[Atmob-discuss] Question about the planets

[Dr. Arthur G. Swedlow]

A. Joseph Ross wrote:
> So here's a question that just occurred to me.  We all know the story 
> of how unexplained irregularities in the motion of Uranus led to the 
> discovery of Neptune.  So how come there weren't irregularities in 
> the motion of Saturn, caused by Uranus, but unexplained before Uranus 
> was discovered?
>
>   
Hi,

I suspect that one reason is that the effect of Neptune's gravity on on 
Saturn, a planet some 6.5 times as massive, would have been rather 
small.  Uranus's motion would have perturbed more by Saturn than Saturn 
by Uranus.