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The observational differences, particularly the "wandering" of the planets on the celestial sphere, attracted a lot of attention from ancient observers of the sky. The attempt to explain these differences ultimately led to the birth of modern astronomy.


Observational Differences between Planets & Stars 

The planets move relative to stars on celestial sphere The relative positions of the stars are fixed on celestial sphere
The nearer and larger planets appear as disks in telescope The stars appear as "points" of light,
even through the telescope
The brighter planets do not "twinkle" The stars appear to "twinkle" 
The planets are always near the imaginary yearly path of the Sun on the celestial sphere (the ecliptic) Stars can be anywhere on the celestial sphere