Every time you look up into the night sky with amazement, you ask yourself the basic question of Cosmology as the science of the Universe as a whole:
- Is the Universe infinite or bounded? (Q1)
An expert physicist will tell you:
- An infinite Universe with uniform non-negative mass is empty.
So you are left with the question typically posed by a child:
- A finite Universe must have a boundary, but what is outside the boundary? (Q2)
A modern expert physicist may tell you that Einstein's General Theory of Relativity offers an answer in the form of an analogy of the surface of a sphere as a 2d surface in 3d space, which is finite but yet without any boundary, in the form of a 3d surface in 4d space, which unfortunately is beyond your finite ability of understanding (and probably so for everybody).
So you are essentially left without answer to Q1+Q2 asking an expert physicist. In the previous post I as non-expert physicist/expert mathematician outlined a possible answer along the following lines:
- Imagine an infinite empty universe Uzero with $\Phi =0$ a zero gravitational potential with corresponding zero mass $\Delta\Phi =0$, with $\Delta$ the Laplacian differential operator.
- Imagine a small scale small amplitude oscillating perturbation/fluctuation of $\phi$ of $\Phi$ with corresponding small scale large amplitude mass density $\rho =\Delta\phi$ of variable sign, thus with both positive and negative mass.
- Gravitational force $-\rho\nabla\phi$, which is attractive/repulsive for mass densities of same/opposite sign, will collect into larger finite regions of same sign with one of them with positive mass density of finite size as the universe U we happen to live in, bordering to universa of negative mass.
- Substantial kinetic energy is collected from gravitational concentration of mass.
We are thus led to an answer to Q1+Q2 in the form:
- The universe U we live in has positive mass + lots of kinetic energy + is finite and is generated by fluctuation of a zero gravitational potential with infinite extension.
Do you see this possibility? You find details to this scenario under tag New View on Gravitation.
PS A vague idea of repulsive gravitation has been floating around as a possible origin of dark energy.
Does negative mass interact/combine with positive mass when they meet? Does negative mass obey the same laws of physics (e.g. have the same periodic table)? Does negative mass have negative kinetic energy?
SvaraRaderaI suppose the relation between addition and multiplication may be somehow like that between negative mass and antiparticles?
SvaraRadera