Sir Isaac Newton may be the most influential physicist who ever lived, although historians are always going to disagree about that. However, the most fundamental theories of mechanics and gravity can generally be traced to him. He also devised the mathematical system through which physicists can properly understand and interpret physics today, which would be calculus.
People’s ability to properly do physics and understand physics is going to be severely limited if they don’t have the advanced mathematics to properly model the situations. There’s a reason that there were very few influential physicists before Sir Isaac Newton, but there were quite a few influential physicists born afterward. Many people in the field know full well that they are following in his footsteps. As for basic physics, Lord Kelvin was also a tremendously influential figure, given his contributions to the fields of thermodynamics.
While few people fully understand quantum theory, including the people who study it for a living, Max Planck is the scientist who more or less founded the entire field. Before the work of Max Planck, humanity’s understanding of time and space was limited. Quantum mechanics, in some ways, is an emerging science compared to many of the other sub-fields within physics. However, before the work of Max Planck, the relevant holes in humanity’s knowledge were even more substantial.
Albert Einstein is perhaps the most famous of all modern physicists. He is a person who has actually become synonymous with the concept of genius, making him a figure that has transcended physics in the minds of many people. However, people tend to think symbolically when it comes to Einstein. People have heard of him and they have heard of his symbols, but far too many people are not truly familiar with his work.
Einstein’s theory of relativity helped completely change physicists’ view of how space and time even worked, so it’s important not to underestimate its contribution to the field. Many people misunderstand the theory of relativity today, which does not mean the same thing as ‘everything is relative’ in the more everyday sense of the word. However, at least this widespread misconception gets people talking and thinking about Einstein and his theories just a little bit more. Einstein’s life is quickly fading out of living memory, but he still seems to have plenty of actual fans today, which is more than can be said for a large portion of other physicists. It is possible that the myth figure elements of Einstein have had their own influence.
Some of the most important physicists of all time are still alive today. Stephen Hawking managed to improve upon the work of both Max Planck and Albert Einstein, given his contributions to the fields of quantum mechanics and the General Theory of Relativity. The famous physicists that are alive in one’s lifetime tend to automatically seem less exotic, but that doesn’t make their work any less important or influential.