In astronomy, what is the difference between mass and weight?

The distinction between mass and weight is fundamental in physics and astronomy. Mass refers to the quantity of matter contained within an object, usually measured in kilograms or grams. It is an intrinsic property, meaning that mass does not change regardless of the object's location or the gravitational force acting on it.

On the other hand, weight is the force exerted on an object due to gravity and is dependent on both the mass of the object and the gravitational acceleration acting on it. This relationship is expressed in the formula: weight = mass x gravitational acceleration (W = m x g). Because gravitational acceleration varies based on the object’s location—such as on the surface of Earth versus that on the Moon—weight can differ depending on where the object is.

This explanation highlights why the correct answer emphasizes that mass is the measure of matter in an object while weight is the gravitational force acting on that mass. It illustrates that while mass remains constant, weight fluctuates with changes in gravitational pull, providing clarity on how these fundamental concepts interact in the study of astronomy.