|loop quantum gravity via commons.wikimedia.org|
The gravitational field is not diffused through space; the gravitational field is that space itself. An entity that undulates, flexes, curves, twists. We are immersed in a gigantic flexible snail-shell. A colourful and amazing world where the unbounded extensions of interstellar space ripple and sway like the surface of the sea.That rather poetic description of the physics of gravity comes from theoretical physicist Carlo Rovelli. He wrote a series of articles that are collected in a brief (78 pages) book about ideas in physics.
Seven Brief Lessons on Physics has no math, no relativity, quantum physics or string theory. Some reviewers compared it in intent to Richard Feynman’s “Six Easy Pieces: Essentials of Physics Explained.” Simple explanations for general readers.
Rovelli is one of the inventors of loop quantum gravity. Not a topic he covers. That theory says that space is not continuous but it is made of grains, significantly smaller than an electron, and they are linked to each other forming a network. He sticks to the classics.
There are excerpts and audio of the author at www.sevenbrieflessons.com
In his seventh lesson, he is both in awe of what is ahead for us and also surprisingly pessimistic about out time on this planet:
I believe that our species will not last long. It does not seem to be made of the stuff that has allowed the turtle, for example to continue to exist more or less unchanged for hundreds of millions of years; for hundreds of times longer, that is, than we have even been in existence. We belong to a short-lived genus of species. All of our cousins are already extinct. What’s more, we do damage. There are frontiers where we are learning, and our desire for knowledge burns. They are in the most minute reaches of the fabric of space, at the origins of the cosmos, in the nature of time, in the phenomenon of black holes, and in the workings of our own thought processes. Here, on the edge of what we know, in contact with the ocean of the unknown, shines the mystery and the beauty of the world. And it’s breathtaking.