I've been reading some articles about the current cosmology theories, and it seems that there are some unexplained phenomenon that are taken for granted. I haven't done any "homework" on this i.e. I haven't read additionally to check the pros and cons of the theories I will talk about, so you can approach this article as just allowing my imagination to run wild for a bit.
We judge that the universe is expanding based on the observations we make of distant objects in space. Hubble detected that light of all astral objects has a red shift, and the further they are, the bigger the shift. That leads to the conclusion that all objects in the universe are moving away from each other, thus the universe is expanding.
In fact we should stress that the objects appear to be moving away due to the red shift, but in fact they do not have any velocity. It's the space that changes! The distance between the objects change without relative movement of the objects themselves. It's like if space springs into existence - "pours into reality". If you take 1 meter of distance and measure it again after few billion years, you will fined that it's now more than a meter. This creates the red shift, as the same thing applies for the space defined by wavelength of light.
To some extend this might explain the "foam" structure of the mapped universe. The space expands underneath our feet, while gravity causes the matter to clump together, instead of being evenly dispersed in space.
Here is the logic that drives the conclusion:
We capture wave with frequency F, which we expect to be a higher value. The further away the observed object, the lower the measured F, compared to the expectations. If the wave phase speed, i.e. the speed of light, has not changed, that the wavelength has. Because:
w = v / f
where w=wavelength[m],f=frequency[Hz] and v=phase speed[m/s]
f = v / w
for f to get smaller, with constant v, the w should get bigger. And since w
One additional side we should consider is why don't we involve time in that logic. If the spatial dimensions could be expanding, why cant we involve time? As it's interlinked with space, it should equally expand over time - what used to take one second, might be a bit more after a millennia has passed.
In fact that cannot be avoided if we allow for spatial dimension expansion:
before: c = 3x10^5 km/s => c = 3x10^8 m/s as 1km=1000m
change: 1km = 1010m
after : cover 1010m with speed 3x10^8 m/s => you will need same increment in [s]
You can try it the other way around:
Let t measure time between two repetitions of the sinusoidal wave, expressed by the frequency f:
f = 1 / t[s] (by definition)
To make f smaller we need to have time t increase. Again we need to relay that concept towards the notion that the speed of light remains the same. The speed is measure in m/s:
lets say that before expansion one second is in 1000 ms, and after the expansion it is 1010ms.
so before the expansion light covers 3x10^8 m/s <=> 3x10^5 m/ms -- that will be our constant speed. Now if we check the expanded time - the light needs to cover distance 3x10^8 m with the same speed while running for 10ms more. Now that can only be achieved if the distance in [m] itself has increased.
We will get back to this line of thought a bit later.
In this context the search for the "dark energy", which counters the gravitation to make our view of the universe match the observations, seems a bit odd. At least to me it does.
It assumes that space by it's nature is static, and there is some underlining force that causes it to stretch/expand. What if space's natural state is ever expanding on it's own? Wouldn't that also match the inflation theory? My concept isn't much different, the main difference is that it accepts the expansion as natural property of space, and not some mysterious force that opposes gravity and drives celestial objects apart.
The expansion of space is countered by gravity, so the space expansion in regions with gravity should be pushed outward. The object linked in gravity pair would have the distance between them expanded, but the gravity will pull them together, so the expansion will not emerge in-between them, but towards the objects outside of the gravitational interaction.
Let's dig a bit around the interaction between light and gravity. Even if light has relativistic mass, it is not directly affected by gravitational force itself. Instead it's affected by the space-time curve created by the gravitational fields. For what I understand the relativistic mass matters when working with different frames of observation. Now let's get some details on the curvature well created by gravity in all the pretty videos we have seen. The representation there is not replacing gravity entirely out of the picture, it just changes the perspective.
1. The space-time is represented by rubber sheet that is stretched - that is to represent two aspects of the medium - (a) it's stretchable, and (b) it has resistance/tension.
The tension is required so that it underlines that the medium would change back to it's original state when it's not under the effect of another object.
2. The medium has no friction - the velocity of the objects is affected by the medium itself.
3. The objects i.e. stars, planets and black holes, are pressed towards the rubber sheet - and that is done via our normal notion of gravity pressing down.
4. The amount of pressure of the object on the sheet is equivalent to it's mass.
5. The rubber sheet is perfectly stretchable - it will not lose stretchability even if it's already significantly stretched. That allows for the objects to form steep slopes of the gravitational wells.
