A theory on the Universe expanding

[Skins]

I was asked a question, "Is the universe expanding". I went on to explain that the universe is expanding and the expansion is accelerating. To use an analogy I described the expansion as accelerating similar to the follow.

 

Imagine you are in the stratosphere and affected by gravity and so falling back to earth (disregard an atmosphere that would cause resistance). At this distance from the earth the gravity will be less than 9.8m/sec² but as you fall the gravity will increase towards this and you will fall faster and faster as the effect of gravity increases.

 

Now look at that in reverse and the universe is expanding but at an accelerated rate that is increasing. The exact opposite to the effect of gravity or like gravity in reverse.

 

Then a wild thought came to me. The effect of gravity on an object with mass is similar but opposite to the expansion of the universe.

 

Let's suggest that gravity does not just pass through space but interacts with it causing a type of anti-gravitational effect. So gravity from objects with mass interact with space causing space to have an inverse relationship to the effect of gravity. So gravity actually causes space to expand and the more space that then exists the more interaction we have resulting in an acceleration of the expansion of the universe.

 

But wait there's more...........

 

Is it possible that is the explanation for the existence of Dark Energy and if so then the so called Dark Energy in the universe is increasing also.

 

[ajb]

Let's suggest that gravity does not just pass through space but interacts with it causing a type of anti-gravitational effect. So gravity from objects with mass interact with space causing space to have an inverse relationship to the effect of gravity. So gravity actually causes space to expand and the more space that then exists the more interaction we have resulting in an acceleration of the expansion of the universe.

The modern theory of gravity, General Relativity, understands gravity as the local geometry of space-time. So, I am not exactly such what you mean here. Small ripples in the geometry, known as gravitational waves propagate on space-time and this maybe the closest to what you have in mind.

 

Anyway, you can have rather exotic situations such as repulsive gravity (for example on test particle near cosmic strings).

 

An expanding universe requires a negative energy density and in the simplest form that is added by hand as Einstein's cosmological constant.

[Strange]

Now look at that in reverse and the universe is expanding but at an accelerated rate that is increasing. The exact opposite to the effect of gravity or like gravity in reverse.

 

One problem with this is that gravity increases with a square law against distance as you fall. The rate at which expansion accelerates is not (as far as I know) a square law. Also it changes with time, not distance.

 

However, you are right in as much as the same model that describes gravity (GR) also describes the expansion of the universe.

 

 

Is it possible that is the explanation for the existence of Dark Energy and if so then the so called Dark Energy in the universe is increasing also.

 

And, indeed, it is thought that dark energy is increasing as the universe expands (it is sometimes described as the "cost" of space). This is why, at some point, expansion started accelerating.

[Skins]

Anyway, you can have rather exotic situations such as repulsive gravity (for example on test particle near cosmic strings).

 

I liked the term repulsive gravity that might be a better term.

 

 

One problem with this is that gravity increases with a square law against distance as you fall. The rate at which expansion accelerates is not (as far as I know) a square law. Also it changes with time, not distance.

 

However, you are right in as much as the same model that describes gravity (GR) also describes the expansion of the universe.

 

And, indeed, it is thought that dark energy is increasing as the universe expands (it is sometimes described as the "cost" of space). This is why, at some point, expansion started accelerating.

 

With that said it may be a repulsive gravity from matter that is actually acting on space. No doubt space is a substance and has properties and may even be one of the further dimensions described in string theory.

 

As strange suggested gravity has a square law and I would assume a repulsive gravity may have a similar effect. But as the universe expanses then the volume of the universe expands and so the interaction between a repulsive gravity and space would increase conforming with the fact that the universe is expanding at an increasing rate.

 

Now consider that as the universe get older then more matter is being converted to energy and the mass of the universe is hence decreasing. If my wild assumption had some substance then all the while the volume of space would continue to increase but....

 

Eventually it may reach a tipping point where as the mass of the universe decreases enough and the total interaction causing expansion may start to reduce and the universe could start to slow and then collapse.

 

I am sure this is one notion no one wants to let go of (everyone always thought the universe would stop expanding and most likely collapse). I find it hard to believe the lights just go out as the universe expands forever.

 

This theory would also satisfy that "at some point expansions started accelerating", this may have happened when the volume of the universe increased to a tipping point that the interaction between a repulsive gravity and space reached a point causing this acceleration and while it looks like a runaway effect it may reverse with matter reducing in the future.

Edited November 10, 2015 by Skins

[Strange]

No doubt space is a substance.

 

I doubt it.

 

Now consider that as the universe get older then more matter is being converted to energy and the mass of the universe is hence decreasing.

