BlOoDy RiPpEr wrote on Jul 16th, 2012 at 7:47am:.
Even science requires creation. |
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Sir Spot of Borg wrote on Jul 16th, 2012 at 8:27am:.
It doesnt "require" anything.
SOB |
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I agree. The vacuum was in a state of thermal equilibrium. Good Science mate !
The vacuum (fundamenatal substance) existed, before spacetime and matter. I don't know for how long but long enough for a number of events to occur.
The gravity of this field is not the gravity of today, where energy and pressure are
negligible contributors, but where they are the dominant contributors. Perhaps it could be described as not yet having gone thru the phase transition that separates 'then' from today
These are the governing physics of Gravity ....
Pressure gravitates (adds to the gravitational force).
Pressure can have a negative value.
Positive Pressure makes a Positive contribution to Gravity.
Negative Pressure makes a Negative contribution to Gravity.If the field has a restless urge to seek the smooth state (thermal equilibrium) then once achieved, its energy value would measure zero, and we would measure zero if we measured its rate of change of this value. We would say metaphysically that we found '
nothing' to measure ? If we arbitrarily raised the value of the whole field uniformly, or lowered it uniformly, we would still measure zero/zero across the field. The field when still (or smooth) is contributing the least possible energy it can.
In the electro-weak theory, above 10^15 degrees this field has an average value of zero, all fundamental matter particles are mass-less and all force particles are mass-less as well.
Above 10^28 degrees (
grand unified Higgs) photons, gluons, W and Z particles can all be freely interchanged with no observable consequence. Total symmetry. So as the universe cools the field goes thru phase transitions that break symmetry.
Guth was working on the monopole problem, a separate problem, when he found that his calculations were describing a period of inflation. Also many others working independently came across inflation, especially behind the iron-curtain, but initially they lagged behind. Because firstly, they didn't fully appreciate that it solved many other problems, horizon, flatness, etc, but also it had a serious problem itself. If you don't know what the problem is, I'll try to explain it.
In 'seeking a smooth state', it became implicit that a less smooth-state must be allowed. This can be explained by QM, but I digress. As the field goes from un-smooth (is there such a word .. ?) to smooth, equations exist that define the shape of the 'energy bowl', which in its smoothest state would have the field values at the lowest part of the bowl, just as water would settle in a bowl. As the field rolls down the bowl Guth was trying to understand what phase transitions occur (humps in the bowl), fast, slow, could it become stuck, could it be delayed, etc. he thought this was relevant to the monopole problem.
The fields previous random QM fluctuations (un-smooth) have caused the field to cool slightly, this is why its descending to the bottom of the bowl.
Random QM fluctuations now govern the wave front, values may be high here, low over there, but on average the wave front is descending smoothly. Guth discovered that the average value could plataeu momentarily. As the universe continues to cool the field value becomes hung on this bump or plateau. The field has become supercooled, latent with potential ... or a phase transition. Latent energy is increasing but no observable change is occurring. This suffuses all of space with energy and a uniform negative pressure.
The latter was Guth's great insight.
Eventually the supercooled Higgs field values, thru QM fluctuations, jumps down to the lower level (off the plateau). But would it happen everywhere in space at the same time? Guth said no, the relaxation of the field to its zero energy value is a process. It drops to zero value at one point and this starts an outward spreading bubble whose 'walls' move at light speed.
Put more simply, when zero energy is reached at a given point, then this value spreads away from that point at the speed of light, or with the passing of the 'wall'. According to Guth many such bubbles would occur as the field stabilised to zero. But all these bubbles would have to join to form a universe with a zero energy inflaton field and because the space between the bubbles was still uniformly suffused with negative pressure which was driving space apart at many times the speed of light, then the bubbles would most likely never coalesce.
Here's the calculation if your interested
Quote:.
It is not difficult to see how accelerated expansion arises. One of Einstein's equations is d^2a/ dt^2/ a = -4 pi/ 3(P + 3p) Where a, P, p are scale factors of the universe. Its 'size', the energy density and the pressure density respectively.
Notice that if the right hand side of the equation is positive, the scale factor will grow at an increasing rate: the universe's rate of growth will accelerate with time. For a Higgs field perched on a plateau its pressure density turns out to be equal the negative of its energy density. The same is true for the cosmological constant. And so the right hand side of the equation is indeed positive. |
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This equation is what drives expansion at an exponential rate.
So ... if the bubbles never coalesce maybe each bubble is a different universe ? No, this turned out to be incorrect. Guth needed the bubble walls to coalesce because, as the field reaches its zero energy value its energy is not lost, but is converted into normal matter and radiation that inhabits it now. In Guths mechanism this conversion occurs as the bubbles collide and coalesce. But insights by Linde and others corrected all this.
New calculations prolonged the initial inflationary burst so that a single bubble grew large enough to encompass the entire observable universe.
But then it was found that you did not need the whole value of the field to plateau. Instead Random QM variations in the value occur across the field the whole time. When they are small or medium, nothing happens and they revert to the void, but when the value is high (eureka) even in an area less than 10^-33 cm, a cosmic 'friction' sets in, due, I think, to the latent energy conversion that is occurring at the wavefront between the two values. QM fluctuations are governing the wave front's rate of change. This resistance is consistent and causes the field to roll down the energy bowl slowly. This causes the field to contribute a nearly constant energy and a nearly constant negative pressure.
According to the calculations above, this is exactly what you need to drive a period of inflationary expansion. This is called chaotic inflation, and so far as I know is considered the most convincing. The graph below graphically displays the initial fluctuations of the field
Quote: Unfortunately I cannot put the graph here as this site requires you to make 40 posts first ....
Perhaps a kind mod would put it here for me ?
sigh .... Zac da Black |
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The microwave cosmic background radiation is around 2.7 k but it does vary. But not till around the fourth decimal point.
So if you measure the temp difference between 2 points in space you will get variations up to 1/10000 of a degree (photons have had to travel thru more and less dense gravitational areas and their energy varies depending on the gravitational fields they have had to overcome)
Using the CMBR (cosmic microwave background radiation) as a 'fossilised record' inflationary theory graphed and predicted the temp variations across a region of space and this graph exactly matches the COBE satellite and WMAP satellite temp measurements.
The long predicted Higgs boson has now been experimentally found ...
The Higgs field exists.I agree wif dat cat wif da one eye ...
Spot ON Borg !!
Zac da Black
