Further to Sean Carroll and the Time with Two Heads, a friend writes to ask about a quantum equation that rolled through earlier this year, that predicts the universe has no beginning:
The universe may have existed forever, according to a new model that applies quantum correction terms to complement Einstein’s theory of general relativity. The model may also account for dark matter and dark energy, resolving multiple problems at once.
Although the Big Bang singularity arises directly and unavoidably from the mathematics of general relativity, some scientists see it as problematic because the math can explain only what happened immediately after—not at or before—the singularity.
“The Big Bang singularity is the most serious problem of general relativity because the laws of physics appear to break down there,” Ahmed Farag Ali at Benha University and the Zewail City of Science and Technology, both in Egypt, told Phys.org.
Ali and coauthor Saurya Das at the University of Lethbridge in Alberta, Canada, have shown in a paper published in Physics Letters B that the Big Bang singularity can be resolved by their new model in which the universe has no beginning and no end.
More.
Friend asks, would this pose problem for the Kalam cosmological argument? (“If the universe had been here forever, it would have run out of usable energy by now,” due to the Second Law of Thermodynamics).
So where is all the hooplah that must have greeted such a find? The Big Bang has never been popular, merely well-evidenced.
Indeed, Rob Sheldon tells us,
The authors have generated a debate about the validity of their results and a “Bohmian fluid” [prt of the authors’ hypothesis] corresponds to a QM wavefunction that mostly of passing theoretical interest. Why isn’t the blogosphere going gonzo for an eternal universe? After all, as Jastrow and Jaki have both recorded, many theorists have sacrificed a lot of physics on the altar of eternity.
Because it doesn’t answer anything interesting. The singularity of the big bang is where spacetime contracts down to a point. But since Bohm’s wavefunctions don’t have points, spacetime contracts down to a QM blob, and then stays a blob for eternity.
Is this really an alternative to “Big Bang Theory”? I doubt it, it rather seems to be a case of semantics: “It’s not a singularity, it’s a blob.” As best I understand this stuff (which isn’t that great), there are no predictions as to how to tell a blob from a singularity.
Of course, the eternal universe is valued by, among others, the anything-can-happen-given-enough-time lobby, often seen rushing in to support a Darwinian origin and development of life when the big timelines just plain don’t work. So we will be hearing about it frequently regardless of its evidence status.
Another friend writes to note that “no beginning” could mean either an endless extent of linear time or timelessness (time is not real). It might be well to know which meaning a given hypothesis adopts.
See also: Sean Carroll and the Time with Two Heads. Carroll’s ideas are interesting but — as noted earlier in this space — a mystic could have thunk it up on a meditation mat millennia ago. What makes this science?
and
Big Bang exterminator wanted, will train
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Here’s the abstract:
It was shown recently that replacing classical geodesics with quantal (Bohmian) trajectories gives rise to a quantum corrected Raychaudhuri equation (QRE). In this article we derive the second order Friedmann equations from the QRE, and show that this also contains a couple of quantum correction terms, the first of which can be interpreted as cosmological constant (and gives a correct estimate of its observed value), while the second as a radiation term in the early universe, which gets rid of the big-bang singularity and predicts an infinite age of our universe. … (public access) – Ahmed Farag Ali and Saurya Das. “Cosmology from quantum potential.” Physics Letters B. Volume 741, 4 February 2015, Pages 276–279. DOI: 10.1016/j.physletb.2014.12.057. Also at: arXiv:1404.3093[gr-qc].
Saurya Das and Rajat K. Bhaduri, “Dark matter and dark energy from Bose-Einstein condensate”, preprint: arXiv:1411.0753[gr-qc]