Can a planet's day can be longer than it's year?

Answer 1

Yes, a planet's day can be longer than it's year. One example is Venus, whose year is 225 Earth days long and it's day is 243 Earth days long. It's time around the sun (revolution) takes less time than the time it spins around on it's axis (rotation).

Because Venus's day is so long (and opposite of the Earth's), scientists are lead to believe it was hit by a large object.

Venus's orbit is also closer to the sun, so it takes less time to go around the sun. That would be why the year seems so short.

Just some extra sites:

http:/nineplanets.org/venus.html

(about 5 paragraphs down)

Why_is_Venus'_day_longer_than_a_year

Answer 2

Yes, a planet's day can be longer than it's year. One example would be Venus, whose year is 225 Earth days long and it's day is 243 Earth days long. It's time around the sun (it's revolution) takes less time than the time it spins around on it's axis (it's rotation).

Because Venus's day is so long (and opposite of the Earth's ... the sun goes west to east), scientists are lead to believe it was hit by a large object.

Venus's orbit is closer to the sun, so it takes a smaller amount of time to go around the sun. That's why the year is so much shorter.

Just some other sites:
http:/nineplanets.org/venus.html
(about 5 paragraphs down)
Why_is_Venus'_day_longer_than_a_year

Answer 3

The length of a planet's solar day is its rotation (or spin) about its axis, relative to the sun. The solar day on a planet is how long it would take the sun to set, rise and return to its relative position in the sky that someone standing on some point on the planet sees. This is affected by the planet's spin and its orbit around the sun. If the planet did not have any axial spin at all, its day and its year would be the same length. If a planet's rotation were equal to its revolution, it would not have any days at all -- the sun would appear frozen in a relatively fixed position in the sky for half the planet, the other half of the planet would be in perpetual night. This has actually happened to the Moon orbitting the earth; the earth is always visible at the same point in the lunar sky from one hemisphere (half) of the moon; on the other half (the 'dark side of the moon'), the earth is never visible because the moon is tidally locked with the earth; its rotation and orbit are the same.

There are myriads of possibilities in between, as the complexities involved in planetary formation have resulted in a wide contrast of planetary spins in the solar system. Jupiter has the shortest day (at less than 10 hours), whilst Venus has the longest (243 earth-days to one day on Venus; Venus spins in the opposite direction of all the other planets, and because of this, on Venus the sun would appear to rise in the west and set in the east).

Answer 4

Not a problem. All it takes is that the planet's time to spin on its axis (its "sidereal day" length) is longer than its period of revolution around the Sun (its year).