Some questions for better understanding of Main Stream Cosmology

I actually agree that there is a family of related inflation hypotheses. There are many proposed mechanisms for inflation that are consistent with the observations.

I am close to provisionally accepting inflation because of the evidence about the distribution of inhomogeneities in the very early universe, but it doesn't look like inflation is pinned down very much by the available evidence. There isn't anything that establishes the mechanism of inflation or even all the (what I consider) important details of its operation in our history. Inflation is very close to being part of the standard cosmological model, but even if it is accepted, it is much more tenuous than the rest of the cosmological model which includes expansion and primordial nucleosynthesis.
 
RajeshTrivedi said:
Again slipped. You have developed this severe tendency of foot in mouth syndrome..Take some rest, cosmology and its prevalent theories will stay put even without your defense and of course even with as you mistakenly call agenda driven questions.
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:)
It's not me that refuses to accept legitimate answers to agenda loaded questions, and refusing to accept the evidence supporting present standard cosmology.
In that respect it may be a case of you having "two feet in the mouth syndrome".
And yes, of course most of cosmology and a few mainstream theories will stay put without my defence, but as I explained, I'm not defending it, as much as deriding silly unsupported alternative hypothesis, just for the sake of it, and probably a pinch of anti mainstream bias.
You may see me as a cheer leader for mainstream science, but the facts are simply that for any new hypothesis, I just would like to see some observational evidence supporting said hypothesis, or even some aspect of the tons and tons of data being gathered from state of the art equipment both on Earth, in orbit, and beyond.
 
FOLZONI said:
So have you read Eric Lerner's "The Big Bang Never Happened" and the implications of his Plasma Cosmology? It gets rid of dark matter & through Winston Bostick's work, confirms that the cosmological redshift is indeed an indicator of velocity between source and observer.
FOLZONI
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Yep, sure I have read it......And I have had it reviewed by two qualified respected scientists, one an astronomer, the other a SR/GR physicist, and both dismissed his many unsupported claims as fringe rubbish and pseudoquackery.
In fact I still have the book amongst my many other more reputable science books.
 
origin said:
I hope you are purposely try to be funny.
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This is no joke. As you probably know time slows down based upon relative velocity, Special Relativity, and also based upon gravity, General Relativity. As it does so, so does the distance traveled of light. Although the relative speed of light changes, the actual speed accordingly does not chance since the speed of light is a ratio, the distance traveled per time period. We had a very long discussion of it in this forum, in the "speed of light is not constant" thread presented by Farsight.

Really what are these different hypotheses?
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It is common knowledge that there have been many Inflation hypothesis proposed and that there is no consensus version of it.
 
forrest noble said:
This is no joke. As you probably know time slows down based upon relative velocity, Special Relativity, and also based upon gravity, General Relativity. As it does so, so does the distance traveled of light. Although the relative speed of light changes, the actual speed accordingly does not chance since the speed of light is a ratio, the distance traveled per time period. We had a very long discussion of it in this forum, in the "speed of light is not constant" thread presented by Farsight.
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This is why I take the time to try to correct Farsight or at least demonstrate that he is sowing chaos and disinformation.

The "speed of light" in relativity theory, like all speeds, is a ratio of a sorts: it is a distance given by two spatial coordinates over a distance given by two time coordinates. As such, it will vary as allowed by the way that one can assign coordinates. In SR, one can only assign coordinate values such that the speed of light in a vacuum cannot vary (except by a change of units). In GR, one can use all kinds of crazy coordinates but at the level of an infinitesimal distance, all coordinates must operate as SR. So if one is talking about a finite distance in GR, the speed of light can be an arbitrary amount that can shift from location to location and from path to path. That is why responsible people say that the speed of light remains constant in GR for infinitesimal distances (or "locally"). It is certainly possible in GR to assign coordinates where the speed of light is constant over finite distances, but this is not always the preferred system of coordinates for an application.
 
OK, first up, I have pinched the following post, and ask forgiveness of the poster concerned. :)
I just believe it applies here quite well, and probably any thread where we have the usual criticism of science from the usual anti mainstream uneducated alternative hypothesis pushers.
It sums up the situation quite well


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CptBork:
Ironically, it's almost entirely the pseudoscience posters here who engage in the kinds of behaviour about which the OP complains. I haven't seen a single alternative theory presented here that didn't involve completely ignoring our existing understanding and all the evidence on which it's based (other than borrowing from conventional jargon to make reference to "electrons", "spacetime" and whatnot), and in lieu of any supporting evidence for the proposed alternatives, the only justification given is that existing science is "boring", incomplete and takes a long time to learn. Scientists are human beings like everyone else, they can be sweethearts or complete utter pricks or even both at the same time, but it doesn't make someone an asshole to call an old wives' tale what it is.
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One of my original question on lensing is still stuck in my mind...

I understand that the light follows the path of spacetime curvature, and an object creates the curvature in the spacetime and hence lensing.

