Force of attration of two massive bodies...

[BobbyJoeCool]

I was doing some calulations for someone showing the point of neutral gravety between two equal sized masses. The vectors from points not between the two masses (I hope that's clear...) all seem to point at the midpoint between the two masses... Is that what happens always? or is it just a conicidence (or misdrawing/calulation on my part)?

[Martin]

I was doing some calulations for someone showing the point of neutral gravety between two equal sized masses. The vectors from points not between the two masses (I hope that's clear...) all seem to point at the midpoint between the two masses... Is that what happens always? or is it just a conicidence (or misdrawing/calulation on my part)?

 

suppose A and B are identical round balls, like two planets with same mass

and suppose they are in circular orbit

they both appear to orbit the point halfway between

 

sort of like the earth and moon except both the same mass.

 

the force vectors would NOT ordinarily point at midway spot.

 

if something is much nearer A than B, then the force it feels will be mostly towards the center of A

 

like if I stand on the moon, I feel a force towards the center of the moon, not towards some Lagrange point in between earth and moon.