1902 Tyrannosaurus skeleton in relation to a human skeleton ever published. Tyrannosaurus, a bipedal carnivore, is a genus of theropod dinosaur. The species Tyrannosaurus rex, commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other
tyrannosaurids. Fossils are found in a variety of rock formations dating to the last two million years of the
Cretaceous Period, 67 to 66 million years ago. It was among the last non-avian dinosaurs to exist prior to the
Cretaceous–Tertiary extinction event. In 1902, the first skeleton of Tyrannosaurus was discovered in
Hell Creek, Montana by American paleontologist
Barnum Brown. In 1908, Brown discovered a better preserved skeleton of Tyrannosaurus.
1908 Seyfert galaxies • Seyfert galaxies are a class of galaxies with nuclei that produce spectral line emission from highly ionized gas, named after
Carl Keenan Seyfert, the astronomer who first identified the class in 1943 although they were first discovered by Edward A. Fath in 1908 while he was at the
Lick Observatory.
1909 Burgess Shale seen excavating the
Burgess Shale (near
Field, British Columbia) with his wife Helen and son Sidney, in the quarry which now bears his name. The formation of Burgess Shale — located in the
Canadian Rockies of
British Columbia — is one of the world's most celebrated fossil fields, and the best of its kind. It is famous for the exceptional preservation of the soft parts of its fossils. It is (Middle
Cambrian) old, one of the earliest soft-parts fossil beds. The rock unit is a black
shale, and crops out at a number of localities near the town of
Field, British Columbia in the
Yoho National Park. The Burgess Shale was discovered by American palaeontologist
Charles Doolittle Walcott in 1909, towards the end of the season's fieldwork. He returned in 1910 with his sons, establishing a quarry on the flanks of Fossil Ridge. The significance of soft-bodied preservation, and the range of organisms he recognized as new to science, led him to return to the quarry almost every year until 1924. At this point, aged 74, he had amassed over 65,000 specimens. Describing the fossils was a vast task, pursued by Walcott until his death in 1927.
1912 Golden Delicious Golden Delicious is a large, yellow skinned cultivar of apple and very sweet to the taste. The original Golden Delicious tree is thought to have been discovered by Anderson Mullins on a hill near Porter Creek in Clay County, West Virginia. The
Stark Brothers Nursery soon purchased the tree which spawned a leading cultivar in the United States and abroad. The Golden Delicious is the state fruit of West Virginia.
1912 Smoking-cancer link • Dr. Isaac Adler was the first to strongly suggest that lung cancer is related to smoking in 1912.
1914 Sinope • Sinope is a retrograde irregular satellite of Jupiter discovered by
Seth Barnes Nicholson at
Lick Observatory in 1914.
1915 Zener diodes • A Zener diode is a type of diode that permits current in the forward direction like a normal diode, but also in the reverse direction if the voltage is larger than the
breakdown voltage known as "Zener knee voltage" or "Zener voltage". The device was named after
Clarence Zener, who discovered this electrical property. '''1916
Barnard's Star''' • Barnard's Star is a very low-mass
red dwarf star. At a distance of about 1.8 parsecs from the
Solar System, or just under six light-years, Barnard's Star is the nearest-known star in the constellation
Ophiuchus, and the fourth-closest known individual star to the Sun, after the three components of the
Alpha Centauri system. In 1916, Barnard's Star was discovered by American astronomer
Edward Emerson Barnard, whom the star was named after.
1916 Covalent bonding • The idea of covalent bonding can be traced several years to
Gilbert N. Lewis, who in 1916 described the sharing of electron pairs between atoms. He introduced the so-called
Lewis notation or electron dot notation or The Lewis Dot Structure in which valence electrons are represented as dots around the atomic symbols.
1916 Heparin • Heparin, a highly sulfated
glycosaminoglycan, is widely used as an injectable anticoagulant and has the highest negative charge density of any known biological molecule. It can also be used to form an inner anticoagulant surface on various experimental and medical devices such as test tubes and renal dialysis machines. It was discovered by Jay McLean and
William Henry Howell in 1916.
