September: 30 years ago; 70 years ago; 100 years ago; 240 years ago

30 years ago 

The Viking 2 lander made it to Mars. Viking 1 had landed in July of the same year. The Viking orbiters took the first pictures of the surface of Mars. They also collected and analysed surface samples. Viking 2 ended communications in 1980, and Viking 1 in 1982. 

70 years ago 

Ferid Murad was born in Albania. He won the 1998 Nobel prize in physiology or medicine for his role in the discovery that nitric oxide is a signalling molecule in the cardiovascular system. The work uncovered an entirely new mechanism for how blood vessels in the body relax and widen.

100 years ago 

Luis Federico Leloir was born in Paris, France but moved to Buenos Aires, Argentina, at the age of two. He won the 1970 Nobel prize in chemistry for his discovery of sugar nucleotides and their role in the biosynthesis of carbohydrates.  

130 years ago

Fritz Henke and two partners founded Henkel & Cie in Aachen, Germany, and marketed its first product, ’Universalwaschmittel’, a universal detergent based on silicate.  

240 years ago 

John Dalton was born in the UK. He is best known for his universal atomic theory. An unofficial unit of mass has been named after him - the Dalton (Da), equal to the unified atomic mass unit.