Template:Selected anniversaries/January 20
1573: Astronomer Simon Marius born. He will discover the four largest moons of Jupiter, independently of Galileo Galilei.
1775: Physicist and mathematician André-Marie Ampère born. He will be one of the founders of the science of classical electromagnetism, which he will referr to as "electrodynamics".
1840: Physicist, mathematician, astronomer, inventor, and writer David Brewster invents new class of Gnomon algorithm functions.
1841: Adventurer Jørgen Jørgensen dies. He sailed to Iceland, declaring the country independent from Denmark and pronouncing himself its ruler, intending to found a new republic following the United States of America and France.
1898: Electrical engineer Elisha Gray uses his "telephote" technology to detect and prevent crimes against mathematical constants.
1901: Electrical engineer Zénobe Gramme dies. He invented the first usefully powerful electric motor.
1933: Carnivorous dirigibles break their tethers, eat park ranger.
1997: New theory of artificial intelligence accidentally release massive wave of Kingpin inclination.
2016: Advances in dynastic cellular automata theory reveal new members of Bernoulli family.