# Could dark energy and expansion of space be just a topological effect?

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1. Oct 2, 2012

### Artifex 28

Sigh. My first post. I wrote rather long message here and as I tried posting it, "you need to login" - and it vanished. :(

Anyways. I have no high physics/math education but still I consider myself enthusiasts. So be gentle! :)

Consider the following "my way of filling sudokus", just thinking stuff to pass time and foolishly try to make sense of this all. :p

Here we go. My question / hypothesis / mindgame is following: Could the expansion of space - and dark energy (that´s the "mainstream" cause of acceöerated expansion, isn´t it?) - be just a topological effect of gravity to space-time fabric itself?

Gravity stretches space-time. Or (rest) mass - suppose those two go together anyways.
If the gravitational field is strong enough, black hole is created with event horizon being the point of no turning back for even light.

Massless space-time fabric can be thought as a "2 dimensional sheet of paper, without borders".

As you introduce gravity/mass, it is stretched. So could this stretching of space-time be the actual topological effect of whole space-time expanding? The greater the gravity, the "faster the streching" of space-time. As the gravity stretches the space-time, the greater the actual area of the space-time is. So could this be the reason why we are actually observing our universe expanding? The space-time IS actually stretched via gravity, generating more observed space in accelerated manner?

This could also explain the voids we have around the universe. They are virtually massless areas where the gravitational fields are very weak compared to the "mass focus points". The mass focus points around the void keep "sinking deeper" in the stretching space-time, expanding the actual space "between" the mass focus points and the "voids" - ever extending from everywhere.

Gravity is measured as acceleration towards the field. So could the "sinking" in space-time itself be "accelerated" through gravity - causing the observed universe to expand faster and faster? As we "fall deeper" to the ever stretching space-time, everything around us is speeding away from us. And the same applies to any point in space of course.

Currently dark energy, as far as I know, is the "number #1 subject" of the expansion. But what if that does not really exist as a particle at all and the whole expansion is nothing but a topological effect/constant we keep observing?

Well, although this most probably causes but facepalms, I still thought I´d type it up - again - just to see what the people with the skills think of a "mortals thoughts". :D

...and could the whole observable universe work another way around? "Where there is gravity, there is mass?" That would give an interesting twist to E=mc^2

Last edited: Oct 2, 2012
2. Oct 2, 2012

### Drakkith

Staff Emeritus
Gravity doesn't stretch spacetime, gravity IS the stretching and curving of spacetime. The stress-energy tensor in General Relativity describes how stress and energy cause this curvature. Energy being both rest mass and energy in all its forms.
Voids are simply large areas of space that are devoid of large amounts of matter. They have little gravity because there is little mass and energy to cause any gravity. They are a result of the initial fluctuations in the density of the early universe. Denser areas collapsed under gravity to form galaxies and other objects, while less dense areas grew into large voids.

I have read that dark energy isn't actually necessary to explain the accelerating expansion, and that it could simply be the cosmological constant. (Which is something completely different that I cannot explain)

3. Oct 3, 2012

### clamtrox

If I'm understanding you correctly, you are visualizing a 2d rubber sheet, which is bent by masses. As the bending goes on, the area of the rubber sheet is increasing. You then interpret the area of the rubber sheet as the volume of the universe, and say this means universe is expanding.

But then you would expect that, observing a galaxy far far away, the more stuff there were between us and the galaxy, the faster the galaxy would appear to move away from us. This is not at all what is observed.

The reason your thinking fails is that the area of the rubber sheet does not correspond well to any notion of volume.