On the Moon, which one touches the ground first: the feather or the hammer?

At the end of the last Apollo 15 release, David Scott presents two objects to the cameras: a geologist’s hammer and a feather. One of them seems to be promising a faster fall. At least that’s what many scenes on Earth have accustomed us to expect.

The astronaut drops them from the same height. They reach the lunar soil together, in the precision of this demonstration. The familiar difference came from the resistance of the air, especially important for a feather. On the Moon, the absence of an atmosphere comparable to ours removes this obstacle.

Experience has not discovered a new law and does not show that objects are devoid of weight. It makes visible an already ancient prediction about falling into the void. After complex machines, calculations and travel, a feather is enough to recall what the air often hides: very different masses can share the same acceleration.