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How does gravity keep the Moon in orbit around Earth?

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A diagram of a cylindrical vessel containing gas, with a movable piston held down by a weight. Countless small dots beneath the piston represent gas particles in rapid, random motion, illustrating Bernoulli's model of gas pressure. — physics As conceived by Daniel Bernoulli in *Hydrodynamica* (1738), gases consist of numerous particles in rapid random motion. He assumed that the pressure of a gas is produced by the direct impact of the particles on the walls of the container.

Gravity keeps the Moon in orbit around Earth by acting as a constant inward, or centripetal, force that prevents the Moon from moving in a straight line.12

According to the law of inertia, an object in motion will travel in a straight line at a constant speed unless acted upon by an external force. Because the Moon’s velocity is always tangent to its orbital path, it would fly off into space if not for the gravitational attraction exerted by Earth.123

This gravitational force acts as a continuous pull toward the center of Earth, effectively "falling" the Moon toward the planet. The orbital path is the result of a balance between this gravitational pull and the Moon's inertia. Essentially, the Moon is in a state of constant, free-falling motion around Earth, where its forward velocity is perfectly matched by the curvature of its path around the planet. This relationship is governed by the same principles of celestial mechanics that describe the motion of all massive bodies in space.1324