What IS space?

[nkt]

Why do you think a photon needs something to travel through? If you think of a ball or a bullet, they move rather better without anything in the way, so why should a photon require a medium?

Space is probably quantised, if you get down small enough. Everything has to be, really. A continuous analogue slider is limited by the granularity of the atoms and the tunneling effects in the materials, and so is only capable of being set to discrete levels. It is just that they are so close as to blur into one range at almost any resolution.

[WebFeet]

Originally Posted by nkt

Why do you think a photon needs something to travel through? If you think of a ball or a bullet, they move rather better without anything in the way, so why should a photon require a medium?

The medium that a photon travels through enables distance to be defined.

IMO, a photon travels at inifinite velocity, except where it encounters other photons.

Photons are their own medium.
A bit like a drop of water in a pond. The environment of the pond determines how the drop of water reacts, but at the same time the drop of water is an integral part of that environment.

One of Maxwell's equations relates the speed of light to the permittivity and permeability of free space. The speed of light is determined by how much energy is contained in a section of free space and the rate at which that section will allow energy through.

If a photon is energy, then this could be interpretted as the speed of a photon is determined by the rate at which a section of free space will allow a photon to pass through it, which is in turn determined by how photons that section of free space contains.

The more photons you add, you less permeable and subsequently slower a photon can travel.

[infamous]

Let's preform a little thought experiment; Before the Big Bang, there existed a nothingness which nothing could exist within. As the great energy of the Big Bang was released, it created an energy matrix within which matter could exist. As this "energy bubble" expanded and cooled our present universe took on it's present character. At a point very distant in the future our universe will cool to the ultimate measure and Entropy will have reached it's limit. This raises a question in my mind; When this limit is reached, will this "energy bubble universe" cease to exist collapsing back into nothingness?????

[virtualmeet]

Originally Posted by Buffy

To paraphrase Einstein, Space is the thing that keeps everything from happening in the same place...

Cheers,
Buffy

Yes buffy, and also according to string theory, space is also a substract for strings, the indivisible part of energy: strings use "space" to "move" between hyperspace.
According to string theory, everything made frome energy can be described by a sets of strings...so I'm thinking that, perhaps, the only way to describe "space" is to say that is the "incountable" part of our universe, since eveything else can be "countable" according to string theory... Or, if you want, apace is the "incountable" part of our universe (also, nature seems always be made from two opposites parts).
In short terms :
Space = !Strings
According to this view, space is no longer an "entity" in itself, it's existance is tied to the existance of strings: No strings ==> No space !!

[WebFeet]

Originally Posted by virtualmeet

Space = !Strings
According to this view, space is no longer an "entity" in itself, it's existance is tied to the existance of strings: No strings ==> No space !!

I think the other way around works better.

!Space = Strings (?)
No Strings != No Space

[virtualmeet]

Originally Posted by WebFeet

I think the other way around works better.

!Space = Strings (?)
No Strings != No Space

Oh yes, this is an opposite view to what I have said

[WebFeet]

Originally Posted by infamous

As this "energy bubble" expanded and cooled our present universe took on it's present character.

I've always had a problem with this.

How does energy cool ?

The only way that an energy bubble can cool, is by dissipating its heat (energy). Where does it get dissipated? Into the void surrounding the bubble, resulting in the bubble expanding.
So isn't it correct to say that expansion and cooling are one and the same thing ?
Basically, the density of the energy bubble/cloud kept reducing.

Here's my view on the whole creation thing.

In the beginning there was a single pythagorian point containing all the energy in the Universe. This pythagorian energy point had a single identity and subsequently had no dimensions. The concept of a pythagorian point is usually viewed as the smallest thing imaginable - basically a coordinate. However, if there is nothing else to measure it against, it can be huge, in fact it could be the size of the Universe.
The Big Bang doesn't have to come from something small. A single uniform energy particle the size of the Universe.

Somewhere within this particle, there is flaw in the uniformity. This sets up a difference in potential between one side of the particle and the other. The result is Particle Mitosis. The particle splits to become two energy particles with seperate identities.
This Mitosis will continue until all the particles are the same size and have ceased to move. At which point we are back to having a single identity for all the energy - and the whole process starts over again.

If the energy between us and a distant galaxy were going through this Particle Mitosis, then it would give the impression that the space between us was increasing exponentially, making it look as though the galaxy was accellerating away from us.

[Qfwfq]

Originally Posted by nkt

Everything has to be, really.

Why in the universe does everything have to be quantized?

[lindagarrette]

Originally Posted by infamous

Let's preform a little thought experiment; Before the Big Bang, there existed a nothingness which nothing could exist within. As the great energy of the Big Bang was released, it created an energy matrix within which matter could exist. As this "energy bubble" expanded and cooled our present universe took on it's present character. At a point very distant in the future our universe will cool to the ultimate measure and Entropy will have reached it's limit. This raises a question in my mind; When this limit is reached, will this "energy bubble universe" cease to exist collapsing back into nothingness?????

Yes. It's called "the big rip' theory.

[Iron4ever]

Originally Posted by lindagarrette

Yes. It's called "the big rip' theory.

Here is a big rip of my own from MSNBC that may explain this theory a little better.

The universe is expanding at an ever-increasing pace, and something unknown is vacuuming everything outward.

What would happen if the rate of acceleration increased?

The big rip theory states that a phenomenal pace would overwhelm the normal, trusted effects of gravity right down to the local level. Even the nuclear forces that bind things in the subatomic world will cease to be effective.

The expansion could become so fast that it literally rips apart all bound objects. It rips apart clusters of galaxies. It rips apart stars. It rips apart planets and solar systems. And it eventually rips apart all matter.

Driving the known acceleration of the universe’s expansion is a mysterious thing is called dark energy, thought of by scientists as anti-gravity working over large distances.

The Big Rip theory has dark energy’s prowess increasing with time, until it’s an out-of-control phantom energy. Think of our car accelerating an additional 10 mph every half mile, then every hundred yards, then every foot.

Before long, the bumpers are bound to fly off. Sooner or later, our hypothetical engine will come apart, regardless of how much we spend on motor oil.

There are many unknowns. It is not clear if the dark energy driving expansion is a force not currently described by physics, or if it is merely a different manifestation of gravity over huge distances. The repulsion could be a response to dark matter, unseen stuff that is known to comprise 23 percent of the universe, based on firm observations.

Dark matter has unknown properties, and it may be related to dark energy. Einstein considered that gravity might work repulsively, in a manner consistent with his theory of general relativity.

Dark energy, being quantified only recently, tends to be discussed as some strange new force, in addition to the four fundamental forces: gravity, electromagnetism, and the strong and weak nuclear forces that govern atoms. But the repulsion is possibly just the way gravity behaves in the presence of dark energy. In that sense, it is not a new force.