[Info-vax] CRTL and RMS vs SSIO

[Lawrence D’Oliveiro]

On Friday, October 15, 2021 at 11:36:27 PM UTC+13, Phillip Helbig (undress to reply) wrote:
> The point about which both orbit is inside the Earth ...

Which, given what physics I was able to pick up, seems an entirely arbitrary thing to focus on. As the Moon recedes from the Earth, at some point that common point will exit the Earth’s surface. There is no special energy barrier to cross at that point, no special physical change in the system: it will simply exit and continue on its way.

> ... the orbit of the Moon is 
> always concave relative to the Sun, which emphasizes the independence of 
> the Moon.

That, to me, is the most important thing. Because without it, you can have no understanding of how the Moon moves.

> The current definition, 
> which demoted Pluto, is that it is a body which dominates its orbit, so 
> that applies to the Earth and not to the Moon.

Given the effect that the Moon has on the Earth, I’m not sure that’s so clear cut ...