Now since no specific orientation can be assigned to an object in the space so we should get a closed curvature around this object, and light falling on this object must get trapped, kind of around the object only. But it does not happen.

I will clarify further..

1. Take a sphere and put it on a thick soft rubber sheet.
2. A kind of dent is created on the rubber sheet.

3. Rotate the rubber sheet in anticlockwise direction by an infinitesimally small angle, a new dent is created. (For easy understanding ignore the solid angle aspect and consider only one plane of sphere).

4. Now repeat the step 3 for the entire planar 360 Degree, then we get a closed curvature.

Now the question is, we have a closed spacetime curvature, then a light incidental on this curvature should follow this closed path, where is the exit path and how ?? Creating a laminar flow kind of path around the object appears confusing.
 
RajeshTrivedi said:
Now since no specific orientation can be assigned to an object in the space so we should get a closed curvature around this object, and light falling on this object must get trapped, kind of around the object only. But it does not happen.
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Light will only be trapped when the object in question is so dense that the escape velocity equals "c"
Or a BH.
 
Trapped here not in the sense used for Black Holes....It means the spacetime curvature is in closed path, so how the light will come out of it ??

I checked the Geodesic part also, this also implies closed curvature only.

If you refer to the lensing calculations (or lensing representation on paper), it kind of shows a flow of light around the object as if that object is creating some kind of laminar obstruction in the flow of light, but that is not the space time curvature..

Again please refer the deflection calculations around an object... The light is shown as deflected (following the path of curvature) near the object and after that a straight tangential line is drawn till observer, which is further extrapolated to give the false image.. But the point is what is significance of this exit point from curvature, how can it exit when the curvature is a closed surface.

Another related question, how can we extrapolate on spacetime curvature ?? It is stated that space time curvature for the light is a straight line, so extrapolation will no longer be a straight path.
 
RajeshTrivedi said:
Trapped here not in the sense used for Black Holes....It means the spacetime curvature is in closed path, so how the light will come out of it ??

I checked the Geodesic part also, this also implies closed curvature only.

Another related question, how can we extrapolate on spacetime curvature ?? It is stated that space time curvature for the light is a straight line, so extrapolation will no longer be a straight path.
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Please show me an object that creates a gravity well, so deep/curved that the "curvature is in a closed path" to use your own words. Other then a BH of course, which I have already mentioned.

Q2: What the hell do you mean by your last paragraph?
Again, you seem to be trying to "manufacture " problems which in my opinion make no sense.
 
Who is talking about Gravity Well ??

Q1 : I just stated that the curvature will be around the object in closed path, so how light exit ?? I have explained why the curvature should be closed, simply because the object in space does not have orientation, it is omni-directional. Had it been a plane 2-D case, no problem.


Q2 : How can we extrapolate ? In general in optics we extrapolate the path of light for images (Refer to optical lenses), but these extrapolated paths are supposed to be the paths of light rays ? In spacetime curvature the curvature itself is the path of light, so how can we extrapolate ??

Hope you have understood the questions.
 
Who is talking about Gravity Well ??

Q1 : I just stated that the curvature will be around the object in closed path, so how light exit ?? I have explained why the curvature should be closed, simply because the object in space does not have orientation, it is omni-directional. Had it been a plane 2-D case, no problem.


Q2 : How can we extrapolate ? In general in optics we extrapolate the path of light for images (Refer to optical lenses), but these extrapolated paths are supposed to be the paths of light rays ? In spacetime curvature the curvature itself is the path of light, so how can we extrapolate ??

Hope you have understood the questions.
 
forrest noble said:
all speeds are a ratio of distance traveled per unit of time.
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In contemporary physics, all speeds are the differential of distance considered over time, at least in the sense that the integral of speed over time is distance traveled. It is important to be able to describe velocity at an instant of time, when no distance is traveled. Thus, while the units of speed are a ratio of distance and time, we consider velocity as something that is a vector quantity that can exist at individual points, regardless of whether we are describing the velocity of an object that may or may not have constant velocity over a period of time.
 
RajeshTrivedi said:
Q1 : I just stated that the curvature will be around the object in closed path, so how light exit ?? I have explained why the curvature should be closed, simply because the object in space does not have orientation, it is omni-directional. Had it been a plane 2-D case, no problem.
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That makes no sense.


Q2 : How can we extrapolate ? In general in optics we extrapolate the path of light for images (Refer to optical lenses), but these extrapolated paths are supposed to be the paths of light rays ?
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Yes they are light rays.
In spacetime curvature the curvature itself is the path of light, so how can we extrapolate ??
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Take into account the curvature of space.:shrug:
 
RajeshTrivedi said:
Who is talking about Gravity Well ??
I just stated that the curvature will be around the object in closed path, so how light exit ??
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You are unaware that curved/warped spacetime will exhibit a property we call gravity?
No wonder the rest of your questions make no sense, as others have alluded to.

You were given some advice back in the thread about reading up on cosmological terminology and the discipline in general. Obviously you should seriously consider taking that advice.
 
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