# Earth moon system

I have some confusion understanding some concepts of earth moon system . Why conservation of momentum requires both the Earth and the Moon to revolve around the centre of mass ? What happens if they do not revolve around the centre of mass ? Plz clarify and guide me .

Heres a thing, the earth and moon have equal momentum (same as all two body systems)
Ive attached a two-body data sheet to chew on.

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• 2 body data sheet.docx
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A.T.
If they revolved around a different point, then their net center of mass would revolve too, so their net linear momentum would change it's direction continuously. That they revolve at all is a matter angular momentum conservation.

Thanks for ur answers . But a small query " so their net linear momentum would change it's direction continuously." . What's wrong if this happens ?

A.T.
Thanks for ur answers . But a small query " so their net linear momentum would change it's direction continuously." . What's wrong if this happens ?
It wouldn't be conserved.

Thanks a lot for answering my queries . Thanks for all those wonderful answers !

phinds