Carlos J. A. P. Martins
IA

Abstract
Does gravity affect light? The question was first discussed by Newton, and its the first experimental test is known as the Eddington Experiment, executed at the 29 May 1919 total solar eclipse. The Eddington experiment is one of the canonical tests of General Relativity, and one of the most important experiments in the history of science. It proved decisively that gravity affects light, but it also provided supporting evidence for a General Relativity prediction, falsifying the analogous Newtonian one.
More stringent tests of General Relativity now exist, but the historical importance of the Eddington experiment motivates modern replications, which improve its precision and accuracy. Just as the 1919 total solar eclipse was the best possible one, in the XX century, for this purpose, in the XXI century the best eclipse for the Eddington experiment is the one of 2 August 2027. This is closely preceded by another total solar eclipse on 12 August 2026, and both paths of totality go through the Iberian Peninsula. This is a once-in-a-lifetime opportunity for which several international teams are actively preparing.
In this talk I will summarize the specific historical context of the Eddington experiment and the broader scientific relevance of previous central solar eclipses observed in the Iberian Peninsula. I will then present our team's ongoing preparations for the two eclipses, including our own re-analysis of the 21 August 2017 total solar eclipse data, which provides the most stringent constraints so far obtained by this method. Finally, I will discuss some of the training, education and outreach opportunities enabled, both in the short and long term, by this project.

2025 September 26, 13:30

IA/U.Porto
Centro de Astrofísica da Universidade do Porto (Classroom)
Rua das Estrelas, 4150-762 Porto