Scientific theories need reconstruction every now and then. If they didn't need reconstruction they would be facts, not theories. The more facts we know, the less radical become the changes in our theories. Hence they are becoming more and more constant. But take the theory of gravitation; it has not been changed in four hundred years.

Electricity is doing for the distribution of energy what the railroads have done for the distribution of materials.

Money is a stupid measure of achievement, but unfortunately it is the only universal measure we have.

The scientist knows that the ultimate of everything is unknowable. No matter What subject you take, the current theory of it if carried to the ultimate becomes ridiculous. Time and space are excellent examples of this.

Scientific theories need reconstruction every now and then. If they didn't need reconstruction they would be facts, not theories. The more facts we know, the less radical become the changes in our theories. Hence they are becoming more and more constant. But take the theory of gravitation; it has not been changed in four hundred years.

The mercury light doesn't show red. It makes the blood in your skin look blue-black. But see how splendidly it brings out the green in the plants.

From a mathematical standpoint it is possible to have infinite space. In a mathematical sense space is manifoldness, or combinations of numbers. Physical space is known as the 3-dimension system. There is the 4-dimension system, the 10-dimension system.