|1 Engr. Ravi||New evidence: Dark Energy Key Assumption is Wrong||Tuesday 7 January 2020|
|2 tjrob137||Re :New evidence: Dark Energy Key Assumption is Wrong||Wednesday 8 January 2020|
|3 tjrob137||Re :New evidence: Dark Energy Key Assumption is Wrong||Saturday 11 January 2020|
|4 tjrob137||Re :New evidence: Dark Energy Key Assumption is Wrong||Sunday 12 January 2020|
|5 tjrob137||Re :New evidence: Dark Energy Key Assumption is Wrong||Monday 13 January 2020|
|6 tjrob137||Re :New evidence: Dark Energy Key Assumption is Wrong||Thursday 16 January 2020|
New evidence: Dark Energy Key Assumption is Wrong
96 posts by 20 authors
|>||(The actual theory is there is no center, everything moves away from everything else, like dots painted onto an inflating balloon. No one particular dot can be singled out as the center of the balloon's surface, but all dots will see all other dots moving away from it)|
Yes. But that is an ANALOGY that misses a key aspect of the universe. On the balloon, Ed Lake can use a pen to place a mark on the balloon midway between two dots, and his discussion makes sense (the mark persists and remains midway between the dots).
But in the universe, which we model as a spacetime manifold, Ed Lake cannot "draw" any marks, and in any case he would have to mark a WORLDLINE, not just a single point. There is no a priori way to determine the inclination of that worldline, and one simply cannot say "the EARTH is moving away from that point midway between us and Galaxy-X", because there is no such POINT, there is at best only a WORLDLINE, which could be inclined toward earth, toward Galaxy-X, or neither. So his discussion presumes he can do something (mark a "midpoint") that is not possible.
|>||Your "model" does not represent reality if it cannot show a point midway between two moving galaxies.|
Nonsense! There can be no such "point", but for a given definition of simultaneity there is a worldline that is midway between a given pair of galaxies. But different definitions of simultaneity will give different worldlines, so there is no generality to this -- you only get out what you put in (drawing that worldline is equivalent to selecting a definition of simultaneity).
|>||Visualize it as a V with a vertical line down the center of the V. That, in effect, creates two Vs with a common base point. The base point is the point of the Big Bang.|
You merely display your personal ignorance of cosmology. There is no "point of the big bang", because the big bang occurred everywhere: for any given point right now, at cosmological scales [#] all galaxies are moving away from it, with speeds increasing with distance. This is known as the cosmological principle: 'Viewed on a sufficiently large scale, the properties of the universe are the same for all observers' (i.e. there is no special location in the cosmos).
[#] ignoring local proper motions.
Worse, you are implicitly assuming some sort of "absolute space" in which you can make your drawing. There is no such thing. There is only an infinite number of definitions of simultaneity, each with a DIFFERENT worldline midway between the two galaxies.
|>||The material that formed Galaxy-X followed the left arm of the V, the material that formed the Milky Way followed the right arm of the V, and the center line is the midway point between those two galaxies as they formed and moved away from the Big Bang. Yes, that is a "worldline." It does not actually exist as an object, but it can be easily visualized and understood.|
Only for a given definition of simultaneity. Different definitions yield different worldlines. Your claims simply do not hold up.
|>||The redshift of a galaxy does NOT represent how fast is it moving away from us. It represents how fast WE are moving away from that half-way point.|
Except that any calculation of the redshift does not involve that fictitious "half-way point" in any way. The calculation involves the metric and geometry at the point of emission, parallel transport to the observer along the line-of-sight, and the metric and geometry at the point of observation. Unless some massive object is located near the line-of-sight, the redshift can be related to the proper motion of the galaxy relative to earth.
|>||That is because, as Einstein's Second Postulate says, "light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body." So, the light emitted by Galaxy-X is not redshifted due to any movement of Galaxy-X.|
When you quote Einstein, you must apply the quote AS HE GAVE IT; you MUST NOT make up something else and fantasize that the quote applies to your fabrication. You confuse redshift with the (local) speed of light. If your claim were true, there could never be any Doppler effect on light at all. There is.
Hint: since "light is always propagated in empty space with a definite velocity c", redshift cannot possibly be related to the speed of light.
