Are physical forces alone at work there, or has evolution begotten something more complex, something not akin to what we know on Earth as life? It is in this that lies the peculiar interest of Mars.

Imagination is as vital to any advance in science as learning and precision are essential for starting points.

Bright points in the sky or a blow on the head will equally cause one to see stars.

If astronomy teaches anything, it teaches that man is but a detail in the evolution of the universe, and the resemblant though diverse details are inevitably to be expected in the hosts of orbs around him. He learns that, though he will probably never find his double anywhere, he is destined to discover any number of cousins scattered through space.

Imagination is as vital to any advance in science as learning and precision are essential for starting points. Let me warn you to beware of two opposite errors: of letting your imagination soar unballasted by facts, but on the other hand, of shackling it so solidly that it loses all incentive to rise.

Are physical forces alone at work there, or has evolution begotten something more complex, something not akin to what we know on Earth as life? It is in this that lies the peculiar interest of Mars.

Ever since celestial mechanics in the skillful hands of Leverrier and Adams led to the world-amazed discovery of Neptune, a belief has existed begotten of that success that still other planets lay beyond, only waiting to be found.