Whichever one you drop first will hit the ground first. If you drop them simultaneously, and they don't interfere with each other on the way down, then they will hit the ground simultaneously.
They will both hit the ground at the same time, as there is no air resistance in a vacuum, and weight does not determine which object will fall faster even where there is gravity.
In a vacuum, a feather and an elephant dropped from the same height will hit the ground simultaneously due to gravity acting equally on both objects. This principle was confirmed by Galileo's experiments and later illustrated by astronaut David Scott during the Apollo 15 mission. Without air resistance, all objects fall at the same rate regardless of their mass.
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