The Expanding Universe2019 Nov 7
Standard cosmology says that the universe is expanding, and the most distant objects are expanding away from us at the greatest rate. However, there are problems that I see with this model that cannot be reconciled. note
I have been trying to learn the best explanations for these problems in the standard cosmological model, but the information seems limited. Occasionally I see papers or articles that address some issues with new explanations, but generally it seems that there is poor description of remaining problems in the theory. It is almost like it is not acceptable to show doubt on what must be believed.
I may have to correct aspects of what I have written here if I learn more and if some of these problems in the standard theory are actually solved.
Last century, astronomer Edwin Hubble observed that distant stars in all directions give off light that is more red note than normal, and that the greater the distance, note the redder the light. He suggested that this could be like as if the stars were moving away from us at high velocity. Just as the siren of an emergency vehicle drops in pitch as it speeds away from us (and it drops a greater pitch the faster it is traveling away from us), the light would drop in color because of the star’s velocity away from us. (This is quantified by a number called "z".)
The method of determining how far away things are is called a distance ladder. Primarily this is a technique that relies on things we call standard candles which have known brightness at their location.
- Type Ia supernovae are stars that explode with a very predictable brightness output pattern. We can determine how bright the explosion would be at their location from the brightness pattern.
- Cepheid variable stars pulsate with a pattern that has been found to correlate with their brightness. We can observe their pulsing rate and determine their brightness at their location.
We use the brightness that we observe of standard candles at our location to calculate their distance. (The more dim, the more distant.) The distance ladder uses this (and additional indicators) to assemble enough data to determine total distance to objects in the universe.
When matter gets hot, it gives off energy as light. The characteristics of this light is determined by the type of the heated matter. This is why candle light has a characteristic color. The same is true of other lights: incandescent, sodium, neon, chemical fireworks, etc. The characteristic color pattern is a result of the atomic nature of the light emitter. These patterns are so characteristic that we can use emitted light to identify what made the light. (For example: you can instantly recognize when a room is being lit by candlelight.)
Also, the frequency of the light is correlated to the color. Light with a lower frequency is more red, and with an increased frequency is more blue. (More correctly a longer wavelength is more red, a shorter wavelength is more blue.)
Using this information, when we look at the patterns in the light from distant stars, they look like the light produced by nearby stars and light made on earth, but the color pattern is shifted lower, redder.
However according to the amount of redshift of the most distant stars, if they were actually moving at the velocity needed to produce the observed redshift, they would be moving away from us around the speed of light. (z > 1) Special relativity says this would be impossible. note
You can’t accelerate to the speed of light because the amount of energy needed for the acceleration becomes infinite as your speed approaches the speed of light.
This z > 1 problem was not observed initially. These highest redshift stars are the most distant ones, so they were not seen before (with the less sensitive older telescopes). Therefore, the concept of the recessional velocity due to actual motion used to be plausible because the highest observed "velocities" were reasonable. After these high-z stars were observed with improved telescopes, then the original concept of physical velocity was changed instead to be an expansion “velocity”.
Cosmological theorists instead now say that that space itself everywhere (between us and all distant stars) is expanding. note As the light travels through the expanding space, the photon wavelengths become stretched. This redshifts them and only then gives the appearance of having come from stars with a high velocity. This expansion causes the stars to become separated without changing their relative positions in space, so they aren’t really moving in a normal sense. This is called cosmological redshift. note
Note that there are two additional explanations for observed color shifting.
- Individual stars that we really do know are moving in relation to us have either a Doppler red or a Doppler blue shift (from physically moving away or towards us respectively).
- There is also a red shift that is caused by an effect of strong gravitational fields.
The important point is that these other two causes of the redshift are not related to the distance of the star, so we can ignore them for this discussion.
The original concept of physical velocity was changed instead to be an expansion “velocity”.
However, in a universe where expansion was happening the same everywhere, this explanation fails. The devices on earth for measuring the color of light would be stretching the same as the light would be stretched. Because the scale of everything would stay in sync, our measurement devices would not be able to detect any difference in light due to the expansion, whether redder or otherwise.