So we still need notion of gravity to make this work, and we have only replaced the gravity of one of the objects with the space-time distortion - the gravitational well.
Now if we follow these rules for light, it shouldn't bend at all as it's not affected by gravity directly. It will follow the space-time curve, as it cannot escape out of it, but would keep it's direction. Just like the space-time is restored to it's normal state away from the gravity well, the light ray will keep it's original direction. Imagine it as another line of the medium grid.
Now how can we fix all that to make the light bend as we do observe?
What if we allow for the medium to expand/flow on it's own.
Imagine pretty much the same thing, but allow for the rubber to expand slowly at every point, and for it to drip down inside the gravity wells. That will create a constant flow of medium towards the center of the gravity well. The light will be carried/dragged along as it passes through the medium, which is being pulled "under its feet".
Let me put it in a bit different way - start with the empty space-time with network of with a grid of lines for reference. Imagine how space-time distortion changes if our gravity centre starts with zero mass and then accumulates more and more. Simply the stretching of the grid lines will be more and more. Now imagine the two things together - constant undergoing warping of spacetime and the ray of light passing through. At some small time intervals, the ray will get distorted not only by the curved spacetime, but also by the increase of the that curvature. This change over time allows the exit direction of the light ray to be at a different angle to the entrance one. We know that the mass of the objects causing the gravitational lensing does not increase (at least not that fast), but we see that this change in the curvature is what accounts for the lensing effect. So we should view the gravity not as a bowling ball on a trampoline, which is static, but rather as a liquid falling into an circular drain. The spiral effect is also present, but it's motion is much less compared to the vertical motion of the water falling through the drain. So the surface representing the spacetime is constantly fed into the gravitational centre.
When working with this picture, we still need to account for:
1. For this to work in proper scope we need the medium to be special liquid that has high viscosity, which becomes lower and lower as closing on the centre of gravity. This is very important because it needs to represent the same dependence as the gravity law:
(a) the closer the objects the stronger the effect
(b) this also accounts for the masses, as not only the object we have as a centre of the reference frame will cause low viscosity, but also the object "falling" towards it. When it has higher mass it will cause it's own affect on the viscosity thus increasing the interaction effect.
2. the objects velocity - the faster the object moves, the less time it spends under the influence
Have to account for circular orbits - is that a failure? This causes the whole concept to crumble, as any constant flow of spacetime will be unable to account for circular orbits.
Not quite. Don't forget that objects are not pinned to spacetime, but could actually move through it. The "resistance" to the spacetime flow is momentum the object has in the outward direction. The orbiter object has to have momentum tangential to the orbit curve. The path traced on the spacetime fabric being consumed, is a straight line matching that momentum. (It's hard to visualize because we need a fabric gradient that preserves the perspective in both locations - deep in the well, and out of it.
So we have something like the continental plates on earth - ocean floor is recycled at the submerging points, and new one is created at the central ocean rifts. In our case spacetime is created constantly on it's own, even with a small margin, while the gravitational wells recycle it.
Let's take one step further and add time to the picture. We kind of said that space expands over time to stretch the light waves. That's why it takes billions of years to cause significant red shift. Let's view this as time being defined by the stretch of space. IF space(time) expansion is the underlining the notion of time, then the expansion is quite small, compared to the cosmic scale. Since it takes billions of years for light to get observable red shift we can try to estimate the space(time) expansion that occurs in one second. We are bound to get a very small value. Small enough to enter the realm of quantum mechanics? If I had the time, I'd make a research on the scales and make a rough estimation, but I have a feeling that this would be something on scale of string theory, rather than the quantum theory.
added on 18, Mar, 2011:
The Hubble Constant - the expansion rate - has been calculated with a three percent margin of error. The constant is 73.8 kilometers per second per megaparsec. A parsec is 3.26 light-years, and a megaparsec is a million parsecs. So we have 3.26 million light-years, and a light-year is 31 trillion kilometers. 3.26 million * 31 trillion = 1.0106e+20 km. So every 1.0106*10^20 km between two objects, every second adds 73.8 kilometers between them.
Let's round the 73.8 to a 100 and drop from km to m. 1017 m gives 100 m, so 1015 m gives 1 m. The size of hydrogen nucleus is 1.75×10−15 m. In other words - every meter expands with a half of hydrogen atom core size every second.
