Astronomy1 min read

On Venus, one day is longer than one year

One spin takes about 243 Earth days; one trip around the Sun takes only 225.

A global radar map of Venus (Magellan data)
Photo: NASA Magellan radar mosaic (Wikimedia Commons, public domain)

1On Earth a day lasts 24 hours and a year 365. Venus is the opposite: it takes about 243 Earth days to spin once on its axis, but only about 225 Earth days to orbit the Sun — so on Venus, a 'day' is genuinely longer than a 'year'.

2Stranger still, Venus spins backwards compared with Earth: the Sun rises in the west and sets in the east. Scientists suspect an ancient impact or long-term atmospheric tides slowed the spin until it reversed.

3One more oddity: although the planet itself turns slowly, its upper clouds race around Venus in about four Earth days — roughly sixty times faster than the planet spins. This 'super-rotation' of the atmosphere is still not fully explained.

One line to remember

One spin: 243 days. One orbit: 225 days. On Venus the day really is longer than the year — and the Sun rises in the west.

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