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Universe Has 100x More Entropy Than We Thought
eldavojohn writes "Previous estimates are now thought to skimp on the entropy of the observable universe. The researchers contend that super-massive black holes are the largest contributor of entropy. Since they contribute two orders of magnitude more than previously thought, the total of all the observable universe is correspondingly higher. The paper highlights (in gruesome detail) new issues that arise with these new calculations — like estimating us a little bit closer to heat death (moving entropy totals from 10^102 to 10^104 out of a maximum of 10^122)."
Because of Neutron decay we've only 10^49 years anyway.
It's interesting to note that even with the new estimate being 100X greater than the old, the new data is still only a billionth of a billionth of the maximum value. What, if anything, does that mean for the past and future of the universe? Reminds me of the Stephen Baxter book Manifold: Time, where the age of stars and galaxies is thought of in the same way we think of the instant right after the big bang.
The universe is still expanding in all directions at the speed of light, then the entropy per unit volume will still stay low enough to be habitable, right? Or is the problem that the rate of increase in volume will not keep pace, since it takes longer and longer for the universe to double in volume at a constant rate of expansion?
The flaw is that entropy is not exactly synonymous with disorder. Sometimes it is, if a disordered state has a lower energy potential than a higher ordered states. But in many cases, such as falling to the bottom of a gravity well, the "ordered" - actually just more compact - state is the lower energy state. Entropy is just the degree to which a system has moved from a higher energy potential to a lower energy potential. If we had more potential energy after falling into a gravity well than before it, then we'd need rockets to blast ourselves from space back to Earth, rather than the other way around.
If you don't know where you are going, you will wind up somewhere else.
I'm afraid the BAC analogy really isn't appilcable. You're describing an impurity which builds up to a critical level to "kill" the host, and pointing out that if you could sequester the impurity the sequestered quantity wouldn't matter. Entropy is not an impurity that is slowly building up to eventually cause the universe to break; it's nothing like that at all.
I find it conceptually confusing to think about entropy as a finite/positive quantity. The way it's defined mathematically, of course, it is ... but at a physical level there's just something backwards about it.
Entropy describes the degree to which energy in a system isn't usable. If you consider as a closed system a bit of ice in a glass of hot water: the heat in the water is "useful" in this system. It will melt the ice, and then equalize the temperature of the water from the melted ice to that of the rest of the water. (That may not seem "useful"; I suppose the point is other processes could capture and use the energy for other ends.)
But, as the ice melts and the water temperature equalizes (or as any other process fuels itself by accelerating this process), you don't run out of energy (which is constant) - but you do run out of "usability" of energy. When your system contains only water at a fixed temperature, there is no way to make heat flow, and all of teh energy in the system is useless. (Again, this assumesa closed system.)
So the point with black holes is, they aren't sequestering entropy to keep it from harming the universe in some way (like your BAC example); if anything they sequester energy and keep it from interacting with the rest of the universe, rendering it useless. (Not sure how Hawking radiation fits in that analysis, though.)
Not RTFA.
TFS fails to use them, so I must ask,
What are the units of entropy? Can they be useful at a macroscopic level... like in describing how much entropy your bedroom contains (before it simply must be cleaned)?
The Admin and the Engineer
Fully understanding this concept led me to drink heavily in college and drop chemistry as a major. Seriously.
Jesus was all right but his disciples were thick and ordinary. -John Lennon
Not to be a smart ass and shit, but the "mind" you describe, sounds like a "book", or a symphony. We already have "minds" that survives. If there's no input or output, nobody can hear the tree falls. And hence whether it is objectively alive (or conscious) isn't meaningful.
The problem I see is, when the sun explodes, when all suns explodes, your book won't be there. Not going in the multiverse thing at all here.