"It is not possible that such a small difference in the atomic weights of hydrogen and helium could have such tremendous consequences."

"The universe is not only stranger than we imagine, it is stranger than we can imagine."

"The fundamental problem is to find out if we can make a chain reaction go. If we can, then we have a new source of power. If we can't, then we don't."

"The only constant in life is change."

"There are two possible outcomes: if the result confirms the hypothesis, then you've made a measurement. If the result is contrary to the hypothesis, then you've made a discovery."