1917 Vitamin A • Vitamin A, a bi-polar molecule formed with bi-polar covalent bonds between carbon and hydrogen, is linked to a family of similarly shaped molecules, the retinoids, which complete the remainder of the vitamin sequence. Its important part is the retinyl group, which can be found in several forms. In foods of animal origin, the major form of vitamin A is an ester, primarily retinyl palmitate, which is converted to an alcohol in the small intestine. Vitamin A can also exist as an aldehyde, or as an acid. The discovery of vitamin A stemmed from research dating back to 1906, indicating that factors other than carbohydrates, proteins, and fats were necessary to keep cattle healthy. By 1917 one of these substances was independently discovered by
Elmer McCollum at the University of Wisconsin–Madison, and
Lafayette Mendel and Thomas Osborne at Yale University.
1923 Oviraptor • Oviraptor is a genus of small Mongolian theropod dinosaur that lived during the late Campanian stage about 75 million years ago. In 1923,
Roy Chapman Andrews discovered the first and so far the only fossils of Oviraptor to ever be found at the
Djadochta Formation in
Inner Mongolia. This species of dinosaur was named and described by
Henry Fairfield Osborn in 1924.
1924 Uncle Sam Diamond • Uncle Sam is a 40.23-carat white diamond, the largest diamond ever found in North America. Discovered in 1924 at the
Crater of Diamonds State Park in Arkansas, the diamond was named after its discoverer, Wesley Oley Basham, who went by the nickname "Uncle Sam". Over the years, the Uncle Sam diamond was cut twice with the second cutting resulting in a 12.42-carat, emerald-cut gem.
1925 Cepheid variables • Extragalactic astronomy is the branch of astronomy concerned with objects outside the Milky Way Galaxy. In other words, it is the study of all astronomical objects which are not covered by galactic astronomy. It was started by
Edwin Hubble when, in 1925, he discovered the existence of
Cepheid variables in the Andromeda Galaxy. This discovery proved the existence of a galaxy over one million light-years away and thus extragalactic astronomy was created.
1927 Electron diffraction • Electron diffraction is a collective scattering phenomenon with electrons being scattered by atoms in a regular crystal array. This can be understood in analogy to the Huygens principle for the diffraction of light. The incoming plane electron wave interacts with the atoms, and secondary waves are generated which interfere with each other. In 1927, two Americans named
Clinton Davisson and
Lester Germer had proven
de Broglie's theory by discovering electron diffraction. This confirmation of the wavelike nature of an electron was discovered independently of Englishman
George Paget Thomson.
1928 Jones Diamond • The Jones Diamond is a bluish-white diamond weighing 34.48 carats (6.896 g), measuring 5/8 of an inch (15.8 mm) across, and possessing 12 diamond-shaped faces. It is considered to be the largest alluvial diamond from North America. The Jones Diamond was discovered by William P. "Punch" Jones and his father Grover while pitching horseshoes in 1928. They thought the stone was a piece of quartz which was common in the area. Keeping it in a cigar box in their tool shed for 14 years, the Jones's sent the gem to the geology department at
Virginia Polytechnic Institute in 1942 where they were informed that it was an alluvial diamond and not a quartz crystal. The diamond was then sent to the
Smithsonian Institution in Washington D.C. for safekeeping until 1964, when it returned to the Jones family who kept it for another 20 years in a safe deposit box at their local bank in Virginia. In 1984, the Jones family finally sold the diamond at
Sotheby's auction in New York City to a private collector of jewelry.
1930 Pluto , the American astronomer who discovered
Pluto in 1930. Following the discovery of the planet Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. The search began in the mid-19th century but culminated at the start of the 20th century with a quest for Planet X.
Percival Lowell proposed the Planet X hypothesis to explain apparent discrepancies in the orbits of the gas giants, particularly Uranus and Neptune, speculating that the gravity of a large unseen planet could have perturbed Uranus enough to account for the irregularities. The discovery of Pluto by
Clyde Tombaugh in 1930 initially appeared to validate Lowell's hypothesis, and
Pluto was considered the ninth planet until 2006.
