Element 113 (ununtrium) and 115 (ununpentium)
2004 — The Degree Angular Scale Interferometer (DASI) first obtained the E-mode polarization spectrum of the cosmic microwave background radiation.
2004 discovery of Pallene
2004 discovery of Polydeuces
October 27 - Remains of a previously unknown species of human is discovered in Indonesia. Named Homo floresiensis, the hominin is a dwarfed version that lived 18,000 years ago on the island of Flores.
January 19 - The Hubble Space Telescope Program receives notification of the cancellation of all further HST on-orbit servicing.
March 15 - Astronomers announce the discovery last year of trans-Neptunian object 90377 Sedna, one of the most distant objects in the Solar System.
April 19 - Partial solar eclipse
May 18 - Scientists using the Chandra X-ray Observatory announced their findings that supports the notion that the expansion of the Universe is accelerating.
June 8 - Transit of Venus across the Sun.
September 13 - Astronomers from the European Southern Observatory (ESO) announce images that appear to show a planet orbiting a brown dwarf about 230 light years away. The system is believed to be only around 8 million years old.
October 14 - Partial solar eclipse
November 20 - Launch of the Swift satellite to investigate gamma-ray bursts (GRB) and perform an X-ray all sky survey.
December 27 - A flare of radiation from an explosion on the super-magnetic neutron star (Magnetar) SGR 1806-20 reaches Earth - astronomers later calculate that it is the largest explosion observed in the Milky Way galaxy for 400 years.
July 30 - Marine biologists from the Monterey Bay Aquarium Research Institute announce in the journal Science the discovery of the genus Osedax, deep sea worms that feed on lipids in decaying whale carcasses.
September 28 - A long awaited earthquake strikes Parkfield, California, the most closely monitored earthquake zone in the world. The earthquake, which had been expected to have occurred by the late 1980s, strikes as a magnitude 6.0. The network of instruments that had been installed in the region make this the most well-recorded earthquake in history.
December 26 - Indian Ocean earthquake and tsunami.
Michael Aschbacher and Stephen D. Smith publish their work on quasithin groups, filling the last (known) gap in the classification of finite simple groups.
Summer - A team led by Neil Shubin discover fossils of the sarcopterygian Tiktaalik on Ellesmere Island in Nunavut, Canada, significant in the evolution of tetrapods.
January 14 - Physicists from Pennsylvania State University produce the first solid Bose–Einstein condensate.
January - A team from the JILA laboratory in Boulder, Colorado announce the creation of a fermionic condensate, the first such condensate made from atoms rather than molecules.
February 3 - Russian and American physicists produce results that indicate the discovery of elements 113 and 115.
March 22 - A team from Australia, Russia and Greece announce a new material, made from a nano-foam of carbon that has the lowest density ever reported for a solid.
April 20 - NASA launches Gravity Probe B in an effort to test Einstein's general theory of relativity.
May 19 - A team of European scientists produces the first Tonks-Girardeau gas.
September 24 - Physicists from the Université Joseph Fourier and the Institut Laue-Langevin in Grenoble, France announce the discovery of a solution (a-cyclodextrine, water, and 4-methylpyridine) that changes from liquid to solid when heated, and melts again when cooled down.
March 27 - NASA succeeds in a second attempt to fly its X-43A experimental airplane from the Hyper-X project, attaining speeds in excess of Mach 7, the fastest free flying air-breathing hypersonic flight.
April 30 - Scientists from the University of California at Irvine announce the first high-speed transistor made from a carbon nanotube, operating at microwave frequencies.
January 3 - NASA's Spirit, the first of two Mars Exploration Rovers, lands successfully on Mars.
January 24 - NASA's Opportunity, the second of the Mars Exploration Rovers, lands successfully on Mars.
March 2 - NASA report that the area where their Mars probe Opportunity touched down shows unmistakable signs of contact with water in the geological past.
March 2 - ESA's Rosetta mission launches, aiming to land on Comet Churyumov-Gerasimenko in 2014.
March 4- NASA's Spirit finds evidence of past contact with water in volcanic rocks on Mars.
April 1 - The Genesis probe closes and seals its particle collection instrument, and begins to return to Earth.
June 11 - Cassini-Huygens, the NASA/ESA mission to Saturn, makes a flyby of one of Saturn's small outer moons, Phoebe.
