# Thread: The curious motions of venus... Can we explain it?

1. Hi all astronomers and curious people.

Looking into some stuff recently, i won't say what, I found comments about the orbit and 'behaviour' of venus:

"An interesting phenomena is that from noon to noon the venusian day is 116.8 earth days... the synodic cycle where venus repeats an allignment with respect to earth and sun is 584 days this means venus has 5 days for everytime it completes it's synodic... (584/5=116.8) this is most curious and seems to indicate that the earth somehow may play a part in the cycle of venus? Venus - The Rotation Rate Of Venus - Planet, Surface, Venusian, and Days - JRank Articles

Also venus is slowing down rapidly (6.5 minutes slower than 16 yrs ago) Venus Spinning Even Slower Than Thought which goes against your comment that nothing has changed since copernicus 500 yrs ago."

I was hoping some of you experts might be able to give an explaination for the 'correlation?', relationship? between the orbit of venus and the orbit of the earth

The quote above is mine, but it's more or less word for word from a website... if this comment is inacurate please mention and I will source the original text.

2.

3. Originally Posted by question for you
Hi all astronomers and curious people.

Looking into some stuff recently, i won't say what, I found comments about the orbit and 'behaviour' of venus:

"An interesting phenomena is that from noon to noon the venusian day is 116.8 earth days... the synodic cycle where venus repeats an allignment with respect to earth and sun is 584 days this means venus has 5 days for everytime it completes it's synodic... (584/5=116.8) this is most curious and seems to indicate that the earth somehow may play a part in the cycle of venus? Venus - The Rotation Rate Of Venus - Planet, Surface, Venusian, and Days - JRank Articles
A simple reading of the Wiki page on Venus would have told you that:"A curious aspect of the Venusian orbit and rotation periods is the 584-day average interval between successive close approaches to the Earth is almost exactly equal to five Venusian solar days.[73] However, the hypothesis of a spin–orbit resonance with Earth has been discounted.[74]" Following that reference #74 would have given you this (hoping the pdf link works) PDF paper, from the Astrophysical Journal in 1979, concluding with: "It is concluded that Venus is not rotating with a resonance spin period relative to the orbit of earth and that the spin of Venus may be in a generalized Cassini state."

In other words, any superficial correlation is merely coincidence.

Also venus is slowing down rapidly (6.5 minutes slower than 16 yrs ago) Venus Spinning Even Slower Than Thought which goes against your comment that nothing has changed since copernicus 500 yrs ago."
This appears to be true, but there are numerous possible explanations for this, chief among which is that Venus' dense atmosphere can have large effects on the rotation period of Venus, for instance if very long lived storms were to take place. Interesting, but really not indicative of anything beyond what current science would be to able to explain with more data.

4. Originally Posted by KALSTER
In other words, any superficial correlation is merely coincidence.
This may not be the case. In "Venus II, Geology, Geophysics, Atmosphere and Solar Wind" there is a paper that examines the controls on Venus's rotation that concludes, as I recall, that there may be a resonance with the Earth. This was published in 1997 and so is more current than your citation. I shall check on its details when I get back to my home library.

5. I must admit, I wasn't overly impressed with kalstars refference to an artical from the 70's. The first real accurate measurement of venus' spin was done in 93/94 and the following measurment, which found a potential decrease in spin, taken 16 yrs later. With science and technology moving at such speed, we need to always look for the latest work. one of the things with wikipedia, is that anybody can write an artical. A harvard student might write an artical after coming home from a night drinking in which he argued with his buddy about a subject. It isn't robust. But cheers anyway kalstar, all input is welcome here.

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