1931 Heavy hydrogen • Deuterium, also called heavy hydrogen, is a stable isotope of hydrogen with a natural abundance in the oceans of Earth of approximately one atom in 6500 of hydrogen (~154
PPM). It was discovered in 1931 by
Harold Urey, who obtained a sample of hydrogen enriched in deuterium by distillation at low temperature and pressure.
1931 Cosmic radio waves • Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. While trying to track down a source of electrical interference on telephone transmissions,
Karl Guthe Jansky of Bell Telephone Laboratories discovered radio waves emanating from stars in outer space while investigating static that interfered with short wave transatlantic voice transmissions. Thus, the field of radio astronomy was born.
1932 Positrons • The existence of positrons was first postulated in 1928 by
Paul Dirac as a consequence of the
Dirac equation and later discovered in 1932 by
Carl D. Anderson, who gave the positron its name.
1932 Homeostasis • Homeostasis is the property of a system, either open or closed, that regulates its internal environment so as to maintain a stable, constant condition. It was first proposed and coined by
Walter Bradford Cannon, a former professor and chairman of the Department of Physiology at
Harvard Medical School, and popularized it in his book
The Wisdom of the Body.
1933 Heavy water •
Harold Urey discovered the isotope
deuterium in 1931 and was later able to concentrate it in water. Urey's mentor
Gilbert Newton Lewis isolated the first sample of pure heavy water by electrolysis in 1933.
1933 Polyvinylidene chloride • Polyvinylidene chloride is a polymer derived from vinylidene chloride. Its use can be found in water-based coating, the production of household items and industrial products. Ralph Wiley, a
Dow Chemical lab worker, accidentally discovered polyvinylidene chloride in 1933.
1936 Elliptical galaxies • An elliptical galaxy is a galaxy having an approximately
elliptical shape and a smooth, nearly featureless brightness profile. They range in shape from nearly spherical to highly flattened and in size from hundreds of millions to over one trillion
stars. It was originally described by
Edwin Hubble in his 1936 work "The Realm of the Nebulae"
1936 Muons • The muon is an elementary particle similar to the electron, with negative electric charge and a spin of 1⁄2. It was discovered by
Carl D. Anderson and Seth Henry Neddermeyer in 1936 while they studied cosmic radiation.
1936 Vitamin E •
Tocopherol, a class of chemical compounds of which many have vitamin E activity, describes a series of organic compounds consisting of various methylated phenols. During feeding experiments with rats
Herbert McLean Evans concluded in 1922 that besides vitamins B and C, an unknown vitamin existed. Although every other nutrition was present, the rats were not fertile. This condition could be changed by additional feeding with wheat germ. It took several years until 1936 when the substance was isolated from wheat germ and the formula C29H50O2 was determined by Herbert McLean Evans and K.S. Bishop. The structure was determined shortly thereafter in 1938.
1936 Sodium thiopental • Sodium thiopental, better known as Sodium Pentothal, thiopentone sodium, or trapanal, is a rapid-onset short-acting barbiturate. It was discovered in the early 1936 by
Ernest H. Volwiler and Donalee L. Tabern while working for Abbott Laboratories.
1937 Niacin • Niacin, also known as vitamin B3, is a water-soluble vitamin which prevents the deficiency disease pellagra. Niacin was extracted from livers by
Conrad Elvehjem who later discovered the active ingredient, then referred to as the "pellagra-preventing factor" and the "anti-blacktongue factor".
1937 Electron capture • Electron capture is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom and insufficient energy to emit a positron. However, it continues to be a viable decay mode for radioactive isotopes that can decay by positron emission. K-electron capture was discovered by
Luis Alvarez, who demonstrated it in 1937 and reported it in The Physical Review in April 1938.
1938 Fluropolymers • A fluoropolymer is a
fluorocarbon based polymer with multiple strong
carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. Fluoropolymers were discovered in 1938 by
Dr. Roy Plunkett when he accidentally polymerized
tetrafluoroethylene to form
polytetrafluoroethylene.
1938 Animal echolocation • Echolocation, also called biosonar, is the biological sonar used by several animals such as dolphins, shrews, bats, and whales. The term was coined by
Donald Griffin and Robert Galambos, who discovered its use by bats in 1938.
