Is the mass of the universe (including dark matter) increasing? And I guess another way of wording it – is the total energy of the universe increasing? If not, how did all of that ‘fit’ immediately after the big bang? If yes, dafuq dude, where is it coming from?
OCDC said:
Is the mass of the universe (including dark matter) increasing? And I guess another way of wording it – is the total energy of the universe increasing? If not, how did all of that ‘fit’ immediately after the big bang? If yes, dafuq dude, where is it coming from?
as far as I understand, neutron mass grows at an exponential rate to that of protons and electrons. still trying to figure them out but I think there are some interesting questions to answer around this subject
OCDC said:
Is the mass of the universe (including dark matter) increasing? And I guess another way of wording it – is the total energy of the universe increasing? If not, how did all of that ‘fit’ immediately after the big bang? If yes, dafuq dude, where is it coming from?
No. Things were very hot.
The universe was very much more dense in the past than it is now. The same amount of energy is spread over an ever-increasing volume.
Of course it’s all complicated a bit by the concept of dark energy:
Dark energy
Not to be confused with Dark flow, Dark fluid, or Dark matter.
In physical cosmology and astronomy, dark energy is a hypothetical form of energy that permeates all of space and tends to accelerate the expansion of the universe. Dark energy is the most accepted hypothesis to explain observations since the 1990s that indicate that the universe is expanding at an accelerating rate. According to the Planck mission team, and based on the standard model of cosmology, the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.
Two proposed forms for dark energy are the cosmological constant, a constant energy density filling space homogeneously, and scalar fields such as quintessence or moduli, dynamic quantities whose energy density can vary in time and space. Contributions from scalar fields that are constant in space are usually also included in the cosmological constant. The cosmological constant can be formulated to be equivalent to vacuum energy. Scalar fields which do change in space can be difficult to distinguish from a cosmological constant because the change may be extremely slow.
High-precision measurements of the expansion of the universe are required to understand how the expansion rate changes over time. In general relativity, the evolution of the expansion rate is parameterized by the cosmological equation of state (the relationship between temperature, pressure, and combined matter, energy, and vacuum energy density for any region of space). Measuring the equation of state for dark energy is one of the biggest efforts in observational cosmology today.
Adding the cosmological constant to cosmology’s standard FLRW metric leads to the Lambda-CDM model, which has been referred to as the “standard model” of cosmology because of its precise agreement with observations. Dark energy has been used as a crucial ingredient in a recent attempt to formulate a cyclic model for the universe.
http://en.wikipedia.org/wiki/Dark_energy
Bubblecar said:
The universe was very much more dense in the past than it is now. The same amount of energy is spread over an ever-increasing volume.
the question is how it has been dispersed in time more than through space. energy has evolved from plasma based particles to atomic complexity.
The universe is losing energy through expansion but it’s also infinite in size and always was and oh look my brain exploded.
Dropbear said:
The universe is losing energy through expansion but it’s also infinite in size and always was and oh look my brain exploded.
Refs?
Carmen_Sandiego said:
Dropbear said:
The universe is losing energy through expansion but it’s also infinite in size and always was and oh look my brain exploded.Refs?
Riff-in-Thyme said:
Carmen_Sandiego said:
Dropbear said:
The universe is losing energy through expansion but it’s also infinite in size and always was and oh look my brain exploded.Refs?
noted
Is the mass of the universe (including dark matter) increasing?
————————————-
Yes.
As long as you consider BHs to be in this Universe…
OCDC said:
Is the mass of the universe (including dark matter) increasing? And I guess another way of wording it – is the total energy of the universe increasing? If not, how did all of that ‘fit’ immediately after the big bang? If yes, dafuq dude, where is it coming from?
It depends. :) Let’s see what John Baez has to say…
Energy is a torsor : we can’t measure absolute amounts of energy, only energy differences, so we need to specify some sort of baseline if we want to talk about the energy content of a system. And it’s not easy to come up with a good baseline to measure the total energy content of a curved, expanding, possibly infinite universe.
Traditionally (i.e. in Newtonian physics), we conventionally treat all gravitational potential energy (GPE) as negative. As you lift something up out of a gravity well, its GPE increases, approaching zero as the distance approaches infinity. We can adopt that convention in GR to give us a convenient energy baseline. For small, flat, static regions of spacetime, that convention is fine, but it gets a bit tricky when we have to take curvature and expansion into account.
The question of global energy conservation in General Relativity is not straight-forward. In small, flat, static regions of spacetime, energy is locally conserved as expected, but things get tricky when you try to determine the total energy content of a curved region, and even trickier when you add expansion to the mix.
GR says that spacetime is always locally flat, so you can generally deal with a curved region of spacetime by cutting it up into small enough pieces. However, there isn’t an unambiguous way to combine the local energy content of a bunch of small flat pieces to determine the total energy content of the whole curved region.
See Is Energy Conserved in General Relativity? for further details.
But if we ignore expansion and use a “simple” Hamiltonian approach to determine the total energy content of the universe, it appears that the total GPE of the universe’s contents balances all the other forms of energy, i.e., the total energy content of the universe is zero. So that nicely answers the question of where did the BB energy come from. Unfortunately, there are problems in applying the Hamiltonian approach to expanding spacetime.
Riff-in-Thyme said:
as far as I understand, neutron mass grows at an exponential rate to that of protons and electrons.
The proportion of neutrons to protons in a given region of space is slowly increasing due to stars converting hydrogen into helium, and also due to some stars going supernova and creating neutron star remnants. But that process is certainly not one of exponential growth.
As for the rest masses of individual neutrons, protons and electrons, they are static, according to the Standard Model. Of course, it’s possible that the masses of these particles have changed over time, but if they did, it would have observable effects on the behaviour of stars, and we have zero evidence of such effects.
