Be A Stargazer: A Guide to Astronomy

All sciences are making an advance, but Astronomy is moving at high
speed. Since the principles of this science were settled by Copernicus,
four hundred years ago, it has never had to beat a retreat. It is
rewritten not to correct material errors, but to incorporate new
discoveries.

At one time, Astronomy studied mostly tides, seasons, and telescopic
aspects of the planets; now these are only primary matters. Once it
considered stars as mere fixed points of light; now it studies them as
suns, determines their age, size, color, movements, chemical
constitution, and the revolution of their planets.

Once it considered space as empty; now it knows that every cubic inch of it quivers with greater intensity of force than that which is visible in Niagara. Every inch of surface that can be conceived of between suns is more wavetossed
than the ocean in a storm.

The invention of the telescope constituted one era in Astronomy; its
perfection in our day, another; and the discoveries of the spectroscope
a third—no less important than either of the others. New discoveries
are made every day with the advancement of telescopes.