If you point a telescope at the sun,

you'll go blind. If you point it just

next to the sun, you'll just get washed

out by the corona of the sun and you

won't see anything. Except, there's one

time when you won't get washed out, and

that's during [music] a total solar

eclipse. So, during the 1910s, there was

a whole bunch of expeditions sent

[music] to measure the deflection of

light. They'd go, park out in the path

of totality, and [music] look uh through

telescopes at the stars right next to

the sun, and see if they moved in the

sky.

>> [music]

>> And if they moved, how much they moved.

There was a German expedition sponsored

by the arms manufacturer Krupp, who

[music] went to the Crimea, and and just

before the solar eclipse happens, uh

World War I breaks out, and now Germany

and and Russia are at war, and they're

all like arrested and interned for the

rest of the war, and so that that also

fails. And it actually turns [music] out

to be a good thing for Einstein that

they all failed, cuz it turned out that

before he had full general relativity,

his original equivalence principle

argument was wrong,

>> [music]

>> and led him to predict that the bending

of light in general relativity would be

the same as it was in Newtonian physics.

And so, during the war, while everything

shut down, and no one is thinking about

[music] eclipse expeditions, he corrects

his mistake, and comes up with a new

prediction that actually will be double

the Newtonian [music] prediction. And

then in 1919, Sir Arthur Eddington

launches a British expedition [music] to

go and observe the eclipses, and

successfully comes back and declares

that indeed it was the Einstein

prediction. [music] And that's really

what launches Einstein as a global

celebrity.