Equipped with our five senses - along with telescopes and microscopes and mass spectrometers and seismographs and magnetometers and particle accelerators and detectors sensitive to the entire electromagnetic spectrum - we explore the universe around us and call the adventure science.

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

Equipped with our five senses - along with telescopes and microscopes and mass spectrometers and seismographs and magnetometers and particle accelerators and detectors sensitive to the entire electromagnetic spectrum - we explore the universe around us and call the adventure science.

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

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.

Observation always involves theory.