At first the Earth was the universe, and the sky was only a part of it, one of its appendages. The idea of us being a small part of a huge universe is a very recent concept, maybe only 200-300 years old.
This model of the universe placed the Earth at the center of the universe
Earth
The Earth was at the centerback then....
He placed the Sun at the center of what is now called the Solar System instead of the Earth.
Ptolemy's view proposed a geocentric model where Earth was at the center of the universe, while Aristarchus suggested a heliocentric model with the Sun at the center and Earth revolving around it. This fundamental difference in perspective laid the groundwork for later advancements in understanding the solar system.
He placed the Sun at the center of what is now called the Solar System instead of the Earth.
If a simple pendulum is placed at the center of the Earth, it will experience zero net gravitational force because it is equidistant from all directions. As a result, the pendulum's motion would be unaffected and it would not swing back and forth due to the absence of a gravitational pull.
The weight of an object will be minimum at high point like mountain. This is because weight depends on acceleration due to gravity and acceleration due to gravity is inversely proportional to the square of distance from center of earth to the object. As high places like mountain is far from earth center, there is minimun weight. But at the center of earth the weight becomes null as gravity pull takes place in all direction from the center.
The philosopher who placed the Earth at the center of the solar system was Claudius Ptolemy. His geocentric model, developed in the 2nd century AD, posited that the Earth was the stationary center of the universe, with the sun, moon, and planets revolving around it. This view dominated astronomical thought for over a millennium until the heliocentric model proposed by Nicolaus Copernicus gained acceptance in the 16th century.
The belief that Earth was the center of the universe was prominent in ancient times, especially during the Ptolemaic system in the 2nd century AD. This geocentric view was modified by Copernicus in the 16th century with his heliocentric model, which placed the Sun at the center of the universe.
Center out i think
He presented the first known model that placed the sun at the center of the known universe with the earth revolving around it. This was in the 3rd century.