# Alternative to straight universe expansion (Question)

## Recommended Posts

So I had an interesting thought, what if instead of the universe expanding due to an unknown cause it is expanding due to something right under our noses? What if the universe is one constant size but the things beyond it's 'boundary' are invisible to us because their light has not reached us yet? There could be a way to account for redshift in ways other than straight expansion due to an unknown cause,. This sounds absolutely preposterous and most likely is, but what if photons produced a warping effect on space? Tiny wakes for each photon, this could explain why Dark energy causes 'expansion' and how such an amazing amount of energy exists at all, because imagine that each and every photon produced a tiny wake and lump that combine energy together. If this proves to be true it could be that the universe is not expanding at all is expanding due to photon wakes and that these tiny photon wakes are warping and increasing the distance between say us and the moon or any points by stretching space a tiny bit. Imagine when you fill the balloon up with water that this represents the effect of the photon wakes despite the fact that the balloon, and that could account for redshift.

A. What do you think of the thought? It's just a shower thought really but I found it interesting.

B. Given each photon produces a wake, then there must be a way to physically measure that amount of energy based on displacement at the speed of light.

C. Is there a way to hypothetically calculate the number of photons in the universe?

D. Given each photon produces a wake, and the amount of displacement at the speed of light equals the quantity of dark energy in the observable universe, what would this mean?

Edited by DanTrentfield

##### Share on other sites
8 minutes ago, DanTrentfield said:

What if the universe is one constant size but the things beyond it's 'boundary' are invisible to us because their light has not reached us yet?

That is basically correct.

But the only reason that the light hasn't reached us from beyond the observable horizon is ... because of expansion!

10 minutes ago, DanTrentfield said:

There could be a way to account for redshift

Various other explanations have been tried. And some work - as standalone explanations that don't have to fit with any of the other evidence. So when Lemaitre and then Hubble published the red-shift data, it was consistent with the idea of expansion but, by itself, it wasn't convincing.

11 minutes ago, DanTrentfield said:

but what if photons produced a warping effect on space? Tiny wakes for each photon, this could explain why Dark energy causes 'expansion' and how such an amazing amount of energy exists at all, because imagine that each and every photon produced a tiny wake and lump that combine energy together.

Photons do cause curvature of space-time. Every source of energy does. But first you would need to quantify how large an effect this is and if it is enough to account for any observed effects. (I am fairly sure I have seen some calculations along the lines - and for neutrinos - but I don't think I could find them right away).

Also, not that dark energy is not required to explain expansion, but only to explain the accelerating expansion. And that requires an increasing amount of energy - and I would guess that the number of photons flying around is fairly constant. And they are, on average, decreasing in energy because ... expansion!

(Expansion is kind of a given, and is determined by the initial conditions of the universe.)

16 minutes ago, DanTrentfield said:

C. Is there a way to hypothetically calculate the number of photons in the universe?

I have seen estimates of this. I think (I may be wrong) that the majority are in the CMB. (Which is also the most compelling evidence for ... expansion!)

I think it is a reasonable idea to investigate (and I bet it has been) although I suspect the numbers would show it doesn't work. (If I have time later, I'll see if I can dig something up.)

• 1

##### Share on other sites

Thanks Strange!

Also, I must beg the question, even though as you said it is a 'given', what causes the universe to expand in the first place, not to mention the accelerating expansion that I forgot to mention.

I personally think that it could be that the expansion isn't really "expansion" per-se in the way that most people think of it, yes the universe is expanding but it's really more of the shockwave of the big bang is continuing to go outwards and space is duplicating itself and more visible light is appearing to us, and this can happen in a variety of ways ranging from thinly supported hypothesis above to extremely exotic methods such as it being a side effect of gravity or another force which has a strange and currently unrecognized side affect. (Because if Newtons third law is universally correct then there should be something weird going on due to gravity existing as each force should have it's equal and opposite according to the law). Also: To support the big rip theory, could it be that the great void in the cosmos (The area where there is nothing, no light, no stars, no radiation, nothing) is a piece of rips beginning to appear and expanding slowly over billions if not trillions of years from continual duplication of space? And that the universe is actually a lot more fragmented than we think? Because light from that far away takes hundreds of millions to billions of years to reach us, then that means the universe could literally be in like six pieces and we would not know it, if the big rip theory is correct.

Edited by DanTrentfield
Forgot to mention my thoughts on something and major mistake

##### Share on other sites
1 hour ago, DanTrentfield said:

If this proves to be true it could be that the universe is not expanding at all is expanding due to photon wakes and that these tiny photon wakes are warping and increasing the distance between say us and the moon or any points by stretching space a tiny bit.

The expansion of the universe is only evident over larger scales. Over smaller scales, say our local group of galaxies, the gravity of the mass energy within such regions, overcome the expansion we observe over the larger scales. And even smaller scales will see the EMFs and strong and weak nuclear forces overcome the observed large scale expansion. That explains why planets, stars, us etc are not affected by the expansion of spacetime over larger scales.

