All nature is a vast symbolism: Every material fact has sheathed within it a spiritual truth.

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

A scientist naturally and inevitably ... mulls over the data and guesses at a solution. He proceeds to testing of the guess by new data-predicting the consequences of the guess and then dispassionately inquiring whether or not the predictions are verified.

Observation always involves theory.

The universe is unfolding as it should.

There we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial.

At the last dim horizon, we search among ghostly errors of observations for landmarks that are scarcely more substantial. The search will continue. The urge is older than history. It is not satisfied and it will not be oppressed.

Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.

I knew that even if I were second or third rate, it was astronomy that mattered.

The outstanding feature, however, is the possibility that the velocity-distance relation may represent the de Sitter effect, and hence that numerical data may be introduced into discussions of the general curvature of space.

The great spirals, with their enormous radial velocities and insensible proper motions, apparently lie outside our Solar system.

Astronomy is something like the ministry. No one should go into it without a call. I got that unmistakable call, and I know that even if I were second-rate or third-rate, it was astronomy that mattered.

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

The history of astronomy is a history of receding horizons.

With increasing distance, our knowledge fades, and fades rapidly. Eventually, we reach the dim boundary-the utmost limits of our telescopes. There, we measure shadows, and we search among ghostly errors of measurement for landmarks that are scarcely more substantial. The search will continue. Not until the empirical resources are exhausted, need we pass on to the dreamy realms of speculation.

Observations always involve theory.

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

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.