This "holographic universe" keeps bothering me, because it is so different from classical physics. The physical size of a black hole is set by its _mass_ content, according to Schwarzchild. The physical size of a black hole is set by its _information_ content in bits, according to Bekenstein. So, either information = mass, or information = mass + "dark matter" + "dark energy" I.e., "dark matter" (and perhaps "dark energy") is the informational difference between the traditional "matter" and whatever it is that causes gravitational attraction at the largest scales. At 09:19 AM 12/15/2012, meekerdb wrote:
The observable 'local' entropy density is far below the 'local' maximum (i.e. we're not in 'heat death'). But that is consistent with a holographic principle in which the entropy is maximum on the surface at the Hubble radius. At least I think that's the theory.
Brent
On 12/15/2012 4:26 AM, Henry Baker wrote:
But if the holographic universe is encoding all of the information in the _surface area_, and if the total entropy is smaller than expected, wouldn't that also make the universe itself smaller than ~15Billion lightyears in radius?
I'd love to hear Verlinde's ideas about black holes. Perhaps Hawking et al. are wrong, and black holes can eat info after all?
At 09:05 PM 12/14/2012, meekerdb wrote:
There's another possibility. QM allows negative entropy, essentially entropy that is subtracted to avoid over counting the states of entangled particles. It may be that the total entropy of the universe is much smaller than it appears because of correlations that we are not taking into account.
Brent