exists in space and a triangle that's only drawn a piece of paper

It appears axiomatic (so obvious that it hardly needs to be said) that three points in space, connected by three straight lines, would have all the geometric properties of a triangle drawn on a piece of paper. But that would not be the case if space were not flat, but curved; which, just to confuse matters, it is, due to the gravity of massive objects.

 

[Eddi]

It appears axiomatic (so obvious that it hardly needs to be said) that three points in space, connected by three straight lines, would have all the geometric properties of a triangle drawn on a piece of paper. But that would not be the case if space were not flat, but curved; which, just to confuse matters, it is, due to the gravity of massive objects.

So space can be mis-shaped and bent by gravity?

How can that be so? I thought space was literally nothing?

 

[RestlessSoul]

So space can be mis-shaped and bent by gravity?

How can that be so? I thought space was literally nothing?

Well gravity, in Einstein's theory of General Relativity, is a geometric property of space and time. And if space has properties, it is something rather than nothing, since nothing, by definition, has no properties.

So space is not just emptiness, it is comprised of fields such as the electro-magnetic field, gravitational field etc: and the energy of a field in empty space is never zero. Theoretically something, rather than nothing, exists even in a void. And even where there is nothing, there is the potential for something - some random excitation of a field - to occur.

 

[Eddi]

What does "field" mean in this context?

Would even space in the middle of nowhere that is not next to any magnets or anything with gravity contain fields?

 

[ChristineM]

What does "field" mean in this context?

Would even space in the middle of nowhere that is not next to any magnets or anything with gravity contain fields?

You are getting into quantum theory here its a very heavy sibject.

Space is not empty, it's full of dust, gas, molecules, atoms, and quantum particles

 

[Eddi]

You are getting into quantum theory here its a very heavy sibject.

Oh no!

Space is not empty, it's full of dust, gas, molecules, atoms, and quantum particles

So is it impossible for there to be empty space?

Is there anywhere in the universe where it is truly empty?

 

[RestlessSoul]

What does "field" mean in this context?

Would even space in the middle of nowhere that is not next to any magnets or anything with gravity contain fields?

There may be regions in our universe beyond the influence of any gravitational or electro-magnetic fields. Or there may not - gravity is a weak force, but it's range is immense.

How Quantum Field Theory would apply in such conditions (if such conditions exist) I confess I don't know.

 

[Altfish]

I have a question that's been bugging me for years

I don't know how to explain this, it's simple to understand but hard to put in words.....

Imagine a chess board

Imagine you move a piece all the way to the edge of the opposite side, so that it is right at the top of the board

Now imagine you move it forward one space

And it reappears on the opposite edge of the board, right on the bottom of the board, to where it begun at the end of the game, on the same line

Now, imagine you have another piece and you move it to a square that is on the right edge of the board

You then move it one space to the right and it reappears on the left edge of the board, on the same row as it was before you last moved it

As though it has gone all around to the other side and as though the board is in some bizarre way round

What do you call this?

If the chess board works like that, does that mean that it is in effect never ending, as it is circular and has no edges?

Is that a type of infinity, or is it finite? It is at least endless and circular?

Might the universe work like that?

Didn't some of the early computer games (e.g. Pacman) work like that - I seem to remember going off screen on one side and appearing again on the other side.

 

[Eddi]

There may be regions in our universe beyond the influence of any gravitational or electro-magnetic fields. Or there may not - gravity is a weak force, but it's range is immense.

How Quantum Field Theory would apply in such conditions (if such conditions exist) I confess I don't know.

I want to learn about these things

I'll see if there is a good video on YouTube about it

 

[Eddi]

Didn't some of the early computer games (e.g. Pacman) work like that - I seem to remember going off screen on one side and appearing again on the other side.

Video games are what made me wonder about all this!

In Civilization II it did sideways, from East to West, but not from North to South, because that would be unlike a round globe, it would have to emerge elsewhere in the same hemisphere as it moved up in

 

[ChristineM]

Oh no!

So is it impossible for there to be empty space?

Is there anywhere in the universe where it is truly empty?

Not that i know of...

No one knows what the universe is expanding into, probabe it's making its own space as it expands though it could be expanding into nothingness, truly empty space.

 

[ChristineM]

gravity is a weak force, but it's range is immense.

It's range is infinite on the inverse square rule, getting weaker and weaker but never reaching zero.

 

[Yokefellow]

Video games are what made me wonder about all this!

Then there is your answer. We exist in a Simulation.

 

[Eddi]

Then there is your answer. We exist in a Simulation.

I used to very strongly believe that

I made lots of threads on RF about it

Now I think it's ridiculous