That does sound rather weird. Space or spacetime can undergo warpage, twisting, or even a wave like nature caused by collisions of large masses or assymetric supernova explosions.
It's called gravitational radiation or gravity waves.
Photon?
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That does sound rather weird. Space or spacetime can undergo warpage, twisting, or even a wave like nature caused by collisions of large masses or assymetric supernova explosions.
It's called gravitational radiation or gravity waves.
You're still not appreciating this space is the medium business. You know how I was talking about ghostly gin-clear elastic jelly, and injecting more of the same to create a gravitational field? Flip it around. Imagine you used the hypodermic to extract the jelly. If you keep doing this you aren't left with empty space. You're left with no space. Have a read of this where Einstein talked about field theory. See this bit:
"Expanding the Theory.
This theory having brought together the metric and gravitation would have been completely satisfactory of the world had only gravitational fields and no electro-magnetic fields. Not it is true that the latter can be included within the general theory of relativity by taking over and appropriately modifying Maxwell's equations of the electro-magnetic field, but they do not then appear like the gravitational fields as structural properties of the space - time continuum, but as logically independent constructions. The two types of field are causally linked in this theory, but still not fused to an identity. It can, however, scarcely be imagined that empty space has conditions or states of two essentially different kinds, and it is natural to suspect that this only appears to be so because the structure of the physical continuum is not completely described by the Riemannian metric."
See how a field is "a state of space"? You can't separate the field from the space like you can skin a rabbit. Nor can you take some "medium" out of space. Because space is the medium. When a wave moves through space, space waves.
People say that gravity is all about curved spacetime. See the Baez website, but note the caveat: "similarly, in general relativity gravity is not really a 'force', but just a manifestation of the curvature of spacetime. Note: not the curvature of space, but of spacetime. The distinction is crucial." And as Quackhead pointed out, spacetime is not something through which light moves. Instead it moves through space. When light curves, it doesn't curve because space is curved, or because spacetime is curved. It curves because space is inhomogeneous, this being modelled as the spacetime "tilt" you see in the bowling-ball pictures:
GNU FDL image by Johnstone, see Riemann curvature tensor on English Wikipedia.
Electromagnetism is all about curved space. Google on electromagnetic geometry.
We all know that you say this. We also know that you are incapable of using this to do a physics application, so that it is no better than your own fantasy.
That's a nice argument from authority, but even there you are showing Einstein argue from the fallacy that he able to imagine something, but just barely able to imagine it. That is not evidence. Additionally, Einstein admits that he has not produced evidence that this idea is correct, so to argue from the authority of Einstein that space is a medium for electromagnetic phenomena is entirely baseless, given the complete content of the piece.
Yet again, Farsight merely cherry-picks a short passage from Einstein, ignoring the other points Einstein makes.
Note also the importance that Einstein places in the first part of the passage on the mathematical work that he has done, as if this is the really important part of physics. Indeed, Einstein sees the primary task of establishing the claim Farsight wants to make as a mathematical task.
So, please show us an example of how something falls due to inhomogeneous space. Every physicist shows us the equations. Every school child learns to measure things in physics so they can tell the theory is correct. Let's see how inhomogeneous space works.
And before you say that it is all Einstein, Einstein seems to have used the phrase "inhomogeneous space" exactly once, so it would be a lie to say that this is his theory.
It has seemed like a small distinction, whether space containes a medium or space is the medium, until you gave the example of turning it around and extracting some jelly, implying that you would eventually be left with no space. This is the "something from nothing" explanation for the existence of the universe, where a point of space and infinitely dense energy expanded and now amounts to everything in our Hubble view. Your model features new space being continually created, and not just empty space to accomodate expansion of matter and energy, but gin-clear elastic jelly space, out of nothing.
Please, consider the option that space and time have always existed. The model you have not only doesn't accommodate such a scenario, but is closer to magic or the Supernatural. I will leave you alone about my alternative ideas if you, or anyone else, just says Yes to something from nothing, because that scenario falsifies my entire model just like my scenario flasifies your model.
"Always existed" features time with no beginning and no end:
It actually makes a difference if spacetime is the medium. If there is a medium that is space or that sits in space, then speeds will be relative to this medium and we can, in theory, tell the difference between rest according to this medium and movement according to this medium. If spacetime is the medium, this gives us the opportunity to do away with the physical notion of absolute rest. For if the relationships of the wave in the medium are defined on the 4D metric of spacetime and can be decomposed into movement into space and time given an arbitrary decomposition (i.e., we can chose difference frames of reference), then the motion of the wave does not depend on the particular choice of spacial and temporal coordinates associated with the medium.
Not exactly. In the standard picture, there is no time when there is nothing. There is simply the past history of the universe that does not extend past a certain point. There is no before that point for there to be nothing.
Actually it doesn't. The jelly started off compressed, and it's expanding. Like that stress ball in your fist when you open your fist. And IMHO the early universe was something like Oppenheimer's original "frozen star" black hole. It was never some little point of infinitely dense energy. If you see some explosion caused by the detonation of a block of C4, you don't claim it all began as some little point of infinite density.
I do. I can't see how you get something from nothing.
