Night Sky: Going to the Antipodes?

A close look shows the bizarre hexagon that surrounds Saturn’s North pole. But nothing special sits at Saturn’s antipode, despite identical temperatures and winds. (Cassini Spacecraft, NASA and ESA)

Two weeks ago, Jeopardy! contestants were asked to come up with a word that meant opposites. One got it right, though she wasn’t sure how to pronounce antipodes. No blame: it’s a genuine head-scratcher for most, because antipode and its plural antipodes are challengingly pronounced AN-ti-pode and an-TIP-uh-deez.  The British liked the concept enough to name the New Zealand region The Antipodes because they’re opposite England on the globe. Kingston, New York’s antipode is in the ocean southwest of Australia.

The universe’s bodies are mostly spheres, and, obviously, every location on each of those balls has a spot precisely opposite it — its antipode. Some of them cry out for our attention.

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For example, Saturn’s south pole is an unremarkable place with round hurricane-like storms and no straight lines. But every 15 years the opposite pole points in our direction and lets us have a look. Saturn’s antipodal (an-TIP-uh-d’l) extremities are a study in strangeness because its north pole — the one aimed our way this past decade — is surrounded by an enormous hexagon whose sides are each longer than Earth’s diameter. Despite some unconvincing guesses, there’s no plausible explanation for how nature could possibly create and preserve such an enormous geometrical shape, especially when Saturn’s antipode doesn’t have one despite similar temperatures, pressures and winds.

Antipodal phenomena inhabit the sky itself, even if relatively few people associate this aspect of nature with marvels ranging from the common and beautiful to the rare and subtle. Many antipodal phenoms lie precisely opposite the Sun alone, like the rainbow, the lunar eclipse and the glory.

With constellations, antipodality sometimes played a central role in their folklore, as when Scorpius, which hovers opposite to Orion, was supposedly placed there so that after the Hunter had been mythologically slain by the arachnid, the two enemies would never again lay eyes on each other.

An original revelation I uncovered by studying a star atlas is that two of the five brightest stars, Canopus and Vega, are antipodal to each other on the celestial sphere. So after pondering that Vega will be the north star 12,000 years from now, if anyone wonders what will then be the south star, we have our answer. And what a spectacular situation — a dazzling, zero magnitude luminary marking each of the poles and appearing straight up to visitors at either place.

It’s clear that the search for antipodes can uncover surprising revelations, making this a worthy enterprise — the opposite of what we might have imagined.

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