1938 Carme • Carme is a retrograde irregular satellite of Jupiter. It was discovered by
Seth Barnes Nicholson at
Mount Wilson Observatory in California in July 1938.
1938 Lysithea • Lysithea is a prograde irregular satellite of Jupiter. It was discovered by
Seth Barnes Nicholson in 1938 at
Mount Wilson Observatory.
1940 Plutonium • Plutonium is a synthetic transuranic radioactive chemical element with the chemical symbol Pu and atomic number 94. It is an actinide metal of silvery-white appearance that tarnishes when exposed to air, forming a dull coating when oxidized. Plutonium was co-discovered by
Glenn T. Seaborg, A.C. Wahl, and J.W. Kennedy in 1940.
1942 Cyanoacrylate • Cyanoacrylates are a class of fast-acting adhesives and glues. Better known under the brand name "Super Glue," cyanoacrylates are used to assemble prototype electronics (see
Wire wrap), flying model aircraft, and as retention dressings for nuts and bolts. Their effectiveness in bonding metal and general versatility have also made them popular for use in simple woodworking, industrial binding, and appliance repair. The history of cyanoacrylates is one of accidental discovery when researchers under Dr.
Harry Coover conducted experiments on adhesive chemicals in order to devise a clear plastic that could be used for precision gunsights for soldiers fighting in World War II. Failing in their experimentations, the practical usefulness of cyanoarcrylates did not materialize until much later when in 1951, Coover, who was then working at
Eastman Kodak, came to the realization that the sticky adhesives had unique properties in that they required no heat or pressure to permanently bond two items together. In light of his invention of "Super Glue," Coover filed U.S. patent #2,768,109 on June 2, 1954, and it was issued to him on October 23, 1956.
1943 Streptomycin • Streptomycin is an antibiotic drug, the first of a class of drugs called aminoglycosides to be discovered, and was the first antibiotic remedy for tuberculosis. Streptomycin cannot be given orally as it must be administered by regular intramuscular injection. In 1943,
Albert Schatz discovered Streptomycin.
1944 Americium • Americium is a synthetic element that has the symbol Am and atomic number 95. A radioactive metallic element, americium is an actinide that is used in commercial ionization chamber smoke detectors, as well as in neutron sources and industrial gauges. Americium was co-discovered by
Glenn T. Seaborg, Ralph James, L. Morgan, and Albert Ghiorso during their work on the
Manhattan Project in 1944.
1944 Curium • Curium is a synthetic chemical element with the symbol Cm and atomic number 96. A radioactive metallic transuranic element of the actinide series, curium is produced by bombarding plutonium with alpha particles (helium ions) and was named after
Marie Curie and her husband
Pierre Curie. Curium was co-discovered by
Glenn T. Seaborg, Ralph A. James, and
Albert Ghiorso at the University of California at Berkeley in 1944.
1945 Promethium • Promethium is a chemical element whose existence was first predicted by
Bohuslav Brauner in 1902. It was first discovered and proven to exist at
Oak Ridge National Laboratory (ORNL) in 1945 by
Jacob A. Marinsky,
Lawrence E. Glendenin, and
Charles D. Coryell by separation and analysis of the fission products of uranium fuel irradiated in the Graphite Reactor.
1946 Cloud seeding • Cloud seeding, a form of weather modification, is the attempt to change the amount or type of precipitation that falls from clouds, by dispersing substances into the air that serve as cloud condensation or ice nuclei, which alter the microphysical processes within the cloud. The usual intent is to increase precipitation but hail and fog suppression are also widely practiced in airports. The method's use has ranged from increasing precipitation in areas experiencing drought to removing radioactive particles from clouds. Cloud seeding was discovered by
Vincent Schaefer in 1946.
1948 Warfarin • Warfarin is an anticoagulant and pesticide. It was initially used as a pesticide but was later found to be effective and relatively safe for preventing thrombosis and embolism in many disorders and is currently the most widely used anticoagulant worldwide. It was discovered by
Karl Paul Link and chemists at the University of Wisconsin–Madison.