I don't really have a "my model". It's just big bang cosmology without the point-singularity, and taking note of Einstein's variable speed of light along with the energy-pressure diagonal and a shear-stress term in the stress-energy-momentum tensor. I can't explain why these don't feature in the cosmology you read about. You know, sometimes I feel like it's like relativity never happened.
Sure, but time is just a measure of motion. The beginning of time is the beginning of motion.
Well said, but from my perspective it is word smithing. If you deny that it is "something from nothing" because there never was nothing, i.e. because there was no "before the beginning", is not the same as saying that it has always existed. As opposed to "always existed", you are describing "something from nothing", even if you talk nothingness out of existence.
It looks like you have contemplated the current model and concluded, like me, that something from nothing is hard to accept, so you put it into the context of something; the frozen-star black hole. Don't you think that there had to be preconditions to that too?
I just don't know. I look at gravity and then the black hole, then liken that to the early universe, and then I hit the buffers. You have this strange solid space in which there is no motion, and the whole universe is like the gravastar "void in the fabric of space and time". That's as far as I can get. How did it get there? Pass. What came before it? Don't know.
Re what PhysBang said, note what Quarkhead conceded in this post about no motion through spacetime. Spacetime isn't the medium. Space is the medium. NB: Is it my imagination, or has Quarkhead removed the bit that said Farsight is right?
Re what PhysBang said, note what Quarkhead conceded in this post about no motion through spacetime. Spacetime isn't the medium. Space is the medium. NB: Is it my imagination, or has Quarkhead removed the bit that said Farsight is right?
There is another aspect of time, that is pseudo-time, that is not discussed. This can be understood with a distance based analogy of motion blur. Motion blur occurs when the shutter speed is slower than the motion in the photo. The result is motion blur. The motion blur create an uncertainty in space, that can create the impression motion, even though time has stopped in the still photo. One can sense the action below even with time stopped. The difference in time between shutter speed and action speed cause excess time to be left in the photo. With time stopped and unable to propagate, the excess time appears as distance uncertainty due to space-time being connected.
The distance stopping analogy to motion blue, I will call time blur. This is where uncertainty in time appears due to excess distance is left, when distance is fixed by focus. This will appear as time uncertainty. As an example, picture watching a sports events on an HD TV. We can see the faces in the audience. The cameraman focusing on a face of a cute gal in the front row who is watching the game. Distance has stopped, so to speak, due to the camera fixing one position. Time is still moving forward as we watch the expressions change on her face as the game goes on.
There is a thunder storm and a power surge fries our good TV. We go to the closet and take out our old TV with a low definition picture. We notice the cameraman is still focusing on the pretty gal, but now her head is the size of one pixel on the old TV. We have limited distance to this one large pixel, but this pixel can't do justice to all the distance separation that was seen on the new TV.
This is excess distance becomes merged into the one pixel of the old TV. This is similar to the excess time appearing as motion blur. In this case, we notice a pixel flicker in time and try to image or extrapolate the changes of state of her expression, based on assumptions that her state of mind is related to the action of the game. Below is an example of a still picture using a man with less pixelation.
In other words, we are interpreting distance potential of the left photo, not seen in the right photo as time blur. We may image him smiling. If this was an action film in real time, phase changes of the face will not keep up with real time.This is not the same as time, proper, anymore than motion blur is a type of movement in space-time. It is important to calibrate the mind before doing science at frontiers. This is not required of science so we get dozens on distance and time blur theories with good math.
There is a significant difference. In the standard picture, there is no point in which the universe had nothing in it. Every moment in the history of the universe is accounted for.
I am not sure that it is more than a matter of taste to prefer one over the other.
That is the part that is well said, but at the same time denies "something from nothing" in such a way as to not address the other explanation for the existence of the universe, "always existed"
To me it is more than a matter of taste, it changes the history from there being an eternal past, to one that has a finite past. It is the difference between there being an unexplainable beginning, vs. not having a beginning that can't be explained. And it is the difference between there being preconditions to the big bang vs. ignoring that the actual event was a precondition to the start of time.
You can say this, but you have no evidence, you merely assume that there is an infinite past and proceed to reject any evidence that might suggest otherwise.
True, it is easy for me to say, and there is no evidence.
As for assuming an infinite past, I see no difference between that and assuming a beginning. We share the same evidence, call it the raw redshift data, or the very slight anisotropy of the CMB. What evidence am I rejecting that might suggest I'm wrong, or that you are right? Certainly not logic.
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One does not have to assume that there was a beginning to come to the conclusion that there was only a finite past. Indeed, in the standard picture there does not need to be a beginning, no first point. One need only make assumptions that certain energy constraints that we see in the universe hold in all circumstances (which might not be true to all energies) and then follow the expansion of the universe backwards.
Fine. Either way, in the not too distant future our discussion will be forgotten, and we will go on our ways with two different models of the universe to keep us warm, lol.
Mine features the infinities, and yours the finites
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http://phys.org/news/2015-01-astronomers-widest-view-universe-telescope.html
The universe is expanding at an accelerating rate, and more evidence of that is coming in all the time. Your model can't explain it. In my model the explanation is simple, given preconditions to the Big Bang, i.e. preexisting space and time. The observable universe is expanding into preexisting space, and the energy density between our high density big bang arena and the low energy density space surrounding it causes the acceleration in the rate of expansion. It is an application of the inverse square rule, that as objects get further apart, their gravitational attraction diminishes.