The Song of Urania

Joe Antognini

A history of astronomy, from antiquity to the present.

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47 episodes
Updated Nov 2, 2024

Episodes47

Newest first

Mar 11, 2023 · 55 min
Episode 27: Astronomica
In this episode we examine the work of two Roman astrologers to see how Roman astrology worked in practice: Marcus Manilius, who wrote Astronomica, and Firmicus Maternus, who wrote the Matheseos.
Feb 9, 2023 · 1 hr 15 min
Episode 26: Matters of Life & Death in Roman Astrology
As Rome expanded to the East, the cultural influence of the Greeks deepened, and this included a strong interest in astrology. Despite resistance from conservative Romans, by the Imperial Era, astrology played a critical role in Roman politics, both as a tool to support conspirators attempting to assassinate emperors, and wielded by emperors as a way to eliminate challenges to their power.
Jan 7, 2023 · 1 hr 8 min
Episode 25: The Stars of Bethlehem
This month the full moon falls on Three Kings' Day, traditionally a day that celebrates the adoration of the magi, so we investigate the famous Star of Bethlehem story. Through the centuries there have been dozens of astronomical and astrological theories put forward as to what the Star of Bethlehem was. We look at a few of the more prominent theories and their shortcomings, finishing with what is plausibly the leading candidate, the astrological theory of Michael Molnar, though as we'll see, th
Dec 8, 2022 · 1 hr 4 min
Episode 24: Etruscan & Roman Astronomy
Rome, the great empire of the Mediterranean, is not known for its astronomy. But while it lagged behind other civilizations, it is a mistake to think that they were entirely uninterested in the subject. Astronomical references permeated the Roman calendar and one of Rome's longest lasting contributions to Western civilization, the Julian calendar, was devised by the Roman astronomer Sosigenes.
Nov 11, 2022 · 1 hr 11 min
Episode 23: The Culmination of Ancient Greek Astronomy
During the half millennium of the Roman Era in Ancient Greece, only two astronomers made any major advances. At the beginning of the Roman Era, Posidonius measured the size of the Earth and discovered the relationship between the Moon and the tides. But the triumph of Greek astronomy came 300 years later with the intricate planetary model of Ptolemy, which stood unchallenged for some 1400 years.
Oct 10, 2022 · 56 min
Episode 22: The Antikythera Mechanism & Friends
In the year 1900 a team of sea sponge divers stumbled upon a shipwreck from the late Hellenistic Era. Among the statues, coins, and jewellery, the salvage crew pulled out a small box covered in moss. Initially ignored, the contents of this box proved to be the most sophisticated mechanical device that survives from the ancient world. The Antikythera mechanism computed all the known motions of the heavens and its complexity was described by one scholar as "like finding a jet engine in King Tut's
Sep 12, 2022 · 1 hr 9 min
Episode 21: Hipparchus the GOAT
After briefly examining the astronomy of Timocharis and Aristyllus, who developed the first known stellar catalog, we turn our attention to Hipparchus, who I claim was the greatest astronomer of ancient times. Hipparchus made major developments in virtually every area of astronomy known to him. His measurement of the lengths of the year and month were of unprecedented accuracy, he measured the distance to the Moon, and he developed a star catalog that was an order of magnitude larger than the ea
Aug 13, 2022 · 47 min
Episode 20: The Theory of Epicycles & Deferents
In the Hellenistic Era the astronomer Apollonius of Perga (maybe) developed the model of epicycles and deferents that was to dominate Western astronomy for more than 1500 years. Around the same time, Eratosthenes, who was the head librarian at the Library of Alexandria, developed a novel technique to measure the circumference of the Earth and arrived at a suspiciously accurate result.
Jul 13, 2022 · 1 hr 5 min
Episode 19: The Forerunners of Copernicus
At the dawn of the Hellenistic Age, two Greek astronomers developed radical new cosmologies. Heraclides of Pontica proposed that the Earth rotated on its axis and that Mercury and Venus revolved around the Sun instead of the Earth. Aristarchus of Samos went further and proposed that all the planets, including the Earth, revolved around the Sun. In addition, Aristarchus made the first quantitative measurement of the distances to the Sun and the Moon, along with their sizes.
Jun 15, 2022 · 1 hr 17 min
Episode 18: Aristotle, Plato's Other Student
Two of Plato's students were notable astronomers. We looked at one of them, Eudoxus, in the last two episodes. In this episode we turn to Plato's other student, Aristotle. Aristotle embellished Eudoxus's model of planetary motion, but also developed a comprehensive physics and cosmology that ultimately became the standard model of the universe during the High Middle Ages.
May 17, 2022 · 59 min
