Learn about the history of science by reading about the significant scientific events that took place on this day in history.
2006 - James Alfred Van Allen died.
Library of Congress
Van Allan was an American physicist who discovered the Van Allen radiation belts. The belts are twin banded regions of high energy ions trapped by the Earth's magnetic field. They were detected because Van Allan convinced NASA to include a geiger counter aboard the first American satellite, Explorer 1.
1969 - Cecil Frank Powell died.
Powell was a British physicist who was awarded the 1950 Nobel Prize in Physics for the development of the photographic nuclear emulsion plate technique of studying nuclear processes and the discovery of the pi meson or pion. Pions are a class of mesons that help explain the strong nuclear force in particle physics.1945 - U.S. drops second atomic bomb on Japan.
US Department of Defense
The United States dropped a second atomic weapon. The 'Fat Man' atomic bomb was dropped on the Japanese seaport city of Nagasaki. Nagasaki was a secondary target for the second atomic bomb. The primary target was the city of Kokura, but was covered by clouds that morning. Casualty estimates range from 40,000 to 75,000 immediate deaths and up to 80,000 by the end of 1945.
1911 - William Alfred Fowler was born.
Fowler was an American astrophysicist who was awarded half the 1983 Nobel Prize in Physics for his studies of nuclear reactions and the formation of elements. He described how elements could be formed and explained their abundance by the process of nucleosynthesis in stars.1899 - Edward Frankland died.
Wikimedia Commons
Frankland was a English chemist who was a pioneer in structural and organometallic chemistry. He proposed the theory of valence to show how individual atoms of elements would combine only with certain limited numbers of atoms of other elements. He was also involved with the discovery of the element helium from the Sun's spectra with Norman Lockyer and Pierre Jules César Janssen.
1819 - Jonathan Homer Lane was born
Lane was an American astrophysicist who was the first to build a mathematical analysis of the Sun as a gaseous body. He demonstrated the thermodynamics of pressure, temperature, and density of the gas within the Sun. His work was the basis of the theory of stellar evolution in use today.1897 - Ralph Walter Graystone Wyckoff was born.
National Institutes of Health
Wyckoff was an American scientist who was a pioneer of x-ray crystallography of bacteria. He also developed a method of three dimensional electron microscopy called metal shadowing. He placed a biological sample in a vacuum next to a gold plated tungsten filament. When the filament was heated, the gold would vaporize and coat one side of the sample. The other side would be shadowed from the gold and would reveal details of structure, size and shape.
1776 - Amedeo Avogadro was born.
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.