Therefore the theorists have another compensation: They believe the expansion force is much weaker than gravity. Areas with significant gravity are assumed to be arrested from expansion by that gravity. They assume the matter that is gravity-bound doesn’t expand along with the rest of the universe. The universe away from these pockets expands, but the gravity-bound areas don't. By this thinking, measuring sticks and all other measuring devices on earth would be stable for measuring the redshift.
Now, we know that gravity reaches everywhere in the universe. (We measure gravity waves from distant stars.) Additionally, gravity has effects in direct proportion to its strength. (It is not a case of gravity turned on vs gravity turned off.) If expansion of the universe is ongoing it is always happening in the context of some amount of gravity. Where gravity is stronger, it might make sense that the expansion is slowed in proportion to how strong the gravity is pulling things together. However, the theorists are suggesting that above some threshold the gravity-bound pockets simply have a stable size.
Note that gravity only attracts objects with mass. Gravity could have effect on the expansion of massive objects, but gravity has no attraction on the vacuum of space itself. note Therefore gravity cannot arrest the expansion rate of empty space. This should leave the space in between all objects everywhere to be expanding, even in gravity fields. (It would be expanding between objects both near to us, as well as the far.) And note that gravity also has no attractive powers on photons (they are massless). So this leaves the redshift in this model as happening in the time of transit by “stuff” and in “stuff” that is unaffected (for this purpose) by gravity. note Therefore gravity would not be affecting cosmological redshift.
I was speaking of space as being empty, but it is not. It is filled with plasma. Some problem questions that are still unanswered to me:
- Would this plasma cause sufficient self-gravity to arrest space from expanding?
- Is there a difference if the plasma is very hot (e.g. 1^9 K) or very cold?
- At what density does matter create enough gravity to arrest expansion?
Notes on gravity:
According to standard quantum electrodynamics (QED), space is filled with a virtual zero point energy (ZPE).
- Real energy itself gravitates (it causes gravity). However, since energy does not have mass, energy is not attracted by gravity.
- In QED theory the ZPE is virtual; therefore in QED there isn’t any actual real energy. QED provides no actual vacuum energy to gravitate.
According to standard models, gravity works in spacetime, which has three dimensions of space, and one of time. (Time only moves in one direction, but in the dimensions of space, movement could be either forward or backward.) We can think of everything as moving through spacetime at a speed in those four dimensions that sums equal to the speed of light.
- Photons in a vacuum travel only through space and don't travel through time.
- All conventional physical objects are in physical motion, and they travel in some combination of space and time.
- An object (theoretically) standing completely still, travels only through time and not through space.
- So then an object suspended (non-moving) in gravity is moving through time and not (so to speak) in space. The suspension constrains its movement. Then when it is let go, the acceleration of gravity changes some of the object's speed in time into an increased speed in space. The object will then move through time more slowly. For most falling objects, their change of speed through time is tiny (but in some cases is measurable).
According to standard models, another way to think of gravity is that it curves space. This is not physical movement. It is an effect to change the path of least energy, that is, the path we would travel while coasting. It is an effect that changes the travel path of things (both massive and massless) through regions of space. Depending on the observer it would have a temporary effect on the speed of a massive object, but it would have no effect on the speed of massless particles.
So then as observers ourselves with mass (assumed to be gravitationally bound), how can we come to know if we are in a Goldilocks context where the expansion forces of our physical context is precisely at a balance of stability against gravitational forces? To be precisely at a such a balance would be incredibly unlikely (like a pencil balancing on its tip is unlikely). note If we are not balanced, then our expansion is changing and measurements we make are uncalibrated in relation to all other areas of the universe.
We actually know that the gravity fields that we are in change as we move through and around the gravitational fields of other bodies. The moon is constantly changing our gravity field. The strength of gravity is different at different places on the earth. How could we then have a balanced stable size just from or because of gravity?
Another problem with the standard model is that as the photons shift red, they are loosing energy. (The energy of photons is correlated with their frequency - or more properly with 1/wavelength.) A fundamental law of physics is that energy cannot be created or destroyed, and yet this redshift model is constantly destroying energy.
