A philosophical question

Rubecula

Something occured to me.

We are on the Earth and it is spinning. We are unaware of the spinning and would be until we observe the outside universe. Indeed once upon a time it was believed the Earth was the cwentre of the universe and all other things moved around us.

Does the universe in it's entirety spin in a four dimensional way? (Earth's spin being three dimensional) Would some form of four dimensional centripetal force be the "Dark Energy" now in popular science? The constant expansion of the universe (accelerating too it seems) be down to something as simple as a four dimensional equivalent of centripetal force that being within the universe itself we are unable to observe until we can see outside of the universe?

Just a philosophical question, I do not know the answer, or even if there is one. But what do you think of the idea?

Knifey Spoony

Rubecula wrote: »

Something occured to me.

We are on the Earth and it is spinning. We are unaware of the spinning and would be until we observe the outside universe. Indeed once upon a time it was believed the Earth was the cwentre of the universe and all other things moved around us.

Does the universe in it's entirety spin in a four dimensional way? (Earth's spin being three dimensional) Would some form of four dimensional centripetal force be the "Dark Energy" now in popular science? The constant expansion of the universe (accelerating too it seems) be down to something as simple as a four dimensional equivalent of centripetal force that being within the universe itself we are unable to observe until we can see outside of the universe?

Just a philosophical question, I do not know the answer, or even if there is one. But what do you think of the idea?

The word "simple" and higher dimensions should not be used in the same sentence. Trying to think about the fourth dimension is head wrecking stuff.

Or as a lecturer of mine once put it, when he was discussing some sort of mathematics, "If you believe that you think in the fourth dimension, please go see a doctor!"

But, I think that if we could, theoretically, leave the Universe and observe it from somewhere outside of it (whatever that might be) we still wouldn't be able to observe this motion, since we are three dimensional beings and cannot see any thing in higher dimensions.

Interesting explanation of why we can't see the fourth dimension here:

https://www.youtube.com/watch?v=N0WjV6MmCyM

Mr CJ

Rubecula wrote: »

Something occured to me.

We are on the Earth and it is spinning. We are unaware of the spinning and would be until we observe the outside universe. Indeed once upon a time it was believed the Earth was the cwentre of the universe and all other things moved around us.

Does the universe in it's entirety spin in a four dimensional way? (Earth's spin being three dimensional) Would some form of four dimensional centripetal force be the "Dark Energy" now in popular science? The constant expansion of the universe (accelerating too it seems) be down to something as simple as a four dimensional equivalent of centripetal force that being within the universe itself we are unable to observe until we can see outside of the universe?

Just a philosophical question, I do not know the answer, or even if there is one. But what do you think of the idea?

Very interesting idea but if that was the case would we not see some sort of relationship with local galaxies to us and something completely different with galaxies much further away i.e. some galaxies getting closer others going further away? There appears to be a repulsive force all around in all directions, that seems to be constant, I would not be well up on 4th dimensional dynamics :rolleyes: but to me the motions we know of does not appear to be higher dimensional.

But you could be on to something in a different way, perhaps dark matter, dark energy, negative energy, dark flow etc could be certain properties of higher dimensional space??

The other idea of the accelerating universe caused by the attraction of other universes within an omniverse is totally mind blowing (makes you feel tiny) string theory & universe expansion supports this idea.

Rubecula

My idea stems from simple 3D (or even 2D) spinning. If a top or flat surfaced gyro spins, anything on it is forced outward. As it gets further out it's velocity increases with respect to the central point. (This of course is not unlimited as it soon gets to the edge but I am ignoring that bit for the moment)

Now we look at Galaxies as an example, they are not moving in a flat plane but in every direction, which (if it is due to 'spin') indicates not a flat plane at all.

It takes a 3D gyro to move objects in a flat plane so I am thinking it takes at least 4D to move something in 3D?

Yes there is movement other than away from each other too, but then if you look at gyroscopic movement that is not necessarily in dead straight lines either, as small inconsitancies will cause bumps and shifts in a gyro too. And A little 3D wobble will cause movement in the 2D. Could the same not also be true of a 4D wobble affecting a 3D expansion?

