July 20: Armstrong and Aldrin walk on the moon; Viking I lands on Mars; Mendel, Marconi, Allbutt

Cosmos Magazine


Cosmos is a quarterly science magazine. We aim to inspire curiosity in ‘The Science of Everything’ and make the world of science accessible to everyone.

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Armstrong and Aldrin walk on the moon

Today in 1969, Apollo 11 astronauts Neil Armstrong and Edwin “Buzz” Aldrin became the first men to walk on the Moon.

Neil armstrong on the surface of the moon
Neil Armstrong on the surface of the moon (Credit: NASA)

“That’s one small step for (a) man, one giant leap for mankind”


Gregor Mendel

Gregor Johann Mendel, born 20 July, 1822 was a biologist, meteorologist, mathematician, Augustinian friar and abbot of St. Thomas’ Abbey in Brünn (Margraviate of Moravia). Although farmers had known for millennia that crossbreeding of animals and plants could favour certain desirable traits, Mendel’s pea plant experiments conducted between 1856 and 1863 established many of the rules of heredity, which are today referred to as the laws of Mendelian inheritance.


Viking 1 lands on Mars

Today in 1976, the NASA Viking 1 Lander, which had been launched on 20 August, 1975, successfully made the first-ever landing on Mars at Chryse Planitia and began transmitting pictures. Later, a robot arm that could scoop up samples of material and deposit it into on-board experiments, investigated for signs of life on Mars.


Guglielmo Marconi

We commemorate the death of Italian electrical engineer and inventor Guglielmo Marconi, who died on 20 July 1937 at the age of 63. In 1909 he shared the Nobel Prize in Physics with German electrical engineer Karl Ferdinand Braun. In 1894, Marconi began experimenting on the “Hertzian Waves”, the radio waves Heinrich Hertz had first produced in his laboratory a few years earlier. Lacking support from the Italian Ministry of Posts and Telegraphs, Marconi turned to the British Post Office. Encouraging demonstrations in London and on Salisbury Plain followed. Marconi obtained the world’s first patent for a system of wireless telegraphy in 1897 and opened the world’s first radio factory at Chelmsford, England in 1898. In 1900 he took out his famous patent No. 7777 for “tuned or syntonic telegraphy”.


Sir Thomas Clifford Allbutt

We remember the 20 July 1836 birth of Sir Thomas Clifford Allbutt, inventor of the short clinical thermometer in 1866.  Sir Thomas invented the pocket-sized, six-inch (15.2cm) clinical thermometer, which could take a temperature in five minutes. Before his improvement, the instruments used were a foot long (30.5cm) and required 20 minutes to measure a patient’s temperature. He also demonstrated that angina was caused by a narrowing of the coronary artery. This understanding was an important contribution to improving procedures to treat arterial diseases.




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