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Author Topic: Why do we think that the expansion of the Universe is accelerating?  (Read 8195 times)

Offline MikeS

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"The evidence for an accelerating expansion comes from observations of the brightness of distant supernovae. We observe the redshift of a supernova which tells us by what the factor the Universe has expanded since the supernova exploded. This factor is (1+z), where z is the redshift. But in order to determine the expected brightness of the supernova, we need to know its distance now. If the expansion of the Universe is accelerating due to a cosmological constant, then the expansion was slower in the past, and thus the time required to expand by a given factor is longer, and the distance NOW is larger. But if the expansion is decelerating, it was faster in the past and the distance NOW is smaller. Thus for an accelerating expansion the supernovae at high redshifts will appear to be fainter than they would for a decelerating expansion because their current distances are larger. Note that these distances are all proportional to the age of the Universe [or 1/Ho], but this dependence cancels out when the brightness of a nearby supernova at z close to 0.1 is compared to a distant supernova with z close to 1. " http://www.astro.ucla.edu/~wright/cosmology_faq.html#CC

clip "If the expansion of the Universe is accelerating due to a cosmological constant, then the expansion was slower in the past, and thus the time required to expand by a given factor is longer, and the distance NOW is larger. But if the expansion is decelerating, it was faster in the past and the distance NOW is smaller. Thus for an accelerating expansion the supernovae at high redshifts will appear to be fainter than they would for a decelerating expansion because their current distances are larger. "

This argument for the expansion of space can be turned around as follows:-   "If the expansion of the Universe is accelerating ..."  The acceleration may be in time not necessarily in distance.  In which case the distance NOW could be the same but time NOW is smaller (shorter).
"Thus for an accelerating expansion the supernovae at high redshifts will appear to be fainter than they would for a decelerating expansion because their current distances are larger. "
What that means is due to the inverse square law of brightness, less photons arrive per second the greater the distance.  The above could be re-written "Thus for an accelerating expansion the supernovae at high redshifts will appear to be fainter than they would for a decelerating expansion because  their current distances are larger   " time is contracting.  That is, less photons arrive per second because each second is progressively shorter.


"Hubble's law.  From Wikipedia, the free encyclopedia
Hubble's law (Lemaītre's Law) is the name for the astronomical observation in physical cosmology that: (1) all objects observed in deep space (interstellar space) are found to have a doppler shift observable relative velocity to Earth, and to each other; and (2) that this doppler-shift-measured velocity, of various galaxies receding from the Earth, is proportional to their distance from the Earth and all other interstellar bodies. In effect, the space-time volume of the observable universe is expanding and Hubble's law is the direct physical observation of this process.[1] It is considered the first observational basis for the expanding space paradigm and today serves as one of the pieces of evidence most often cited in support of the Big Bang model." 
http://en.wikipedia.org/wiki/Hubble's_law

"In effect, the SPACE-time volume of the observable universe is expanding ..."

This is generally interpreted,  by ignoring the time factor, as meaning that as it's velocity is increasing at an alarming rate then to balance the books space must be expanding.   It could equally mean that time is contracting (getting faster).  For space to expand requires something new, dark energy.  For time to contract requires nothing new.  Time contraction perfectly explains the phenomon and is the simplest explanation and should therefore be the prefered explanation.


Apart from the cosmological red-shift as applied to objects, what other evidence is there that time is contracting?  The first is expansion itself.  If the Universe is expanding then mass is becoming more dilute and gravity should be getting weaker.  Weaker gravity implies a contraction of time.  The second is the CBR.  The CBR shows a larger wavelength (lower frequency) as less cycles arrive per unit time as each unit time gets shorter.


Apart from the evidence, the cosmological red-shift of distant objects and the CBR, what is the reasoning that time was dilated in the past?


After an early epoch in the universe, energy converted largely into mass.  Ever since that period that mass (matter) has been converting steadily inside stars to other forms of matter and releasing energy in the process.  This ongoing process has happened through nearly all of the history of the universe.  The proportion of energy to mass in the Universe is constantly changing in favour of energy.  The time dilation factor follows this relationship with time steadily contracting.  In other words, time passed progressively slower in the past.


"Why do we think that the expansion of the Universe is accelerating?"  The question should be.  Why do we think that the expansion of the Universe is accelerating in distance (the SPACE in space-time) and not the TIME in space-time?


Conclusion.  The Universe may be expanding but the Hubble red-shift and standard candles are not proof of it.  It could equally well be due to time continually contracting since the early Universe.  Of the two scenarios, time contraction is by far the simplest explanation.
« Last Edit: 16/04/2012 05:45:46 by MikeS »


 

Offline MikeS

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I feel sure that many of you will dispute my hypothesis and say there is lots of evidence for an expanding universe.  But is there?

The only evidence I have been able to find is firstly the Hubble red-shift.  This is only made possible to calibrate by the use of standard candles.  Secondly, the CBR.

