"Violations" of a Basic Law of Physics Created Mysterious Dark Energy, Propose Scientists

Physicists propose that violations of a fundamental law of physics in early stages of the universe are responsible for the mysterious dark energy.

Physicists have proposed that one of the fundamental laws of physics, the law of conversation of energy, had a “violation” in the early stages of the universe. This could explain the issue of the “cosmological constant” which has troubled physics since Einstein and has been linked in recent physics to the emergence of the theorized dark energy.


The “cosmological constant” is a controversial topic in physics, believed by some, rejected by others. It’s been dubbedthe worst theoretical prediction in the history of physics."

Einstein added the cosmological constant, a mathematical term, to his theory of general relativity in 1917 to address a bewildering problem of “vacuum energy”. The constant is supposed to represent an anti-gravitational force. It was believed at the time the Universe was static and the equations just didn’t make sense to Einstein as they predicted the Universe was expanding. 

"The term is necessary only for the purpose of making possible a quasi-static distribution of matter, as required by the fact of the small velocities of the stars”, Einstein wrote at the time, somewhat begrudgingly.

Physicist Albert Einstein (centre) with a group recipients of the National Science Foundation's fellowship, (L-R) Arthur Taub, Kurt Eisemann, Simon Auster, William Frank and Seymour Aronson, at the Institute for Advanced Study, Princeton, New Jersey, August 14th 1952. (Photo by Keystone/Hulton Archive/Getty Images)

Of course, when observations by Edward Hubble in 1929 proved the universe is actually expanding, Einstein gave up on the constant and most cosmology researchers set the constant to be zero. In fact, Einstein was rather disappointed with himself for utilizing the constant in the first place, reportedly calling it “the biggest blunder of my career”.

But in early 1990s, further observations saw that the universe is not only expanding but at an accelerating rate. This is when the constant came back under consideration, this time to reflect the influence of the theorized “dark energy,” which is predicted to make up about 68% of the known universe, affecting its acceleration.

One big issue with the new vision of the constant has been is that there’s a large discrepancy, up to 120 orders of magnitude, between its predicted and the small observed value.

What the physicists Thibaut Josset and Alejandro Perez at the University of Aix-Marseille, France, and Daniel Sudarsky at the National Autonomous University of Mexico, propose is that there is an “unexpected relation” between “the acceleration expansion of the universe and microscopic physics”.

What they are saying in their new paper is that there were tiny violations in the law of conservation of energy during the early stages of the universe. They were small enough to not be replicable by modern experiments, but their existence affected the cosmological constant as we know it today.  

How could a basic law of physics be broken? The possibility is that on the grand cosmological scale, it doesn’t work quite the same way. In particular, violations of energy conservations have been investigated in relation to such phenomena as the creation and evaporation of black holes, the collapse of the wavefunction in quantum mechanics, and the recombination period of early universe when photons decoupled from electrons. 

"Energy from matter components can be ceded to the gravitational field, and this 'loss of energy' will behave as a cosmological constant—it will not be diluted by later expansion of the universe," said Josset. "Therefore a tiny loss or creation of energy in the remote past may have significant consequences today on large scale."

One way the physicists suggest to regard their idea is that the cosmological constant (and its incarnation as "dark energy") could in essence be a kind of historical record of instances of energy non-conservation. It would actually not be that constant, varying based on the energy flows in the universe.

"In the model, dark energy is something that keeps track of how much energy and momentum has been lost over the history of the universe," said Alejandro Perez.

While there is no current method to test if they are right, the physicists plan to continue research into the matter, with possible future tests like observing the expansion of supernovae.

"Our proposal is very general and any violation of energy conservation is expected to contribute to an effective cosmological constant," explained Josset. "This could allow to set new constraints on phenomenological models beyond standard quantum mechanics. On the other hand, direct evidence that dark energy is sourced by energy non-conservation seems largely out-of-reach, as we have access to the value of lambda [the cosmological constant] today and constraints on its evolution at late time only."

If the scientists are correct in their hypothesis, their ideas could lead to a total rethinking of the law of conservation of energy.

"Just as heat is energy stored in the chaotic motion of molecules, the cosmological constant would be 'energy' stored in the dynamics of atoms of space–time," pointed out Perez. "This energy would only appear to be lost if space–time is assumed to be smooth."

Some scientists have come out in cautious but optimistic support of this work. As reported by Edwin Cartlidge of "Physics World", Lee Smolin from the Canadian Perimeter Institute for Theoretical Physics in Canada, was supportive of the challenging idea, calling it "speculative, but in the best way". He also added that the idea is "probably wrong" but would be "revolutionary" if proven correct.

You can read their paper “Dark Energy from Violation of Energy Conservationhere, in Physical Review Letters.

Cover photo:

This undated artist's impression shows how the very early universe (less than 1 billion years old) might have looked when it went through a voracious onset of star formation, converting primordial hydrogen into myriad stars at an unprecedented rate. The sky would have looked markedly different from the sea of quiescent galaxies around us today. A foreground starburst galaxy at lower right is sculpted with hot bubbles from supernova explosions and torrential stellar winds. Unlike today there, is very little dust in these galaxies, because the heavier elements have not yet been cooked up through nucleosynthesis in stars. (Photo by NASA/Getty Images)

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Yale scientists restore brain function to 32 clinically dead pigs

Researchers hope the technology will further our understanding of the brain, but lawmakers may not be ready for the ethical challenges.