Unfortunately I have no grounding in physics (Normal or quantum or macro or any other kind) So I can't explain things in 'proper' terms, but I hope you understand my drift. (No pun intended)

slade_x

Rubecula wrote: »

Would some form of four dimensional centripetal force be the "Dark Energy" now in popular science? The constant expansion of the universe (accelerating too it seems) be down to something as simple as a four dimensional equivalent of centripetal force

No if that were the case the expansion would not be sustained and would not be increasing exponentially

Rubecula wrote: »

If a top or flat surfaced gyro spins, anything on it is forced outward. As it gets further out it's velocity increases with respect to the central point. (This of course is not unlimited as it soon gets to the edge but I am ignoring that bit for the moment)

I believe you are confusing distance and speed with velocity. Angular velocity decreases in this scenario not the other way around, the further out form the spinning axis (that is the increase in radius) the moment of inertia increases. To use the most used analogy for conservation of angular momentum of a closed system a spinning ice skater decreases their moment of inertia and consequentially increases their angular velocity by pulling their hands and /or leg, closer to their center of rotation.

An even easier way to think of it is use a compact disc, and draw a straight line from the center to the edge. if you then spin the compact disc at any point does the angular velocity at the line furthest from the center increase. if it does increase then you will see something strange. That is, the part of the line closest to the edge of the disc will seemingly overtake the part of the line drawn closest to the center.

http://en.wikipedia.org/wiki/Velocity


Also the planets (which formed from the same protoplanetary disc) would have the same orbital rotation period despite their increased orbital distance if it were true which they do not. A jupiter year is 12 times the length of an earth year.

also while on the subject:
http://en.wikipedia.org/wiki/Vacuum_energy

Other predictions are harder to verify. Vacuum fluctuations are always created as particle/antiparticle pairs. The creation of these virtual particles near the event horizon of a black hole has been hypothesized by physicist Stephen Hawking to be a mechanism for the eventual "evaporation" of black holes. The net energy of the Universe remains zero so long as the particle pairs annihilate each other within Planck time. If one of the pair is pulled into the black hole before this, then the other particle becomes "real" and energy/mass is essentially radiated into space from the black hole. This loss is cumulative and could result in the black hole's disappearance over time. The time required is dependent on the mass of the black hole but could be on the order of 10100 years for large solar-mass black holes.

The vacuum energy also has important consequences for physical cosmology. Special relativity predicts that energy is equivalent to mass, and therefore, if the vacuum energy is "really there", it should exert a gravitational force. Essentially, a non-zero vacuum energy is expected to contribute to the cosmological constant, which affects the expansion of the universe. In the special case of vacuum energy, general relativity stipulates that the gravitational field is proportional to ρ-3p (where ρ is the mass-energy density, and p is the pressure). Quantum theory of the vacuum further stipulates that the pressure of the zero-state vacuum energy is always negative and equal to ρ. Thus, the total of ρ-3p becomes -2ρ: A negative value. This calculation implies a repulsive gravitational field, giving rise to expansion, if indeed the vacuum ground state has non-zero energy. However, the vacuum energy is mathematically infinite without renormalization, which is based on the assumption that we can only measure energy in a relative sense, which is not true if we can observe it indirectly via the cosmological constant.

ps200306

Rubecula wrote: »

Something occured to me.

We are on the Earth and it is spinning. We are unaware of the spinning and would be until we observe the outside universe. Indeed once upon a time it was believed the Earth was the cwentre of the universe and all other things moved around us.

Does the universe in it's entirety spin in a four dimensional way? (Earth's spin being three dimensional) Would some form of four dimensional centripetal force be the "Dark Energy" now in popular science? The constant expansion of the universe (accelerating too it seems) be down to something as simple as a four dimensional equivalent of centripetal force that being within the universe itself we are unable to observe until we can see outside of the universe?

Just a philosophical question, I do not know the answer, or even if there is one. But what do you think of the idea?

It's a long-standing philosophical question. There is one notion that says all motion is relative, and that absolute motion is meaningless. But Isaac Newton considered that rotational motion produces effects that are not defined relative to any other object, but to "absolute space" -- see Newton's bucket. Ernst Mach took up the question and reintroduced the idea of relative rotational motion -- he considered that rotational motion might be relative to the "fixed stars" or to the general distribution of matter in the universe (see Mach's Principle). According to Mach, we cannot distinguish the effect on the surface of a spinning bucket of water from the effect that would be produced by a rotating universe. But nobody so far has answered the question of what a rotating universe would be rotating relative to.