In fewer than 80 pages, Rovelli talks about General Relativity, Quantum Physics, Cosmology, Particle Physics, Loop Quantum Physics, Thermodynamics and the nature of time, and Ourselves; I have taught Physics for 33 years and I have been a human for even longer and yet I still, repeatedly, learned fascinating things from this brilliant book. Plus it is superbly written and it tells so eloquently of the joys and challenges of being a scientist.
Just some of the brilliant insights from this wonderful little book.
- "the gravitational field is not diffused through space; the gravitational field is that space itself." (p 6) This is a triumph of Descartes over Newton: a vortex space rather than one filled with action-at-a-distance. Space undulates. :
- light curves round heavy objects
- time goes more quickly at altitude
- black holes exist
- "space cannot stand still; it must be expanding" (p 8)
- "space moves like the surface of the sea" (p 9)
- "Why does the periodic table have this particular structure, with these periods, and with the elements having these particular properties? The answer is that each element corresponds to one solution of the main equation of quantum mechanics." (p 15)
- "an electron is a series of jumps from one interaction to another. When nothing disturbs it, it is not in any particular place. It is not in a 'place' at all." (p 15)
- Loop Quantum Gravity proposes that space is quantised in very small linked rings: "Space is created by the linking of these individual quanta of gravity" (p 41)
- "The passage of time ... is born in the world itself in the relationship between the quantum events that comprise the world and are themselves the source of time." (p 42).
- "Our universe may have been born from a bounce in a prior phase, passing through an intermediate stage in which there was neither space nor time." (p 47)
- "How the gravitational field behaves when it heats up is still an unsolved problem. ... when heat is diffused to the gravitational field, time and space themselves must vibrate ... what is a vibrating time?" (p 56)
- "There is a detectable difference between the past and the future only when there is flow of heat. Heat is linked to probability; and probability in turn is linked to the fact that our interactions with the rest of the world do not register the fine details of reality ... due to the limitations of our consciousness we only perceive a blurred vision of the world, and live in time." (p 60)
- "The heat of black holes is a quantum effect upon an object, the black hole, which is gravitational in nature. ... The heat of black holes is like a Rosetta Stone of physics, written in a combination of three languages - Quantum, Gravitational and Thermodynamic - still awaiting decipherment in order to reveal the true nature of time." (p 62)
- "We are like an only child who on growing up realizes that the world does not revolve around them alone, as they thought when little. They must learn to be one among others. Mirrored by others, and by other things, we learn who we are." (p 65)
- "All things are continually interacting with each other, and in doing so each bears the traces of that with which it has interacted: and in this sense all things continuously exchange information about each other." (p 68)
- "It would be absurd to ask whether 'I' can do something different from what the whole complex of my neurons has decided: the two things ... are the same." (p 71)
- "Our reality is tears and laughter, gratitude and altruism, loyalty and betrayal, the past which haunts us and serenity." (p 74)
- "We are nature, in one of its innumerable and infinitely variable expressions." (p 74)
- "And to the very last: doubt." (p 19)
What a way for my dad to end his reading career.
Magnificent. July 2017, 79 pages
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