4 October
1957: On 4 October 1957, the Soviet Union launched Sputnik 1, the world's first artificial satellite, about the size of a football and taking about 98 minutes to orbit Earth ...
27 FEB. 2004
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1923: On 5 October 1923, the US astronomer Edwin Hubble identified the first Cepheid variable star in the Andromeda galaxy. This proved that the galaxy was not part of the Milky Way.
A Cepheid variable star one of a class of variable stars whose periods (i.e., the time for one cycle) of variation are proportional to their luminosity. Because of this correlation (discovered by Henrietta Swan Leavitt in 1912), Cepheid variables can be used as a standard to determine the distance to their host globular clusters or galaxies. Since the period-luminosity relation can be calibrated with great precision using the nearest Cepheid stars, the distances found with this method are among the most accurate available.
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3 October
1932: On 3 October 1932, Maximilian (Max) Wolf died.Wolf was a German astronomer who founded and directed the Königstuhl Observatory. He used wide-field photography to study the Milky Way and ...
2 October
1920: On 2 October 1920, Giuseppe (Bepi) Colombo was born.He was an Italian mathematician and engineer whose bald head and grey moustache were familiar in the corridors of both ESA ...
1 October
1958: On 1 October 1990, Jean-Marie Luton became Director General of ESA.He was the fourth Director General of ESA, succeeding Prof. Dr Reimar Lüst, and serving until 1997. Prior to ...
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