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Science

Universe Closer To Heat Death Than Once Thought 237

Posted by Soulskill
from the we're-doomed dept.
TapeCutter writes "In a paper soon to be published (PDF) in the Astrophysical Journal, Australian researchers have estimated the entropy of the universe is about 30 times higher than previous estimates. According to their research, super-massive black holes 'are the largest contributor to the entropy of the observable universe, contributing at least an order of magnitude more entropy than previously estimated.' For those of us who like their science in the form of a car analogy, Dr. Lineweaver compared their results to a car's gas tank. He states, 'It's a bit like looking at your gas gauge and saying "I thought I had half a gas tank, but I only have a quarter of a tank."'" Fortunately, that quarter of a tank will still get us as far as we need to go and then some.
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Universe Closer To Heat Death Than Once Thought

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  • by neurogeneticist (1631367) on Tuesday January 26, 2010 @10:42AM (#30904094)
    So is this 30x higher than the 100x higher that was reported here on Slashdot a few months ago? http://science.slashdot.org/story/09/10/06/1641232/Universe-Has-100x-More-Entropy-Than-We-Thought [slashdot.org]
  • by fuzzyfuzzyfungus (1223518) on Tuesday January 26, 2010 @11:13AM (#30904650) Journal
    Entropy is actually "the old CO2". Enough of the fundamentals of thermodynamics had been worked out by the Victorian period that the prospect of the "heat death" of the universe became visible. Life is a comparatively low entropy state. Entropy in a closed system increases over time. Game over, man. Game over. There was a certain amount of fretting about this.

    Nobody(outside of physicists doing thought experiments and Kurzweil planning his next move) really cares anymore; because subsequent research has uncovered such a long list of stuff that will almost definitely kill us before the heat death of the universe does.
  • by bluie- (1172769) on Tuesday January 26, 2010 @11:50AM (#30905192)
    best short story ever. [multivax.com]
  • Re:heat death (Score:4, Informative)

    by khallow (566160) on Tuesday January 26, 2010 @12:41PM (#30906066)
    "The universe is a machine." What does that mean? That the universe is deterministic? There may well be some sort of as yet, undiscovered observer (the unobserved observer?) for which the universe is indeed wholly deterministic.

    emperically, thermodynamics is fundamentally wrong. consider events around the end of the 19th century. thermodynamics was around. the equations were established. in fact, there was, based on a flakey idea that physics was finite, the thought that we knew everything. There were a few unimportant oddities. One of them was radioactivity. so the thermo equations on the blackboard got rewritten. right at that point, thermodynamics did not hold. so what does this say about the fundamental nature of the universe?

    The only thing that thermodynamics can't explain is why aren't we already at maximum entropy? Everything else that we know of (such as radioactivity) is fully consistent with thermodynamics.

  • Re:Physicist anyone? (Score:3, Informative)

    by Eudial (590661) on Tuesday January 26, 2010 @01:47PM (#30907056)

    Entropy is a statistical thing. When you consume energy, it looses order. A charged capacitor is very ordered: You have a positive charge on one side, and a negative charge on the other. When you hook it up to a lightbulb, the energy will transform into heat and light. But try as you might, warming and shining light on a lightbulb hooked up to a capacitor will not charge it up again, because out of all the ways this light and warmth can go, very few of them act towards charging the capacitor.

    Ordered energy is more useful than "random" energy. What the second law of thermodynamics says is that on average, energy tends to become more "random". While you can turn random energy into ordered energy, it is never efficient: You always spend more energy turning it into ordered energy, than you gain spending it again.

    So it's not that energy with high entropy is unable to do work, it's that the work it can do is less useful.

    Which is for example why you should never use resistive heating to warm stuff, it's a waste of entropy. You should use that electricity to do meaningful work while creating heat as a by product, not as a goal in it self.

  • by MillionthMonkey (240664) on Tuesday January 26, 2010 @03:09PM (#30908296)

    Black holes can contain lots of usable energy, for those that might be in the black holes.

    No, there's a large amount of energy inside, but it's all in the form of a high temperature, and there's no colder heat reservoir available to anyone down there that would try to extract useful work from it. (Since nothing outside the singularity is reachable once you're there.) Useful work could be extracted from outside the hole by letting stuff fall in, like the way a hydroelectric generator works, but not if there's nothing outside left to fall in.

    There's an asymptotic limit to the universe's entropy that is approached but not necessarily reached, where everything would have fallen into one massive hole, free to explore an immensely large number of quantum states available to it at its high temperature. When you fall in your mass contributes to the number of states (and the temperature). The entropy rises with the logarithm of the number of states. A black hole singularity is postulated as being some single particle with a complicated wave function composed of a large number of available component states.

  • Re:"Fortunately"?! (Score:3, Informative)

    by ichigo 2.0 (900288) on Tuesday January 26, 2010 @05:02PM (#30909832)
    You're off by about 4.5 billion years [wikipedia.org] unless something has changed recently.

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