If a marble and a grain of sand were placed in a region of space devoid of gravitational influence would the grain of sand be drawn to the marble?

Answer 1

No, the sand would not be drawn to the marble. Gravity is the force that draws smaller objects to larger ones; this force occurs because objects (with mass) bend the space around them. The concept of a "space" existing that is devoid of gravitational influence is counterintuitive to what we know about physics - this is almost like a trick question (not unlike one that may be found in a text book)... The above may be correct; I am not an expert. But from my amateur reading, I have some doubts. First, gravity is not the force that draws "smaller objects to larger ones". It is an essential property of all mass, including atoms and sub-atomic particles (other than photons and other massless particles). Any 2 masses exert a mutual pull; it's not one of the objects pulling on the other. The movement of the bodies will depend on the inertia of the bodies.

I think the marble and the grain of sand would indeed eventually come together as a result of gravity, but only under certain conditions. The 2 masses would have to be stationary relative to each other; in other words, at a constant and absolutely unchanging distance from one another [initially]. If there is any movement, then they may be displacing from one another at a velocity greater than the "escape velocity" needed to maintain an eternally increasing distance between them. This might even be true if they are moving toward each other.

In the far reaches of inter-galactic space, where all the gravity of all the distant stuff everywhere balances out, and assuming that there will be no errant forces or bits of flotsam and jetsam zipping around, and given the absolutely motionless initial state, I believe the grain will eventually crash land on the marble by way of gravity alone. They will bounce off of each other and do this over and over again, absorbing the heat of the collisions as they go. Eventually, they will rest together in a gravitational embrace. == == If you're only concerned with gravity and are willing for the sake of argument to dismiss all other objectionable factors, yes, they would be drawn together.

Two (hypothetically at absolute rest) electrons a trillion parsecs apart would be pulled together by gravity and eventually collide, or atleast collide as much as two barely moving electrons are wont to do, granted you provide adequate time for the subtle warping of spacetime to propagate and cause the two of them to each start slowly rolling down the hyperspatial indentation in the other's direction. You can watch, if you want. Feel free to start the popcorn anytime, though, 'cause it'll be a while.

Answer 2

YES!!! Every object of mass. Because it has mass it will have gravitational attraction to another object of mass.

However, Newton's first law of universal dynamics states that a body will remain stationary of in uniform motion unless acted upon by a force. The gravitational attraction is a force making it move. However, the gravitational attraction between these two bodies will so small as to be unmeasurable.

It was once calculated that two VLCC's (Super tankers , each of approximately 100,000 tons, and moored six feet apart), has an gravitational attraction between then of only 0.5 kg. ( 1 pound).