Category Archives: books

From Eternity to Book Club: Chapter Twelve

Here is a link to this week’s instalment of the book club for From Eternity to Here by Sean Carroll:

From Eternity to Book Club: Chapter Twelve “Black Holes: The Ends of Time.”

In the blog, Sean Carroll writes black holes are important for two reasons:

… we care about the entropy of the universe and gravity plays a crucial role in how the universe evolves … when the system is a black hole; Bekenstein and Hawking gave us a formula that allows us to calculate the entropy with confidence.

… the answer that Bekenstein and Hawking derive is somewhat surprising, and ultimately game-changing. The entropy is not proportional to the volume inside the black hole (whatever that might have meant, anyway) — it’s proportional to the area of the event horizon. That’s the origin of the holographic principle …

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From Eternity to Book Club: Chapter Eleven

Here is a link to last week’s blog posting of the book club for From Eternity to Here by Sean Carroll:

From Eternity to Book Club: Chapter Eleven

Sean Carroll makes the following couple points in the blog posting:

Some people labor under the impression that the transition from classical mechanics to quantum mechanics ends up “quantizing” everything, and turning continuous parameters into discrete ones, perhaps even including time. It doesn’t work that way; the conventional formalism of quantum mechanics (such as the Schrödinger equation) implies that time should be a continuous parameter. Things could conceivably change when we eventually understand quantum gravity, but they just as conceivably might not.

I personally come down on the side that believes that there’s no fundamental irreversibility, only apparent irreversibility, in quantum mechanics.

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From Eternity to Book Club: Chapter Ten

Here is a link to this week’s blog posting of the book club for From Eternity to Here by Sean Carroll:

From Eternity to Book Club: Chapter Ten

Sean Carroll writes in the blog posting:

One of the fun things about this chapter is the extent to which it is driven by direct quotations from great thinkers — Boltzmann, of course, but also Poincare, Nietzsche, Lucretius, Eddington, Feynman … It’s very educational to learn that ideas like “the multiverse” and “the anthropic principle” aren’t recent inventions of a new generation of postmodern physicists, but in fact have been part of respectable scientific discourse for over a century.

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From Eternity to Book Club: Chapter Nine

Here is a link to this week’s blog posting of the book club for From Eternity to Here by Sean Carroll:

From Eternity to Book Club: Chapter Nine

Sean Carroll writes in the blog posting:

This chapter starts with something very important: the relationship between entropy and memory. Namely, the reason why we can “remember” the past and not the future is that the past features a low-entropy boundary condition, while the future does not. [But] I don’t go into great detail about this …

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From Eternity to Book Club: Chapter Eight

Here is a link to this week’s blog posting of the book club for From Eternity to Here by Sean Carroll:

From Eternity to Book Club: Chapter Eight

Some points mentioned by Sean Carroll as chapter 8 “Entropy and Disorder” is reviewed:

  • Chapter 8 “… and the next two are the heart and soul of the book.”
    • “… the truth is that we don’t yet know the final answers. We do know the questions, however, and here is where they are being asked.”

  • We cannot prove the Second Law of Thermodynamics using only Boltzmann’s definition of entropy and the underlying dynamics of atoms. We need additional hypotheses from outside the formalism. In particular, the Principle of Indifference, which states that we assign equal probability to every microstate within any given macrostate; and the Past Hypothesis, which states that the universe began in a state of very low entropy.

  • There are opposing views held by some including the philosopher, Craig Callender

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