In her journal, Miss Leonard describes in somewhat unconventional terms a cosmological theory explaining the origin of the universe.

Click on the small dot to simulate the Big Bang.

The Big Bang theory, built upon Albert Einstein’s theory of relativity, was developed in the 1920s by Belgian physicist Georges Lemaitre, who reasoned that if the distance between galaxy clusters is increasing today, then everything must have been closer together in the past, perhaps a densely packed singularity that exploded outward, its substance still expanding through space-time.

Astronomer Edwin Hubble, who verified and popularized the theory of an expanding universe in a 1929 publication, based his calculations on observations done earlier in the 20th century at Lowell Observatory by astronomer Vesto M. Slipher.

It is certainly possible that Miss Leonard was familiar with Slipher’s findings, and entirely plausible that her journal contains the first written description of the Big Bang and the subsequent expanding universe.