Exploring the Origin of Big Bang Energy

[schwarzchildradius]

Space is equivalent to the energy-momentum tensor, in the Friedman eq. So the geometry of space is dependant on the distribution of massive objects & energy in it - 'space tells matter how to move, matter tells space how to curve.' A homogeneous distribution of mass in space with universal gravitation causes a collapse of space. Some universal force must be acting against gravity to yield an expanding universe.
Why didn't the universe collapse at the moment of the big bang?

 

[Eh]

In the link I posted, I think there is a section that covers the bubble universes in a self reproducing universe.

 

[wolram]

http://superstringtheory.com/cosmo/cosmo41.html
this link gives a possible explanation, I am not a fan of SST,
but i read all i can, i do not understand all of it but no one
else does either.
i think MARCUS did a poll," several", you only have to look at
replys to see how differently people think.
http://nowscape.com/big-ban2.htm
an interesting read.
best wishes.

 

[Netme]

Isnt space "shrinking" now?

 

[Phobos]

Originally posted by Netme
Isnt space "shrinking" now?

No, it's apparently expanding at an accelerating rate.

 

[wolram]

my question is what is shrinking, expanding? if it is
"space time", what is its unit of measure?
if one can say ST started at 0 dimentions what is the upper limit
to its expansion?
will space always stay in step with time?
to expand ,"increase volume" space has to have a" volume" to expand into, if that is true then a volume must always have existed.
best wishes.

 

[Phobos]

Originally posted by wolram
my question is what is shrinking, expanding?

We see objects (galaxies) moving apart from each other, not because of their own movement through space (which can also be measured), but because more space is forming inbetween those objects. How can we be sure? Hmm...is there a cosmologist in the house?

if it is
"space time", what is its unit of measure?

The speed of light essentially.
The rate of expansion is measured in units of kilometers per second per megaparsec (all of which can be referred back to the speed of light which moves at a constant speed).

if one can say ST started at 0 dimentions what is the upper limit
to its expansion?

Unknown? Infinity?

will space always stay in step with time?

Unknown? Or, probably yes, since space & time are linked at the very fabric of the universe. See also below.

to expand ,"increase volume" space has to have a" volume" to expand into, if that is true then a volume must always have existed.
best wishes.

It does confound "common sense", but then again, so does Relativity, Quantum Mechanics, and the fact that this is a heliocentric solar system.

This question bugs me too. The easiest answer is "we don't know". Another answer that bugs me (due to implications of predestination which don't sit well with me) is that the new space (volume) comes from the future. In other words, the universe is made of space and time...and the time dimension may already be in-place and space is simply proceeding along that time line. We simply experience slices of the whole space continuum (which already exists) as the timeline unfolds.

But I'm speculating out on a limb here.

 

[Netme]

Originally posted by Phobos
No, it's apparently expanding at an accelerating rate.

Ive heard that it has stopped expanding and is now shrinking at an accerlerating rate. How could you tell the difference between shrinking and expanding if there is no center point to extinguish it from? An infinite universe has always been questionable to me...

 

[marcus]

Originally posted by Netme
Ive heard that it has stopped expanding and is now shrinking at an accerlerating rate.

In my own thinking I've found it helps to make a clear distinction between our personal views and the professional consensus (which is quite a new thing---cosmologists are still commenting with pleasure and astonishment about the emergence over the past 3 or 4 years of a "concordance" model of the universe)

The point though is that we don't have to accept it. We are free to imagine the universe and its history with the images we like.

But it would be a good idea to be familiar with the consensus picture that has emerged recently in cosmology. A good source is:

Lineweaver (a leader of the COBE team)
http://arxiv.org/astro-ph/0305179

but there are also articles online by other recognized people
Michael Turner---"Making Sense of the New Cosmology"
Plionis
Eric Linder
Ned Wright

They all say pretty much the same thing and it is the view
you are getting from Phobos too.

In particular they don't think the universe has started contracting at a accelerating rate!

But in my opinion it is great that you think this! Why should we not hold different opinions about the cosmos! Why should we
think we have to agree with the consensus of experts! There must be room for poetry and mysticism---radical as this sounds---the universe is not just the stuff of science it is the stuff of myths and free imagination. Like Blake said:

To see a World in a Grain of Sand,
And a Heaven in a Wild Flower,
Hold Infinity in the palm of your hand,
And Eternity in an hour.

Blake was not bound and constrained by the contemporary views of cosmologists circa 1800, thank goodness.

