Aheliocentric model of the solar system has earth at the center.

Wrong. A heliocentric model of the solar system has the Sun at the center.

Explanation:

Despite the difficulty of understanding and explaining the observed movement of planets from the geocentric point of view (Earth at the center of the Universe), geocentrism was a dominant idea in Astronomy throughout Antiquity and the Middle Ages. The geocentric system is also known as the Ptolemaic system, because it was Claudius Ptolemy (Figure 01.05.02), the last of the great Greek astronomers (150 AD), who built the most complete and efficient geocentric model. The idea that the Earth orbits the Sun had already been suggested, but without acceptance, by the Greek astronomer Aristarchus in 260 BC. 18 centuries later, the heliocentric hypothesis was revived and developed by the Polish astronomer and mathematician Nicolaus Copernicus (1473-1543). At that time, the tables of planetary movements based on the Ptolemaic model were already highly outdated, which led Copernicus to provide a system that explains these movements in a simpler way. Copernicus's heliocentric theory was described in his book De Revolutionibus, published in 1543, the same year he died.

the mongolian invasion of china and central asia resulted in a disruption of the silk road as the chinese garrisons lost support from the chinese kingdoms which fell under the mongols. however, as the mongols established a formal dynasty in china, the successors of genghis khan restored the garrisons along the silk road allowing the safe travel caravans again.