To recap: Because of the redshift, it seemed like space was expanding. However if the expansion was happening uniform everywhere, then the expansion could never have been detected. So then, it is proposed that we are locally “gravity bound” in such a way that our area does not experience expansion. However, this arrested-by-gravitation idea is inconsistent with basic physics of gravity.
There are substantial problems with this story:
- Our measuring sticks on earth are only valid here in the space right around us. They wouldn’t have a calibrated meaning in any other places in the universe which would have expanded to a different size than our own space. note This means we can’t trust any of our measurements here to apply elsewhere. It seems this would go against the cosmological principle. note It also would make all our color shift measurements have no calibration to the rest of the universe, and therefore all our expansion rate measurements of the universe are only a local opinion and valid only on earth. We can observe our light is different, but can't know much more.
The cosmological principle is the idea that the universe is the same everywhere when view on a large-enough scale.
- Wikipedia Cosmological principle
Curiously, what is also logical with this idea is that if a calibrated measuring stick from earth was carried around in distant space it would change size as it stayed in the non-gravity bound expanding space. If it was then returned to earth, it would no longer be the same size as another calibrated stick that stayed on earth. Therefore measuring devices on earth have no calibration in relation to the rest of the universe. From this it can be seen that the theory self-refutes in regard to truthful knowledge about the external universe.
If the counter explanation is that a measuring stick does not change size because of its own self-gravity, then my conclusion is that the expansion force on the universe is too weak to have the effect that is claimed. If it is incapable of expanding objects with mass simply because of their self-gravity, and gravity is known to be a very weak effect, then it cannot be strong enough to stretch the space between stellar objects either.
In my reading, the discussion of being gravity-bound is usually in the context of being in the vicinity of large objects like stars and galaxies. If self-gravity is sufficient to cause gravity binding, then what is the effect of being in a deep gravity well such as that of a planet, star or black hole? Does the size of space in those contexts remain stable, or is it shrinking in proportion to the gravity? I have seen no public answers on this.
It seems to me that all of this is a problem of the science because it does not seem to be based on experiments or measurements of sizes, dimensions, etc. If the science is disconnected from experiment, it is not science (even if the math is consistent). It is imaginary speculation.
- The expansion rate of the universe is called the Hubble constant. The value for this as calculated from red shifting measurements is 73 km/s/Mpc. The same parameter calculated from cosmic microwave background measurements is 68 km/s/Mpc. This is a substantial discrepancy and is severely troubling. The interesting point for the purposes of this discussion is that this has some researchers seriously questioning the basic physics involved. note
Note that these two very different Hubble constant values have been determined with very good precision. Because of this, their gulf becomes more stark.
Another researcher is of the opinion that this discrepancy would be solved if there was a large bubble 250 million light years in diameter where matter is of a different density from the rest of the universe. Maybe if that were to be true then the discrepancy would be resolved, but there is no known reason for why this idea should be true, therefore it is not an explanation, it is speculation.
- Redshift was shown by Arp, Tifft and others to be quantized in jumps of about 2.7 km/s. note The standard expansion model only predicts a smooth redshift effect. It is unable to account for this observed quantization effect.
Barry Setterfield: Zero Point Energy and the Redshift
Redshift is the primary evidence for the expanding universe. note However this acts as evidence for expansion only if you infer as Hubble did that the redshift is caused by the expansion “velocity”. If however, you don’t see that the redshift comes from a “velocity” then redshift is not evidence of expansion. Redshift then is theory-laden circular evidence for expansion. The view of a continuing expansion of the universe however is widely accepted because it seems to match to many of the observations, and because it matches to accepted philosophies. note
There is also an idea that there is no preferred special places in the universe; this is the so-called Copernican principle. It is a philosophical point of view, and not a scientific principle. However, it does have a large effect on practitioners of science.
An expanding universe matches well with this idea because red-shifting is seen consistently in all directions away from the earth. Other observations also match with this principle: distant stars, gamma-ray bursts & supernovae that are all seen smoothly across the whole sky canopy, the cosmic microwave background which is an extremely smooth background in all directions.
