Death by Black Hole by Neil deGrasse Tyson

“The water you drink each day was delivered to Earth in part by comets more than 4 billion years ago.”

Of course, there have been many chemical intermediaries and reactions that have taken place since then, but the fact that pretty much all of the Earth had its components fully stocked (save minor continual accretion) 4 billion years ago is fascinating.

It is such gems of information that occur frequently in Death by Black Hole, a collection of 44 essays originally published in Natural History magazine. Although much of it was review, I quite enjoyed the accessible writing, interesting information and diverse subject matter.

A brief tour of what I read about and learned:

• The nature of Science.
• It can take a million years for ‘sunlight’ to go from the centre of the sun to the outer layer (because it keeps colliding with things) even though it only takes 8.3 minutes to get from the surface of the Sun to us.
• The sun isn’t yellow!
• How the colour in photos of cosmological objects is created.
• What can be learned about time and space from just putting a stick in the mud.
• Various orbital distances/heights.
• How the electromagnetic spectrum is used to analyze the universe (i.e., imagine you could ‘see’ radio waves or infrared or microwaves).
• The history of discovery and how knowledge has been increasing over time.
• Relativity (little bit).
• Plasma (electrons).
• Our Milky Way Galaxy will have a collision with the Andromeda galaxy in 7 billion years (but the Sun will engulf the Earth in 5 billion, so don’t worry).
• We are stardust (and where the elements came from).
• That the neutron only discovered in 1932, after quantum mechanics.
• Electromagnetic pollution.
• Life in the universe (could have isolated planets flung out of their solar system).
• Asteroid impacts.
• The first few minutes of our universe.
• Out radio bubble extends 100 light-years (but might not be as pervasive as some think).
• Science and religion.

I was pleased with this great variety, but I do wish he had provided essays on (a) the light-cone and our limitations of knowing; (b) similarly, just how is something 10 billion light-years away in an infinite universe in which both everything and nothing is the centre?; and perhaps more on how most of the theories of astrophysics are filled and supported by dense math compared to overt observation.