1990 in science

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.
April 24 – The Space Shuttle Discovery places the Hubble Space Telescope into orbit.
August 16 – Steven Balbus makes his first discovery leading to elucidation of magnetorotational instability.
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.

February – Adobe Photoshop 1.0 graphics software, devised by Thomas Knoll, is released.
May 22 - Windows 3.0 is shipped by Microsoft
November 12 – Tim Berners-Lee publishes a more formal proposal for the World Wide Web.
November 13 – The first known web page is written.
Approx. November 22 – Satoshi Tajiri begins creating the first Pokémon game.

Thomas W. Laqueur publishes Making Sex: Body and Gender From the Greeks to Freud.

Alan E. Gelfand and Adrian Smith publish a paper drawing attention to the significance of the Gibbs sampler technique for Bayesian numerical integration problems.
Victor Kolyvagin introduces Euler systems.
Ruth Lawrence publishes a paper on homological representations of the Hecke algebra, introducing, among other things, certain novel linear representations of the braid group, the Lawrence–Krammer representation.

August 12 – "Sue", the best preserved Tyrannosaurus rex specimen ever found, is discovered in South Dakota by Sue Hendrickson.

June 25 – Cruzan v. Director, Missouri Department of Health decided in the Supreme Court of the United States allowing public officials to intervene in questions of termination of life support in the absence of an advance healthcare directive.
The Human Genome Project is founded.
The first evidence for the existence of the BRCA gene encoding for a DNA repair enzyme involved in breast cancer susceptibility Is provided by Mary-Claire King's laboratory at University of California, Berkeley.
The inherited mutations of the tumor suppressor gene, p53, are identified as the underlying mechanism for Li–Fraumeni syndrome in most affected families.