ASTROPHYSICS FOR PEOPLE IN A HURRY by Neil de Grasse Tyson

• Science thrives not only on the universality of physical laws but also on the existence and persistence of physical constants.
• All measurements suggest that the known fundamental constants, and the physical laws that reference them, are neither time-dependent nor location-dependent. They’re truly constant and universal.
• After the big bang, the main agenda of the cosmos was expansion, ever diluting the concentration of energy that filled space.
• When something glows from being heated, it emits light in all parts of the spectrum, but will always peak somewhere.
• Our senses detect infrared only in the form of warmth on our skin.
• Because light takes time to reach us from distant places in the universe, if we look out in deep space we actually see eons back in time.
• Further research has revealed that the dark matter cannot consist of ordinary matter that happens to be under-luminous, or nonluminous.
• Science is not just about seeing, it’s about measuring, preferably with something that’s not your own eyes, which are inextricably conjoined with the baggage of your brain. That baggage is more often than not a satchel of preconceived ideas, post-conceived notions, and outright bias.
• Trivial questions sometimes require deep and expansive knowledge of the cosmos just to answer them.
• The element carbon can be found in more kinds of molecules than the sum of all other kinds of molecules combined.
• Spheres in nature are made by forces, such as surface tension, that want to make objects smaller in all directions.
• For large cosmic objects, energy and gravity conspire to turn objects into spheres. Gravity is the force that serves to collapse matter in all directions, but gravity does not always win—chemical bonds of solid objects are strong.
• The cosmic mountain-building recipe is simple: the weaker the gravity on the surface of an object, the higher its mountains can reach. Mount Everest is about as tall as a mountain on Earth can grow before the lower rock layers succumb to their own plasticity under the mountain’s weight.
• Well-conducted experiments require a “control”—a measurement where you expect no effect at all, and which serves as a kind of idiot-check on what you are measuring.
• Computer studies of meteor strikes demonstrate conclusively that surface rocks near impact zones can get thrust upward with enough speed to escape the body’s gravitational tether.
• Earth’s Moon is about 1/400th the diameter of the Sun, but it is also 1/400th as far from us, making the Sun and the Moon the same size on the sky—a coincidence not shared by any other planet–moon combination in the solar system, allowing for uniquely photogenic total solar eclipses.
• Even if you’re bad at math, you’re probably much better at it than the smartest chimpanzee, whose genetic identity varies in only trifling ways from ours.