Episode 17: The Attic Calendar and its Discontents
We turn back the clock and see how a variety of Greek astronomers over the centuries contributed to the Greek calendar, and how Greek politicians ignored their developments. Then we see how the discovery that the seasons are not of equal lengths posed a problem for Eudoxus's theory of planetary motion.
Apr 18, 2022 · 1 hr
Episode 16: The Homocentric Spheres of Eudoxus
In working on the problem of doubling the cube, Plato's friend Archytas devised an ingenious solution that involved a three dimensional curve determined by the intersection of a torus with a cylinder. Archytas's student Eudoxus then seems to have been inspired by this solution to develop the first serious model of planetary motions in ancient Greece, his theory of homocentric spheres.
Mar 22, 2022 · 1 hr 9 min
Episode 15: On Plato's Broad Shoulders
Before leaving the world of the Pre-Socratics, we look briefly at the astronomy of Oenopides, which had a more observational character than many of his contemporaries. Then we turn to Plato, the first of the great astronomers in the Socratic tradition, whose astronomy synthesized the best ideas of his predecessors.
Feb 17, 2022 · 52 min
Episode 14: The Atomic Philosophers
Two philosophers, Leucippus and Democritus, attempted to synthesize the monist theories of the earlier natural philosophers with the pluralist theories of Empedocles and Anaxagoras. To do this, they proposed a revolutionary idea — that all matter is made of atoms.
Jan 20, 2022 · 52 min
Episode 13: Ex Uno, Plura
As we transition from the Archaic Period of Greece to the Classical Period, two philosophers, Empedocles and Anaxagoras, rebel against the prevailing dogma of monism and present a new idea — that matter consists of mixtures of multiple fundamental elements. Thanks to William Little of Ohio State for help with the Latin to get the opposite of "E pluribus unum" for the title. If you would like to register for the Stellar Spectacles symposium that I mentioned at the beginning of the episode
Dec 21, 2021 · 1 hr 3 min
Episode 12: The Eleatic School & the Way of Truthiness
After the Median invasion, the Ionian philosopher Xenophanes, a student of the Anaximander, was forced to flee to Elea in Magna Graecia and brought the philosophy of the Ionians to the Eleans. His student, Parmenides, then founded the Eleatic School, which was skeptical of the senses, and argued that despite its appearance to the contrary, the Earth was round. Parmenides's student, Zeno, in turn developed his famous paradoxes to prove his teacher's assertion that motion was an illusion.
Nov 24, 2021 · 1 hr 19 min
Episode 11: The So-Called Pythagoreans
We turn to the enigmatic, charismatic philosopher Pythagoras and the following that he inspired. Though Pythagoras is today associated with the Pythagorean theorem, he developed a school whose secrets were jealously guarded. The Pythagoreans studied astronomy, mathematics, and music, but also developed a unique philosophy centering around numbers that heavily influenced Plato.
Oct 20, 2021 · 52 min
Episode 10: The Ionian School
Miletus became a wealthy Greek city during the Archaic Period and developed a thriving intellectual culture which included many of the most important pre-Socratic astronomers. We looked at Thales in the last episode and now we try to understand the astronomy of other members of the Ionian School — Anaximander, Anaximenes, and Heraclitus. What did their astronomy have in common with each other and what are the connections between their ideas and the ideas of modern physics?
Sep 22, 2021 · 1 hr 1 min
Episode 9: Thales, through a Glass Darkly
Thales was the first of the Greek astronomers and became known as one of the Seven Sages of Greece. Over the centuries many astronomical discoveries were attributed to him, but what was the reality and what was the hyperbole?
Aug 23, 2021 · 50 min
Episode 8: The Bards Sing of the Skies
We outline the early development of Greek civilization after the Late Bronze Age Collapse and how the unique geography of Greece influenced its culture, and ultimately, its astronomy....

The Song of Urania

Episode 27: Astronomica

Episode 26: Matters of Life & Death in Roman Astrology

Episode 25: The Stars of Bethlehem

Episode 24: Etruscan & Roman Astronomy

Episode 23: The Culmination of Ancient Greek Astronomy

Episode 22: The Antikythera Mechanism & Friends

Episode 21: Hipparchus the GOAT

Episode 20: The Theory of Epicycles & Deferents

Episode 19: The Forerunners of Copernicus

Episode 18: Aristotle, Plato's Other Student

Episode 17: The Attic Calendar and its Discontents

Episode 16: The Homocentric Spheres of Eudoxus

Episode 15: On Plato's Broad Shoulders

Episode 14: The Atomic Philosophers

Episode 13: Ex Uno, Plura

Episode 12: The Eleatic School & the Way of Truthiness

Episode 11: The So-Called Pythagoreans

Episode 10: The Ionian School

Episode 9: Thales, through a Glass Darkly

Episode 8: The Bards Sing of the Skies