#emergent gravity

[xponentialdesign]

Ad certamen adversus emergens gravitas. This is life. You are the blue marble.  DIGITAL ARCHIVE (REMIX)

[startswithabang]

Are Space, Time, And Gravity All Just Illusions?

"Sound waves emerge from molecular interactions; atoms emerge from quarks, gluons and electrons and the strong and electromagnetic interactions; planetary systems emerge from gravitation in General Relativity. But in the idea of entropic gravity — as well as some other scenarios (like qbits) — gravitation or even space and time themselves might emerge from other entities in a similar fashion. There are well-known, close relationships between the equations that govern thermodynamics and the ones that govern gravitation. It's known that the laws of thermodynamics emerge from the more fundamental field of statistical mechanics, but is there something out there more fundamental from which gravity emerges? That's the idea of entropic gravity."

There are many attempts out there to reconcile the quantum field theories that describe the electromagnetic and nuclear forces with general relativity, which describes the gravitational force. Certain questions, about gravitational properties in strong fields and on small scales, will never be answered otherwise. In order to make that happen, we'd need a quantum theory of gravity. While string theory is the most popular idea, there are others, such as asymptotic safety, loop quantum gravity, and causal dynamical triangulations. But perhaps the most radical idea came from Erik Verlinde in 2009: the idea that gravity itself is not fundamental, but rather arises from a truly fundamental entity: the entropy of quantum bits of information. Verlinde's work has been intriguing and especially controversial, and I myself have spotted a number of problem areas with his results so far, but it's certainly an idea worth exploring further. At 7 PM ET / 4 PM PT tonight, he delivers the Perimeter Institute's inaugural public lecture of their 2017-2018 series.

What will he say? And what will I have to say when I weigh in on it? Find out then on our live-blog of Verlinde's talk tonight! 

[startswithabang]

Recent Claims Invalid: Emergent Gravity Might Deliver A Universe Without Dark Matter

“The real challenge for emergent gravity, I think, is not galactic rotation curves. That is the one domain where we already know that modified gravity – at last some variants thereof – work well. The real challenge is to also explain structure formation in the early universe, or any gravitational phenomena on larger (tens of millions of light years or more) scales.”

When it comes to galaxies, clusters of galaxies or the largest-scales on the Universe, dark matter is absolutely required. There’s no way to explain colliding galaxy clusters, correlations between different galaxies, the filamentary structure of the Universe or the fluctuations in the Cosmic Microwave Background without it. But it isn’t just dark matter that hopes to solve these problems, and there’s a new contender in town: emergent gravity. 20 years ago, Ted Jacobson proposed, after noting similarities between gravitation and thermodynamics, that gravity might be an emergent phenomenon. Erik Verlinde has run with it, producing a formalism to get dark matter and dark energy-like effects out of a Universe where a new kind of entropy exists. Recently, it’s made predictions for galactic rotation curves, and with marginal successes, may be poised to test those larger scales.

But can emergent gravity really challenge dark matter for explaining the full suite of astronomical phenomena in the Universe? Sabine Hossenfelder has the story!

[chriszillarawr]

Read here.

[chriszillarawr]

From chapter one of my fic Emergent Gravity.

Story is an AU based on a key choice made by Suguru's mother to follow her dreams, a decision that resulted in a different career, husband, and child. Still named Suguru, still an immensely powerful sorcerer, but a very different personality. Still also inexorably tied to Satoru Gojo.

If you ever pondered the hyper-specific notion of "Hey, what if Suguru's mom was an MMA champion and his dad was a Taiwanese punk rocker turned house-husband and also was a girl now." Well, friend, thanks for visiting my brain, I apologize for the mess and I sincerely hope that you like this tory.

Story is rated E for some smut and violence, though not together. At least at this point in time, that is not the plan.

[misternakul]

cant babe, new gravity just dropped

[timespanner]

Erik Verlinde's Gravity Minus Dark Matter | Quanta Magazine

A proposed theory of gravity does away with dark matter, even as new astrophysical findings challenge the need for galaxies full of the invisible mystery

[davidrussellschilling]

Theory of Emergent Gravity May Explain Dark Matter

Theory of Emergent Gravity May Explain Dark Matter

C O N T E N T S:

KEY TOPICS

By treating gravity as an emergent phenomenon instead of a fundamental force, emergent gravity theory negates the need for dark matter and dark energy to explain the universe.(More…)

Namely, effectively the apparent dark matter that comes out of our emergent gravity description also leads to a gravitational potential that attracts the baryonic matter as cold dark…

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