Chapter 12

Are We There Yet?

“The Universe is under no obligation to make sense to you.” 
~ Neil deGrasse Tyson

Is It the Destination, or the Journey?

Aristotle’s proclamations about gravity were just common sense. But their usefulness was limited.

Galileo’s experiments revealed how gravity actually works. And his explanations pulled back the curtains of belief that had hidden the real world for millennia.

Newton asked the question on every two-year-old’s mind. “Why?” His answers, in terms of gravity and the Laws of Motion, are still in use to this day. If you limit yourself to the human scale of existence, you have arrived at your destination. You can get off the bus here.

But if you are unable to ignore the experimental results that started rolling out in the 1800s, stay on the bus.

If your concern is strictly for gravity itself, Einstein’s general relativity is your stop. General relativity absolutely nails how gravity works in our universe. You can get off the bus here.


Unless you desire a totally rational, consistent framework of theories to describe all of the aspects of our universe from the quantum realm out to the furthest reaches of spacetime. In that case, stay on the bus. We ain’t there yet.

As Dr. Tyson said, the universe is not obliged to make sense to us puny humans. But I bet we won’t give up. We’re too darned curious.

Here are the links from the text in Chapter 12:

100. Great Video “Apollo 15: The Hammer-Feather drop – YouTube.” 5 Jan. 2015,

101. Great Video “Brian Cox visits the world’s biggest vacuum YouTube.” 24 Oct. 2014

102. Deeper Dive “Gravitational lens – Wikipedia.”

103. Deeper Dive “Precession of the perihelion of Mercury.”