Albert Einstein’s General Theory of Relativity has to be one of the most magnificent scientific theories ever developed. In short, the theory explains how gravity is an infinite curvature of space-time. It is important to note that I am no expert on this topic, although I have studied it independently on a few occasions. However, I will do my best to show you what I do know, as only a minimal understanding of the theory and how it was proven is necessary to appreciate how incredible it is.
In the early 1900s, it was generally accepted that all space around us was filled with ether, and that this ether helped suspend stars and planets all over the universe in place. This idea implied that if you were traveling in the same direction as light, the light would appear to move slower, and that when you turned around and went back the other way, the light would appear to move faster. However, the first accurate experiments conducted on the speed of light proved that light traveled at the same speed, no matter how fast the observer was moving. By 1915, Einstein had drawn up an equation for this idea, which you have probably heard of; E=MC^2. All of the math proved to be correct, so the only thing that Einstein needed to confirm his theory was observational proof of the phenomena he aimed to describe. Specifically, Einstein needed evidence that light would be physically affected by the gravity of any object with mass, and as a result would not necessarily travel in a straight line. The only problem lied in the fact that it was particularly difficult to capture a picture in which the path of light had been noticeably altered. On May 29, 1919, he finally found the proof he was looking for, through Arthur Eddington.
Eddington, a famous British astrophysicist, was leading an expedition to West Africa to observe a solar eclipse. If Einstein’s theory was correct, an eclipse seemed to provide the only scenario in which this morphing of light could be observed, as light would be bent greatly around an object as massive as the sun. However, the sun had to be pictured during an eclipse, and not just at any time, because photographing the sun when it was out during the day would just cause the pictures to be blurry and inaccurate. Something as simple as a cloudy night would have completely ruined Eddington’s plans of photographing the sun, but luckily, the skies were clear that Thursday night. As expected, when the eclipse was at its peak, light from stars that lie great distances behind the sun seemed to be curving as it passed the sun (picture below). Just as Einstein had predicted, the light was physically shifted as it passed by our enormous star, which showed that light could be affected by gravity just as any other matter would be. For most of the leading scientists at the time, this was enough evidence to confirm Einstein’s brilliant General Theory of Relativity, and earn him the 1922 Nobel Prize in Physics.
Arthur Eddington’s famous picture of the sun, which went on to prove Einstein’s General Theory of Relativity
The most amazing part of this story is probably Einstein’s burning desire to achieve his goal. He found out that he would have to somehow photograph the morphing of light around the sun, so what did he do? He realized that the only time where this would be even remotely possible would be during a solar eclipse, so he responded accordingly and eventually had pictures to prove his theory. The results of his hard work are incredible – A Nobel Prize in Physics and the complete reworking of what we now consider to be a primitive, pre-Einstein understanding of gravity.
The following article by Steven Hawking was used for reference in this blogpost:
http://www.cnn.com/ALLPOLITICS/time/1999/12/27/relativity.html