Having said this, however I believe what the cosmologists say---my view is similar to Phobos in most ways I guess

 

[marcus]

wolram said:

Originally posted by wolram
my question is what is shrinking, expanding?


to expand ,"increase volume" space has to have a" volume" to expand into, if that is true then a volume must always have existed.
---------------------------

there is a criterion for something to be standing still

and galaxies are mostly all approximately stationary
(at rest wrt the CMB and the things around them)
approximately

and the distances between them are growing


at bottom all "the expansion of space" means is if you
pick two points far apart
the distance between them is increasing
(in a linear way: the rate proportional to the distance)

atoms and apples and galaxies are not bothered by this because
they fall back together--under the control of the forces which give them structure----they are bound structures

the increase in distances between nearby points (in this galaxy, in this apple) is so slow that the organized bound structures easily adapt and compensate and STAY THE SAME SIZE

but distances between far apart things continually increase


space is not a material
it is not expanding into more space
it does not need space into which to expand (the way an
expanding material object would)
all it needs is a dynamic distance measure which
reads an increasing distance between any given two points.

 

[wolram]

MARCUS it seems a large part of cosmology theory is dependant on
vacuum energy, is there a consensus as to the density of this
energy?, at what time in the inflation model did this energy form?
i may be getting confused but i read that the electron borrows
energy from the vacuum ,if that is correct then it is the
vacuum energy that supports matter.
im sure you can pre empt my next thought.
best wishes.

 

[marcus]

Originally posted by wolram
MARCUS it seems a large part of cosmology theory is dependant on
vacuum energy, is there a consensus as to the density of this
energy?, at what time in the inflation model did this energy form?
i may be getting confused but i read that the electron borrows
energy from the vacuum ,if that is correct then it is the
vacuum energy that supports matter.
im sure you can pre empt my next thought.
best wishes.

I cannot predict your next thought. I have often if not always found your thinking rather deep and therefore unpredictable,
at least as far as coming up with questions goes.

The cosmologists CALL their general agreement on some basic featuires and percentages a "consensus" several even use the term "concordance model"

but that may seem to overstate the agreement.

About cosmological constant or vacuum energy or "dark energy" the only consensus I have detected is that "we don't know what it is"

They agree that it is 70 percent (some say 73 plusminus something) but they also agree they don't know what it is and don't have any immediate means of reliably distinguishing between the various possibilities.

So maybe it is OK to say that at the moment there is an unusual degree of a agreement among cosmologists (in the past they have been a contentious bunch and inclined towards factional strife)
but if it can be described as agreement then it is a consensus with a lot of big gaps and unanswered questions in it.

More I cannot say. Maybe some others who watch the scene more closely can fill in more detail for you.

...well, I will try to respond in more detail. I'll go for a second post.

 

[marcus]

Originally posted by wolram

vacuum energy, is there a consensus as to the density of this
energy?, at what time in the inflation model did this energy form?

The dark energy (which the simplest explanation of it seems to be that it is intrinsic vacuum energy-----which standard quantumfieldtheory predicts too much of and no one understands why there is the amount there is)

is begorra agreed by the experts to be 73 percent of the
total average energy density.

the mind reels that they could have come up with this number and all decided to believe it, well no matter, onwards!

AT WHAT TIME
yes of course, very good question!
but here is a subtle point, it could have been there from time zero
but masked by more dynamic energetic things

you know occams razor, when in doubt choose the simplest model.
well the simplest model of dark energy or vacuum energy is that it is an absolutely constant energy density, not varying either in space or time. vacuum is vacuum now or yesterday here or in the next galaxy

something, say a joule per cubic kilometer, I forget, but something

so when the universe was young, a cubic kilometer (besides this joule of vacuum energy) had a vast lot of OTHER stuff crowded into it---hot radioactive buzzing around stuff
percentagewise the vacuum energy wasnt very important back then

so when the universe was young the vacuum energy was the last thing anyone would care about or would have any affect on events


only NOW when there is SO MUCH VACUUM in comparison with other stuff, light neutrinos, dust , gas, stars, dark matter. Now, with so much vacuum around, this vacuum energy is starting to play a significant role.


This IS THE BASIC REASON that the universe growth curve, the plot of the scale factor, is initially a convex ramp and then a concave (accelerated growth) ramp. Because at first the vacuum energy was unimportant and drowned out by other factors and expansion was decelerating, but then vac energy became a more important part of the picture (because space was emptier) and expansion began to accelerate due to the vacuum energy effect.

