I want your opinions about the "Big Crunch" theory.

[GreenNeo1]

First off, I will say that I believe in the Big Crunch theory, and I hope others are persuaded to think differently until reading my thoughts on it.

 

I know that all of the universe is expanding outward, along with the Milky Way Galaxy. I also know that the Galaxy is moving at high rates of speed, and then the earth is also revolving at and high rate of speed, and rotating even at an higher rate of speed.

 

But, it is believed by some scientists that all of the universe was created from a single point, the "Big Bang" theory, and that the universe is expanding from that explosion. It has also been proven that we are slowing down in our expansion.

 

My question to the community is this: Will we at one point in time, stop moving completely, and then head back towards each other, or will we just keep gradually get slower, but not to a full stop.

[Double K]

is this because you can liken the expanding universe to a torque curve, some point at which it must have a sudden sharp decline?

 

just a thought...

[GreenNeo1]

I see what your talking about. But I'm thinking that all the matter, by the "Big Bang" theory, was all pushed out from a single point, and there is some gravitational pull from the very center. Like a sphere, there is a center point, where there are and infinite amount of radii and diameters. Assuming that the center has a pull on all the radii that is making the expansion slow, there must be a stop, and all the matter has to come back together.

[Double K]

So you could liken it in a way to a centrifuge, in which case...at worst it would just wobble as it slows down and then fall on its side...or just stop spinning all together.

 

Likening it to a spinning ice skater, the closer they bring their arms the faster the spin, and when the mass shifts out they slow down.

 

I guess this depends on if there is a "centre" of the universe about which all other entities spin...but at worst they arent going to implode and reverse direction sucked back in to the middle, it would just stop expanding

[Spyman]

The Big Bang was not an explosion of a massive clump of matter in surrounding space, it was more like every distance between every part in the clump started to grow very fast.

 

Space is expanding equally in all directions.

 

If Big Bang was like an explosion then we could observe the trajectories of other galaxies in the Universe and pinpoint where the center of the explosion should have been, but current observations reveal that everything far away enough to be affected by the expansion are moving away from us equally, in all directions, as if we where in the center of the Universe. Conclusion is that there was no explosion and that space are expanding everywhere and not from a center.

 

The expansion is speeding up with an accelerating rate.

 

In the initial conditions of the Big Bang, the Universe had an extremely rapid exponential expansion during the Inflationary epoch and then it slowed down as if gravity had the upper hand but the speed of expansion has started to accelerate again, which has led to theories of Dark Energy.

 

 

"Misconceptions about the big bang

The key to avoiding the misunderstandings is not to take the term “big bang” too literally. The big bang was not a bomb that went off in the center of the universe and hurled matter outward into a preexisting void. Rather it was an explosion of space itself that happened everywhere, similar to the way the expansion of the surface of a balloon happens everywhere on the surface."

http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

 

"The Big Bang

The Big Bang is the cosmological model of the initial conditions and subsequent development of the Universe that is supported by the most comprehensive and accurate explanations from current scientific evidence and observation.

 

The Big Bang is not an explosion of matter moving outward to fill an empty universe. Instead, space itself expands with time everywhere and increases the physical distance between two comoving points. Because the FLRW metric assumes a uniform distribution of mass and energy, it applies to our Universe only on large scales—local concentrations of matter such as our galaxy are gravitationally bound and as such do not experience the large-scale expansion of space.

 

Independent lines of evidence from Type Ia supernovae and the CMB imply the Universe today is dominated by a mysterious form of energy known as dark energy, which apparently permeates all of space. The observations suggest 72% of the total energy density of today's Universe is in this form. When the Universe was very young, it was likely infused with dark energy, but with less space and everything closer together, gravity had the upper hand, and it was slowly braking the expansion. But eventually, after numerous billion years of expansion, the growing abundance of dark energy caused the expansion of the Universe to slowly begin to accelerate."

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

 

"Dark energy

In physical cosmology, astronomy and celestial mechanics, dark energy is a hypothetical form of energy that permeates all of space and tends to increase the rate of expansion of the universe. Dark energy is the most popular way to explain recent observations and experiments that the universe appears to be expanding at an accelerating rate."

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

 

"The Big Crunch

The Hubble Constant measures the current state of expansion in the universe, and the strength of the gravitational force depends on the density and pressure of the matter and in the universe, or in other words, the critical density of the universe. If the density of the universe is greater than the critical density, then the strength of the gravitational force will stop the universe from expanding and the universe will collapse back on itself. Conversely, if the density of the universe is less than the critical density, the universe will continue to expand and the gravitational pull will not be enough to stop the universe from expanding. This scenario would result in the 'Big Freeze', where the universe cools as it expands and reaches a state of entropy. Some theorize that the universe could collapse to the state where it began and then initiate another Big Bang, so in this way the universe would last forever, but would pass through phases of expansion (Big Bang) and contraction (Big Crunch).

