I recently re-read this interesting essay by a one of the most controversial physicists of our time. I do not remember why I did not post my impressions when I first read it, but I’ll fix this now.
I share with prof. Krauss an almost unlimited admiration for Richard Feynman (something some of my readers will certainly know) and a keen interest for quantum physics; Krauss is also a gifted divulgator, perhaps even superior to our common hero.
Despite dealing with some of the most arcane phenomena in modern physics, this book is eminently readable even to the non initiated and offers some plain language explanation of what is perhaps the most advanced thinking about the origin of the Universe.
The first half of the book is totally captivating, to the point of being thrilling: he does not need complex math to explain why there was a beginning to our Universe, what is the evidence of such a beginning and when it took place; the beauty (and power) of the theory is that it precisely accords to the observed values. As Feynman said, such precision is tantamount to predicting the distance between New York and Los Angeles to the thickness of a human hair.
So the Universe began 13.72 billion years ago and it’s made almost entirely (99%) of stuff we cannot observe (dark matter and dark energy) with a precisely flat geometry (one that’s not open nor close): this dark energy does not belong to matter or radiation but, incredibly, is associated with empty space itself. One of the interesting consequences is that the total energy of our Universe is exactly zero.
This seems to be an element of recursive design in Nature: in the infinitely small, empty space is not empty at all, but it teems with a bubbling of particle-antiparticle couples which pop into existence to annihilate on each other in times and distances so small they fall below the limit of the Uncertainty Principle, justifying the macroscopic perception of emptiness, except when this happens next to another wonder of Nature, a black hole, i.e. a region where gravity is so strong nothing – not even light – can escape: when a pair pops in existence next to the horizon event of a black hole, it may happen than one element of the couple falls into said black hole, making annihilation impossible and freeing the other element: to the external viewer, this will look like the black hole has emitted some of its mass as a particle, perhaps ultimately leading to its evaporation.
Back to our Universe, looking farther and farther away we also look back in time: may we one day arrive at seeing the Big Bang itself?
Not so, explains Krauss, because before matter coalesced into protons and neutrons (about 300.000 years after the Big Bang) there was only a plasma that’s opaque to light: what lies before is the so called “inflationary state” where the space expanded at superluminal speed (whose limits concerns only objects or radiation traveling THROUGH space, not space itself) freezing whatever irregularities there might be on the otherwise uniform surface to create all we see today.
If that was all there is to this book, I would wholeheartedly recommend it as a five-star gem; unfortunately Krauss has an agenda which is to show that the concept of Divinity is not necessary: the second half of the book is therefore devoted to demonstrating that since the Universe exists as an oscillation of the otherwise unstable non-existence, the flat universe is a necessary consequence of a “small patch of asymmetry between matter and antimatter rapidly spreading” until it encompasses the unfathomable vastity of our Universe with its 400 billion galaxies.
It requires no ultimate cause, because it simply is as it is.
Since the Universe is expanding at ever increasing speed, galaxies will ultimately recede from each other at superluminal speed, essentially disappearing and making observation of telltale signs of the Big Bang like the redshift of galaxies or the measurement of the Microwave Background Radiation impossible, from which Krauss derives a very unlikely anthropic consequence, i.e. that future cosmologists will have no knowledge that the Big Bang ever occurred nor have any reason to investigate it. When one considers the fact we went from Cro-Magnons to doctor Krauss in less than 50,000 years I daresay the 2 trillion years that will be needed for the space expansion velocity to exceed the speed of light should be more than enough to figure out a solution.
This second “book in the book” is IMHO far less understandable than the first and does not accomplish in the least the purpose the Author announces for it, inasmuch I did not need Krauss to know that it is the individual’ choice to consider the ultimate description of reality divine or not.