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review 2018-12-16 17:25
Time is in Reality's Blurring: "The Order of Time" by Carlo Rovelli
The Order of Time - Carlo Rovelli


In some ways, Rovelli's writing is as influenced by Calvino as it is by Einstein or Feynman - this is not simply writing in the tradition of explicating or popularising scientific inquiry; but rather writing which seeks to open new spaces of possibility for thinking through the very endeavour of the writing itself. There does seem to be an appetite for knowledge out there, although the problem (so it seems to me at least) with physics for a wide audience is that ultimately there is only so much that you can do without resorting to maths.

 

 

 

If you're into stuff like this, you can read the full review.

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review 2018-12-11 09:07
N-Dimensional Topology: "Cosmosapiens" by John Hands
Cosmosapiens: Human Evolution From the Origin Of the Universe - John Hands


Me: 'Whatever happened to Occam's Razor? This stuff makes Plato's Forms look like one of the most sober and parsimonious metaphysics imaginable! I would like to point anyone interested in this stuff to an amazing non-performance of a book called "Cosmosapiens" by John Hands. Hands has the nerve to subject all these theories (the Big Bang, Inflation, multiverse theories and much more) to the actual evidence we have, rather than arcane mathematical models that try to extrapolate from it in various directions, or else wild speculation (or both). None of them come out well. The universe looks as if it is much other than these theorists try to paint it.
 
 
 
If you're into stuff like this, you can read the full review.
 
 

 

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review 2018-12-05 08:34
M87: "Einstein's Shadow: A Black Hole, a Band of Astronomers, and the Quest to See the Unseeable" by Seth Fletcher
Einstein's Shadow: A Black Hole, a Band of Astronomers, and the Quest to See the Unseeable - Seth Fletcher


“The so-called hair-theorem maintains that they can be entirely described by three parameters: mass, angular momentum, and electric charge. They have no bumps of defects, no idiosyncrasies or imperfections – no ‘hair’.”

In “Einstein's Shadow: A Black-Hole, a Band of Astronomers, and the Quest to See the Unseeable” by Seth Fletcher

“There are actually three principles that come into conflict at a black-hole horizon: Einstein’s equivalence principle, which is the basis of general relativity; unitarity, which requires that the equations of quantum mechanics work equally well in both directions; and locality. Locality is the most commonsense notion imaginable; everything exists in some place. Yet it’s surprisingly hard to define locality with scientific rigour. A widely accepted definition is tied to the speed of light. If locality is a general condition of our universe, then the world is a bunch of particles bumping into one another, exchanging forces. Particles carry forces among particles – and nothing can travel faster than the speed of light, including force carrying-particles. But we know that locality sometimes breaks down. Entangled quantum particles, for example, would influence one another instantaneously even if they were in different galaxies. […] And after all, the whole reason black holes hide and destroy information is because of the principle of locality – nothing can travel faster than the speed of light, and therefore nothing can escape a black hole. If some sort of non-local effect could relay information from inside a black hole to the outside universe, all was well with the world.”

In “Einstein's Shadow: A Black-Hole, a Band of Astronomers, and the Quest to See the Unseeable” by Seth Fletcher


“The 20th century produced two spectacularly successfully theories of nature: general theory of relativity, and quantum theory. General relativity says the world is continuous, smoothly evolving, and fundamentally local: influences such as gravity can’t travel instantaneously. Quantum theory says the world is twitchy, probabilistic, and non-local – particles pop in and out of existence randomly and see to subtly influence one another instantly across great distances. If you’re a scientist who wants to dig down tot eh deepest level of reality, the obvious question is: which is it?”

In “Einstein's Shadow: A Black-Hole, a Band of Astronomers, and the Quest to See the Unseeable” by Seth Fletcher
 
 
If you're into stuff like this, you can read the full review.
 

 

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review 2018-11-25 20:03
ΔE Δt ≥ ℏ/2: "Quantum Mechanics: The Theoretical Minimum" by Leonard Susskind, Art Friedman
Quantum Mechanics: The Theoretical Minimum - Leonard Susskind & Art Friedman


I was on a train the other week and I was sitting opposite Einstein who asked me if I would mind changing seats because he liked to see where he was going for a half a journey and then he liked to see where he had been for the other half of the journey and I told him I didn't mind changing seats and I asked him if he minded me asking him if he was dead and he said, "When?"

Why was the universe in such a low entropy initial condition? As many have pointed out, that might be even more unlikely than random macroscopic decreases in entropy. Also, if the universe had a low entropy initial condition, might it have a similar boundary condition at the other end? If so, then someday, entropy will start to decrease!

 

 

If you're into stuff like this, you can read the full review.

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review 2018-11-25 19:02
Closed Time-like Curves: “Brief Answers to the Big Questions” by Stephen Hawking
Brief Answers to the Big Questions - Stephen Hawking


“Is there any point in hosting a party for time travelers? Would you hope anyone would turn up?
Hawking’s answer: In 2009 I held a party for time travelers in my college, Gonville and Caius in Cambridge, for a film about time travel. To ensure that only genuine time travelers came, I didn’t send out the invitation until after the party. On the day of the party, I sat in college, hoping but no one came. I was disappointed, but not surprised, because I had shown that if general relativity is correct and energy density is positive, time travel is not possible. I would have been delighted if one of my assumptions had turned out to be wrong.”

In “Brief Answers to the Big Questions – The Final Book” by Stephen Hawking.



I'm not really asking a question - a lot of what Hawking talks about really isn't even theoretically testable. Theoretical physics does tend in that direction - often it talks about ideas that are not testable yet, and may not be for a long time, or which are mathematical speculation as much as observation.

 

 

If you're into stuff like this, you can read the full review.

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