ἔκλειψις

Eclipse comes from Greek ἔκλειψις (ékleipsis), meaning 'a forsaking, an abandonment, a failure to appear,' from ἐκλείπω (ekleípō, 'to abandon, to leave, to fail'), composed of ἐκ (ek, 'out of, away from') and λείπω (leípō, 'to leave, to forsake'). The word was used for more than astronomical events: a person could suffer an ékleipsis of strength or consciousness; a city could suffer an ékleipsis of men when its army was destroyed. When Greek astronomers applied the word to the darkening of the Sun or Moon, they were describing it as an abandonment — the light had failed, withdrawn, left its post. The eclipsed body had, in the most literal sense of the Greek word, stopped showing up.

Greek astronomy had achieved a sophisticated understanding of eclipses well before the Common Era. Thales of Miletus reportedly predicted a solar eclipse in 585 BCE, possibly using Babylonian eclipse records. Aristarchus of Samos used the geometry of lunar eclipses in the third century BCE to estimate the relative sizes of Earth and Moon. Hipparchus, in the second century BCE, used eclipse observations to calculate the Moon's distance from Earth with remarkable accuracy. The Antikythera mechanism, a Greek computing device from roughly 100 BCE recovered from a shipwreck in 1901, could predict lunar and solar eclipses decades in advance using bronze gears of extraordinary precision. The ékleipsis had been domesticated, made predictable, reduced from divine abandonment to mechanical calculation — at least among those who built the machines.

The cultural weight of eclipses — particularly total solar eclipses — has never been proportional to their actual physical cause. Astronomically, a solar eclipse is a geometrical coincidence: the Moon happens to be almost exactly the same angular diameter as the Sun as seen from Earth, so it can cover it precisely. This coincidence is not permanent — the Moon is slowly moving away from Earth, and in roughly 600 million years, total solar eclipses will no longer be possible. For the moment, however, the geometry is exact, and totality is among the most overwhelming sensory experiences a human being can have: the temperature drops, the horizon glows in sunset colors from every direction simultaneously, stars appear in the middle of the day, and the corona — the Sun's outer atmosphere, normally invisible — blazes around the black disk of the Moon.

The verb ekleípō, 'to forsake,' has left another trace in English: the word 'ellipse' derives from ἔλλειψις (élleipsis), from a related root λείπω (leípō), meaning 'a falling short, a deficiency.' The conic section called an ellipse is named for what it lacks: it falls short of the regularity of a circle. The grammatical term 'ellipsis' — the omission of words understood from context, marked by three dots — comes from the same root. The family of words built on leípō (to leave, to forsake) includes abandonment, astronomical darkening, geometric imperfection, and rhetorical omission. The Greek root of departure and absence has been extraordinarily productive, finding something missing in stars, shapes, and sentences.