When Tony Stark tries to lift Mjolnir using his Iron Man glove, he exerts a large upward force, greater than its weight, and yet the hammer remains at rest. So where does the additional downward force come from? One can only conclude that a unique property of uru metal is that, under the proper stimulus, it can emit large quantities of gravitons. On Earth, these fundamental particles have not been experimentally confirmed to exist, but as stipulated, the Asgardians are ahead of us scientifically. Gravitons are conjectured to transmit the gravitational force, and if an object emits additional gravitons, it is equivalent to increasing its mass. Thus, when an “unworthy” person applies an upward force, the uru metal increases the hammer’s weight to exactly cancel this lift, and the hammer remains unmoved.

If Mjolnir emits gravitons, could enough unworthy persons simultaneously attempting to lift it cause Mjolnir to start to attract objects via gravitation? And could sufficient force be applied that Mjolnir's gravity would be enough to capture light - turning Mjolnir into the center of a black hole?

If so, would Thor be able to lift Mjolnir without being destroyed by the tidal forces of all the attracted matter compressed around it?