Answer:
<u>Geocentric Model</u>: - this model is Earth Centered
-Retrograde motion is explained by epicycles
<u>Heliocentric Model</u>: - This model is Sun Centered
-Retrograde motion is explained by the orbital speeds of planets
<u>Both models</u>:- Epicycles and deferents help explain planetary motion
-Planets move in circular orbits and with uniform motion
-The brightness of a planet increases when the planet is closest to Earth
Explanation:
Retrograde motion is an apparent change in the movement of the planet through the sky. Ptolemy's model of the solar systems was geocentric, where the Sun, Moon, planets and start all orbit the Earth in perfectly circular orbits. However this perfectly circular orbits around the Earth did not explain the occasional retrograde motion of the planets. In the Copernicus' heliocentric model, retrograde motion of planets is naturally explained. The explanation for retrograde motion in a heliocentric model is that retrograde occurs roughly when a faster moving planet catches up to and passes a slower moving planet.
The Great Barrier Reef is the world's largest living structure. It is made up of around 2900 individual reefs and 900 islands. ... Climate change is perhaps the biggest threat to the Great Barrier Reef. Warmer ocean temperatures put stress on coral and lead to coral bleaching.
<span>the angular distance of a place north or south of the earth's equator, or of a celestial object north or south of the celestial equator, usually expressed in degrees and minutes.</span>