Starts With A Bang

How the last great American eclipse almost shocked Einstein (Synopsis)

Images credit: New York Times, 10 November 1919 (L); Illustrated London News, 22 November 1919 (R). If the cloud situation had played out differently, the United States might have confirmed this a year prior.

“Astronomers are greatly disappointed when, having traveled halfway around the world to see an eclipse, clouds prevent a sight of it; and yet a sense of relief accompanies the disappointment.” –Simon Newcomb

Next year, on August 21st, 2017, millions of Americans will delight in the first total solar eclipse to go from coast-to-coast in 99 years. The path of totality will range from Oregon to South Carolina, giving more than two minutes of the Sun being blocked by the Moon’s shadow to all along its central path.

Image credit: Mir / RSA, 1999, of the Moon’s shadow falling on Earth, during a total solar eclipse as seen from space.

During this time, not only the Sun’s corona but also the background stars, never visible otherwise during the day, will be revealed. This isn’t merely a spectacular sight, but provides an opportunity to test Einstein’s general relativity directly: by measuring the deflection of starlight caused by the gravitational presence of the Sun! Although this was famously (and successfully) undertaken in 1919, the United States had a chance to beat the rest of the world in 1918, and almost succeeded!

Image credit: NASA / Cosmic Times / Goddard Space Flight Center, Jim Lochner and Barbara Mattson, via

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