(I repeat: that quote is NOT Einstein's second postulate, it is merely a SUMMARY of the postulate from his introduction.)
|>||Movement of the emitter does not affect the photons that are emitted. The light we see from Galaxy-X is redshifted due to OUR movement away from that midway point between us.|
Except, as I said, the calculation of redshift does not involve that "midway point" at all.
|>>||Ed Lake keeps making stuff up out of his personal FANTASIES, and pretending it is what "relativity says". And since he does not know what many of the words he uses actually mean, he gets VERY confused.|
You just MADE UP the notion of a "midway point" involved in the redshift of a distant galaxy.
|>||It's all really very simple.|
No, it isn't "very simple" at all. GR and cosmology are among the most complicated fields of science. YOU don't have a clue. Making stuff up and pretending it is true is USELESS.
|>||Wow! It appears you are TRULY unable to understand anything except some screwball mathematical representation of the universe.|
No. It's just that YOU are TRULY unable to think abstractly.
|>||Try to visualize the Big Bang. Material is emitted in all directions, not as from an explosion, but as from a highly compressed cluster of rubber balls. [...]|
That is NOT what the big bang is. You are insisting that it is like something you are personally familiar with, but it ISN'T -- the big bang is something completely outside of any human experience. As is most of modern physics. YOU DON'T HAVE A CLUE.
|>>>||I use this illustration to show that "the place of the Big Bang" is far outside of our OBSERVABLE universe: https://i.imgur.com/yCw9Er9.jpg|
Pure fabrication from your personal fantasies. That does not agree with modern cosmological models at all. Note that those models are highly constrained by observations, and COMPLETELY eliminate your picture.
Why do you bother to just make stuff up and pretend it is true? -- All you do is confuse yourself.
|>||It's called "the Big Bang" because all evidence shows that the universe is expanding away from some point.|
This is just plain not true. The evidence shows that at present the universe is expanding from EVERY point of the current universe, not just some single point. Again, your FANTASY does not agree with modern cosmological models and the observational constraints on them.
|>||Many texts refer to the original point as a "singularity."|
You CLEARLY have not understood them: they refer to the BIG BANG as a singularity, not any fictitious "original point" -- that is YOUR fabrication, and indicates how profoundly you do not understand this.
Yes, in modern cosmological models the big bang is a singularity, BUT IT IS NOT A POINT. In such models one can follow a geodesic emanating from the big bang back to a limit point, which is (loosely) as close to the singularity as one can be and still remain in the manifold. For two such geodesics, the distance between their limit points is unbounded -- so the singularity is NOT AT ALL a point (if it were a point, the distance between the limit points of any two such geodesics would be zero).
This is a concept completely outside of your experience or understanding. Forcing it to agree with your LIMITED experience is useless.
|>||On Monday, 13 January 2020 19:27:18 UTC+1, tjrob137 wrote:|
|>>||Yes, in modern cosmological models the big bang is a singularity,|
No, it isn't: the "Big Bang" comes *after* the "singularity", and in standard cosmology even after inflation.
Only in one specific NON-MAINSTREAM model, which is NOT "standard cosmology". And it seems to be using a PUN on "big bang".
The mainstream cosmological model is called "/\CDM": https://en.wikipedia.org/wiki/Lambda-CDM_model
A few quotes: The model includes a single originating event, the "Big Bang" [though "event" is used in its colloquial sense, not its technical meaning of point in the spacetime manifold.]
The model uses the Friedmann–Lemaître–Robertson–Walker metric, [which necessarily has a singularity in the past of every timelike or null geodesic, called "the big bang".]
Various extensions to /\CDM add inflation/quintessence/something-similar after the big bang, which are "current areas of speculation and research in cosmology".
|>||Cosmology Lecture 9 "Leonard Susskind presents the theory of cosmological inflation under which the early universe expanded exponentially **before** the Big Bang." (my emphasis) https://youtu.be/hADOY0TzLic?t=4160>|
Yeah, there are many, NON-MAINSTREAM models. But the big bang is a singularity BY DEFINITION, so it makes no sense to have "something" "before" it. Susskind is making PUNS on technical words and not warning his audience. (I did not watch the 2-hour video, so it could be the YouTube summary that is at fault, not Susskind.)
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