# 2 large objects of equal mass, Will they move each other?

Suppose there are 2 planets the size (diameter) of Jupiter. Both have the exact same mass. They are separated by a distance of about 10 times the diameter of the planet. They are both at rest. Now, will they start moving towards each other or stay in the same place?

This is a sort of thought experiment. So, you can imagine they have no initial velocity and are in rest with respect to each other and that there are no other big objects nearby.

They will start moving towards each other due to gravitational attraction, as described by Newton's law of motion and by general relativity.

Ibix
2020 Award
Yes, of course.

PeterDonis
Mentor
2020 Award
Moderator's note: Thread level changed to "B".

ZapperZ
Staff Emeritus
Suppose there are 2 planets the size (diameter) of Jupiter. Both have the exact same mass. They are separated by a distance of about 10 times the diameter of the planet. They are both at rest. Now, will they start moving towards each other or stay in the same place?

This is a sort of thought experiment. So, you can imagine they have no initial velocity and are in rest with respect to each other and that there are no other big objects nearby.

This is no different than two objects of the same mass connected to each other via a spring. If you are familiar with that, then the scenario you described is analogous.

BTW, this is a good point for you to look up the concept of "center of mass".

Zz.

RobertSpencer