January 20

1920 – Actor DeForest Kelley (Dr. Leonard McCoy) is born.

1930 – Edwin Eugene "Buzz" Aldrin Jr. is born. Best known for being one of the first men to walk on the moon (second after Neil Armstrong).

1969 – Newspaper The New York Times made public the discovery of the first optical pulsar by astronomers at the University of Arizona.

Fun Fact:

Australia is 600 km wider than the moon.