We all confidently believe that there are at present, and have been from time immemorial, many worlds of life besides our own. . . . [This] may seem wild, and visionary; all I maintain is that it is not unscientific.

Although mechanical energy is indestructible, there is a universal tendency to its dissipation, which produces throughout the system a gradual augmentation and diffusion of heat, cessation of motion and exhaustion of the potential energy of the material Universe

Let nobody be afraid of true freedom of thought. Let us be free in thought and criticism; but, with freedom, we are bound to come to the conclusion that science is not antagonistic to religion, but a help to it.

If you study science deep enough and long enough, it will force you to believe in God.

There cannot be a greater mistake than that of looking superciliously upon practical applications of science. The life and soul of science is its practical application.

Heavier-than-air flying machines are impossible.

I have no satisfaction in formulas unless I feel their numerical magnitude.