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Archive for the ‘cosmology’ category: Page 259

Jan 31, 2019

Dark Energy Gets Weirder: Mysterious Force May Vary Over Time

Posted by in categories: cosmology, quantum physics

Dark energy is apparently even more mysterious than astronomers had thought.

Scientists first proposed the existence of this invisible force two decades ago, to explain the surprising discovery that the universe’s expansion is accelerating. (Surprising and incredibly important; the find netted three researchers the Nobel Prize in physics in 2011.)

The most-used astrophysical model of the universe’s structure and evolution regards dark energy as a constant. Indeed, many astronomers believe it to be the cosmological constant, which Einstein posited in 1917 as part of his theory of general relativity. [The History & Structure of the Universe in Pictures].

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Jan 30, 2019

New quantum structures in super-chilled helium may mirror early days of universe

Posted by in categories: cosmology, quantum physics

For the first time, researchers have documented the long-predicted occurrence of ‘walls bound by strings’ in superfluid helium-3. The existence of such an object, originally foreseen by cosmology theorists, may help explaining how the universe cooled down after the Big Bang. With the newfound ability to recreate these structures in the lab, earth-based scientists finally have a way to study some of the possible scenarios that might have taken place in the early universe more closely.

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Jan 28, 2019

New Star Maps Shed Light on Milky Way’s Convulsive History

Posted by in category: cosmology

Hints of ghostly galaxies and ancient cataclysms in data from the Gaia spacecraft offer fresh insights into dark matter.

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Jan 28, 2019

Ghostly Galaxies Hint at Dark Matter Breakthrough

Posted by in categories: cosmology, innovation

Much as a ripple in a pond reveals a thrown stone, the existence of the mysterious stuff known as dark matter is inferred via its wider cosmic influence. Astronomers cannot see it directly, but its gravity sculpts the birth, shape and movement of galaxies. This makes a discovery from last year all the more unexpected: a weirdly diffuse galaxy that seemed to harbor no dark matter at all.

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Jan 26, 2019

New Paper: A ‘Mirror Image’ of Our Universe Existed Before The Big Bang

Posted by in categories: cosmology, physics

The Big Bang didn’t just result in our familiar universe, according to a mind-bending new theory — it also generated a second “anti-universe” that extended backwards in time, like a mirror image of our own.

A new story in Physics World explores the new theory, which was proposed by a trio of Canadian physicists who say that it could explain the existence of dark matter.

The new theory, which is laid out in a recent paper in the journal Physical Review of Letters, aims to preserve a rule of physics called CPT symmetry. In the anti-universe before the Big Bang, it suggests, time ran backwards and the cosmos were made of antimatter instead of matter.

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Jan 25, 2019

Testing Hawking radiation in laboratory black hole analogues

Posted by in category: cosmology

Researchers at Weizmann Institute of Science and Cinvestav recently carried out a study testing the theory of Hawking radiation on laboratory analogues of black holes. In their experiments, they used light pulses in nonlinear fiber optics to establish artificial event horizons.

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Jan 23, 2019

New information surfaces on black hole at the center of our galaxy

Posted by in category: cosmology

Astronomers have announced that they have gathered new data on the black hole that lies at the center of our galaxy. The new information was gleaned when the scientists added the ALMA telescope into the array of telescopes being used to study the black hole. The discovery has found that the emissions from the supermassive black hole, called Sagittarius A (Sgr A), comes from a smaller region than previously believed.

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Jan 21, 2019

Our galaxy’s supermassive black hole may be spewing matter right at us

Posted by in category: cosmology

The best image yet of the supermassive black hole at the centre of the Milky Way shows that if it has a powerful jet like others do, it may be pointing at Earth.

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Jan 19, 2019

Why it is dangerous to build ever larger big bang machines

Posted by in categories: alien life, astronomy, cosmology, energy, engineering, ethics, existential risks, general relativity, governance, gravity, innovation, law, nuclear energy, nuclear weapons, particle physics, philosophy, physics, policy, quantum physics, science, scientific freedom, security, singularity, space travel, supercomputing, theory, time travel

CERN has revealed plans for a gigantic successor of the giant atom smasher LHC, the biggest machine ever built. Particle physicists will never stop to ask for ever larger big bang machines. But where are the limits for the ordinary society concerning costs and existential risks?

CERN boffins are already conducting a mega experiment at the LHC, a 27km circular particle collider, at the cost of several billion Euros to study conditions of matter as it existed fractions of a second after the big bang and to find the smallest particle possible – but the question is how could they ever know? Now, they pretend to be a little bit upset because they could not find any particles beyond the standard model, which means something they would not expect. To achieve that, particle physicists would like to build an even larger “Future Circular Collider” (FCC) near Geneva, where CERN enjoys extraterritorial status, with a ring of 100km – for about 24 billion Euros.

Experts point out that this research could be as limitless as the universe itself. The UK’s former Chief Scientific Advisor, Prof Sir David King told BBC: “We have to draw a line somewhere otherwise we end up with a collider that is so large that it goes around the equator. And if it doesn’t end there perhaps there will be a request for one that goes to the Moon and back.”

“There is always going to be more deep physics to be conducted with larger and larger colliders. My question is to what extent will the knowledge that we already have be extended to benefit humanity?”

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Jan 18, 2019

The Ghost in the Quantum Turing Machine

Posted by in categories: computing, cosmology, neuroscience, quantum physics

Interview with Scott Aaronson — covering whether quantum computers could have subjective experience, whether information is physical and what might be important for consciousness — he touches on classic philosophical conundrums and the observation that while people want to be thorough-going materialists, unlike traditional computers brain-states are not obviously copyable. Aaronson wrote about this his paper ‘The Ghost in the Quantum Turing Machine’ (found here https://arxiv.org/abs/1306.0159). Scott also critiques Tononi’s integrated information theory (IIT).


Scott discusses whether quantum computers could have subjective experience, whether information is physical and what might be important for consciousness — he touches on classic philosophical conundrums and the observation that while people want to be thorough-going materialists, unlike traditional computers brain-states are not obviously copyable. Aaronson wrote about this his paper ‘The Ghost in the Quantum Turing Machine’ (found here https://arxiv.org/abs/1306.0159). Scott also critiques Tononi’s integrated information theory (IIT).

Continue reading “The Ghost in the Quantum Turing Machine” »