Observations always involve theory.

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.

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

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

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

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