1948 Miranda • Miranda is the smallest and innermost of
Uranus' five major moons. It was discovered by
Gerard Kuiper on February 2, 1948, at
McDonald Observatory.
1948 Serotonin • Seratonin is a monoamine neurotransmitter synthesized in serotonergic neurons in the central nervous system (CNS) and enterochromaffin cells in the gastrointestinal tract of animals including humans. It was isolated and named in 1948 by Maurice M. Rapport, Arda Green, and
Irvine Page of the
Cleveland Clinic.
1948 Tetracycline • Tetracycline is a broad-spectrum polyketide antibiotic indicated for use against many bacterial infections. It is commonly used to treat acne today, and played a historical role in stamping out cholera in the developed world. It was discovered by
Benjamin Minge Duggar in 1948.
1949 Nereid • Nereid, also known as Neptune II, is a moon of
Neptune. Nereid was discovered on May 1, 1949, by
Gerard Kuiper, who proposed the name in the report of his discovery. It is named after the
Nereids, sea-nymphs of
Greek mythology.
1949 Berkelium • Berkelium is a synthetic element with the symbol Bk and atomic number 97. A radioactive metallic element in the actinide series, berkelium was first synthesized by bombarding americium with alpha particles (helium ions) and was named for the University of California at Berkeley. Berkelium was co-discovered in December 1949 by
Glenn T. Seaborg, Stanley G. Thompson, and
Albert Ghiorso.
1950 Californium • Californium is a radioactive metallic chemical element with the symbol Cf and atomic number 98. The element was first produced by bombarding curium with alpha particles (helium ions) at the University of California, Berkeley. It was the sixth transuranic element to be synthesized. Californium is one of the highest atomic mass elements to have been produced in weighable amounts. It is named for the U.S. state of
California and the University of California. Californium was co-discovered by Stanley G. Thompson,
Albert Ghiorso, and
Glenn T. Seaborg in 1950.
1951 Barium stars • Barium stars are G to K class giants, whose spectra indicate an overabundance of s-process elements by the presence of singly ionized barium, Ba II, at λ 455.4 nm. Barium stars also show enhanced spectral features of carbon, the bands of the molecules CH, CN and C2. The class was originally recognized and defined by William Bidelman and Philip Keenan.
1951 Ananke • Ananke is a retrograde irregular satellite of Jupiter. It was discovered by
Seth Barnes Nicholson at
Mount Wilson Observatory in 1951.
1952 Polio vaccine • Vaccination works by priming the immune system with an 'immunogen'. Stimulating immune response, via use of an infectious agent, is known as immunization. The development of immunity to polio efficiently blocks person-to-person transmission of wild poliovirus, thereby protecting both individual vaccine recipients and the wider community. In 1952, Dr.
Jonas Salk announced his discovery of a trial vaccine for Polio, or poliomyelitis. Salk's vaccine was composed of "killed" polio virus, which retained the ability to immunize without the risk of infecting the patient. In 1954, Salk published his findings in the
Journal of the American Medical Association, and nationwide testing was carried out. In 1955, Salk's polio vaccine was made public.
1952 Einsteinium • Einsteinium is a metallic synthetic element. On the periodic table, it is represented by the symbol Es and atomic number 99. It is the seventh transuranic element, and an actinide. It was named in honor of
Albert Einstein. Einsteinium was discovered by
Albert Ghioirso in December 1952.
1952 Rapid eye movement • Rapid eye movement (REM) sleep is a normal stage of sleep characterized by rapid movements of the eyes. REM sleep is classified into two categories: tonic and phasic. The phenomenon of REM sleep and its association with dreaming was discovered by
Eugene Aserinsky and
Nathaniel Kleitman with assistance from
William C. Dement, a medical student at the time, in 1952 during their tenures at the University of Chicago. Kleitman and Aserinsky's seminal article was published September 10, 1953.
