ok, the correct word could be power function that has exponential growth. I think we still are in exponential expansion.
All the rest in my question I hope they are correct.
I am not sure I agree with that. Exponential expansion doesn't mean all the time e power that never goes away as you differentiate. It could be x^3 that goes to 3x^2, 6x, 6 and finally 0. That's why I keep asking which line of my graph charts you believe is best describing universe's expansion...
So if I understood correct your answer with fixed Hubble parameter in the far future we should have (as scale factor is concerned) the forth line in my graph.
1. Space exponential expansion
2. The speed of that expansion first exponential and later linear (1st derivative),
3. Acceleration of...
Yes, you are correct. But since the density of matter (dark or not) reduces with universe expansion, repulsive action of dark energy will be getting stronger and stronger in the comparison between them.
This means that dark energy's gradual stronger domination should cause exponential expanion...
Thank you very much for your answer.
You are right that Hubble constant is not exactly just velocity, but velocity over distance and the derivative is more complicated than just the third derivative of the scale factor.
You mentioned that the third derivative is also positive and decreasing...
Since distances increase, their first derivative which is velocity (Hubble constant) should be positive if not increasing too. Accelerated expansion needs the velocity to increase. What about the third derivative which is acceleration? An accelerated universe could have third derivative (called...
I am sorry if I crossed any lines. As I said before "I am wondering how solid is the assumption that there is no negative mass". When I searched for similar threads I understood that anyone that questioned the positivity of mass was getting discouraged from thinking as a possibility mass to be...
QCD of antimatter could also possibly be negative. Due to meson's mass, lifetime and concetration incompetence, we cannot measure gravitational repulsion.
I already explained why antimatter could logically have negative mass. As I said, I am just trying to see how certain we are about non...
If I am not wrong light doesn't fall down, it just follows geodesics that are curved by the Earth's mass.
As far as the machine, I must admit that I never heard of something like this. I can only guess that due to momentum conservation and to ridiculously weak gravitational force, both...
To Mfb
I am not quite sure what you mean. If you are suggesting that (probably or almost) all experiments and physicists take antimatter's mass as positive, shows more like the status quo, rather than a proof. I am aware that this is the status quo, but I have difficulty finding one experiment...
Can you please give examples?
If I am not mistaken, the mass of antimatter is calculated from equations of motion through EM field, which could show the amount of mass and not clearly the sign, as showed.
As for energy I have mentioned in the equations that it could count as positive, even with...
In physics we cannot easily imagine “negative” energy for a particle (not a field) in order to have “negative” mass, although the first concept of Dirac for antiparticles was that they were “holes” that were opposite to particle existence and there was a minus in front of mc2.Regardless of...
In a lecture from a course in QM, it was mentioned that Shroedinger's equation is deterministic in one and two dimensions. But in third dimension it gives unstable solutions, loosing it's determinism.
It was mentioned that "in space of D dimensions Gauss theorem leads to the conclusion that...
How can a curl of 4-vector or 6-vector be writen? Let's say that we have a 4-vector A4=(a1,a2,a3,a4)
how can we write in details the ∇×A4
Can we follow the same procedure for 6-vector?