This summer, many people have organized their holidays around the eclipse that will be seen in Spain on August 12. Without a doubt, many see it as a spectacle that perhaps they can only see once. or very few times in life. However, we must not forget that it is still a phenomenon with very interesting scientific implications. For example, something very curious is that in 1919 It was used to prove Einstein right.
Einstein vs Newton. In 1915, Einstein enunciated his Theory of General Relativity. In it, broadly speaking, he pointed out that the attraction of gravity is due to a space-time curvature caused by the effect of objects with mass and energy. Before him, the most accepted theory about gravity was the one launched by Newton. In it, it was pointed out that the gravitational attraction was due only to the mass of the objects. Energy had nothing to do with it, and of course I had no idea that time and space could be intertwined.
Einstein’s hypothesis was received as interesting, but many physicists of the time were not willing to abandon Newton’s theory. If Einstein wanted to be believed, he would have to prove that he was right. An eclipse ultimately turned out to be the ideal experiment for his demonstration, although it was carried out not by him, but by a British astronomer named Arthur Eddington.
Light issue. Newton considered that light was composed of corpuscles with mass. Therefore, these could also be attracted to massive objects. If the Sun drew light from the stars around it, for example, it would do so with an arc of 0.84 seconds. Einstein, on the other hand, made different calculations.
For him, light is not attracted like a magnet attracts metal or anything like that. What happens, according to his theory, is that massive objects curve space-time, like a ball falling on top of an elastic fabric. The light, to pass through there, must take the easiest path, which is passing through the edges of that groove that the massive object has generated in space-time. In short, it also deviates, but much more so. According to Einstein’s calculations, we would be looking at an arc of 1.74 seconds.
Massive objects warp spacetime
The trick. To know who was right, it would be enough to observe the effects of the Sun on a nearby star cluster. But of course, during the day those stars are not seen. Therefore, the ideal would be to take advantage of an eclipse that blocks the light of the Sun and allows you to see the stars when they are very close to it.
A very useful excursion. To try to prove Einstein right, Arthur Eddington traveled to Africa in May 1919. On the 29th of that month a very interesting eclipse would occur, since at that time the Sun would be very close to the Hyades, a large star cluster. He went to Príncipe Island and made the calculations of the position in which the stars should be when they appeared when the Sun set.
I only had 7 minutes to try to take photographs and the weather did not make it easy for him, but he managed to take advantage of a cloudless moment and take the snapshots that would prove the German physicist right. As he already sensed, the stars in the cluster were deviated from where they should be if the Sun did not exert any gravity on them. Specifically, with an arc of 1.7 seconds.
Nowadays. Eclipses have not been used for a long time to confirm theories that the scientific scene takes with suspicion, but they are still very useful for science. They expose the solar corona, that superficial layer of the sun in which solar storms brew that can affect terrestrial communications so much. Nowadays there are coronagraphs that create a kind of false eclipse so that the corona can be studied. However, eclipses offer a very interesting natural opportunity to see it in all its splendor. That’s also very exciting.
Image | Wikimedia Commons/Luc Viatour |ESA
GIPHY App Key not set. Please check settings