Posts Tagged ‘Laplace’

Discrepancy In Universe’s Expansion & Quantum Interaction

January 17, 2018

In “New Dark Matter Physics Could Solve The Expanding Universe Controversy“, Ethan Siegel points out that:

“Multiple teams of scientists can’t agree on how fast the Universe expands. Dark matter may unlock why.
There’s an enormous controversy in astrophysics today over how quickly the Universe is expanding. One camp of scientists, the same camp that won the Nobel Prize for discovering dark energy, measured the expansion rate to be 73 km/s/Mpc, with an uncertainty of only 2.4%. But a second method, based on the leftover relics from the Big Bang, reveals an answer that’s incompatibly lower at 67 km/s/Mpc, with an uncertainty of only 1%. It’s possible that one of the teams has an unidentified error that’s causing this discrepancy, but independent checks have failed to show any cracks in either analysis. Instead, new physics might be the culprit. If so, we just might have our first real clue to how dark matter might be detected.

20 years ago it was peer-reviewed published, by a number of teams that we were in an ever faster expanding universe (right). The Physics Nobel was given for that to a Berkeley team and to an Australian team. There are now several methods to prove this accelerating expansion, and they (roughly) agree.

Notice the striking differences between different models in the past; only a Universe with dark energy matches our observations. Possible fates of the expanding Universe which used to be considered were, ironically enough, only the three on the left, which are now excluded.  Image credit: The Cosmic Perspective / Jeffrey O. Bennett, Megan O. Donahue, Nicholas Schneider and Mark Voit.

Three main classes of possibilities for why the Universe appears to accelerate have been considered:

  1. Vacuum energy, like a cosmological constant, is energy inherent to space itself, and drives the Universe’s expansion. (This idea comes back to Einstein who introduced a “Cosmological Constant” in the basic gravitational equation… To make the universe static, a weird idea akin to crystal sphere of Ptolemaic astronomy; later Einstein realized that, had he not done that, he could have posed as real smart by predicting the expansion of the universe… So he called it, in a self-congratulating way, his “greatest mistake”… However, in the last 20 years, the “greatest mistake” has turned to be viewed as a master stroke…).
  2. Dynamical dark energy, driven by some kind of field that changes over time, could lead to differences in the Universe’s expansion rate depending on when/how you measure it. (Also called “quintessence”; not really different from 1), from my point of view!)
  3. General Relativity could be wrong, and a modification to gravity might explain what appears to us as an apparent acceleration. (However, the basic idea of the theory of gravitation is so simplest, it’s hard to see how it could be wrong, as long as one doesn’t introduce Quantum effects… Which is exactly what I do! In my own theory, said effect occur only at large cosmic distances, on the scale of large galaxies)

Ethan: “At the dawn of 2018, however, the controversy over the expanding Universe might threaten that picture. Our Universe, made up of 68% dark energy, 27% dark matter, and just 5% of all the “normal” stuff (including stars, planets, gas, dust, plasma, black holes, etc.), should be expanding at the same rate regardless of the method you use to measure it. At least, that would be the case if dark energy were truly a cosmological constant, and if dark matter were truly cold and collisionless, interacting only gravitationally. If everyone measured the same rate for the expanding Universe, there would be nothing to challenge this picture, known as standard (or “vanilla”) ΛCDM.

But everyone doesn’t measure the same rate.”

The standard, oldest, method of measuring the Hubble cosmic expansion rate is through a method known as the cosmic distance ladder. The simplest version only has three rungs. First, you measure the distances to nearby stars directly, through parallax, the variation of the angle of elevation during the year, as the Earth goes around its orbit. Most specifically you measure the distance to the long-period Cepheid stars like this. Cepheids are “standard candles”; they are stars whose luminosities vary, but their maximum power doesn’t, so we can know how far they are by looking how much they shine. Second, you then measure other properties of those same types of Cepheid stars in nearby galaxies, learning how far away those galaxies are. And lastly, in some of those galaxies, you’ll have a specific class of supernovae known as Type Ia supernovae. Those supernovae explode exactly when they accrete 1.4 solar mass, from another orbiting star (a theory of Indian Nobel Chandrasekhar, who taught at the University of Chicago). One can see these 1a supernovae all over the universe. Inside the Milky Way, as well as many of billions of light years away. With just these three steps, you can measure the expanding Universe, arriving at a result of 73.24 ± 1.74 km/s/Mpc.

The other methods makes all sorts of suppositions about the early universe. I view it as a miracle that it is as close as it is: 66.9 km/s/Megaparsec…

Ethan concludes that: “Currently, the fact that distance ladder measurements say the Universe expands 9% faster than the leftover relic method is one of the greatest puzzles in modern cosmology. Whether that’s because there’s a systematic error in one of the two methods used to measure the expansion rate or because there’s new physics afoot is still undetermined, but it’s vital to remain open-minded to both possibilities. As improvements are made to parallax data, as more Cepheids are found, and as we come to better understand the rungs of the distance ladder, it becomes harder and harder to justify blaming systematics. The resolution to this paradox may be new physics, after all. And if it is, it just might teach us something about the dark side of the Universe.”


My own starting point is a revision of Quantum Mechanics: I simply assume that Newton was right (that’s supposed to be a joke, but with wisdom attached). Newton described his own theory of gravitation to be absurd (the basic equation, F = M1 M2/dd. where d was the distance was from a French astronomer, Ishmael Boulliau, as Newton himself said. Actually this “Bullaldius” then spoiled his basic correct reasoning with a number of absurdities which Newton corrected).

Newton was actually insulting against his own theory. He said no one with the slightest understanding of philosophy would assume that gravitation was instantaneous.

Newton’s condemnation was resolved by Laplace, a century later. Laplace just introduced a finite speed for the propagation of the gravitational field. That implied gravitational waves, for the same reason as a whip makes waves.

We are in a similar situation now. Present Quantum Physics assumes that the Quantum Interaction (the one which carries Quantum Entanglement) is instantaneous. This is absurd for exactly the same reason Newton presented, and Laplace took seriously, for gravitation.

Supposing that the Quantum Interaction has a finite speed (it could be bigger than 10^23c, where c is the speed of light.

Supposing this implies (after a number of logical and plausible steps) both Dark Matter and Dark Energy. It is worth looking at. But let’s remember the telescope (which could have been invented in antiquity) was invented not to prove that the Moon was not a crystal ball, but simply to make money (by distinguishing first which sort of cargo was coming back from the Indies).

We see what we want to see, because that’s we have been taught to see, we search what we want to search, because that’s what we have been taught to search. Keeping an open mind is great, but a fully open mind is a most disturbing thing… 

Patrice Aymé