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Wednesday, September 23, 2009

1999 - Mars Climate Observer satellite destroyed.

NASA

NASA's Mars Climate Observer satellite was destroyed when it entered Mars orbit too close to Martian atmosphere. The investigation into the cause discovered a software error in the orbital routine where the programmer used imperial units instead of metric units. This caused the orbiter to underestimate the thrust of the engines and cuased the orbiter to enter a lower orbit than planned.

1929 - Richard Adolf Zsigmondy died.

Nobel Prize Foundation

Zsigmondy was a Austrian-German chemist who was awarded the 1925 Nobel Prize in Chemistry for his research into colloids. The invented the slit ultramicroscope to aid in his work. The ultramicroscope uses a high contrast background and very thin beam of light to illuminate colloid particles.

1915 - John C. Sheehan was born.

Sheehan wasa n American organic chemist who was the first to synthesize penicillin. He also discovered an compound called 6-aminopenicillanic acid (6-APA) that forms the basic foundation for synthetic penicillins. Sheehan used this to develop ampicillin, a synthetic penicillin taken orally instead of by injection. His inventions allowed for the mass production of these useful antibiotics.

1915 - Clifford G. Shull was born.

Oak Ridge National Laboratory

Shull was an American physicist who was awarded half the 1994 Nobel Prize in Physics for his development of neutron diffraction technique. His technique used neutrons produced from nuclear reactors to investigate the structure of atomic nuclei, compounds and the neutron itself. He also was the first to use neutrons to study the magnetic properties of materials at the atomic level.

1846 - Neptune was discovered.

Neptune - Composite Photograph from Voyager 2 Flyby

NASA

The planet Neptune was discovered when Johann Gottfried Galle used Le Verrier's calculations that predicted the existence of a planet that would explain the irregular orbit of Uranus. Galle found the planet withing 1° of the predicted position. Similar calculations were made by British astronomer John Couch Adams, but were largely ignored by the Cambridge Observatory.

1882 - Friedrich Wöhler died.

Wikimedia Commons

Wöhler was a German chemist who first synthesized the organic compound urea from inorganic components. This was one of the first processes that invalidated the popular vitalism theory, in which biochemical reactions need biological catalysts or a 'vital' spark. He also isolated the element aluminumand discovered a method to create acetylene from calcium carbide.