The End of Everything
8.5/10 Great science book with a good dose of existential dread and a right level of detail for someone with little to no prior knowledge. There are many witty footnotes that make it a very pleasurable read while you also learn a bunch. I think I was very much in the intended audience which is probably why I enjoyed the book. For anyone curious about our universe’s faith, this will be on top of my recommendation list. It’s also a good inspiration for anyone with an itch to make accessible scientific content. As said, the author struck the right balance of high-level intuition and low-level details. The math was missing but I think this was a good choice. Plus it also gets to show what an accomplished scientist with a well of knowledge can produce when they team up with people from the book publishing industry. And finally, the excitement in the author’s tone of writing is extremely infectious!
A series of mind blows and brain burns that take you from the beginning of the universe to its very end. In fact, the book ponders 5 possibilities of how the whole thing could end: The Heat Death, The Big Crunch, The Big Rip, Vacuum Decay, and The Bounce. What all these are, how they might happen, and why we won’t be here to observe any of them (except for one if we are unlucky), that’s what you can find out by grabbing a copy and sticking your nose into it. Promised, if you are at least a little bit of a scientist inside, you won’t be dissapointed.
- We can’t see big bang directly because it was too bright. You can’t discern detail when looking directly into a source of light
- Red shifts measure distance, speed, and age of the universe when the light was emitted
- Observable universe is a sphere with diameter of 45 billion years but the age of the universe is just 13.8 billion years. This is because of expansion of space (that’s accelerating since about 5 billion years ago)
- Our current theory of expansion posits that after the big bang there was a speed-up in expansion, aka inflation, then the expansion slowed down and since about 5 billion years ago sped up again. The speed up is attributed to dark energy that only acts in empty space, stretching the fabric of universe between clusters of galaxies
- At the radius of ~14 billion years all the galaxies are speeding away from us faster than the speed of light due to the accelerating expansion of space between all the objects in the universe. This means that we will never be able to observe their evolution in time since they are receding away from us faster than the light can travel to us. The light can try, but it will never reach us. The fact that we can see them at all is thanks to the period of time after the big bang when the expansion was slowing down. The light then caught up with us and entered into our Hubble radius (the name of those 14 billion light years around us)
- Because of this speedup-slowdown-speedup of expansion, very distant objects that are beyond the perimeter of the Hubble radius actually appear bigger than they should. In fact, up until the Hubble radius things we observe shrink in size, but beyond it, they start expanding. This is because the light that’s reaching us comes from the time before the second speedup where these galaxies were much closer, thus much bigger in perspective