Is it true that Venus' days are longer than its years?

Answer 1

The speed at which a planet rotates (spins) determines its "sidereal day", and the period of its orbit around the Sun determines its "year".

The "solar day" is determined by a combination of the spin time and the year.

The rotation of Venus is extremely slow, and it spins "backwards", from east to west (clockwise as seen from from above the Earth's north pole). The time Venus takes to complete a rotation (243 Earth days) is longer than the time it takes to orbit the Sun (225 Earth days). So a "sidereal day" is longer than its year.

However, the "solar day" is about 116.75 Earth days long. So, in that case, the year is about twice the day length. The solar day is shorter than the sidereal day because Venus rotates "backwards". Astronomers call this "retrograde rotation".

On Venus, the Sun (if it were visible) would rise in the west and set in the east. The combination of its rotation and revolution produces an apparent solar day (roughly sunrise to sunrise) of about 116.75 Earth days.

Venus is the only planet, apart from Uranus, that rotates in the clockwise direction. There are several theories why Venus rotates this way. Most involve a collision with another orbiting body in the distant past.

(Uranus's retrograde rotation is a result of the planet being tipped onto its side. Its axial tilt is 98 degrees, meaning its "north pole" is "below" the plane of the orbit. If its north pole was "above" its orbital plane (like the Earth's), it would be rotating "normally".)

Answer 2

Not strictly true for an apparent day.

Venus takes 243 days to spin on its axis relative to the background stars, while it takes 224.7 days to orbit the sun. So its axial rotation time relative to background stars is longer than the time taken to orbit the sun. Although its spin on its axis is longer that its orbital period, an apparent day (e.g. one sunrise to next sunrise) is 116.75 days, since it spins in the other direction to Earth and most other planets.

Answer 3

Yes and no. Venus rotates very slowly and in a "retrograde" direction. The effect is to make the "solar day" on Venus much shorter than the "sidereal day" (the rotation period).

The orbital period for Venus (its "year") is about 225 Earth days.

The sidereal day is about 243 Earth days.

The solar day is about 117 Earth days.

That's why the answer is "yes and no". It depends upon which "day "you mean.

Answer 4

Yes, Venus rotates on its axis very slowly, taking about 243 Earth days to complete one rotation. In contrast, it takes about 225 Earth days for Venus to orbit around the Sun, so a day on Venus is longer than a year.

Answer 5

Because the rotation of Venus takes longer than it takes for it to rotate around the sun