The following is a list of historically important scientific experiments and observations demonstrating something of great scientific interest, typically in an elegant or clever manner. Astronomy Galileo Galilei uses a telescope to observe that the moons of Jupiter appear to circle Jupiter. This evidence supports the heliocentric model, and weakens the geocentric model of the cosmos (1609) Ole Rømer makes the first quantitative estimate of the speed of light in 1676 by timing the motions of Jupiter's satellite Io with a telescope Arno Penzias and Robert Wilson detect the cosmic microwave background radiation, giving support to the theory of the Big Bang (1964) Kerim Kerimov launches Kosmos 186 and Kosmos 188 as experiments on automatic docking eventually leading to the development of space stations (1967) The Supernova Cosmology Project and the High-Z Supernova Search Team discover, by observing Type Ia supernovae, that the expansion of the Universe is accelerating (1998) Biology Robert Hooke, using a microscope, observes cells (1665). Anton van Leeuwenhoek discovers microorganisms (1674–1676). James Lind, publishes 'A Treatise of the Scurvy' which describes a controlled ship board experiment using two identical populations but with only one variable, the consumption of citrus fruit (1753). Edward Jenner tests his hypothesis for the protective action of mild cowpox infection for smallpox, the first vaccine (1796). Gregor Mendel's experiments with the garden pea led him to surmise many of the fundamental laws of genetics (dominant vs recessive genes, the 1–2–1 ratio, see Mendelian inheritance) (1856–1863). Charles Darwin demonstrates evolution by natural selection using many examples (1859). Louis Pasteur uses S-shaped flasks to prevent spores from contaminating broth. This disproves the theory of Spontaneous generation (1861) extending the rancid meat experiment of Francesco Redi (1668) to the micro scale. Charles Darwin and his son Francis, using dark-grown oat seedlings, discover the stimulus for phototropism is detected at the tip of the shoot (the coleoptile tip), but the bending takes place in the region below the tip (1880). Emil von Behring and Kitasato Shibasaburō demonstrate passive immunity, protection of animals from infection by injection of immune serum (1890). Thomas Hunt Morgan identifies a sex chromosome linked gene in Drosophila melanogaster (1910) and his student Alfred Sturtevant develops the first genetic map (1913). Alexander Fleming demonstrates that the zone of inhibition around a growth of penicillin mould on a culture dish of bacteria is caused by a diffusible substance secreted by the mould (1928). Frederick