“I myself have dreamed up a structure intermediate between Dyson spheres and planets. Build a ring 93 million miles in radius - one Earth orbit - around the sun. If we have the mass of Jupiter to work with, and if we make it a thousand miles wide, we get a thickness of about a thousand feet for the base.And it has advantages. The Ringworld will be much sturdier than a Dyson sphere. We can spin it on its axis for gravity. A rotation speed of 770 m/s will give us a gravity of one Earth normal. We wouldn't even need to roof it over. Place walls one thousand miles high at each edge, facing the sun. Very little air will leak over the edges.Lord knows the thing is roomy enough. With three million times the surface area of the Earth, it will be some time before anyone complains of the crowding.”

“[I]n science we have to be particularly cautious about 'why' questions. When we ask, 'Why?' we usually mean 'How?' If we can answer the latter, that generally suffices for our purposes. For example, we might ask: 'Why is the Earth 93 million miles from the Sun?' but what we really probably mean is, 'How is the Earth 93 million miles from the Sun?' That is, we are interested in what physical processes led to the Earth ending up in its present position. 'Why' implicitly suggests purpose, and when we try to understand the solar system in scientific terms, we do not generally ascribe purpose to it.”

“Our brains contain one hundred billion nerve cells (neurons). Each neuron makes links with ten thousand other neurons to form an incredible three dimensional grid. This grid therefore contains a thousand trillion connections - that's 1,000,000,000,000,000 (a quadrillion). It's hard to imagine this, so let's visualise each connection as a disc that's 1mm thick. Stack up the quadrillion discs on top of each other and they will reach the sun (which is ninety-three million miles from the earth) and back, three times over.”

“The fact that we live at the bottom of a deep gravity well, on the surface of a gas covered planet going around a nuclear fireball 90 million miles away and think this to be normal is obviously some indication of how skewed our perspective tends to be.”

“Right now, you and me here, put together entirely from atoms that have been part of millions of other organisms before they became us, sitting on this round rock with a core of liquid iron held down by this force that so troubles you called gravity, all the while spinning around the sun at 67 thousand miles an hour and whizzing through the Milky Way at 600 thousand miles an hour in a universe that very well may be chasing its own tail at the speed of light... and amidst all this frantic activity, fully cognizant of our own imminent demise, which is a very pretty way of saying we all know we're going to die, we reach out, to one another, sometimes for the sake of vanity, sometimes for reasons you're not old enough to understand yet, but a lot of the time we just reach out... and expect nothing in return. Isn't that strange? Isn't that weird? ... Isn't that... weird... enough?”

“Imagine a rotating sphere that is 8,000 miles in diameter, with a bumpy surface, surrounded by a 25-mile-deep mixture of different gases whose concentrations vary both spatially and over time, and heated, along with its surrounding gases, by a nuclear reactor 93 million miles away. Imagine also that this sphere is revolving around the nuclear reactor and that some locations are heated more during parts of the revolution. And imagine that this mixture of gases receives continually inputs from the surface below, generally calmly but sometimes through violent and highly localized injections. Then, imagine that after watching the gaseous mixture you are expected to predict its state at one location on the sphere one, two, or more days into the future. This is essentially the task encountered day by day by a weather forecaster.”