How Long is a Day on Mercury?

1/3 the distance from the Sun than Earth, it should be no surprise that a day on Mercury is a real scorcher with temperatures soaring over 400 ºC. But in addition to its solar proximity it also has an

extremely

slow rotation: a single day on Mercury is 58.6 Earth days long... and you thought

your

Mondays lasted forever!

To be even more precise, for every 2 Mercury years, 3 Mercury days pass -- a 3:2 spin-orbit resonance, caused by the planet's varying elliptical orbit. (This also makes for some

interesting motions of the Sun

in Mercury's sky.)

To illustrate this, UK's

The Open University

has published a new video in their 60 Second Adventures in Astronomy series... check it out above (and see more of their excellent and amusing animations

here.

)

Video: The Open University. Narrated by David Mitchell.