Science is the one human activity that is truly progressive. The body of positive knowledge is transmitted from generation to generation.

Edwin Hubble

Work, to be pleasant, must be toward some great end, an end so great that dreams of it, anticipation of it overcomes all aversion to labor. If only I find some principle, for whose sake I could leave everything else and devote my life.

Edwin Hubble

Past time is finite, future time is infinite.

Edwin Hubble

The history of astronomy is a history of receding horizons.

Edwin Hubble

Equipped with his five senses man explores the universe around him and calls the adventure Science.

Edwin Hubble

Wisdom cannot be directly transmitted, and does not readily accumulate through the ages.

Edwin Hubble

Long ago when the light we now record left the very distant nebulae, the expansion was more rapid than it is today.

Edwin Hubble

The great spirals... apparently lie outside our stellar system.

Edwin Hubble

Eventually, we reach the utmost limits of our telescopes. There, we measure shadows and search among ghostly errors of measurement for landmarks that are scarcely more substantial.

Edwin Hubble

We find them smaller and fainter, in constantly increasing numbers, and we know that we are reaching into space, farther and farther, until, with the faintest nebulae that can be detected with the greatest telescopes.

Edwin Hubble

Many times greater than even the maximum estimates of the smoothed-out density of material concentrated in nebulae, and we find no evidence of any considerable amount of internebular material which might increase the density.

Edwin Hubble

We do not know why we are born into the world, but we can try to find out what sort of a world it is — at least in its physical aspects.

Edwin Hubble