[ 137 ] Earth and Space Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • Geocentric model Heliocentric model Earth Moon Mercury Venus Sun Mars Saturn Geocentric model proposed by Ptolemy (top) and heliocentric model proposed by Copernicus (bottom) One of these images is a heliocentric model of the solar system and the other is a geocentric model of the solar system. What does a geocentric model mean in the context of these images?