Sunday, July 27, 2008

Physics in a Void


Doubts about the existence of "dark energy" have been echoed by Fraser in a Universe Today post. Fraser cites a paper published by Timothy Clifton of Oxford, Living in a Void. Clifton speculates that we could live in a "void" less dense than the surrounding Universe. If so, our region would appear to decelerate slower than distant galaxies, making the Universe appear to accelerate. There would be no need for a hypothetical "dark energy."

Questions about DE have also reached the audience of Amanda Gefter's New Scientist blog.

"Most cosmologists believe that a furtive anti-gravity-like force known as dark energy is to blame...But no one can explain why the observed value of the dark energy is 120 orders of magnitude smaller than what's predicted from quantum physics. In fact, the level of fine-tuning needed to produce such a specifically small but non-zero cosmological constant is so absurd that the best explanation anyone's come up with is that our universe is merely one of an infinite number of universes."

"Scientists shouldn't dismiss ideas just because they might undermine some deeply cherished assumptions...One cosmologist wrote to me in an email: 'There is no fractal or inhomogeneous physical model of the universe of any kind. Therefore although there are particular observations that present a challenge to the standard model, there is no sense in which there is a preferred model that predicts or is explained by inhomogeneity . . . So the observations are interesting, but without a physical model to back them up, they are unlikely to have an impact on our thinking about cosmology.'

"I found this statement rather shocking. Cosmologists are willing to dismiss observations because they don't fit with theory? Isn't science supposed to work the other way round?"

New ideas take a long time to be accepted. Like Ptolemy's epicycles, the "dark energy" hypothesis may take a long time to die. It has produced a divergence of theories to keep physicists employed. Expensive space projects and even trips to Stockholm are dependent on DE existing. Resistance to alternative theories can be expected.

When Earth was believed to be the centre of everything, a divergence of epicycle theories kept academics employed. The Copernican Principle stated that Earth was not the centre, doing away with epicycles. This principle forms a basis of modern cosmology. The hypothesised "dark energy" leads to epicycles not solutions. Before throwing Copernicus away, scientists should consider a changing speed of light.

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6 Comments:

Blogger Kea said...

Funny that the NS blog comments about throwing away the Copernican principle contain some diversions: scathing remarks against a different assumption - a varying speed of light!

9:53 PM  
Blogger L. Riofrio said...

Thanks for noting that. The woman who mentions a changing c gives her real name and the link to her science fiction blog. Anonymous Troll on Patrol does his duty, jumping on her with silly accusations. The trolls really fear a changing speed of light.

5:22 AM  
Blogger Andrew said...

"Resistance to alternative theories can be expected."
I disagree because so little is known about dark energy that what you're thinking could count as an alternative would probably be considered the explanation for dark energy. In other words, you need a theory of dark energy before you can have an alternative theory. Astronomers and cosmologists have merely discovered the phenomenon and don't have a widely accepted theory yet. But maybe more is known about dark energy than I realize...

6:58 AM  
Blogger nige said...

Thanks for this news.

"I found this statement rather shocking. Cosmologists are willing to dismiss observations because they don't fit with theory? Isn't science supposed to work the other way round?"

Of course they don't get rid of the old "standard" theory just because a few observations disagree with it. You have to have a lot of trouble before people start to question an existing theory, and then usually they patch it up by adding on a an epicycle whose size they pick to make the problems go away. So the existing theory is usually just made more complex to overcome problems, instead of being dismissed.

My argument is that the dark energy of the universe is spin-1 graviton energy.

Between large receding masses (larger than a cluster of galaxies), the exchange of spin-1 gravitons causes a repulsive force, giving rise to the observed cosmological acceleration between distant galaxies and clusters.

But over small distances between relatively small masses, the exchange of spin-1 gravitons of each mass creates a far greater net force between each mass and with the receding universe than between the two small masses themselves. The overall effect is therefore that two relatively nearby, small masses get pushed together by the exchange of gravitons with the immense surrounding masses of galaxies and clusters in the universe.

Any receding mass M at distance r gives an outward force of F = M*dv/dt = M*d(Hr)/dt = MHv + 0 = MrH^2. By Newton's 3rd law (the rocket effect), for every force there should be an equal and opposite reaction force. The reaction force is the net inward graviton scattering force from that receding mass towards you. This means that graviton exchange between you and distance masses is causing a repulsion effect!

There's a big inward force from distant receding matter of mass M and at distance r, equal to F = MrH^2. But between two nearby small masses, the exchange of gravitons produces next to zero force, because M and r are both small compared to their values when considering distant receding galaxies and clusters of galaxies.

So between two small nearby masses, like an apple and the Earth, graviton exchange is weaker than the graviton exchange force between each of the masses and the surrounding receding galaxies in the universe. As a result, the apple gets shielded by the Earth, and is pushed towards it.

So the cosmological acceleration effect (a lack of gravitational retardation at great distances) and gravitation can be quantitatively predicted from the same cause: spin-1 graviton exchange between masses.

"Good science requires a willingness to take anomalous observations seriously and to question even our most deeply held assumptions about the world."

This idealistic conclusion by the New Scientist Opinions Editor contradicts to the way science really works, which is to try to ignore anomalies and wallpaper over cracks, while simultaneously attacking "alternative" explanations from a position of high moral ground.

E.g. Lord Kelvin (President of the Royal Society) claimed using his authority alone: "X-rays will prove to be a hoax." He didn't provide any scientific disproof of X-rays, he just dismissed them.

This is the danger from authority in science. Fortunately, Kelvin wasn't able to stop research into X-rays by preventing research funding and peer-review, because they had been discovered by the German physicist Roentgen, who had used fairly standard equipment (such as a high voltage source, vacuum cathode ray tube and photographic plate sealed in black paper). But for a theory, such a damning statement - based similarly on the ignorant prejudice of a scientific "authority" figurehead - can completely kill off any hope of getting funding or unbiased peer-review.

4:34 AM  
Anonymous buy viagra said...

I'm really skeptic about believing in the existence of the called "dark energy" because I have read several papers on that matter and none of them really convince me yet.

5:51 AM  
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