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Today in the world of astrophysics we celebrate the 100th anniversary of an eclipse. But not just any eclipse. This one provided the first observational evidence to the theory we've been using for a century to make sense of the Universe. So, thread #1919Eclipse #onceacosmologist
The theory is Albert Einstein's general relativity, presented in 1915. Why an eclipse, though? Within general relativity, we understand gravity as the way objects that have mass interact with their environment, aka spacetime. Which by the way isn't flat but curved & flexible. Ha!
Massive objects bend spacetime, and with it the paths of everything that moves in it. Including light particles (which by the way have no mass). To test this, you need a massive object in the foreground and sources of light in the background. Like the Sun and the stars, right?
