The year 1998 in science and technology involved many events, some of which are included below.
Astronomy and space exploration
January–September – Cosmologists from the Supernova Cosmology Project led by Saul Perlmutter and the High-z Supernova Search Team led by Adam Riess and Brian Schmidt publish evidence that the expansion rate of the universe is increasing. January 6 – The Lunar Prospector spacecraft is launched into orbit around the Moon and later finds evidence for frozen water on the Moon's surface. February 26 – Total solar eclipse March 2 – Data sent from the Galileo space probe indicates that Jupiter's moon Europa has a liquid ocean under a thick crust of ice. March 5 – NASA announces that the Clementine probe orbiting the Moon has found enough water in polar craters to support a human colony and rocket-fuelling station. March 13 – Penumbral lunar eclipse July 5 – Japan launches a probe to Mars, and thus joins the United States and Russia as a space-exploring nation. August 8 – Penumbral lunar eclipse August 22 – Annular solar eclipse September 6 – Penumbral lunar eclipse October 29 – Space Shuttle Discovery blasts-off with 77-year-old John Glenn on board, making him the oldest person to go into space up to that time. He became the first American to orbit Earth on February 20, 1962. November 20 – Zarya, the first module of the International Space Station, is launched. The first of four 8.4 m reflecting telescopes opens in the Very Large Telescope program of the European Southern Observatory at Cerro Paranal in Chile.
Botany
The Angiosperm Phylogeny Group publishes the first version of the APG System of plant classification.
Computer science
February 10 – XML is published as a recommendation of the W3C. June 2 – The CIH virus is discovered in Taiwan. August 15 – Apple releases the iMac. September 4 – Google, Inc. is founded in Menlo Park, California, by Stanford University PhD candidates Larry Page and Sergey Brin to promote their web search engine. November 7 – Sega release the Dreamcast, the first sixth generation home video game console, in Japan. The first working 2-qubit nuclear magnetic resonance computer is demonstrated at the University of California, Berkeley. Tiger Electronics launch the Furby electronic toy, the first domestic robot.
Geology
February 4 – The 5.9 Afghanistan earthquake shakes the Takhar Province with a maximum Mercalli intensity of VII (Very strong). With 2,323 killed, and 818 injured, damage is considered extreme. March 14 – An earthquake measuring 6.9 on the Richter scale hits southeastern Iran. May 30 – A 6.6 magnitude earthquake hits northern Afghanistan killing up to 5,000. July 17 – The 7.0 Papua New Guinea earthquake shakes the region near Aitape with a maximum Mercalli intensity of VIII (Severe). This submarine earthquake triggered a landslide that caused a destructive tsunami, leaving 2,183–2,700 dead and thousands injured.
Mathematics
Luca Cardelli and Andrew D. Gordon develop ambient calculus. Thomas Callister Hales (almost certainly) proves the Kepler conjecture.
Paleontology
September 11 – First portion of upper body (an upper arm bone, followed later by the skull) of "Little Foot" (Stw 573), a nearly complete young female Australopithecus fossil skeleton capable of walking upright is found in the cave system of Sterkfontein, South Africa eventually dated at around 3.67 million years BP.
Physics
January 1 – Argentinian physicist Juan Maldacena publishes a landmark paper initiating the study of AdS/CFT correspondence, which links string theory and quantum gravity. May 11 & 13 – Nuclear testing: The Pokhran-II: India detonates the five nuclear devices in Pokhran Test Range, an Indian Army base. May 28 – Nuclear testing: The Chagai-I: In response to India, Pakistan conducts five underground and simultaneous nuclear weapon-testing experiments in the Chagai Hills, thus becoming the first nuclear weapon state in the Muslim world and the seventh in the world. May 30 – Nuclear testing: The Chagai-II: As part of a tit-for-tat policy, a final plutonium implosion test is carried out in the Kharan Desert. June 5 – Experimental proof is obtained that neutrinos have mass.