The suppression of uncomfortable ideas may be common in religion or in politics, but it is not the path to knowledge, and there's no place for it in the endeavor of science. We do not know beforehand where fundamental insights will arise from about our mysterious and lovely solar system. The history of our study of our solar system shows us clearly that accepted and conventional ideas are often wrong, and that fundamental insights can arise from the most unexpected sources.

Any civilization that doesn't develop space travel dies.

Life is but a momentary glimpse of the wonder of this astonishing universe, and it is sad to see so many dreaming it away on spiritual fantasy.

Goddard represented a unique combination of visionary dedication and technological brilliance. He studied physics because he needed physics to get to Mars. In reading the notebooks of Robert Goddard, I am struck by how powerful his exploratory and scientific motivations were - and how influental speculative ideas, even erroneous ones, can be on the shaping of the future.

We are like butterflies who flutter for a day and think it is forever.

If our long-term survival is at stake, we have a basic responsibility to our species to venture to other worlds. Sailors on a becalmed sea, we sense the stirring of a breeze.

Much of human history can, I think, be described as a gradual and sometimes painful liberation from provincialism, the emerging awareness that there is more to the world than was generally believed by our ancestors.