In the heliocentric system, retrograde motion is not an actual motion of the planet but appears to occur because of the Earth's movement.

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Retrograde motion is an apparent backward motion of a planet in the sky, as observed from Earth. In the heliocentric system, where the Sun is at the center of the solar system, retrograde motion is caused by the Earth passing by and "overtaking" the slower-moving outer planets. It is an optical illusion caused by relative motion, not an actual change in the planet's movement.

In the Heliocentric System, Retrograde Motion Is Not an Actual