1986 in science

Astronomy and space exploration

• January 24 – NASA Voyager 2 space probe makes first encounter with Uranus.
• January 28 – NASA Space Shuttle Challenger explodes on launch, killing all seven astronauts aboard. Their bodies are located by United States Navy divers on March 9.
• February 19 – The Soviet Union launches the Mir space station.
• March 8 – Japanese spacecraft Suisei flies by Halley's Comet, studying its UV hydrogen corona and solar wind.
• October 10 – Aten asteroid 3753 Cruithne, in co-orbital configuration with Earth, is identified by Duncan Waldron.

  Biology

• May – First reported methods for constructing a monoclonal antibody containing parts from mouse and human antibodies, a required first step toward the development of humanized antibodies used later as medical therapeutics.
• English epidemiologist David Barker proposes his fetal origins hypothesis.

  Computer science

• January 16 – The Internet Engineering Task Force, a standards organization that develops and promotes Internet standards, holds its first meeting, consisting of 21 United States government-funded researchers.
• January 19 – The first MS-DOS-based personal computer virus, Brain, starts to spread.
• April 3 – IBM unveils the PC Convertible, the first laptop computer.
• June 23 – Eric Thomas develops LISTSERV, the first email list management software.
• Internet Message Access Protocol is visualized by Mark Crispin.
• 3D printing is developed by Charles Hull.
• Pixar is founded.

  Mathematics

• Summer – Kenneth Alan Ribet demonstrates proof of the ε-conjecture, subsequently known as Ribet's theorem confirming Gerhard Frey's suggestion that the Taniyama–Shimura conjecture implies Fermat's Last Theorem.
• Lawrence Paulson makes the first release of Isabelle.
• Lee Sallows introduces the alphamagic square.

  Technology

• January 11 – The Gateway Bridge is opened in Brisbane, Australia, the world's largest prestressed concrete single box bridge.
• April 26 – Chernobyl disaster: An RBMK at Chernobyl Nuclear Power Plant in the Ukrainian Soviet Socialist Republic reaches prompt criticality.
• December 23 – Rutan Voyager becomes the first aircraft to fly around the world without stopping or refueling, landing at Edwards Air Force Base in California after a nine-day trip piloted by Dick Rutan and Jeana Yeager.

  Awards

• Crafoord Prize in Geosciences: Gerald Wasserburg and Claude Jean Allègre
• Fields Prize in Mathematics: Simon Donaldson, Gerd Faltings and Michael Freedman
• Nobel Prizes
• * Physics – Ernst Ruska, Gerd Binnig, Heinrich Rohrer
• * Chemistry – Dudley R. Herschbach, Yuan T. Lee, John C. Polanyi
• * Medicine – Stanley Cohen, Rita Levi-Montalcini
• Turing Award – John Hopcroft, Robert Tarjan
• Wollaston Medal for Geology – Claude Jean Allègre

  Deaths

• January 7 – Rex Wailes, English engineer and historian of technology.
• January 28
• * Crew of United States Space Shuttle Challenger mission STS-51-L:
• ** Greg Jarvis
• ** Christa McAuliffe
• ** Ronald McNair
• ** Ellison Onizuka
• ** Judith Resnik
• ** Dick Scobee
• ** Michael J. Smith
• * Dorothée Pullinger, French-born British production engineer.
• April 22 – Dame Honor Fell, English biologist.
• July 6 – William Rashkind, American cardiologist.
• July 21 – Zhang Yuzhe, Chinese astronomer.
• October 22 – Albert Szent-Györgyi, Hungarian physiologist, winner of the Nobel Prize in Physiology or Medicine.
• October 31 – Edward Adelbert Doisy, American biochemist, winner of the Nobel Prize in Physiology or Medicine.
• June 7 – Robert S. Mulliken, American physicist, winner of the Nobel Prize in Chemistry.
• November 25 – Sir Ivan Magill, British anesthesiologist.