"The cosmological constant ... is the value of the energy density of the vacuum of space"
I think that the cosmological constant is actually the integrated sum of all gravitational curvature in a given space, which is a gravitational potential energy in the vacuum of space.
Therefore if matter in space is not evenly distributed, then the area with more mass will have a larger calculated cosmological constant in that area, with more energy density in the vacuum of space in that area, leading to the faster rate of spacetime expansion, ie for supernovas, since they have high mass density compared to the rest of the universe, so have more energy density in the vacuum leading to them expanding into the surrounding space.
Here's an example to calculate the cosmological constant (mass density equivalent) of a surrounding space:
from a supernova's perspective:
knowns:
supernova mass
supernova spacetime acceleration of expansion
supernove spacetime expansion rate
These knowns take into account any supernova that blew up and is expanding into surrounding space (and in this theory expanding into spacetime of a surrounding space with LOWER calculated cosmological constant (mass density equivalent), otherwise the supernova spacetime will shrink in size.
unknown to find:
universe's mass density
The unknown can be found in this case.
Another example from the universe's perspective:
knowns:
universe mass
universe spacetime acceleration of expansion
universe spacetime expansion rate
These knowns take into account a universe expanding into surrounding space (and in this theory expanding into spacetime of a surrounding space with LOWER calculated cosmological constant (mass density equivalent), otherwise the universe spacetime will shrink in size.
unknown to find:
mass density outside the universe
The unknown can be found in this case, however #2 the universe spacetime acceleration of expansion (or deceleration) is currently not known I think, but based on the red shift frequency of matter 15 billion years ago, it implies that the universe was expanding faster in the past than it currently is (assuming it is overall homogeneous) then that can be used to find the current estimate for acceleration or deceleration of expansion.
So this mass density outside the universe should be able to be estimated today!
Possible *static* mass density options outside the universe:
external mass density = 0 (no mass outside the universe)
1.1 If the universe spacetime expansion rate = expanding, then the universe spacetime acceleration rate = rate of acceleration decreasing, but still an accelerating expansion rate
1.2 If the universe spacetime expansion rate = shrinking, then the universe spacetime acceleration rate = decelerating inward shrinking
external mass density = equal to universe (universe essentially infinite)
2.1 If the universe spacetime expansion rate = expanding, then the universe spacetime acceleration rate = no acceleration in expansion rate
2.2 If the universe spacetime expansion rate = shrinking, then the universe spacetime acceleration rate = decelerating inward shrinking
external mass density = greater than universe (our universe is a subset)
3.1 If the universe spacetime expansion rate = expanding, then the universe spacetime acceleration rate = rate of deceleration increasing, eventually will stop expanding and the universe will start shrinking
3.2 If the universe spacetime expansion rate = shrinking, then the universe spacetime acceleration rate = an increasing rate of shrinking will continue until the universe mass density is equal to the external mass density, and then the rate of shrinking will decrease, and possibly the universe will rebound outwards.
*static mass density outside the universe assumes the surroundings of the universe don't have varying mass densities.
Nope. In general relativity, you can set the cosmological constant to zero and still be able to calculate everything. That's how it was done for many years, between the discovery of the expansion of the universe and the discovery of dark energy.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
I appreciate learning and work to get a degree, but for something like foundational physics where there are all these unknowns, I think most of physics education doesn't apply to them since they are fundamental unknowns they are accessible to anyone, no physics education has been enough to answer them yet, so mine would probably be no different!
I think mass itself is what creates a non-zero cosmological constant, and leads to "dark energy", from wiki it says the cosmological constant is the simplest form of dark energy, I think it is too simple as the "constant" is proportional to the matter in the area of space under consideration, so would be the cosmological constant only when considering that area, so the whole universe should have an associated constant, but it will change as expansion happens too!
Mass is already accounted for in the equations. The cosmological constant is an optional fiddle factor that can be used to adjust the stability of solutions - originally to permit a steady state universe.
Jamie you can't just string together random word salad with appropriate buzzwords and expect to be taken seriously. The mathematics of the Big Bang date back to Einstein & Lemaitre and are well understood.
The cosmological constant was originally added as a bodge to permit a static universe solution (which was the prevailing cosmological model in the days before Hubble's observations of galaxy redshifts). Einstein described it as one of his greatest mistakes to tweak his solution so.
It is a curiousity that now it looks like the value of the cosmological constant is non-zero although tiny. TBH I don't like new "dark energy" very much - it dates from a period after my time in astronomy research. I would prefer to believe that our type 1a supernova standard candles were different in the early universe (but I understand that has also been ruled out). Incidentally BBC Astronomy Live is offering a find your own remote supernova deal for anyone interested this week.
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Supernova
We were still haggling over what cold dark matter was then (one wag notably observed that broken chair legs and missing biros would do). That scenario is now completely ruled out by better IR observations.
Nope again. If you don't know the math, you're in the position of someone trying to write the Great American Novel without knowing how to read and write.
In fact the would-be writer is in a better position, because he's writing about common experience. In physics, math is primarily a technology--a set of tools for making logical inferences of a complexity far beyond what anybody can do without it. If you don't know any, you really can't get anywhere at all.
Elementary GR isn't much more difficult than classical electrodynamics--it's taught in senior-level undergraduate courses. I had a dedicated special relativity class as a sophomore.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics
160 North State Road #203
Briarcliff Manor NY 10510
hobbs at electrooptical dot net
http://electrooptical.net
Perhaps what is misleading you into taking this position is the fact that when you watch or read some popular work on cosmology or particle physics, they don't run you through the math.
Any new physical theory, in order to even stay on the table, must meet one criterion, and has a much better chance if it meets a second. The first criterion, which it absolutely must meet, is that it must match existing experimental evidence. You show that your theory does this either by going through every scrap of experimental evidence out there and showing your theory matches, or by showing that your theory matches the second criterion, which is that for all observed energies to date, your theory matches general relativity and the standard model.
The tools you need to show that your shiny new theory satisfies these criteria are the tools that you gain by getting a doctorate in theoretical physics. As an added bonus, if your thesis advisor is willing, you can make your shiny new theory the subject of your doctoral thesis, with as many preliminary proofs as you need to (a) make it look at least semi-acceptable, and (b) bulk the document up to the size of your average thesis.
If you just spin out theories with no more grounding than watching gee- whiz videos on YouTube, then you're doing the physics equivalent of randomly putting components on a circuit board and demanding that experienced electrical engineers stop their work so that they can critique -- respectfully and in detail -- your work.
Well said, I agree with most of that, but the modern age of information makes things accessible to people who wouldn't be able to access them individually, ie the resource you mention of knowledgeable connected people on the internet. It is a two way street and I don't expect any unwilling person to entertain my idea, it is free will, therefore I don't consider it selfish to post half baked ideas, especially since I try to consider (and add to) my own set of experimental evidence, although lacking, a good way to improve it is to ask half baked questions and follow through with them until they are proven or disproven.
Sometimes an uneducated (or self educated) perspective can bring as much to the table as an educated person does, ie new ideas founded in curiousity or partial knowledge. When dealing with unknowns, anyone can be involved there is no proven path to the answer, famous scientists credit imagination over any other trait for discovery in some cases. The sharing of existing experimental evidence by an expert is the cost of evaluating a half baked idea, I still didn't see any compelling refutation of my half baked "dark energy force as a result of gravity integration over a given space" energy, so I will keep it on the back burner for now! :)
A good quote is: "The person who asks a question is a fool for a minute but the person who does not ask is a fool for life"! :D
I ask so many questions per minute, I guess I am a fool for life too ;)
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