1830: Death of Joseph Fourier (born 1768), French mathematician and physicist. Author of the famous Analytic Theory of Heat, he invented Fourier series, a revolutionary mathematical tool allowing any complex signal to be decomposed into simple waves. He is also credited with the first theoretical description of the greenhouse effect, a concept that has become central to the study of contemporary climate.

1969: The Soviet probe Venera 5 enters the atmosphere of Venus. After a 53-minute parachute descent, it transmitted precious data on the chemical composition of the atmosphere (composed of 97% CO2) and the planet's crushing pressure. Although it was crushed by the pressure before reaching the ground, it provided the most accurate measurements of the time regarding our "sister planet".

Image credits : René Houdry