 

I assume you are thinking that gravitational attraction will decrease as mass decreases? But both mass and energy contribute to gravitation (remember e=mc²? mass and energy are equivalent.)

 

Eventually it may reach a tipping point where as the mass of the universe decreases enough and the total interaction causing expansion may start to reduce and the universe could start to slow and then collapse.

 

The accelerating expansion (attributed to some unknown thing labelled "dark energy") suggest that will not happen.

 

I am sure this is one notion no one wants to let go of (everyone always thought the universe would stop expanding and most likely collapse).

 

Actually, until the accelerating expansion was discovered, I think this "big crunch" scenario was assumed possible or even likely.

 

 

I find it hard to believe the lights just go out as the universe expands forever.

 

Unfortunately (or fortunately?) science isn't based on what you or anyone else finds hard to believe. Einstein laid much of the groundwork of quantum theory. But he never believed what the theory predicted (he was wrong).

[Skins]

 

I doubt it.

 

 

I assume you are thinking that gravitational attraction will decrease as mass decreases? But both mass and energy contribute to gravitation (remember e=mc²? mass and energy are equivalent.)

 

 

The accelerating expansion (attributed to some unknown thing labelled "dark energy") suggest that will not happen.

 

 

Actually, until the accelerating expansion was discovered, I think this "big crunch" scenario was assumed possible or even likely.

 

 

Unfortunately (or fortunately?) science isn't based on what you or anyone else finds hard to believe. Einstein laid much of the groundwork of quantum theory. But he never believed what the theory predicted (he was wrong).

 

On the I doubt it. If space is expanding then is has a property of a substance or element. (I would suggest that the space within our universe should be considered a substance as it must abide by the basic laws of physics as we currently know them. It conducts light, magnetism, gravity etc, and the edge of our universe is considered a membrane by many. (but not proven) The space outside our universe may not abide by these laws, but that is leading to another theory I have.) Considering dimensions in string theory it is not likely that all those dimensions will contain tangible elements with atoms etc. but if they have strings of energy then they could be considered and element?

 

If mass could be responsible for repulsion of space then as the universe gets older and mass decreases (as it is converted to energy) it may reach a point where the mass acting on space, in the form of repulsion has less effect then the gravitational effect of the mass acting on other objects with mass. This may not happen until a large amount of the mass is converted to energy E=mc².

 

Scientists are not sure if the acceleration of the universe will continue to increase, but I am presenting a theory or idea whereby I see a possibility that gravity could react with space differently than is does with matter and cause repulsion of space while there is still an attraction of matter.

 

 

 

 

[Strange]

On the I doubt it. If space is expanding then is has a property of a substance or element.

 

I don't see why. You need to understand that "expanding space" is just an analogy and, apparently, a confusing one. What is expanding is something abstract: the distances between points in space.

 

 

If mass could be responsible for repulsion of space then as the universe gets older and mass decreases (as it is converted to energy) it may reach a point where the mass acting on space, in the form of repulsion has less effect then the gravitational effect of the mass acting on other objects with mass.

 

But mass and energy behave identically with regard to gravity.

[Skins]

 

I don't see why. You need to understand that "expanding space" is just an analogy and, apparently, a confusing one. What is expanding is something abstract: the distances between points in space.

 

 

But mass and energy behave identically with regard to gravity.

 

Strange I can see you are switched on and for me this is just an interest so there is lots I don't understand but a fair bit I have looked into and I know a there are lot of assumptions yet to be proven.

 

You may suggest that expanding space is just an analogy and consider the space between points of matter is expanding but in string theory space may be made up of strings that have an intrinsic energy much like a rubber band wanting to expand. I would suggest no one is sure what space is least of all you or me..... but we can guess until we know for sure.

 

For me I think of space as being associated with a dimension. We live in a four dimensional universe space - time, but what is say that space is not made up of strings, it certainly has plenty of properties but does not have matter and hence does not produce gravity.

 

 

And I didn't realise energy can behave identically the same with regards to gravity. I had a bit of a look around and found explanations that photons could produce gravity but....

 

Heat is another form of energy and I have found nothing that would suggest that heat could create gravity.....

 

Now to contradict myself. I know sensible heat is the vibration of atoms but in the void of space we don't have atoms so the only way we could have heat in space is radiation which is part of the electromagnetic spectrum so now we are back to energy does produce gravity because the electromagnetic spectrum is a form of light.

 

Anyone else around who can expand on this and if matter is converted into energy will it produce the same gravitational effect that would have been produced by the matter that was converted?

 

I find this stuff interesting and have joined to make hair-brained suggestions (then again many popular theories now were most certainly not accepted readily at first - like string theory) and learn interesting facts that I will never put into practice.