Clear definitions
Astrology vs. Astronomy
Astronomy and astrology share historical vocabulary and observe many of the same objects, but today they are fundamentally different practices. Astronomy is a science; astrology is a symbolic and interpretive tradition.
Side-by-side comparison
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| Astronomy | Astrology | |
|---|---|---|
| Purpose | Study physical celestial objects and processes | Interpret symbolic meaning from celestial positions |
| Method | Observation, measurement, mathematics, testable models | Traditional interpretive systems and chart symbolism |
| Zodiac use | Historical/coordinate context and constellation regions | Twelve-sign interpretive framework |
| Personality claims | Not part of astronomy | Common in astrological interpretation |
Why do they use some of the same words?
The two traditions share a long history of sky observation. Terms such as planets, zodiac, ecliptic, conjunction and retrograde describe real positions or apparent motions, but astrology adds an interpretive layer that astronomy does not.
Zodiac signs are not the same as constellations
In common tropical astrology, signs are twelve equal 30° sectors. Modern astronomical constellations are unequal regions of the sky with internationally defined boundaries. The names overlap because of history, not because the modern systems are identical.
Retrograde motion is a useful example
Astronomy explains apparent retrograde motion geometrically as a change in apparent planetary motion seen from Earth. Astrology may then assign symbolic meaning to a retrograde period. The astronomical explanation does not validate the astrological interpretation.
What about birth charts?
The positions used to construct a chart can be calculated from astronomy and time/location data. The meanings assigned to those positions belong to astrology.
How this site handles the distinction
If a sentence is about physical astronomy, we source it to astronomers. If it's about what a sign or planet means in astrology, we say so, and we don't dress it up as science.
Further reading
See The Ecliptic and the Zodiac, Constellation Boundaries and Why Planets Appear to Move Backward.