Learn about the history of science by reading about the significant scientific events that took place on this day in history.
1972 - Voyager 2 makes closest approach to Jupiter.
NASA
NASA's space probe Voyager 2 passed by the planet Jupiter to within 350,000 miles of the cloud tops. Voyager 2 discovered a new ring system around the planet and the Great Red Spot was a giant storm system. It also discovered active volcanoes on the surface of Jupiter's moon, Io.
1926 - Ben Roy Mottelson was born.
Mottelson is a Danish-American physicist who shares the 1975 Nobel Prize in Physics with Aage Bohr and James Rainwater for their work on the geometry of the atomic nucleus. Bohr and Rainwater developed theories about the structure of asymmetrical nuclei and Bohr and Mottelson compared the models to experimental data to confirm the theory.1911 - John Archibald Wheeler was born.
Wheeler was an American theoretical physicist who made many contributions to nuclear physics and the Unified field theory. He also coined the term "black hole" to describe the effect of gravitational collapse in the theory of general relativity.1894 - Pyotr Leonidovich Kapitsa was born.
Kapitsa was a Soviet physicist who researched strong magnetic fields, low temperatures and cryogenics. He discovered the superfluidity of helium and developed new methods to liquefy gasses. These discoveries would earn him half the 1978 Nobel Prize in Physics.1894 - Percy Lebron Spencer was born.
Spencer was an American engineer who invented the microwave oven. After working on a radar system he discovered a melted chocolate bar in his pocket. He believed the radiation emitted by the magnetron of the radar melted the chocolate when he walked in front of it. He tested his theory by popping popcorn by increasing the power of the beam.1856 - Amedeo Avogadro died.
Avogadro was an Italian chemist who developed an ideal gas law where equal volumes of gases, at the same temperature and pressure, contain the same number of molecules. The number of particles in one mole of a substance is called Avogadro's number and determined experimentally as 6.023x1023 molecules per gram-mole.
1856 - Nikola Tesla was born.
Wikimedia Commons
Tesla was a Serbian-American engineer and inventor who pioneered the use of alternating current electrical systems. He also developed a wireless method to transmit electricity and attempted to construct a global transmission network before his funding ran out. He is largely responsible for the current use of AC power in the electrical industry. The SI unit of magnetic flux density is named in his honor.