 

Recent experimental evidence (namely the observation of distant supernova as standard candles, and the well-resolved mapping of the cosmic microwave background) have led to speculation that the expansion of the universe is not being slowed down by gravity but rather accelerating. However, since the nature of the dark energy that drives the acceleration is unknown, it is still possible that it might eventually reverse sign and cause a collapse."

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

 

"Theories about the end of universe

The fate of the universe is determined by the density of the universe. The preponderance of evidence to date, based on measurements of the rate of expansion and the mass density, favors a universe that will continue to expand indefinitely, resulting in the "big freeze" scenario below. However new understandings of the nature of dark matter also suggest its interactions with mass and gravity demonstrate the possibility of an oscillating universe."

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

[pioneer]

The question I have is, if the expansion of the universe was due to an expansion of space-time, how could galaxies have formed, since they represent a contraction of space-time?

 

Here is the actual scenario in an analogy. We have 1 cm diameter dots on the surface of a large balloon, where the dots represent galaxies. As we blow up the ballon, the centers between the dots increases, while each dot gets smaller than the original 1cm. If the universe doubles in size, the milky way galaxy stays the same or gets smaller.

 

Does the observation of the space-time expansion and the space-time contraction into galaxies, imply that the universe expands and contracts space-time, simultaneously?

 

The question becomes what is the logical connection?

 

Gravity lowers entropy or degrees of freedom of matter within contracting space and time. While an expansion of space-time increases the degrees of freedom of entropy. This can be explained with relativity. The expanded reference has time speeding up, allowing more things can happen, relative to a reference where time is slower. The watch may tick thousand of ticks in the expanded reference, but it may only tick once in the contracted reference, restricting degrees of freedom.

 

The expanded reference, where the degrees of entropy freedom is higher, needs energy for this higher level of freedom, since increased entropy is endothermic and needs to absorb energy or it can't increase. Where does this energy come from, to increase entropy within expanded space-time, so we are consistent with the conservation of energy?

 

Does the loss of entropy or degrees of freedom, by the galaxies, stars, black holes, etc., all contracting space-time, giving off potential associated with entropy, that allows the potential for entropy to increase via the space-time expansion? Is dark matter and energy expressions of the intermediate entropy spectrum between expansion/contraction, simultaneity?

[Spyman]

The question I have is, if the expansion of the universe was due to an expansion of space-time, how could galaxies have formed, since they represent a contraction of space-time?

Gravity weakens with distance but expansion of space increases with distance, clearly it is obvious that on small scales the gravity will win and clump matter together and on large scales expansion wins and disperses the clumps of matter.

 

 

Here is the actual scenario in an analogy. We have 1 cm diameter dots on the surface of a large balloon, where the dots represent galaxies. As we blow up the ballon, the centers between the dots increases, while each dot gets smaller than the original 1cm. If the universe doubles in size, the milky way galaxy stays the same or gets smaller.

The force of Dark energy is thought to act on objects inside our galaxy and even on a nuclear level inside objects too, but the affect is vanishing small when compared to the other forces on that scale.

 

 

Does the observation of the space-time expansion and the space-time contraction into galaxies, imply that the universe expands and contracts space-time, simultaneously?

I don't know if I understand your question, according to the theory of relativity, space is highly dynamic and fully capable of both contracting and expanding at an abundance of varied levels in different areas at the same time. These levels are also relative the observers frame of reference.

 

 

The question becomes what is the logical connection?

 

Gravity lowers entropy or degrees of freedom of matter within contracting space and time. While an expansion of space-time increases the degrees of freedom of entropy. This can be explained with relativity. The expanded reference has time speeding up, allowing more things can happen, relative to a reference where time is slower. The watch may tick thousand of ticks in the expanded reference, but it may only tick once in the contracted reference, restricting degrees of freedom.

 

The expanded reference, where the degrees of entropy freedom is higher, needs energy for this higher level of freedom, since increased entropy is endothermic and needs to absorb energy or it can't increase. Where does this energy come from, to increase entropy within expanded space-time, so we are consistent with the conservation of energy?

 

Does the loss of entropy or degrees of freedom, by the galaxies, stars, black holes, etc., all contracting space-time, giving off potential associated with entropy, that allows the potential for entropy to increase via the space-time expansion? Is dark matter and energy expressions of the intermediate entropy spectrum between expansion/contraction, simultaneity?

Seems to be a confusion here, entropy needs energy to decrease and will increase for a system not in equilibrium.

 

"The second law of thermodynamics is an expression of the universal principle of entropy, stating that the entropy of an isolated system which is not in equilibrium will tend to increase over time."

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

 

"Since a finite universe is an isolated system then, by the Second Law of Thermodynamics, its total entropy is constantly increasing."

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

 

IMHO I don't think there are any extraction of entropy energy from areas where gravity rules, which then somehows flows towards areas where space is expanding, where it then are expelled to fuel the expansion itself. Any net gain or loss of energy due to changes in entropy are taken care of locally.