Posts Tagged ‘ Lawrence Krauss ’
I recently read theoretical physicist Lawrence Krauss’ newest book, ‘A Universe from Nothing‘. In A Universe from Nothing, Lawrence Krauss not only offers an explanation on how a Universe can arise out of “nothing”, but takes it further by arguing that perhaps “nothing” is precisely the environment which would breed a Universe in the first place. While this book was written to be understandable to those without an education in theoretical physics, fully grasping some of the concepts presented in this book can be challenging if this is your first foray into the subject. It is a book that can only fully be appreciated by setting it down from time-to-time, closing your eyes, and letting your mind fully consume and digest the ideas presented.
When I read, I tend to take notes and highlight passages that jump out at me or get me thinking (Amazon’s Kindle handles this quite well, by the way).
Rather than offer a thorough review of the book — there are many out there — I will share some of my highlighted excerpts and thoughts.
When discussing how we can study “rare” supernovas:
Go out some night into the woods or desert where you can see stars and hold up your hand to the sky, making a tiny circle between your thumb and forefinger about the size of a dime. Hold it up to a dark patch of the sky where there are no visible stars. In that dark patch, with a large enough telescope of the type we now have in service today, you could discern perhaps 100,000 galaxies, each containing billions of stars. Since supernovae explode once per hundred years per, with 100,000 galaxies in view, you should expect to see, on average, about three stars explode on a given night.
This passage is particularly interesting to me, as the concept being discussed here explains how our 14 billion-year-old Universe can be much larger than 14 billion light years across. In fact, understanding this is a major clue in why this blog has the name it has:
… hat would become our observable universe would start to grow faster than the speed of light. This is allowed in general relativity, even though it seems to violate Einstein’s special relativity, which says nothing can travel faster than the speed of light. But one has to be like a lawyer and parse this a little more carefully. Special relativity says nothing can travel through space faster than the speed of light. But space itself can do whatever the heck it wants, at least in general relativity. And as space expands, it can carry distant objects, which are at rest in the space where they are sitting, apart from one another at superluminal speeds.what would become our observable universe would start to grow faster than the speed of light. This is allowed in general relativity, even though it seems to violate Einstein’s special relativity, which says nothing can travel faster than the speed of light. But one has to be like a lawyer and parse this a little more carefully. Special relativity says nothing can travel through space faster than the speed of light. But space itself can do whatever the heck it wants, at least in general relativity. And as space expands, it can carry distant objects, which are at rest in the space where they are sitting, apart from one another at superluminal speeds.
The following is probably one of the most astounding facts I often reflect upon:
Observers in the far future will see more or less precisely what observers in 1915 thought they saw: a single galaxy housing their star and their planet, surrounded by an otherwise vast, empty, static space.
n a strange coincidence, we are living in the only era in the history of the universe when the presence of the dark energy permeating empty space is likely to be detectable. It is true that this era is several hundred billion years long, but in an eternally expanding universe it represents the mere blink of a cosmic eye.
We can consider ourselves lucky that we live at the present time. Or as Bob and I put it in one of the articles we wrote: “We live at a very special time . . . the only time when we can observationally verify that we live at a very special time!”
Since theoretical physics — and in particular, fields such as string theory — can be a mind-bending subject to try and grasp, I appreciated Krauss’ sense of humor when commenting on its challenging nature himself:
Particle physicists are way ahead of cosmologists. Cosmology has produced one totally mysterious quantity: the energy of empty space, about which we understand virtually nothing. However, particle physics has not understood many more quantities for far longer!
Again, the book may be heavy in certain parts, but intriguing and interesting enough to keep you turning pages. This book has also has a way of sticking with you even after you set it down. Don’t be surprised when you find yourself lying awake at night, unable to sleep as you brain works to reorganize your understanding of how things are and how they came to be.
All excerpts from:
Krauss, Lawrence (2012-01-10). A Universe from Nothing. Simon & Schuster, Inc.. Kindle Edition.