was supposed that the planets
shine by their own light, but the phases of Venus and Mars proved that
their light is reflected. The Aristotelian notion, that celestial differ
from terrestrial bodies in being incorruptible, received a rude shock
from the discoveries of Galileo, that there are mountains and valleys in
the moon like those of the earth, that the sun is not perfect, but has
spots on his face, and that he turns on his axis instead of being in a
state of majestic rest. The apparition of new stars had already thrown
serious doubts on this theory of incorruptibility.

These and many other beautiful telescopic discoveries tended to the
establishment of the truth of the Copernican theory and gave unbounded
alarm to the Church. By the low and ignorant ecclesiastics they were
denounced as deceptions or frauds. Some affirmed that the telescope
might be relied on well enough for terrestrial objects, but with the
heavenly bodies it was altogether a different affair. Others declared
that its invention was a mere application of Aristotle's remark that
stars could be seen in the daytime from the bottom of a deep well.
Galileo was accused of imposture, heresy, blasphemy, atheism. With a
view of defending himself, he addressed a letter to the Abbe Castelli,
suggesting that the Scriptures were never intended to be a scientific
authority, but only a moral guide. This made matters worse. He was
summoned before the Holy Inquisition, under an accusation of having
taught that the earth moves round the sun, a doctrine "utterly contrary
to the Scriptures." He was ordered to renounce that heresy, on pain of
being imprisoned. He was directed to desist from teaching and advocating
the Copernican theory, and pledge himself that he would neither publish
nor defend it for the future. Knowing well that Truth has no need of
martyrs, he assented to the required recantation, and gave the promise
demanded.

For sixteen years the Church had rest. But in 1632 Galileo ventured
on the publication of his work entitled "The System of the World," its
object being the vindication of the Copernican doctrine. He was again
summoned before the Inquisition at Rome, accused of having asserted
that the earth moves round the sun. He was declared to have brought
upon himself the penalties of heresy. On his knees, with his hand on the
Bible, he was compelled to abjure and curse the doctrine of the movement
of the earth. What a spectacle! This venerable man, th