Astronomy for Young Folks

asteroids, numerous comets, and meteors

Mercury will never appear except in the morning or evening twilight, when none but the very brightest stars are visible, since it never departs far from the sun. It will only be seen under certain favorable conditions, and usually it will escape our notice altogether unless we know exactly where to look for it although there are but two or three stars in the heavens that surpass it in brightness.

there are two, Uranus and Neptune that we need not consider for Neptune is not visible without the aid of a telescope and Uranus is fainter than any of the stars included in our diagrams.

Of the seven planets

The stars shine by their own light but

the planets shine only by reflected light from the sun