Weight is the force exerted by gravity against a body resting against a larger mass. The moon is in freefall—in orbit—so it doesn’t weigh anything. If it were placed on the surface of the Earth, it would weigh about 7.3476 × 10^22 kilograms—but only for a moment.

Example from the International Space Station (ISS) On Earth, a 70 kg person weighs 706 Newtons (or 160 lbs). In orbit, the astronauts weight is 632 Newtons (142 lbs).

Given that gravity on the Moon has approximately 1/6th of the strength of gravity on Earth, a man who weighs 60kg on Earth would weigh approximately 10kg on the Moon. His mass, however, remains constant.

For example on earth a 70kg person would weigh 686N (70kg x 9.8 ) whereas on the moon, where the gravitational acceleration is about 1.62 , that same 70kg person would weigh 113N. This means on a pair of scales calibrated for earth they would measure 11.5kg. G-force is another name for the acceleration due to gravity.

7.35 x 1022 kg

Moving from the gravity of the Earth to the gravity of the moon, the astronaut’s weight certainly changes, but his mass remains the same. If the mass and the volume don’t change on the moon, you can deduce that the astronaut’s density would be the same.

Density is defined as mass divided by volume. Pressure is defined as force divided by area. Air pressure is the weight of the atmosphere overhead divided by the area the air is resting on.

The mass of the Sun is about 27 million times more than the mass of the Moon. It’s this gravitational interaction that gives the Earth its orbit around the Sun, and the tiny pull of the Moon just causes the Earth to wobble a bit in its movements.