Universe expansion a mirage!

[Sriram]

Hi everyone,

Is the expansion of the universe a mirage?

https://www.space.com/universe-expansion-could-be-a-mirage

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New research looking at the cosmological constant problem suggests the expansion of the universe could be an illusion.

This rethinking of the cosmos also suggests solutions for the puzzles of dark energy and dark matter, which scientists believe account for around 95% of the total energy and matter in the universe  but remain shrouded in mystery.

In Lombriser's mathematical interpretation, the universe isn't expanding but is flat and static, as Einstein once believed. The effects we observe that point to expansion are instead explained by the evolution of the masses of particles — such as protons and electrons — over time.

In this picture, these particles arise from a field that permeates space-time. The cosmological constant is set by the field's mass and because this field fluctuates, the masses of the particles it gives birth to also fluctuate. The cosmological constant still varies with time, but in this model that variation is due to changing particle mass over time, not the expansion of the universe.

"I was surprised that the cosmological constant problem simply seems to disappear in this new perspective on the cosmos," Lombriser said.

In this picture "there is, in principle, no need for dark energy," Lombriser added.

García, who was not involved in the research, told Live Science. "The theory provides an outlet for the current tensions in cosmology."

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Cheers.

Sriram

[Sebastian Toe]

Interesting.
Let's see if it leads anywhere

[Stranger]

Is the expansion of the universe a mirage?

https://www.space.com/universe-expansion-could-be-a-mirage

Okay. This came up on another forum. The paper is here: Cosmology in Minkowski space (pdf).

Now although my general relativity is up to basically getting what sort of thing the author is talking about (the first few equations are familiar) it would take me forever to work through it, so I asked another member of the forum, who is a professor of mathematics and is very familiar with GR, to take a look. He wasn't impressed.

Basically it's a bit of creative mathematics that doesn't really change anything. Apparently you could do the same thing with Newton's laws to make the Earth at rest. It would be way, way more complicated and horribly contrived, but it's possible.

What I do understand about GR is that, because it's formulated in tensors, you are free to choose any coordinate system you want, no matter how contrived (and that includes the time coordinate, so I guess making the universe static is not impossible). This feature is quite deliberate and very useful when considering extreme conditions like black holes (my GR is up to tackling stationary black holes), where, for example, you get a singularity at the event horizon if you use a coordinate system that corresponds to a distant observer's point of view. If you change the coordinate system, however, it's easy to see that it isn't a real singularity of the underlying manifold but is an indication that those coordinates don't work over the event horizon.

One would normally choose coordinates that make things simple and/or are as perceived by some particular observer, but you don't have to do that - it will still all work the same no matter what.

[Maeght]

Hi everyone,

Is the expansion of the universe a mirage?

https://www.space.com/universe-expansion-could-be-a-mirage

*********

New research looking at the cosmological constant problem suggests the expansion of the universe could be an illusion.

This rethinking of the cosmos also suggests solutions for the puzzles of dark energy and dark matter, which scientists believe account for around 95% of the total energy and matter in the universe  but remain shrouded in mystery.

In Lombriser's mathematical interpretation, the universe isn't expanding but is flat and static, as Einstein once believed. The effects we observe that point to expansion are instead explained by the evolution of the masses of particles — such as protons and electrons — over time.

In this picture, these particles arise from a field that permeates space-time. The cosmological constant is set by the field's mass and because this field fluctuates, the masses of the particles it gives birth to also fluctuate. The cosmological constant still varies with time, but in this model that variation is due to changing particle mass over time, not the expansion of the universe.

"I was surprised that the cosmological constant problem simply seems to disappear in this new perspective on the cosmos," Lombriser said.

In this picture "there is, in principle, no need for dark energy," Lombriser added.

García, who was not involved in the research, told Live Science. "The theory provides an outlet for the current tensions in cosmology."

*********

Cheers.

Sriram

Interesting. Thanks.