Definition of a geostationary satellite A geostationary (geosynchronous equatorial) satellite appears fixed over one point on Earth. It orbits with the same angular velocity as which celestial body?

Introduction / Context:
Communication and weather satellites are often placed in geostationary orbit so they appear fixed above a point on the equator. This condition is achieved only if the satellite’s orbital period matches Earth’s rotation and the orbit is equatorial and circular.

Given Data / Assumptions:

• Satellite is over the equator (zero inclination).
• Orbit is circular and prograde.
• Neglect perturbations (idealized definition).

Concept / Approach:

A geostationary satellite must have the same angular velocity as Earth’s spin so that its orbital period equals 1 sidereal day. When this happens, the satellite’s subpoint on Earth does not move in longitude, and it appears stationary to ground observers.

Step-by-Step Solution:

Verification / Alternative check:

If the satellite had the Moon’s angular velocity or any other, it would drift in longitude. Only matching Earth’s rotational angular speed keeps it fixed in the sky.

Why Other Options Are Wrong:

Moon and Sun have very different angular velocities; a “pole” does not define a rotational rate; therefore only Earth’s own rotation is relevant.

Common Pitfalls:

Confusing “geosynchronous” with “geostationary”; the former only matches period, while the latter also requires zero inclination and zero eccentricity to remain fixed over one point.

Final Answer:

The Earth (about its own axis)