How did Galileo use inertia to explain why people do not feel Earth moving?

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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.

Galileo Galilei used the law of inertia to address the concern that if Earth were truly spinning on its axis and orbiting the Sun, humans should be able to sense that motion.

He explained that because we are in motion together with Earth, our natural tendency is to retain that state of motion. Since we share the same velocity as the planet, Earth appears to us to be at rest. This principle posits that a body in motion will remain in motion in a straight line at a constant speed unless acted upon by an external force, such as friction. By applying this concept, Galileo demonstrated that the lack of a perceived sensation of movement does not disprove Earth's rotation, as our bodies and the planet move as a single system.1