There is a kind of S shape to the growth curve that is good to
know about

At any rate you asked AT WHAT TIME did this vacuum energy form and I have to say

because it is simplest let us assume it was always there, but unimportant relative to other things

and there was a much more dynamic thing LIKE vacuum energy (a scalar field, an "inflaton field") that existed briefly and caused inflation-----so people say. I think of it as a different kind of vacuum energy, far more powerful, that was turned on for a split second very near time zero. But I don't think people have a clear idea of what that was----so it is not likely, I would guess, to help much to speculate about the relation between the feeble vacuum energy we see today causing the very gradual acceleration and the very strong vacuum energy (if it was that) which briefly caused the rapidly accelerating expansion we call inflation.

wolram continued

...but i read that the electron borrows
energy from the vacuum ,if that is correct then it is the
vacuum energy that supports matter.

Hmmm, like the banking system supports the industrial economy.
As long as we have a healthy vacuum sector, business will prosper and create jobs for the rest of us etcetera. Wolram I must let you go on without me at this point. You like crashing through the undergrowth and I like sticking to the beaten path.
More power to you, notwithstanding

 

[wolram]

abstract from wikipidia.
http://www.journaloftheoretics.com/Links/Papers/Setterfield.pdf
A paper published in May 1987 shows how the problem may be resolved69. The Abstract
summarizes: “the ground state of the hydrogen atom can be precisely defined as
resulting from a dynamic equilibrium between radiation emitted due to acceleration of
the electron in its ground state orbit and radiation absorbed from the zero-point
fluctuations of the background vacuum electromagnetic field…” In other words, the
electron can be considered as continually radiating away its energy, but simultaneously
absorbing a compensating amount of energy from the ZPE sea in which the atom is
immersed. In a similar way, a child on a swing gets a push just as the swing starts to slow
down, and a resonance is set up between the period of the swing and the frequency of the
pushes. So the orbiting electron also gets resonantly timed pushes from the ZPE that keep
it going. This had been explained earlier in a parallel, but even more enlightening way as
part of a course on stochastic processes applied to physics. The statement was made47:
“With somewhat more quantitative estimations, Boyer 70 and Claverie and Diner 71 have
shown that if one considers circular orbits only, then one obtains an equilibrium radius
of the expected size [the Bohr radius]: for smaller distances, the electron absorbs too
much energy from the [ZPE] field…and tends to escape, whereas for larger distances it
radiates too much and tends to fall towards the nucleus.

A paper published in May 1987 shows how the problem may be resolved69. The Abstract
summarizes: “the ground state of the hydrogen atom can be precisely defined as
resulting from a dynamic equilibrium between radiation emitted due to acceleration of
the electron in its ground state orbit and radiation absorbed from the zero-point
fluctuations of the background vacuum electromagnetic field…” In other words, the
electron can be considered as continually radiating away its energy, but simultaneously
absorbing a compensating amount of energy from the ZPE sea in which the atom is
immersed. In a similar way, a child on a swing gets a push just as the swing starts to slow
down, and a resonance is set up between the period of the swing and the frequency of the
pushes. So the orbiting electron also gets resonantly timed pushes from the ZPE that keep
it going. This had been explained earlier in a parallel, but even more enlightening way as
part of a course on stochastic processes applied to physics. The statement was made47:
“With somewhat more quantitative estimations, Boyer 70 and Claverie and Diner 71 have
shown that if one considers circular orbits only, then one obtains an equilibrium radius
of the expected size [the Bohr radius]: for smaller distances, the electron absorbs too
much energy from the [ZPE] field…and tends to escape, whereas for larger distances it
radiates too much and tends to fall towards the nucleus.

 

[wolram]

thankyou for your input MARCUS ,your views are alaways
unbiased and honest.

 

[wolram]

The actual origin of the ZPE on this approach has several schools of thought. One in
particular is the logical result of this treatment. Since charged particles in motion emit
electromagnetic radiation, this school of thought proposes that “the sum of all particle
motions throughout the Universe generates the zero-point fields” and that in turn “the
zero-point fields drive the motion of all particles of matter in the Universe … as a self-
regenerating cosmological feedback cycle” 16. On this explanation the ZPE becomes an
artifact of atomic particle existence. By contrast, Planck’s second theory reversed this
order; it directly implied that the ZPE was the cosmological entity that influenced atomic
particle behaviour, and not vice versa.
_______________________________________________________________________
this is where i get confused, which came first,vauum energy or
atomic particles ?it seems one cannot exist without the other.
best wishes.

 

[marcus]

Frank and unbiased is high praise indeed and I thank you. In a spirit of reciprocity I have edited out the linebreaks in the interesting passage you posted earlier. This makes it easier for me, and possibly others, to read.