Note that it is not necessary for the universe to still be expanding now to understand that it was smaller, denser and hotter in the past.
A different model could also would work with all the evidence if it had a point beginning for the universe, at an earlier time it was expanded, and then the expansion stopped at the size we see today. This alternate idea would be identically compatible with all the observations attributed as supporting the Copernican principle.
The redshift resulted in the understanding of an expanding universe. A universe expanding now had to have been smaller in earlier times, and logically this worked back to having expanded out of a single point at a beginning.
(This evidence for a beginning of the universe was not received well by the many that preferred a timelessly existing universe. They derisively called this a “big bang” idea, and the name stuck.)
The cosmic microwave background radiation (CMB) is also sometimes cited as supporting evidence for the expanding universe. In reality it is only evidence that the universe had previously expanded (that the universe had a beginning).
The CMB is consistent with a universe that is now expanding. But it would also be consistent with a previously-expanded universe that now has a stable size. Therefore, it is not evidence of continuing expansion. (Because of this, it has not been mentioned in this discussion.)
It can be noted that the CMB is inconsistent with an idea of a universe that had been expanding at a continuous rate from the beginning until now. The universe must have been expanded quickly at the beginning. Standard cosmology therefore requires a so-called inflation period at the beginning to explain the existence of the CMB. (A hypothetical “inflaton” field is suggested as causing this. There is nothing in known standard physics that can explain the cause or mechanism of this inflaton field.)
However, I personally think the standard model is insufficient to explain all these discussed observations. The standard model also has other substantial inconsistencies and holes where it seems to make exceptions around some very basic aspects of well-tested physics. note I find things like this to be troubling for physics.
To be written: Holes in Standard Cosmology
In contrast I think the Setterfield changing zero point energy theory does a better job of accounting for all these observations. note A summary of its physical explanation:
Barry Setterfield: The Redshift
This model is based on stochastic electrodynamics (SED) instead of the more-broadly used quantum electrodynamics (QED). It concerns zero point energy (ZPE), an energy which fills all space. ZPE is a part of both QED and SED. In SED the ZPE is real energy, but in QED it is not. note
Note that in standard QED the ZPE is considered virtual because it is just an effect of the Heisenberg uncertainty principle.
In the Setterfield model the universe quickly (was) expanded during the Big Bang out to a (non-expanding) stable size. The expansion invested tension into the stretched space. This potential energy in the tension converted into the ZPE energy (through a physical process). This conversion was not instantaneous. Although it converted very quickly at first, it then became asymptotically slower as the ZPE approached current levels. This change of ZPE happened everywhere consistently.
As the ZPE increased, it had a direct effect on atoms everywhere to increase their orbital energies. This changed atoms so that they emitted light that became increasingly more blue. This change of color emission happened in small incremental jumps (because of the quantized nature of atoms). The blue-shifting finally came to the color that we now see locally around us today (in our laboratories on earth and from stars that are near to us). The light that we see today from the distant stars, however, was what was emitted back when the ZPE was weaker and therefore the photons had been emitted more red. This light from distant stars has been traveling to us in proportion to stable distance, so what we see is the actual historical color of the emitted light. note
The light from the most distant stars was emitted when the ZPE strength was changing most quickly, following an exponential decay curve. (The initial very high energy in the tension of space was quickly converting over into ZPE energy.)
The rate of change of redshifting is highest from these most distant stars. Under standard models this is interpreted as accelerated expansion at the edge of the universe. However in the Setterfield model, these more dramatic redshift effects are simply a consequence of the initial high rate of ZPE change.
This ZPE-based theory is consistent with all the astronomical observations that have been discussed. It is based on the work of recognized physicists (including Nobel laureates) and continues to be actively developed. It is a minority theory, but it performs well for explanatory power and it accurately models other key observations in physics.
I have come to think that the Setterfield model explains these observations in a way that is more plausible than the standard model, and also that it is more consistent in other ways with established, tested physics.