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  • Researchers at the Yale School of Medicine successfully restored some functions to pig brains that had been dead for hours.
  • They hope the technology will advance our understanding of the brain, potentially developing new treatments for debilitating diseases and disorders.
  • The research raises many ethical questions and puts to the test our current understanding of death.

The image of an undead brain coming back to live again is the stuff of science fiction. Not just any science fiction, specifically B-grade sci fi. What instantly springs to mind is the black-and-white horrors of films like Fiend Without a Face. Bad acting. Plastic monstrosities. Visible strings. And a spinal cord that, for some reason, is also a tentacle?

But like any good science fiction, it's only a matter of time before some manner of it seeps into our reality. This week's Nature published the findings of researchers who managed to restore function to pigs' brains that were clinically dead. At least, what we once thought of as dead.

What's dead may never die, it seems

The researchers did not hail from House Greyjoy — "What is dead may never die" — but came largely from the Yale School of Medicine. They connected 32 pig brains to a system called BrainEx. BrainEx is an artificial perfusion system — that is, a system that takes over the functions normally regulated by the organ. Think a dialysis machine for the mind. The pigs had been killed four hours earlier at a U.S. Department of Agriculture slaughterhouse; their brains completely removed from the skulls.

BrainEx pumped an experiment solution into the brain that essentially mimic blood flow. It brought oxygen and nutrients to the tissues, giving brain cells the resources to begin many normal functions. The cells began consuming and metabolizing sugars. The brains' immune systems kicked in. Neuron samples could carry an electrical signal. Some brain cells even responded to drugs.

The researchers have managed to keep some brains alive for up to 36 hours, and currently do not know if BrainEx can have sustained the brains longer. "It is conceivable we are just preventing the inevitable, and the brain won't be able to recover," said Nenad Sestan, Yale neuroscientist and the lead researcher.

As a control, other brains received either a fake solution or no solution at all. None revived brain activity and deteriorated as normal.

The researchers hope the technology can enhance our ability to study the brain and its cellular functions. One of the main avenues of such studies would be brain disorders and diseases. This could point the way to developing new of treatments for the likes of brain injuries, Alzheimer's, Huntington's, and neurodegenerative conditions.

"This is an extraordinary and very promising breakthrough for neuroscience. It immediately offers a much better model for studying the human brain, which is extraordinarily important, given the vast amount of human suffering from diseases of the mind [and] brain," Nita Farahany, the bioethicists at the Duke University School of Law who wrote the study's commentary, told National Geographic.

An ethical gray matter

Before anyone gets an Island of Dr. Moreau vibe, it's worth noting that the brains did not approach neural activity anywhere near consciousness.

The BrainEx solution contained chemicals that prevented neurons from firing. To be extra cautious, the researchers also monitored the brains for any such activity and were prepared to administer an anesthetic should they have seen signs of consciousness.

Even so, the research signals a massive debate to come regarding medical ethics and our definition of death.

Most countries define death, clinically speaking, as the irreversible loss of brain or circulatory function. This definition was already at odds with some folk- and value-centric understandings, but where do we go if it becomes possible to reverse clinical death with artificial perfusion?

"This is wild," Jonathan Moreno, a bioethicist at the University of Pennsylvania, told the New York Times. "If ever there was an issue that merited big public deliberation on the ethics of science and medicine, this is one."

One possible consequence involves organ donations. Some European countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood throughout the body, but use a "thoracic aortic occlusion balloon" to prevent that blood from reaching the brain.

The system is already controversial because it raises concerns about what caused the patient's death. But what happens when brain death becomes readily reversible? Stuart Younger, a bioethicist at Case Western Reserve University, told Nature that if BrainEx were to become widely available, it could shrink the pool of eligible donors.

"There's a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs," he said.

It will be a while before such experiments go anywhere near human subjects. A more immediate ethical question relates to how such experiments harm animal subjects.

Ethical review boards evaluate research protocols and can reject any that causes undue pain, suffering, or distress. Since dead animals feel no pain, suffer no trauma, they are typically approved as subjects. But how do such boards make a judgement regarding the suffering of a "cellularly active" brain? The distress of a partially alive brain?

The dilemma is unprecedented.

Setting new boundaries

Another science fiction story that comes to mind when discussing this story is, of course, Frankenstein. As Farahany told National Geographic: "It is definitely has [sic] a good science-fiction element to it, and it is restoring cellular function where we previously thought impossible. But to have Frankenstein, you need some degree of consciousness, some 'there' there. [The researchers] did not recover any form of consciousness in this study, and it is still unclear if we ever could. But we are one step closer to that possibility."

She's right. The researchers undertook their research for the betterment of humanity, and we may one day reap some unimaginable medical benefits from it. The ethical questions, however, remain as unsettling as the stories they remind us of.