The year 1990 in science and technology involved some significant events.
Astronomy and space exploration
January 24 – Japan launches the Hiten spacecraft, the first lunar probe launched by a country other than the Soviet Union or the United States.
February 14 – The Pale Blue Dot photograph of Earth is sent back from the Voyager 1 probe after completing its primary mission, from around 3.5 billion miles away.
October 13 – Earth-grazing meteoroid of 13 October 1990: A 44 kilogram, 41.5 km/s meteoroid passes above Czechoslovakia and Poland at 97.9 km. It is the first time calculations of the orbit of such a body based on photographic records from two distant places is made.[3]
^Spurný, P.; Ceplecha, Z.; Borovicka, J. (1991). "Earth-grazing fireball: Czechoslovakia, Poland, October 13, 1990, 03h27m16sUT". WGN. 19 (1): 13. Bibcode:1991JIMO...19...13S. Aphelion of its orbit changed from 2.80 AU to 1.80 AU.
^Foote, Jennifer (1990-02-05). "Trying to Take Back the Planet". Newsweek.
^Gelfand, A. E.; Smith, A. F. M. (1990). "Sampling-Based Approaches to Calculating Marginal Densities". Journal of the American Statistical Association. 85 (410): 398–409. doi:10.2307/2289776. JSTOR2289776.
^Colman, Andrew M. (2009). A Dictionary of Psychology (3 ed.). Oxford University Press. ISBN9780191726828. The illusion was first presented by the US psychologist Roger N(ewland) Shepard (born 1929) in his book Mind Sights: Original Visual Illusions, Ambiguities, and Other Anomalies (1990, p. 48), Shepard commented that 'any knowledge or understanding of the illusion we may gain at the intellectual level remains virtually powerless to diminish the magnitude of the illusion' (p. 128).
