Interesting... math
Dark energy and dark mass unified?
Sort:
Dec 7, 2018
0
#5
Oh dear, astrophysics, wheres RPaulB he can always explain things by way of 'the universe is a particle'.
Has the negative mass idea been around for a few years, seem to recall it from a while ago.
Dec 7, 2018
0
#6
You are absolutely right. The wikipedia article on negative mass is full of interesting history for the concept. Neither, it turns out, is it the first time a negative mass substance has been used to try to explain the observations that have been explained by dark energy and dark mass: two physicists called Jean Pierre Petit and Gilles d'Agostini have collaborated on two papers on this topic.
I am not entirely sure about the sign for the rest energy of negative mass. I think it should be positive and for it to be negative could be problematic, but it seems others think otherwise. I can't see any problems with positive energy for negative mass - as a relativistic invariant, it gets conserved under the weird dynamics.
I am concerned about the stability of systems with a mixture of positive and negative mass. The fact that an equal positive and negative mass can chase each other, getting faster and faster, is weird. But if they are imbalanced, the centre of mass of the system moves at constant velocity. If the total mass is positive, I think the system remains bound, if negative, the lighter positive mass speeds away from the lighter negative mass (which accelerates in the same direction but can't keep up). Weirdly, this is consistent with the constant velocity of the centre of mass because of the unfamiliar opposing momentum and velocity of negative mass.
Dec 7, 2018
0
#7
The negative mass idea has come up a few times, but I think the real novelty of this paper is the creation Tensor, which has been applied to positive mass in the past, but never negative mass. I don't know enough about GR or tensor calculus to know what all the implications are, but its a nice change of pace from the usual dark matter theories that don't seem to be going anywhere. Also, I'm curious as to how the negative mass hypothesis explains something like the bullet cluster (https://en.wikipedia.org/wiki/Bullet_Cluster) which seems to include large regions of invisible positive mass.
Dec 7, 2018
0
#8
There have been some quite negative comments on this work by some experts, partly because the author gave it a larger profile by sending a press release to some new services, but mainly because they think there are a lot of problems with making this work that lead to pessimism that it does.
Presumably, someone is going to doing the sorts of tests of this model against the more difficult experimental data that it needs.
Amazingly, it appears to have only just happened that anyone has realised that dark energy and dark matter can be explained by a single substance with negative mass. Farnes from Oxford University has published a paper including the following simple diagram which explains how a negative mass (but I presume positive energy, because
gets rid of the negative sign) substance can both (1) cluster around galaxies and explain their rotation and (2) accelerate the expansion of the Universe.
Ponder on it a bit and you may see why.