Galileo Galilei played another major role and vastly improved the telescope, allowing future astronomers to make much more accurate calculations because of improved observations. Through his updated telescope, he was able to observe and record the phases of Venus as well as discover several of Jupiter's larger moons. Sir Isaac Newton was another major figure that helped create the ideas of modern astronomy. Through his work in physics, Newton created his theory of the laws of motion and the concept of gravity. The laws of motion and gravity became a way to understand and explain the movements of the planets and other celestial bodies. Without these men's great achievements, modern astronomy would be much different than it is today.

Planets can be either Jovian or terrestrial. There are a number of major differences between these two types of planets. Terrestrial planets are rocky masses that have solid surfaces, often made...
[ View Full Essay]