(to be continued)
We judge that the universe is expanding based on the observations we make of distant objects in space. Hubble detected that light of all astral objects has a red shift, and the further they are, the bigger the shift. That leads to the conclusion that all objects in the universe are moving away from each other, thus the universe is expanding.
In fact we should stress that the objects appear to be moving away due to the red shift, but in fact they do not have any velocity. It's the space that changes! The distance between the objects change without relative movement of the objects themselves. It's like if space springs into existence - "pours into reality". If you take 1 meter of distance and measure it again after few billion years, you will fined that it's now more than a meter. This creates the red shift, as the same thing applies for the space defined by wavelength of light.
To some extend this might explain the "foam" structure of the mapped universe. The space expands underneath our feet, while gravity causes the matter to clump together, instead of being evenly dispersed in space.
Here is the logic that drives the conclusion:
We capture wave with frequency F, which we expect to be a higher value. The further away the observed object, the lower the measured F, compared to the expectations. If the wave phase speed, i.e. the speed of light, has not changed, that the wavelength has. Because:
w = v / f
where w=wavelength[m],f=frequency[Hz] and v=phase speed[m/s]
f = v / w
for f to get smaller, with constant v, the w should get bigger. And since w
wavelength of a sinusoidal wave is the spatial period of the wave – the distance over which the wave's shape repeats, that will call for the distance increase.
One additional side we should consider is why don't we involve time in that logic. If the spatial dimensions could be expanding, why cant we involve time? As it's interlinked with space, it should equally expand over time - what used to take one second, might be a bit more after a millennia has passed.
In fact that cannot be avoided if we allow for spatial dimension expansion:
before: c = 3x10^5 km/s => c = 3x10^8 m/s as 1km=1000m
change: 1km = 1010m
after : cover 1010m with speed 3x10^8 m/s => you will need same increment in [s]
You can try it the other way around:
Let t measure time between two repetitions of the sinusoidal wave, expressed by the frequency f:
f = 1 / t[s] (by definition)
To make f smaller we need to have time t increase. Again we need to relay that concept towards the notion that the speed of light remains the same. The speed is measure in m/s:
lets say that before expansion one second is in 1000 ms, and after the expansion it is 1010ms.
so before the expansion light covers 3x10^8 m/s <=> 3x10^5 m/ms -- that will be our constant speed. Now if we check the expanded time - the light needs to cover distance 3x10^8 m with the same speed while running for 10ms more. Now that can only be achieved if the distance in [m] itself has increased.
We will get back to this line of thought a bit later.
In this context the search for the "dark energy", which counters the gravitation to make our view of the universe match the observations, seems a bit odd. At least to me it does.
It assumes that space by it's nature is static, and there is some underlining force that causes it to stretch/expand. What if space's natural state is ever expanding on it's own? Wouldn't that also match the inflation theory? My concept isn't much different, the main difference is that it accepts the expansion as natural property of space, and not some mysterious force that opposes gravity and drives celestial objects apart.
The expansion of space is countered by gravity, so the space expansion in regions with gravity should be pushed outward. The object linked in gravity pair would have the distance between them expanded, but the gravity will pull them together, so the expansion will not emerge in-between them, but towards the objects outside of the gravitational interaction.
Let's dig a bit around the interaction between light and gravity. Even if light has relativistic mass, it is not directly affected by gravitational force itself. Instead it's affected by the space-time curve created by the gravitational fields. For what I understand the relativistic mass matters when working with different frames of observation. Now let's get some details on the curvature well created by gravity in all the pretty videos we have seen. The representation there is not replacing gravity entirely out of the picture, it just changes the perspective.
1. The space-time is represented by rubber sheet that is stretched - that is to represent two aspects of the medium - (a) it's stretchable, and (b) it has resistance/tension.
The tension is required so that it underlines that the medium would change back to it's original state when it's not under the effect of another object.
2. The medium has no friction - the velocity of the objects is affected by the medium itself.
3. The objects i.e. stars, planets and black holes, are pressed towards the rubber sheet - and that is done via our normal notion of gravity pressing down.
4. The amount of pressure of the object on the sheet is equivalent to it's mass.
5. The rubber sheet is perfectly stretchable - it will not lose stretchability even if it's already significantly stretched. That allows for the objects to form steep slopes of the gravitational wells.