PM 2Ring said:
Riff-in-Thyme said:as far as I understand, neutron mass grows at an exponential rate to that of protons and electrons.
Huh?The proportion of neutrons to protons in a given region of space is slowly increasing due to stars converting hydrogen into helium, and also due to some stars going supernova and creating neutron star remnants. But that process is certainly not one of exponential growth.
As for the rest masses of individual neutrons, protons and electrons, they are static, according to the Standard Model. Of course, it’s possible that the masses of these particles have changed over time, but if they did, it would have observable effects on the behaviour of stars, and we have zero evidence of such effects.
hmm, i guess I was applying exponential in terms of the foreseeable final neutron mass of the universe that would coincide with heat death. If there is a difference between the spacetime natures of the basic atomic components, the end of the universe would be when this would be most apparent, at least intuitively
Seems to me it must be losing mass
Losing Higgs bosons you think?
OCDC said:
Is the mass of the universe (including dark matter) increasing? And I guess another way of wording it – is the total energy of the universe increasing? If not, how did all of that ‘fit’ immediately after the big bang? If yes, dafuq dude, where is it coming from?
From the above responses, the answer is given as all of the following:
A) yes increasing,
B) no decreasing,
C) no, staying the same,
D) it’s complicated, and
E) don’t know.
Let’s take this slowly. I’ll distinguish between the visible universe and the total universe, between baryonic matter, dark matter, dark energy and black holes, between the very early universe (inflationary era) and the modern universe, and between mass-energy and mass separate from energy.
If we take “universe” to be “visible universe”, then … even that is complicated. Because the expansion rate of the visible universe is slowing due to the effect of gravity, galaxies and quasars and dark matter are appearing from over the visible horizon so the mass of the visible universe can be considered to be increasing. The inclusion of cosmic acceleration due to dark energy doesn’t change that – unless dark energy happens to be in the form of “quintessence”, which is unlikely, when at some time in the far future will overcome gravity resulting in a decrease in the decrease in mass of the visible universe. In the far past during the “inflationary era” the mass of the visible universe decreased rapidly as it was lost over the visible horizon, although there could have been no observers at that time.
If we take “universe” to be “total universe”, but restrict do not include energy with mass, then the mass of the universe is decreasing. The conversion of baryonic mass into energy occurs faster than that reverse process of the conversion of energy into mass. Dark matter may or may not be converted into energy (In the neutralino dark matter model it is, but in others it is not. The lack of a high concentration of dark matter in the center of the Milky Way suggests that it is, but the lack of gamma rays from there strongly suggests that it is not). If protons decay then this would add a little to the rate of reduction in mass.
If we take “universe” to be “total universe”, and include energy with mass, then the mass of the universe is probably constant. The law of conservation of mass-energy is always taken to hold for both baryonic matter and dark matter. And if the dark energy is in the form of the cosmological constant, which is the most likely scenario, then that is constant as well. One exception to this rule would be if dark energy is in the form of “quintessence”, in which case the total mass-energy of the universe is increasing. A second exception would be if we are in a multiverse accessible through either travel into a black hole or travel out to vast distances, a multiverse allows leakage of mass-energy from one universe to another.
So to summarize:
A) yes increasing, if the “universe” is taken to be synonymous with the “visible universe”.
B) no decreasing, if “mass” excludes energy.
C) no, staying the same, through the law of conservation of mass-energy in the total universe.
D) it’s complicated, in the far past and far future and if the universe is part of a multiverse. And,
E) don’t know, because the universe is probably stranger then we can imagine at present.
So the answer really is “all of the above”. Good question for QI to ask.
> If not, how did all of that ‘fit’ immediately after the big bang?
At the time of the big bang, temperature was infinite. Nanoseconds after the big bang, as the universe cooled, this thermal energy was already being slowly converted into other forms of mass-energy.
Matter/Energy cannot be created or destroyed but it can be changed.
That used to be a given, don’t know if it has been superceded.
Anyway here’s my theory.
The Universe is finite in terms of matter/energy however the firmament ( whatever you want to call it ) into which it is expanding is infinite.
And there you have it.
Peak Warming Man said:
Matter/Energy cannot be created or destroyed but it can be changed.
That used to be a given, don’t know if it has been superceded.Anyway here’s my theory.
The Universe is finite in terms of matter/energy however the firmament ( whatever you want to call it ) into which it is expanding is infinite.And there you have it.
wookiemeister said:
Peak Warming Man said:
Matter/Energy cannot be created or destroyed but it can be changed.
That used to be a given, don’t know if it has been superceded.Anyway here’s my theory.
The Universe is finite in terms of matter/energy however the firmament ( whatever you want to call it ) into which it is expanding is infinite.And there you have it.
where is the universe?
wookiemeister said:
Peak Warming Man said:
Matter/Energy cannot be created or destroyed but it can be changed.
That used to be a given, don’t know if it has been superceded.Anyway here’s my theory.
The Universe is finite in terms of matter/energy however the firmament ( whatever you want to call it ) into which it is expanding is infinite.And there you have it.
where is the universe?
No one knows my Lord, no one.
Peak Warming Man said:
wookiemeister said:
Peak Warming Man said:
Matter/Energy cannot be created or destroyed but it can be changed.
That used to be a given, don’t know if it has been superceded.Anyway here’s my theory.
The Universe is finite in terms of matter/energy however the firmament ( whatever you want to call it ) into which it is expanding is infinite.And there you have it.
where is the universe?No one knows my Lord, no one.
well I know one thing, I’m at the centre of it.
into which it is expanding is infinite.
we assume that it isn’t expanding into anything as that complicates matters.