The Great Conversation: Astronomy
By Gabriel Blanchard
Now a specialized field, astronomy was once among the principal subjects for all scholars.
Studying the heavens is, forgive the pun, a universal pursuit. Using the cycles of the Moon to measure time has been common to many civilizations—the word month originally referred to this. Other celestial bodies have served as reference points as well: the Egyptians governed their calendar by Sirius because its rise corresponded to the flooding of the Nile, and the Chinese system relied on the movement of Jupiter, which takes about twelve years to orbit the Sun (which is why Chinese astrology relies on birth years instead of birth months). Ultimately, most civilizations settled on a solar calendar.
It may have been either through this general usefulness, or through the mere pleasure of looking at the stars, but ancient sages had a high opinion of astronomy. Plato considered it one of the chief inducements to philosophy, as did Lucretius, who believed that studying the stars would lead people to dismiss superstition. Astronomy had become one of the seven liberal arts, the standard universal curriculum, by the time the Medieval universities were being founded. It retained this status for centuries; Kant, who was an astronomer as well as a philosopher, famously wrote: “Two things fill the mind with ever new and increasing admiration and awe, the oftener and more steadily we reflect on them: the starry heavens above and the moral law within.”
The dispute over whether the Earth or the Sun is at the center of the universe actually has a long history behind it. In the third century BC, the Greek scholar Aristarchus proposed a heliocentric cosmos, but it was rejected by most astronomers at the time because the stars did not appear to move. Ptolemy detailed the observed motions of the planets, caluclating with great precision what their orbits must be—based on the assumption that their orbits were perfect circles. This was originally another objection to heliocentrism, since circular orbits around the Sun did not align with the observed data; it was not until 1609, almost a hundred years after Copernicus, that Johannes Kepler determined that orbits were ellipses rather than circules, solving the problem.
Astrology accompanied astronomy from a very early period, possibly beginning in Mesopotamia. Some taught that the stars and planets controlled human fates, while others admitted only an influence, which a person of intelligence and character could overcome—not unlike rival theories of psychology today. Astrology and its concomitant beliefs, like the Pythagorean idea that the spheres emitted music, began to decline during the Enlightenment; from the notion of a sublimely ordered, integrated, and finite cosmos, we moved to an eerie limitlessness. Pascal expressed the modern rather than the classical sentiment when he said that “The silence of those infinite spaces terrifies me.”
Modern astrophysics has remained an exciting field of discovery. The tension between the strictly ordered theories of Einstein and the subatomic chaos posited by Bohr has left the field in two “halves,” and the search for a unified theory of the cosmos that explains both macro- and micro-level physics exercises the minds of scientists in our own day. The paradoxes in how gravity, light, and atomic nuclear forces operate have prompted subtle theories about not only nature, but reality as such—bending science back towards its parent discipline of philosophy. Perhaps, given the ways it can tie subjects together, astronomy deserves to be restored as a fundamental element of education.
C. S. Lewis, The Discarded Image
Hawking, A Brief History of Time