Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: IzzieC on 21/11/2017 09:54:29

Title: Why does Venus rotate differently to other planets?
Post by: IzzieC on 21/11/2017 09:54:29

Connie wants to know...

Why is it that Venus is the only planet in our solar system that rotates in a clockwise rotation while the others rotate counter-clockwise?

Can you help?

Title: Re: Why does Venus rotate differently to other planets?
Post by: Janus on 21/11/2017 16:11:37

Venus is not the only planet that rotates retrograde, Uranus does also.  Uranus is "tipped over on its side" by better than 90 degrees, so technically it rotates counter-clockwise.  Something in the past tilted its axis by a large amount.
 One of the present theories for Venus assumes that something similar happened to it.   It originally rotated like the other planets, but various imbalanced effects caused it to "flip over".  Another theory is that it slowed down due to tidal forces caused by the Sun, and would have become tidally locked if it hadn't been for tidal influences from the other planets, which caused a slight retrograde rotation to be a more stable outcome.

Title: Re: Why does Venus rotate differently to other planets?
Post by: evan_au on 21/11/2017 20:08:30

We know that the Solar System had some major bombardment in its past (just look at the Moon through a telescope).
- In fact, it is thought that just such an event formed the Moon

A big object crashing into a planet off-center could change its axis of rotation significantly.

See: https://en.wikipedia.org/wiki/Late_Heavy_Bombardment

Title: Re: Why does Venus rotate differently to other planets?
Post by: Bigjoemonger on 24/11/2017 06:05:55

To answer your question we don't actually know.

Theres lots of theories as to why but whatever caused it, happened billions of years ago so all we can do is speculate.