As proposed by the Heliocentric Theory, the Sun is the center of the Solar System.
Galileo's most important invention was the telescope, which he used to make groundbreaking astronomical observations that supported the heliocentric model of the solar system. His discoveries revolutionized our understanding of the universe and sparked the scientific revolution.
The first person to examine space through a telescope was Galileo Galilei in the early 17th century. He made significant astronomical discoveries, such as the moons of Jupiter and the phases of Venus, which supported the heliocentric model of the solar system.
Galileo disproved the notion that the Earth was the center of the universe by observing the phases of Venus through a telescope, which supported the heliocentric model proposed by Copernicus. This provided evidence that Earth and other planets revolve around the sun, not Earth being the center of the universe.
The idea that the Sun is at the centre of the planetary system is called the heliocentric concept. Nicholas Copernicus came up with a complete heliocentric theory of circles and epicycles published in 1543 that modelled the positions of the known planets quite accurately and at least as accurately as the previous geocentric model of Ptolemy. Later, measurements made by Tycho Brahe with unprecedented accuracy showed up some discrepancies in the previous models. Kepler used the results to form the modern model of the planetary orbits. It used the heliocentric idea, but the rest of Copernicus's theory was abandoned as Kepler introduced the new idea of elliptical orbits, with each orbit lying in its own plane, slightly inclined to the ecliptic by a different amount for each planet. So, the idea that the Earth revolves round the Sun is called the heliocentric theory but it is hardly a theory at all, it is better described as an idea or a concept. The next stage, carried out by Newton and others, described how the force of gravity held the planets in their orbits and it was able to determine the mass of each planet and the Sun.
The astronomical telescope.
Galileo
200 billion years ago
Galileo Galilei . He only helped support the theory through his observations , he didn't invent the model, Copernicus did.
It was Galileo.
Galileo
Data gathered using Galileo's early telescope, such as observations of the phases of Venus and the moons of Jupiter, provided evidence supporting the heliocentric model. These observations showed that not all celestial bodies orbit the Earth, as previously believed, but instead supported the idea that they orbited the Sun. This challenged the geocentric view and provided observational proof for the heliocentric model proposed by Copernicus.
Although Galileo's telescope was the first to be used for astronomical purposes, he didn't invent the telescope. A man named Hans Lipperhey invented the telescope. Many people claimed to have invented the telescope however Hans Lipperhey was the only one to apply for a patent.
Galileo did not prove that Earth was not flat (It had already been agreed that it was round). Galileo invented the telescope and used it to prove that there were objects which did not orbit the Earth, supporting Copernicus' Heliocentric model for the universe. The Earth was known to be round by the ancient Greeks, but I do not who it found out initially (sorry).
He didn't know it, he just brought out a new theory that showed that with the Sun at the centre the planets' paths could be explained more simply. That was in 1543 and Kepler produced another heliocentric theory in 1609 which had the planets moving in elliptical orbits round the Sun. The only thing in favour of Kepler's theory at the time was that it explained the planets' positions more accurately than previous theories. But 80-90 years later Newton's discoveries in gravity and the laws of motion were used to prove by theory that the planets must move in elliptical orbits.
Kepler used Tycho Brahe's data to establish the heliocentric theory of the solar system.
Yes, Galileo used a telescope to observe the phases of Jupiter in 1610. He discovered that the planet showed different phases similar to the Moon, which supported the heliocentric model of the solar system.