June 21 - SpaceShipOne, the first civilian space ship is launched in California, reaching an altitude of 100 km (62 mi), just passing the edge of space.
July 1 - The Cassini-Huygens space probe arrives at Saturn and begins its nominal 4 year mission after successfully reaching orbit.
August 2 - NASA successfully launches the MESSENGER probe on its 5 year trip to Mercury.
September 8 - The Genesis spacecraft returns to Earth with captured solar wind particles, but crash-lands because of a failure to deploy any parachute.
October 4 - SpaceShipOne wins the Ansari X Prize after reaching an altitude of over 100 km (62 mi) for the second time in less than five days.
November 15 - The Smart 1 space probe reaches orbit around the Moon. It is the first European space mission to do so.
December 25 - The Cassini probe successfully drops the Huygens probe, sending it onto a trip to land on Saturn's moon Titan.
February 12 - Arden Bement, acting director of the U.S.A's National Science Foundation.
August 26 - Neurobiologist Susan Hockfield is appointed as President of MIT.
November 19 - Particle physicist Piermaria Oddone is appointed to succeed Michael Witherell as director of Fermilab (from July 1, 2005).
February 6 - Humphry Osmond (b. 1917), English-born psychiatrist.
William Pickering (b. 1910), former head of NASA's Jet Propulsion Laboratory.
Sir John Pople (b. 1925), British Nobel prize winning chemist.
April 19 - John Maynard Smith (b. 1920), evolutionary biologist and geneticist.
July 3 - Andrian Nikolayev (b. 1929), cosmonaut.
July 28 - Francis Crick (b. 1916), American Nobelaureate in Physiology for discovering the double helix structure for DNA.
August 12 - John Clark (b. 1951), head of the Roslin Institute and part of the team that cloned Dolly the Sheep.
August 15 - Sune K. Bergström (b. 1916), Swedish biochemist, winner of the 1982 Nobel Prize for Medicine.
August 31 - Fred Whipple (b. 1906), American astronomer who coined the term "dirty snowball" to explain the nature of comets.
October 5 - Maurice Wilkins (b. 1916), Nobelaureate in Physiology for discovering the double helix structure for DNA using X-ray diffraction.
October 19 - Lewis Urry (b. 1927), inventor of the long-lasting alkaline battery.
November 18 - Robert Bacher (b. 1905), nuclear physicist and one of the leaders of the Manhattan Project, Professor and Provost of the California Institute of Technology.
December 26 - Frank Pantridge (b. 1916), cardiologist.
December 29 - Julius Axelrod, (b. 1912), biochemist, Nobel Prize in Physiology for work with catecholamine neurotransmitters.
^ Brown, P.; Sutikna, T.; Morwood, M. J.; Soejono, R. P.; Jatmiko, Wayhu Saptomo, E.; Rokus Awe Due (October 27, 2004). "A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia". Nature 431 (7012): 1055–1061. doi:10.1038/nature02999. PMID 15514638.
^ Brown, Michael E.; Trujillo, Chadwick; Rabinowitz, David (10 December 2004). "Discovery of a Candidate Inner Oort Cloud Planetoid". The Astrophysical Journal 617 (1): 645–649. arXiv:astro-ph/0404456. Bibcode 2004ApJ...617..645B. doi:10.1086/422095. Retrieved 2011-10-27.
^ Chandra :: Photo Album :: Galaxy Clusters and Dark Energy :: 18 May 04
^ Access : Huge explosion traced to exotic star : Nature News
^ Daeschler, Edward B.; Shubin, Neil H.; Jenkins, Farish A., Jr (6 April 2006). "A Devonian tetrapod-like fish and the evolution of the tetrapod body plan". Nature 440 (7085): 757–763. doi:10.1038/nature04639. PMID 16598249.
^ http://www.nature.com/doifinder/10.1038/nature02220 Nature
^ Phys. Rev. C 69 021601
^ Nano-foam makes magnetic debut - physicsworld.com
^ Journal of Chemical Physics
14 November 2004 Death of David Stanley Evans in Austin, Texas, USA
2004 Death of Mervyn Hine
Physiology or Medicine to Richard Axel and Linda B. Buck "for their discoveries of odorant receptors and the organization of the olfactory system"
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