The CBR and standard candles are both affected by red-shift, so it's a circular argument.  In which case the only evidence for the expansion of the Universe comes down to the red-shift.  The red-shift, as pointed out above, may have another, simpler and therefore more likely reason which is continuous time contraction.

To my mind, it all comes down to one very shaky piece of evidence, the interpretation of the red-shift.

Does anyone know of any other evidence other than red-shift and that is unaffected by red-shift, to confirm the accelerating expansion of the Universe hypothesis?
 

Offline Ęthelwulf

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I feel sure that many of you will dispute my hypothesis and say there is lots of evidence for an expanding universe.  But is there?


Actually, no I agree with you. I don't believe the big bang is correct. I still entertain it from time to time... I have something for you to read... If I can find it. BBR
 

Offline Ęthelwulf

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Offline Ęthelwulf

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but I don't agree with this:

"Why do we think that the expansion of the Universe is accelerating?"  The question should be.  Why do we think that the expansion of the Universe is accelerating in distance (the SPACE in space-time) and not the TIME in space-time?

I don't know why you would adopt a notion of an expanding time and not space. I mean, if we take the Minkowski Space seriously, relativity cannot deal with time alone without space. Of course, we know for certain you can deal with space and not time. This is how relativity was in the beginning.

 

Offline MikeS

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but I don't agree with this:

"Why do we think that the expansion of the Universe is accelerating?"  The question should be.  Why do we think that the expansion of the Universe is accelerating in distance (the SPACE in space-time) and not the TIME in space-time?

I don't know why you would adopt a notion of an expanding time and not space. I mean, if we take the Minkowski Space seriously, relativity cannot deal with time alone without space. Of course, we know for certain you can deal with space and not time. This is how relativity was in the beginning.



I did explain the reasoning in detail as it shows why an accelerating Universe need not necessarily lead to an increase in size.  What I actually said was "Why do we think that the expansion of the Universe is accelerating in distance (the SPACE in space-time) and not the TIME in space-time?"  That means that time is contracting not expanding (dilating). 

What I said was "...and not the TIME in space-time?"  Meaning the time aspect of space-time as opposed to the space aspect of space-time.  There is no reference to excluding space.
 

Offline MikeS

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"In physics, acceleration is the rate of change of velocity with time.[1] In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity."
http://en.wikipedia.org/wiki/Acceleration

We normally only consider velocity to be the variable but it is equally true to say that it is still acceleration if time is the variable.  That is the time dilation factor is the variable (from the perspective of the future or the past), not elapsed time.  From a local perspective as time would still appear to flow as normal so the velocity would appear to change.
 

Offline Ęthelwulf

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"In physics, acceleration is the rate of change of velocity with time.[1] In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity."
http://en.wikipedia.org/wiki/Acceleration

We normally only consider velocity to be the variable but it is equally true to say that it is still acceleration if time is the variable.  That is the time dilation factor is the variable (from the perspective of the future or the past), not elapsed time.  From a local perspective as time would still appear to flow as normal so the velocity would appear to change.

I am fair, and I will consider your rebuttal. I will come back to it later.

This is not meant to mean I have made a decision on your idea's yet.
 

Offline MikeS

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"In physics, acceleration is the rate of change of velocity with time.[1] In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity."
http://en.wikipedia.org/wiki/Acceleration

We normally only consider velocity to be the variable but it is equally true to say that it is still acceleration if time is the variable.  That is the time dilation factor is the variable (from the perspective of the future or the past), not elapsed time.  From a local perspective as time would still appear to flow as normal so the velocity would appear to change.

This is what we observe, the universe appears to be accelerating.  However, this apparent acceleration may be no more than an illusion caused by continuous time contraction.


As the Earth accelerates through time without getting any larger, so the Universe accelerates through time without getting any larger.

The point being, the universe expanding and time contracting both look the same from our perspective.  What appears to be expansion may simply be a contraction in time.
« Last Edit: 17/04/2012 06:41:12 by MikeS »
 

Offline MikeS

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Speed = distance/time.  s = d/t
if d = 10 and t = 1 then s = 10

If the length of a second decreases by 50% compared to the past.
In local time the answer is still 10 but in comparrison to the past the answer is 10/0.5 = 20.  Speed has doubled.  The increase in speed is known as acceleration.


Average acceleration = vf - vi /t

If t is a variable (the length of a second is variable) then vf  is variable.  vf  can never be the same as vi  (other than in it's own local time frame) .   If vf - vi  is non-zero then this is acceleration.
« Last Edit: 17/04/2012 08:35:09 by MikeS »
 

Offline Ęthelwulf

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"In physics, acceleration is the rate of change of velocity with time.[1] In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity."
http://en.wikipedia.org/wiki/Acceleration

We normally only consider velocity to be the variable but it is equally true to say that it is still acceleration if time is the variable.  That is the time dilation factor is the variable (from the perspective of the future or the past), not elapsed time.  From a local perspective as time would still appear to flow as normal so the velocity would appear to change.

