On this night in science
Measuring the size of a star
December 13, 1920
On this night in 1920, the astronomers Albert Michelson and Francis Pease used a special instrument on a giant telescope in California to measure how wide a star called Betelgeuse is. It was the first time anyone had measured the size of any star besides our sun.
Why it mattered
Betelgeuse turned out to be enormous, so big that if it sat where our sun is, it would stretch out past the Earth. Stars that look like tiny dots can be giants.
Wonder together
How do you think you could measure something so far away that it looks like a tiny dot?