Astrophysics for People in a Hurry
I haven't read a book about space in quite a long time, and most of my knowledge about the topic came from videos on YouTube, or what we have been taught in middle school. What inspired me to read this book was my curiosity about the unknown world above us and Neil's perspective about our daily lives on Earth. I also wanted to be more informed about news headlines covering topics about space and get a really good understanding of the basics. While reading, I learned so much that just "clicked", such as how formulas and equations are used to predict occurrences in space, like comets or solar eclipses. I know that sounds like a simple observation, but it shows exactly how astrophysicists test these theories, though refining, and tweaking the numbers behind the equations. Another example of what I learned is many of these theories only cover a small understanding of how the universe works and there still is a lot more to figure out, such as how did the big bang start, and the mysterious dark matter/energy that can only be measured by its effect on gravity. To sum it up, I enjoyed the book and open to reading more books about space, as the topic deeply fascinates me.
So first, some background information. Newton's laws of gravity and Albert Einstein’s General relativity both cover about gravity, but on a different scale. Newton's laws cover all the small interactions, such as an apple falling from a tree, while Einstein’s theory helps explain the powers of gravity between whole planets and solar systems, because huge concentrations of mass cause distortions of space and time. Einstein’s theory also helped to predict another anti-gravity tension in the universe. It was called "Lambda, and describes the cosmos as unstable and static at the same time. What this means, is the universe is expanding. In Einstein’s time, there was no other case in science where an unstable condition was used to describe the universe, it created a powerful precedent. Over the next couple years, Einstein discarded the lambda, calling it his life's "greatest blunder" (pg 103). When Lambda is yanked from the equation, it throws off all the calculations for General Relativity, and assumes the Lambda value to 0. Off and on, theorists would try and work Lambda back into the equation, and test to see what the universe would be like if it had one of these cosmological constants. What's interesting to me about this story, is in 1988, astrophysicists plugged in Lambda one last time to try and explain why distant supernovas were noticeably dimmer than expected. Once lambda re-entered the equation, it matched what they expected. Einstein made a prediction on something he couldn't even measure, and just thought it up, is crazy. This is one of my favorite stories from this book.
List of words that were new to me:
| Term | Definition |
| Strata Page 69 |
a sheetlike mass of sedimentary rock or earth of one kind lying between beds of other kinds |
| Inextricably Page 90 |
incapable of being disentangled or untied |
| Precarious Page 100 |
dependent on chance circumstances, unknown conditions, or uncertain developments |
| Confabulations Page 117 |
to fill in gaps in memory by fabrication |
| Diminutive Page 131 |
a word, affix, or name usually indicating small size |
| Vernacular Page 144 |
using a language or dialect native to a region or country rather than a literary, cultured, or foreign language |
| Thanks Merriam-Webster! | |
Neil DeGrasee Tyson adds humor throughout the book in between of his explanations of space in just the right way where it complements the material. One such example is when Neil is talking about the speed of light and how you will never overtake it. He says, "Highway signs for interstellar travelers of the future will justifiably read:
