Moon and Jupiter

StarDate

Jupiter might have “blinked” for more than a century. A storm in its southern hemisphere might have winked out, with another eventually taking its place – today’s Great Red Spot.

Scientists first reported a spot in Jupiter’s southern hemisphere as early as 1632, and definitely by 1665. But there were no records of it from the early 1700s to the early 1800s. So there’s been a debate about whether the spot disappeared, or astronomers simply missed it.

A recent study argues that the original spot vanished. Researchers combed through all the records of Jupiter they could find – including those by some of the most accomplished observers of the time. And there were no reports of a big, dark spot. That suggests the original storm fizzled out, and a new one fired up in the same location.

The current version was first reported in 1831. Since then, it’s changed dramatically. At first, it was an oval about three times as wide as Earth. Today, it’s rounder, and about the same size as Earth.

The new study says the Great Red Spot probably sprang from the interplay of two powerful jet streams. Today, winds at its perimeter reach almost 300 miles per hour. And they’re getting faster as the spot shrinks – perhaps to once again blink out.

Jupiter stands to the right of the Moon as they climb into good view, around midnight. It looks like a brilliant star. A small telescope will reveal the Great Red Spot.

Script by Damond Benningfield