More on this book
Community
Kindle Notes & Highlights
Read between
May 15 - June 1, 2020
People who believe they are ignorant of nothing have neither looked for, nor stumbled upon, the boundary between what is known and unknown in the universe.
On ignorance
Einstein’s 1916 general theory of relativity expanded on the principles of Newton’s gravity in a way that also applied to objects of extremely high mass. Newton’s law of gravity breaks down in this expanded realm, which was unknown to him. The lesson here is that our confidence flows through the range of conditions over which a law has been tested and verified. The broader that range, the more potent and powerful the law becomes in describing the cosmos.
On Changes to Newton's law
The power and beauty of physical laws is that they apply everywhere, whether or not you choose to believe in them. In other words, after the laws of physics, everything else is opinion.
Science vs opinion
After I told the waiter that my cocoa had no whipped cream, he asserted I couldn’t see it because it sank to the bottom. But whipped cream has low density, and floats on all liquids that humans consume. So I offered the waiter two possible explanations: either somebody forgot to add the whipped cream to my hot cocoa or the universal laws of physics were different in his restaurant.
Universal laws of physics joke
When constrained by other observations of the contemporary and distant universe, the CMB enables you to decode all sorts of fundamental cosmic properties. Compare the distribution of sizes and temperatures of the warm and cool areas and you can infer how strong the force of gravity was at the time and how quickly matter accumulated, allowing you to then deduce how much ordinary matter, dark matter, and dark energy there is
Cosmic Microwave Background
Ordinary matter is what we are all made of. It has gravity and interacts with light. Dark matter is a mysterious substance that has gravity but does not interact with light in any known way. Dark energy is a mysterious pressure in the vacuum of space that acts in the opposite direction of gravity, forcing the universe to expand faster than it otherwise would.
Nature of matter
Cosmologists have plenty of ego. How could you not when your job is to deduce what brought the universe into existence? Without data, their explanations were just hypotheses. Now, each new observation, each morsel of data, wields a two-edged sword: it enables cosmology to thrive on the kind of foundation that so much of the rest of science enjoys, but it also constrains theories that people thought up when there wasn’t enough data to say whether they were right or wrong. No science achieves maturity without it.
Power of data
“Matter tells space how to curve; space tells matter how to move.”††††
On gravity
Filling out the entire electromagnetic spectrum, in order of low-energy and low-frequency to high-energy and high-frequency, we have: radio waves, microwaves, infrared, ROYGBIV, ultraviolet, X-rays, and gamma rays.
Rays
But nobody on Earth saw the invisible X-rays or gamma rays from the last two supernova spectaculars hosted by our galaxy—one in 1572 and another in 1604—yet their wondrous visible light was widely reported.
Super novas
We achieved true cosmic vision only after seeing the unseeable: a dazzlingly rich collection of objects and phenomena across space and across time that we may now dream of in our philosophy.
Cosmic vision
During our brief stay on planet Earth, we owe ourselves and our descendants the opportunity to explore—in part because it’s fun to do. But there’s a far nobler reason. The day our knowledge of the cosmos ceases to expand, we risk regressing to the childish view that the universe figuratively and literally revolves around us. In that bleak world, arms-bearing, resource-hungry people and nations would be prone to act on their “low contracted prejudices.” And that would be the last gasp of human enlightenment—until the rise of a visionary new culture that could once again embrace, rather than
...more
Human mission