• 1

##### Share on other sites
1 minute ago, beecee said:

The expansion of the universe is only evident over larger scales. Over smaller scales, say our local group of galaxies, the gravity of the mass energy within such regions, overcome the expansion we observe over the larger scales. And even smaller scales will see the EMFs and strong and weak nuclear forces overcome the observed large scale expansion. That explains why planets, stars, us etc are not affected by the expansion of spacetime over larger scales.

This is why we have peer review!  You see I missed that.

##### Share on other sites
1 minute ago, DanTrentfield said:

Also, I must beg the question, even though as you said it is a 'given', what causes the universe to expand in the first place

That is due to the initial conditions of the universe - hot, dense and expanding (and therefore cooling). Why was the universe in that initial state? No one knows.

The description of space-time in GR shows that space-time containing a (roughly) homogeneous distribution of mass must either expand or contract - it isn't stable. The initial conditions caused to to expand. It used to be thought that gravity would slow it down and lead to it contracting, but the (unexplained) acceleration makes that look unlikely.

Quote

Because if Newtons third law is universally correct then there should be something weird going on due to gravity existing as each force should have it's equal and opposite according to the law

Oooh. Careful. That doesn't mean that each type of force must have an opposite, but that the forces on a body must be equal and opposite. So, for example, gravity is a force pushing you down into your chair while the (electromagnetic) forces  in the material of the chair push back the same amount (and, therefore, you don't move).

##### Share on other sites
11 minutes ago, DanTrentfield said:

Thanks Strange!

Also, I must beg the question, even though as you said it is a 'given', what causes the universe to expand in the first place, not to mention the accelerating expansion that I forgot to mention.

I think the answer to that is the same as the answer to what caused the BB. We don't know.

The way I view the whole picture [I may stand to be corrected on this issue] is that just after the initial BB or a part of it, Inflation took part. The density of the universe at that time saw the incredible rate of inflation gradually slowed to a more sedate pace, until a period was reached where due to the continued, albeit slowing expanding rate, the density eventually dropped to such a figure, that the large scale expansion rate again took over and we observed an acceleration. This is where we find ourselves now.

Edited by beecee

##### Share on other sites
13 minutes ago, Strange said:

That is due to the initial conditions of the universe - hot, dense and expanding (and therefore cooling). Why was the universe in that initial state? No one knows.

The description of space-time in GR shows that space-time containing a (roughly) homogeneous distribution of mass must either expand or contract - it isn't stable. The initial conditions caused to to expand. It used to be thought that gravity would slow it down and lead to it contracting, but the (unexplained) acceleration makes that look unlikely.

Oooh. Careful. That doesn't mean that each type of force must have an opposite, but that the forces on a body must be equal and opposite. So, for example, gravity is a force pushing you down into your chair while the (electromagnetic) forces  in the material of the chair push back the same amount (and, therefore, you don't move).

Whoops  Even people with degrees in science still make silly makes like this from time to time because they are focused on the big picture instead of nuances, which is why peer review is so damn important, because imagine how many brilliant scientists that win Nobel prizes would appear like babbling buffoons that forget that acceleration due to gravity is equal to g=GM/r2 because they are looking at why two planets are in a position in the sky instead of focusing on little nuances like that.

11 minutes ago, beecee said:

I think the answer to that is the same as the answer to what caused the BB. We don't know.

The way I view the whole picture [I may stand to be corrected on this issue] is that just after the initial BB or a part of it, Inflation took part. The density of the universe at that time saw the incredible rate of inflation gradually slowed to a more sedate pace, until a period was reached where due to the continued, albeit slowing expanding rate, the density eventually dropped to such a figure, that the large scale expansion rate again took over and we observed an acceleration. This is where we find ourselves now.

I think you'd be correct, because it appears the amount of energy put into the expansion was initially constant in the first few moments (or millions of years, lack of evidence) and then a runaway effect happened. Kind of like you start a diesel engine and it has a runaway and continues until it destroys itself. This runaway effect could be a result of early effects of the big rip which caused the universe to behave like a balloon that is popping but retains it's shape and keeps expanding faster and faster.

Edited by DanTrentfield

##### Share on other sites

You get down to it expansion or contraction is heavily related to the thermodynamic properties of each particle species. Of which we can sort their equations of state into  fundamental groups.

1) matter only (can still cause expansion, depending on density compared to critical density).

2) Radiation ie photons, neutrinos etc (relativistic particles primarily) ie high kinetic term.

3) The Cosmological constant aka dark energy as a possible contributor. ( scalar field equation of state for this group)

The key components to an equation of state is the ratio of  mass/energy density (kinetic terms) to pressure or potential energy. This is simplified to the $w=\frac{\rho[{p}$ see link.

Edited by Mordred