So we still need notion of gravity to make this work, and we have only replaced the gravity of one of the objects with the space-time distortion - the gravitational well.
Now if we follow these rules for light, it shouldn't bend at all as it's not affected by gravity directly. It will follow the space-time curve, as it cannot escape out of it, but would keep it's direction. Just like the space-time is restored to it's normal state away from the gravity well, the light ray will keep it's original direction. Imagine it as another line of the medium grid.
Now how can we fix all that to make the light bend as we do observe?
What if we allow for the medium to expand/flow on it's own.
Imagine pretty much the same thing, but allow for the rubber to expand slowly at every point, and for it to drip down inside the gravity wells. That will create a constant flow of medium towards the center of the gravity well. The light will be carried/dragged along as it passes through the medium, which is being pulled "under its feet".
Let me put it in a bit different way - start with the empty space-time with network of with a grid of lines for reference. Imagine how space-time distortion changes if our gravity centre starts with zero mass and then accumulates more and more. Simply the stretching of the grid lines will be more and more. Now imagine the two things together - constant undergoing warping of spacetime and the ray of light passing through. At some small time intervals, the ray will get distorted not only by the curved spacetime, but also by the increase of the that curvature. This change over time allows the exit direction of the light ray to be at a different angle to the entrance one. We know that the mass of the objects causing the gravitational lensing does not increase (at least not that fast), but we see that this change in the curvature is what accounts for the lensing effect. So we should view the gravity not as a bowling ball on a trampoline, which is static, but rather as a liquid falling into an circular drain. The spiral effect is also present, but it's motion is much less compared to the vertical motion of the water falling through the drain. So the surface representing the spacetime is constantly fed into the gravitational centre.
When working with this picture, we still need to account for:
1. For this to work in proper scope we need the medium to be special liquid that has high viscosity, which becomes lower and lower as closing on the centre of gravity. This is very important because it needs to represent the same dependence as the gravity law:
(a) the closer the objects the stronger the effect
(b) this also accounts for the masses, as not only the object we have as a centre of the reference frame will cause low viscosity, but also the object "falling" towards it. When it has higher mass it will cause it's own affect on the viscosity thus increasing the interaction effect.
2. the objects velocity - the faster the object moves, the less time it spends under the influence
Have to account for circular orbits - is that a failure? This causes the whole concept to crumble, as any constant flow of spacetime will be unable to account for circular orbits.
Not quite. Don't forget that objects are not pinned to spacetime, but could actually move through it. The "resistance" to the spacetime flow is momentum the object has in the outward direction. The orbiter object has to have momentum tangential to the orbit curve. The path traced on the spacetime fabric being consumed, is a straight line matching that momentum. (It's hard to visualize because we need a fabric gradient that preserves the perspective in both locations - deep in the well, and out of it.
So we have something like the continental plates on earth - ocean floor is recycled at the submerging points, and new one is created at the central ocean rifts. In our case spacetime is created constantly on it's own, even with a small margin, while the gravitational wells recycle it.
Let's take one step further and add time to the picture. We kind of said that space expands over time to stretch the light waves. That's why it takes billions of years to cause significant red shift. Let's view this as time being defined by the stretch of space. IF space(time) expansion is the underlining the notion of time, then the expansion is quite small, compared to the cosmic scale. Since it takes billions of years for light to get observable red shift we can try to estimate the space(time) expansion that occurs in one second. We are bound to get a very small value. Small enough to enter the realm of quantum mechanics? If I had the time, I'd make a research on the scales and make a rough estimation, but I have a feeling that this would be something on scale of string theory, rather than the quantum theory.
added on 18, Mar, 2011:
The Hubble Constant - the expansion rate - has been calculated with a three percent margin of error. The constant is 73.8 kilometers per second per megaparsec. A parsec is 3.26 light-years, and a megaparsec is a million parsecs. So we have 3.26 million light-years, and a light-year is 31 trillion kilometers. 3.26 million * 31 trillion = 1.0106e+20 km. So every 1.0106*10^20 km between two objects, every second adds 73.8 kilometers between them.
Let's round the 73.8 to a 100 and drop from km to m. 1017 m gives 100 m, so 1015 m gives 1 m. The size of hydrogen nucleus is 1.75×10−15 m. In other words - every meter expands with a half of hydrogen atom core size every second.
(to be continued)
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