If such a thing had happened once, it must surely have happened many times in this galaxy of a hundred billion suns.
Interpretation
The quote suggests that extraordinary events in the universe are likely to recur, given the vastness of space and time.
Arthur C. Clarke's quote reflects on the immense scale of the universe, indicating that if a rare or remarkable event occurred once, it is plausible it has occurred multiple times throughout the cosmos. It invites contemplation about the possibilities of life and experiences in a galaxy with such a phenomenal number of stars, encouraging an appreciation for the complexity and mystery of the universe.
In practice
During a lecture about astronomy, one could use this quote to emphasize the vast possibilities in the universe.
Nowhere in space will we rest our eyes upon the familiar shapes of trees and plants, or any of the animals that share our world. Whatsoever life we meet will be as strange and alien as the nightmare creatures of the ocean abyss, or of the insect empire whose horrors are normally hidden from us by their microscopic scale.
As our own species is in the process of proving, one cannot have superior science and inferior morals. The combination is unstable and self-destroying.
It has yet to be proven that intelligence has any survival value.
The best measure of a man's honesty isn't his income tax return. It's the zero adjust on his bathroom scale.
It was the mark of a barbarian to destroy something one could not understand.
My favorite definition of an intellectual: 'Someone who has been educated beyond his/her intelligence'.
Science is often misrepresented as "the body of knowledge acquired by performing replicated controlled experiments in the laboratory." Actually, science is something broader: the acquisition of reliable knowledge about the world.
Scientific and technological progress themselves are value-neutral. They are just very good at doing what they do. If you want to do selfish, greedy, intolerant and violent things, scientific technology will provide you with by far the most efficient way of doing so. But if you want to do good, to solve the world's problems, to progress in the best value-laden sense, once again, there is no better means to those ends than the scientific way.
Using e-mail, I can communicate with scientists all over the world.
You're never going to get the amount of CO2 emitted to go down unless you deal with the one magic metric, which is CO2 per kilowatt-hour.
At the heart of quantum mechanics is a rule that sometimes governs politicians or CEOs-as long as no one is watching, anything goes.
I have also a paper afloat, with an electromagnetic theory of light, which, till I am convinced to the contrary, I hold to be great guns.
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