As I've gone deeper into understanding more about gravitational waves the history of Einstein's initial postulation has fascinated me. It's pretty wild to think that back in 1916 Einstein came up with an idea for one of the most powerful concepts in physics, using only math.
I'm still brushing up on my Calculus so haven't done a deep dive into the equations that led to the discovery of gravitational waves, but I have gone down the rabbit hole of the world in 1916 - a world not very open to wild and crazy theories based on nothing but numbers.
And this is where Eddington comes in. While we can't go back in time and see how events would have unfolded if one thing changed, I do think that without Eddington there's a chance that Einstein would never have become as famous as he did. What's been the most shocking for me lately is that Arthur Eddington is mostly unknown, but that might be what also makes him so fascinating.
If you don't know who Eddington is - here's a very brief overview. In the early 1900's Arthur Eddington was known as the best person at measuring things in the world. At the time Eddington was in England and in many ways was put in his position to help maintain faith and proof that Newtonian Mechanics was correct.
But Eddington became fascinated by Einstein even though it was both relatively difficult to get access to his published papers and incredibly uncool to like them, and almost sacrilegious to think they could be true.
Still, as a true scientist, Eddington was intrigued by Einstein's theory of gravitation waves and while Einstein tried everything he could to prove his theory correct - Eddington was the one to actually do it. How he did it is almost as incredible as doing it because of how complex and exotic the method ended up being.
Essentially Eddington realized he had a once in a lifetime opportunity during a solar eclipse, flew to Africa, setup a telescope and took photographs during the day, when it was dark and you could see stars. He then overlayed these photographs on top of those taken at night and saw that the stars were not in exactly the same place and boom - proved that gravitation waves must exist.
Okay maybe this is a little too brief so for anyone that wants a deeper dive, here's a paragraph that goes into the genius behind Eddington's experiment.
During this eclipse, the Sun would sit in front of the Hyades, a cluster of bright stars in the constellation of Taurus. Thus, at totality, many stars would be visible near the eclipsed disk. (This was key because the light-bending effect predicted by Einstein is greatest for stars observed close to the Sun.) The stars’ positions relative to the Sun could be recorded and measured on photographic plates, and then compared with reference plates showing the stars when the Sun was nowhere near the field of view. Any apparent shifts, caused by the Sun’s gravitational field, could then be calculated. The more stars measured, the better the chance the observers would have of correcting for systematic errors and reducing random ones. (Source - Nature)
What makes Eddington so fascinating to me is that he put his entire career and reputation on the line, at a time in history when everything really was against him. While you might think that Einstein and Eddington were great friends and that's what motivated Eddington, that wasn't the case - they didn't really know each other and only met years later after World War one ended.
So as I find myself fascinated by gravitational waves and getting my Calculus chops back in action so I can dive into the math myself, I also have found a wonderful diversion that is Sir Arthur Eddington, and everything I read continues to make him even more fascinating to me.
It just goes to show what a different one person can make, and somewhat shockingly, when it comes to gravitational waves, what Einstein is probably the most famous for - that one person was Eddington...