Stand still near the equator and Earth's rotation carries you eastward at roughly 1,670 kilometres per hour. That sounds like a journey that should come with wind, dizziness and a very firm seat belt. Instead, your cup stays on the table.
The number is real, but speed alone does not tell us what motion feels like. Our bodies respond much more clearly to changes in motion, while the ground, buildings and most of the atmosphere share the planet's overall rotation.
You are already travelling with the planet
Inside a smoothly moving train, a dropped object does not instantly shoot toward the back of the carriage. Before being dropped, it already shares the train's forward motion. You and the objects around you are travelling together.
Earth provides a similar starting point. Jumping does not leave the planet free to spin away beneath you because you retain your existing eastward motion. The atmosphere also broadly rotates with Earth, though winds move within that rotating system.
The train analogy explains shared motion, but it is not the entire answer. Earth is rotating, not travelling in a perfectly straight line, and circular motion does involve acceleration.
A fast trip around a very large circle
Even at constant speed, changing direction counts as acceleration. Rotation continually changes the direction of your motion. Gravity and the supporting ground together provide the conditions for you to follow Earth's turning surface.
The relevant acceleration is nevertheless small compared with gravity. Earth's huge radius and slow rotation rate—about one turn a day—make the rotational effect only a small fraction of ordinary weight, even at the equator.
We experience that effect as part of the familiar local conditions of weight, not as a dramatic new push. A fairground ride completes turns much more rapidly and can impose conspicuous changes on the body. Its sensation cannot be predicted merely by comparing its speed with Earth's equatorial speed.
The spin leaves measurable clues
Not feeling rotation does not mean it is undetectable. Earth's turning helps shape the paths of large-scale moving air and water through the Coriolis effect. From our rotating viewpoint, their paths are deflected.
The effect contributes to weather patterns and the organization of large storms. It is not a universal explanation for the direction water drains from an ordinary sink, where small local influences usually dominate.
Astronomers and spacecraft navigators also account carefully for Earth's orientation. Measurements can detect tiny changes in the length of a day and shifts in the rotation axis that nobody would notice while walking to work.
Why the view feels still
Most everyday reference points are attached to Earth. A nearby tree is rotating with you, so watching it does not reveal the shared motion. Looking at the sky over time provides a different reference, showing the apparent daily movement of celestial objects.
Our stillness is therefore local and relative. You can be motionless compared with your chair while travelling rapidly around Earth's axis. Physics permits both descriptions—and your senses are especially good at the one that matters for keeping your balance.
Sources and further reading
NASA: Why we do not feel Earth's rotation
NASA Cosmicopia: Physics in everyday activities