This is what we observe, the universe appears to be accelerating.  However, this apparent acceleration may be no more than an illusion caused by continuous time contraction.


As the Earth accelerates through time without getting any larger, so the Universe accelerates through time without getting any larger.

The point being, the universe expanding and time contracting both look the same from our perspective.  What appears to be expansion may simply be a contraction in time.
You know I detest the idea that time even exists :) It looks like you are pushing my horror to new extremes.

Anyway, this part:

''As the Earth accelerates through time without getting any larger, so the Universe accelerates through time without getting any larger.''

How is this any different to a static universe, or some kind of steady state for a more precise word?
 

Offline MikeS

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As I understand it, a static universe and a steady state universe are not the same thing. 

I don't necessary believe that the Universe is not expanding at the moment, it's just that I don't see any real evidence for it that is not also evidence for time contraction.  I am not saying that the universe is static or steady state or not expanding.  I am saying that I do not believe there is any real evidence for expansion that is not also evidence for time contraction.

Personally I believe that the Universe is closed.  That is it expands and will ultimately contract.  I also think it is cyclic with matter cycle following antimatter cycle but as yet that is pure conjecture but within the realms of possibility.  If cyclic, that leaves much of the big bang theory untouched.
« Last Edit: 18/04/2012 06:05:27 by MikeS »
 

Offline Ęthelwulf

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As I understand it, a static universe and a steady state universe are not the same thing. 

I don't necessary believe that the Universe is not expanding at the moment, it's just that I don't see any real evidence for it that is not also evidence for time contraction.  I am not saying that the universe is static or steady state or not expanding.  I am saying that I do not believe there is any real evidence for expansion that is not also evidence for time contraction.

Personally I believe that the Universe is closed.  That is it expands and will ultimately contract.  I also think it is cyclic with matter cycle following antimatter cycle but as yet that is pure conjecture but within the realms of possibility.  If cyclic, that leaves much of the big bang theory untouched.

They are essentially the same principles, if we call one the Hoyle Model and the other the Einstein Model, which predated the steady state known to Cosmology. Einstein did not believe there was a beginning to time, he believed there was some amount of space which niether expanded or contracted and the way he acheived this was by using what we call today the Cosmological Constant.

Now, the steady state theory is essentially that, but it also attempts to explain how matter emerges in the universe. The Cosmological Constant (which to current belief is some negative form of vacuum energy), is replaced by a fancier name, the Creation Field - equally, this is some negative energy field, and as more matter moves apart, new matter appears inbetween. The steady state also means exactly what it says on the tin, that it is ''steady'', it does not contract or expand in any way.

So in principle the Steady State and what Einstein called ''static'' are really using all the same principles.
 

Offline MikeS

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I feel sure that many of you will dispute my hypothesis and say there is lots of evidence for an expanding universe.  But is there?

The only evidence I have been able to find is firstly the Hubble red-shift.  This is only made possible to calibrate by the use of standard candles.  Secondly, the CBR.

The CBR and standard candles are both affected by red-shift, so it's a circular argument.  In which case the only evidence for the expansion of the Universe comes down to the red-shift.  The red-shift, as pointed out above, may have another, simpler and therefore more likely reason which is continuous time contraction.

To my mind, it all comes down to one very shaky piece of evidence, the interpretation of the red-shift.

Does anyone know of any other evidence other than red-shift and that is unaffected by red-shift, to confirm the accelerating expansion of the Universe hypothesis?

It is deeply entrenched that the Universe is expanding and that expansion is accelerating.  What is the evidence?

"Does anyone know of any evidence other than red-shift and that is unaffected by red-shift, to confirm the accelerating expansion of the Universe hypothesis?"

Do I take this lack of feedback to mean that you all agree with me, surely not? 
 

Offline MikeS

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If space were expanding then the wavelength of light would also expand.  This is taken as being the explanation for the red-shift.

There is another interpretation that means the same thing.  If the universe is expanding at approaching c then we observe galaxies at great distance to be time dilated.  More photons are emitted per second from that distant galaxy in reference to us as a second at that galaxy is longer.  Our seconds are by comparrison shorter so we recieve less number of cycles per second.  That is red shift.  The red shift has been caused by the stretching of space-time.  Space time has two components distance and time.  Stretching the SPACE component of space-time produces a red-shift.  Stretching space weakens gravity which in turn weakens the time dilation factor and time contracts.  TIME contracting produces a red-shift.  Therefore the red-shift can be caused by space expanding or time contracting.  They both look identical.


Is it possible that time is contracting?   Thought most of the history of the Universe, stars have been converting mass into energy.  Therefore the energy/mass ratio is constantly changing.  Energy increases as mass decreases.  The derease in mass allows time to continuously contract.

If the expansion of space and time contraction both look identical how do we know which is real?  As far as I am aware, we don't.  However, time contraction is by far the simplest explanation and should therefore be the preferred explanation.
« Last Edit: 28/04/2012 09:40:03 by MikeS »
 

Offline daniel.balasa

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What if TIME doesn't exist ?
 

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