Simplify the following text for a Grade 13 native English-speaking person.
Original: Although the Greek philosopher Aristarchus of Samos had speculated on a heliocentric reordering of the cosmos , Nicolaus Copernicus was the first to develop a mathematically predictive heliocentric system .
Simplified: Although the Greek philosopher Aristarchus of Samos suggested that there was a special order in the sky , Nicolaus Copernicus was the first to develop a mathematical system .