Another contemporary of Kepler's who also bought into the notion of a heliocentric solar system and was the Italian scientist Galileo Galilei.
But unlike Kepler, Galileo didn't believe that planets moved in an elliptical orbit and stuck with the perspective that planetary motions were circular in some way. Still, Galileo's work produced evidence that helped bolster the Copernican view and in the process further undermine the church's position.
In 1610, using a telescope he built himself, Galileo began fixing its lens on the planets and made a series of important discoveries. He found that the moon was not flat and smooth, but had mountains, craters and valleys. He spotted spots on the sun and saw that Jupiter had moons that orbited it, rather than the Earth. Tracking Venus, he found that it had phases like the Moon, which proved that the planet rotated around the sun.
Much of his observations contradicted the established Ptolemic notion that all planetary bodies revolved around the Earth and instead supported the heliocentric model. He published some of these earlier observations in the same year under the title Sidereus Nuncius (Starry Messenger). The book, along with subsequent findings led many astronomers to convert to Copernicus' school of thought and put Galileo in very hot water with the church.
Yet despite this, in the years that followed, Galileo continued his "heretical" ways, which would further deepen his conflict with both the Catholic and Lutheran church. In 1612, he refuted the Aristotelian explanation of why objects floated on water by explaining that it was due to the object's weight relative to the water and not because an object's flat shape.
In 1624, Galileo got permission to write and publish a description of both the Ptolemic and Copernican systems under the condition that he does not do so in a manner that favors the heliocentric model. The resulting book, "Dialogue Concerning the Two Chief World Systems" was published in 1632 and was interpreted to have violated the agreement.
The church quickly launched the inquisition and put Galileo on trial for heresy. Though he was spared harsh punishment after admitting to have supported Copernican theory, he was put under house arrest for the remainder of his life. Still, Galileo never stopped his research, publishing several theories until his death in 1642.
While both Kepler and Galileo's work helped to make a case for the Copernican heliocentric system, there was still a hole in the theory. Neither can adequately explain what force kept the planets in motion around the sun and why they moved this particular way. It wasn't until several decades later that the heliocentric model was proven by the English mathematician Isaac Newton.
Isaac Newton, whose discoveries in many ways marked the end of the Scientific Revolution, can very well be considered among one of the most important figures of that era. What he achieved during his time has since become the foundation for modern physics and many of his theories detailed in Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural Philosophy) has been called the most influential work on physics.
In Principa, published in 1687, Newton described three laws of motion that can be used to help explain the mechanics behind elliptical planetary orbits. The first law postulates that an object that is stationary will remain so unless an external force is applied to it. The second law states that force is equal to mass times acceleration and a change in motion is proportional to the force applied. The third law simply stipulates that for every action there is an equal and opposite reaction.
Although it was Newton's three laws of motion, along with law of universal gravitation, that ultimately made him a star among the scientific community, he also made several other important contributions to the field of optics, such as building he first practical reflecting telescope and developing a theory of color.Tuan Nguyen is a researcher. The article appeared in www.thoughtco.com
Tuan Nguyen is a researcher.
The article appeared in www.thoughtco.com
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