Originally posted by wolram
abstract from wikipidia.
http://www.journaloftheoretics.com/Links/Papers/Setterfield.pdf
A paper published in May 1987 shows how the problem may be resolved[69]. The Abstract summarizes: “the ground state of the hydrogen atom can be precisely defined as resulting from a dynamic equilibrium between radiation emitted due to acceleration of the electron in its ground state orbit and radiation absorbed from the zero-point fluctuations of the background vacuum electromagnetic field…” In other words, the electron can be considered as continually radiating away its energy, but simultaneously absorbing a compensating amount of energy from the ZPE sea in which the atom is immersed.

In a similar way, a child on a swing gets a push just as the swing starts to slow down, and a resonance is set up between the period of the swing and the frequency of the pushes. So the orbiting electron also gets resonantly timed pushes from the ZPE that keep it going.

This had been explained earlier in a parallel, but even more enlightening way as part of a course on stochastic processes applied to physics. The statement was made[47]:
“With somewhat more quantitative estimations, Boyer [70] and Claverie and Diner [71] have shown that if one considers circular orbits only, then one obtains an equilibrium radius of the expected size [the Bohr radius]: for smaller distances, the electron absorbs too much energy from the [ZPE] field…and tends to escape, whereas for larger distances it radiates too much and tends to fall towards the nucleus."

 

[marcus]

Originally posted by wolram
this is where i get confused, which came first,vauum energy or
atomic particles? it seems one cannot exist without the other.
best wishes.

are you really confused
or are simply making a point that
here is a scientific theory with two component
(vacuum and matter)
and it is impossible, within the theory, to
ascribe priority to one over the other

it may be that this symmetric interdependence
is a desirable feature of a theory

since I am not familiar with this I must stop
discussing it, at least for the present
all I can tell you is that cosmologists say
the (unexplained, dark, cosmological etc) energy
density is roughly one joule per cubic kilometer
or, more precisely 0.6 joules per cubic km.
I find it astonishing if not preposterous that they can claim
to know this, but must accept the opinion of
established professional experts, given the
extent of agreement.

 

[zydubion]

Physical space can't expand. Space is not physical, that's why it's called space. There are however physical particles in space that move about or expand out into further reaches of space. Space is the non-physical universe. It has no size, it is infinite. It is infinite nothingness until you come upon an occasional star or whatever.

 

[wolram]

thankyou for your support, but your opinions are in
the minority along with mine.
my mind cannot comprehend a bounded space so i think of
space as infinite
but beware there are minds out there that can comprehend
allmost anything.
best wishes

 

[Eh]

Originally posted by zydubion
Physical space can't expand. Space is not physical, that's why it's called space.

What is it then, spiritual? According to GR "space" is not "nothingness" and is just the metric of something else. See http://itss.raytheon.com/cafe/qadir/q2442.html

There are however physical particles in space that move about or expand out into further reaches of space. Space is the non-physical universe. It has no size, it is infinite. It is infinite nothingness until you come upon an occasional star or whatever.

But remember that space in modern physics is the dynamic spacetime of GR, and can curve, expand, contract, etc.

 

[marcus]

zudubion says this:

Physical space can't expand. Space is not physical, that's why it's called space. There are however physical particles in space that move about or expand out into further reaches of space. Space is the non-physical universe. It has no size, it is infinite. It is infinite nothingness until you come upon an occasional star or whatever.

------------------
maybe we have only verbal disagreements

a relativist does not claim that space is material, but only that there can be distances defined between things----a "metric" function, which is relationall

when a cosmologist says "space expands" it simply means that the distance function is increasing. It is a (perhaps confusing, perhaps unwise) manner of speaking

"space expands" is a statement about distance-relations, and it is unfortunate if the listener gets the notion that space is an object with some absolute existence which is somehow realer than the relations between things.
---------

wolrams replies to zudubion

thankyou for your support, but your opinions are in
the minority along with mine.
my mind cannot comprehend a bounded space so i think of
space as infinite...

________________

this sounds amazingly mainstream for someone who claims minority status

This is just my take on it but I believe it is normal for astronomers to assume space infinite largely because it would be an infernal nuisance to add junk to the model to make it bounded
there's no solid evidence that it is bounded so the simplest thing is to assume it isnt
and by good fortune that seems also to generate a good fit to cosmological data
or so it seems at present anyway

as for minds out there which are capable of believing anything probably the barbarians have always been and always will be at the gates especially at physicsforums which seems to be a noteworthy kook-magnet.

 

[wolram]

it was just a mommentary slip MARCUS i promise to be more
anti establishment in the future