The year 2005 in science and technology involved some significant events.
Astronomy
January 5 – Eris, the most massive known dwarf planet in the Solar System, is identified by a team the Palomar Observatory in California from images taken on October 21, 2003 (discovery announced July 29, 2005).
February 23 – Astronomers announce the discovery of a galaxy, VIRGOHI21, that consists almost entirely of dark matter.
October 5 – The Spanish flu virus is reconstructed and shown to be closely related to the Avian influenza virus.
November 27 – French oral and maxillofacial surgeon Dr. Bernard Devauchelle and colleagues perform the world's first partial face transplant on a living human, replacing Isabelle Dinoire's face, which had been mutilated by her dog.
The Stitchbird is reintroduced to mainland New Zealand.
January 27 – Scientists behind the climateprediction.net project, a distributed computing project run from Oxford University, announce that first results indicate a long term surface temperature increase due to global warming of between 2 and 11 degrees Celsius as a consequence of doubling carbon dioxide levels, with most of the simulations predicting a temperature rise of around 3.4°C.
January 13 – Chinese paleontologists announce the discovery of fossils of Repenomamus robustus and Repenomamus giganticus, mammals that lived 130 million years ago. The fossil discoveries indicate that these mammals preyed on small dinosaurs.
February 17 – Two Ethiopian fossil skulls originally found in 1967 by Richard Leakey, Omo I and Omo II, are re-dated at 195,000 years old, making them the oldest Homo sapiens remains known.
December 15 – European and Canadian researchers announce the dating of flint artefacts from Pakefield, Suffolk, UK to around 700,000 years ago, representing the earliest unequivocal evidence for human presence north of the Alps.
January 14 – The Huygens probe is successfully sent into the atmosphere of Titan and returns science data to Earth via the Cassini orbiter. It survives the landing on the surface of Titan and sends pictures and other data for more than an hour afterwards.
January 26 – ESA's SMART-1 begins sending back close range pictures of the lunar surface
February 7 – NASA announce budget plans – in the announcement, they state that a mission to service the Hubble Space Telescope will not take place, and that a robotic mission to deorbit the telescope with a safe descent into an ocean will take place. The Jupiter Icy Moons Orbiter (Jimo) mission is also cancelled.
February 12 – ESA successfully launch an Ariane 5 ECA carrying three satellites. The previous attempt to launch the new design of rocket, in December 2002, failed when the rocket deviated from its course minutes into the flight.
July 4 – The Deep Impact spacecraft successfully observes the disintegration of its "impactor" section colliding with the comet Tempel 1. A large number of other telescopes also provide data on this event.
February 6 – Hubert Curien (b. 1924), French physicist, President of CERN and first chairman of ESA.
February 10 – D. Allan Bromley (b. 1926), Canadian-American director of Yale's A. W. Wright Nuclear Structure Laboratory.
March 6 – Hans Bethe (b. 1906), German-American Nobel laureate in Physics (1967) for his discoveries concerning the energy production mechanism in stars.
Charles David Keeling (b. 1928), American climate scientist, first to make frequent measurements of atmospheric carbon dioxide (CO2) concentration, plotted on the Keeling Curve.
November 16 – Henry Taube (b. 1915), Canadian-American Nobel laureate in Chemistry (1983) for his work in the mechanisms of electron transfer reactions, especially in metal complexes.
