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The End Of Gravity As a Fundamental Force
An anonymous reader writes "At a symposium at the Dutch Spinoza-instituut on 8 December, 2009, string theorist Erik Verlinde introduced a theory that derives Newton's classical mechanics. In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings. He does not consider gravity as fundamental, but as an emergent phenomenon that arises from a deeper microscopic reality. A relativistic extension of his argument leads directly to Einstein's equations." Here are two blog entries discussing Verlinde's proposal in somewhat more accessible terms.
Update: 01/12 04:48 GMT by KD : Dr. Verlinde has put up a blog post explaining in simpler terms the logic of the gravity from entropy paper. He introduces it with: "Because the logic of the paper is being misrepresented in some reports, I add here some clarifications."
Update: 01/12 04:48 GMT by KD : Dr. Verlinde has put up a blog post explaining in simpler terms the logic of the gravity from entropy paper. He introduces it with: "Because the logic of the paper is being misrepresented in some reports, I add here some clarifications."
I do like the idea of not needing an explanatory tool like "Dark Energy" ... that has always bothered me. Far more than "Dark Matter".
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Dude! Information is a perfectly useful theoretical property in theoretical physics, directly related to entropy. Observe, for instance, all the cool stuff Stephen Hawking has done is related to black hole entropy in some manner or another. (Black holes have to have entropy, otherwise you could violate the second law of thermodynamics by tossing stuff into them.... but if they have entropy, they should emit radiation.... hey, guys, look, a way for black holes to emit radiation and evaporate!!)
As Jacob Bekenstein put it, the trend in physics is to "regard the physical world as made of information, with energy and matter as incidentals." (Bekenstein came up with the Bekenstein bound, a fundamental limit on the amount of information/entropy which can be contained within a space. If you could come up with a system with more entropy in a given space, then you might be able to violate the Second Law of Thermodynamics by tossing it into a black hole.)
In his theory, gravity exists because of a difference in concentration of information in the empty space between two masses and its surroundings.
In his theory, gravity exists because of a difference in concentration of entropy in the empty space between two masses and its surroundings.
Same darned thing.
The World Wide Web is dying. Soon, we shall have only the Internet.
what does this potentially bring us
The paper posits that gravity is an entropic force, not a fundamental one. He does this by starting with the assumption of a reduced dimensionality universe with one emergent direction for space and shows that as a mass approaches the holographic boundary he can combine statistical mechanics equations and Einsteins equations for mass & energy (throw in a couple hand waves about average energy and degrees of freedom) and he derives Newton's laws and more.
This is fundamentally a different view of how gravity, inertia and space arise compared to the current "fundamental forces" understanding in physics. An accurate and testable understanding of gravity could potentially lead to areas impossible to predict: anti-gravity, energy production, warping and changing space, usable action at a distance for communication or transportation.
This is analogous to the shift in understanding when humans understood and then used the electrical force. Who could have dreamed before electric power of mobile phones, global Internet connectivity, HDTV, Twitter, Superbowl broadcasts, images from Mars, superconducting MRI coils, particle accelerators, etc. etc. A functional understanding of gravity could be even more revolutionary than the change in the human condition from understanding electricity.