1955 Mendelevium • Mendelevium is a synthetic element with the symbol Md (formerly Mv) and the atomic number 101. A metallic radioactive transuranic element of the actinides, mendelevium is usually synthesized by bombarding einsteinium with alpha particles and was named after the Russian chemist
Dmitri Mendeleev, who was responsible for the
Periodic Table. Mendelevium was co-discovered by
Albert Ghiorso, Bernard G. Harvey, Gregory R. Choppin, Stanley G. Thompson, and
Glenn T. Seaborg in 1955.
1955 Antiproton • The antiproton is the antiparticle of the proton. It was discovered by University of California, Berkeley physicists
Thomas Ypsilantis,
Emilio Segrè,
Clyde Wiegand, and
Owen Chamberlain in 1955. '
1956 Porous silicon • Porous silicon (pSi) is a form of the chemical element silicon which has an introduced nanoporous holes in its microstructure, rendering a large surface to volume ratio in the order of 500m2/cm3. It was first discovered by accident in 1956 at Bell Labs by Arthur Uhlir Jr. and Ingeborg Uhlir.
1956 Kaon • A kaon is any one of a group of four mesons distinguished by the fact that they carry a quantum number called strangeness. It was first discovered by
Leon Lederman and a group of scientists from Columbia University at
Brookhaven National Laboratory.
1956 Antineutron • The antineutron is the antiparticle of the neutron. An antineutron has the same mass as a neutron, and no net electric charge. However, it is different from a neutron by being composed of anti-quarks, rather than quarks. It was discovered by
Bruce Cork, William Wenzell, Glenn Lambertson, and Oreste Piccioni in 1956.
1956 Neutrino • Neutrinos are elementary particles that travel close to the speed of light, lack an electric charge, are able to pass through ordinary matter almost undisturbed, and are thus extremely difficult to detect. The neutrino was first postulated in 1930 by
Wolfgang Pauli and later discovered in 1956 by
Clyde Cowan,
Frederick Reines, F. B. Harrison, H. W. Kruse, and A. D. McGuire.
1956 Nucleic acid hybridization • Hybridization, discovered by
Alexander Rich and David R. Davies in 1956, is the process of combining complementary, single-stranded nucleic acids into a single molecule.
1958 Van Allen radiation belt • The Van Allen radiation belt is a torus of energy charged particles around Earth, held in place by Earth's magnetic field. On the sun side, it is compressed because of the solar wind and on the other side, it is elongated to around three earth radii. This creates a cavity called the Chapman Ferraro Cavity, in which the Van Allen radiation belts reside. The existence of the belt was confirmed by the
Explorer 1 and
Explorer 3 missions in early 1958, under
Dr. James Van Allen at the University of Iowa.
1959 Antiproton • The antiproton is the antiparticle of the proton. It was discovered in 1955 by University of California, Berkeley physicists
Owen Chamberlain and
Emilio Segrè for which they earned the 1959 Nobel Prize in Physics.
1960 Seafloor spreading • Seafloor spreading occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Seafloor spreading helps explain continental drift in the theory of plate tectonics. It was first proposed by
Harry Hammond Hess and
Robert S. Dietz in 1960.
1961 Eta meson • The eta meson is a meson made of a mix of up quark, down quark, strange quark, quarks, and anti-quarks. It was discovered by a team at the University of California, Berkeley using the
Bevatron.
1964 Xi baryon • In particle physics, subatomic particle (Xi) is a name given to a range of baryons with one up or down quark and two heavier quarks. They are sometimes called the cascade particles because of their unstable state, they decay rapidly into lighter particles through a chain of decays. The first discovery of the Xi particle was at
Brookhaven National Laboratory in 1964.
1964 Cosmic microwave background radiation • In cosmology, the cosmic microwave background radiation CMB is a form of electromagnetic radiation filling the universe. The CMB's discovery in 1964 by astronomers
Arno Penzias and
Robert Wilson was the culmination of work initiated in the 1940s, earning them a Nobel Prize in 1978.
1964 Quark • A quark is a type of elementary particle found in nucleons and other subatomic particles. They are a major constituent of matter, along with leptons. The quark model was first postulated independently by physicist
Murray Gell-Mann in 1964.
1964 1930 Lucifer • 1930 Lucifer was a main-belt asteroid discovered at the
United States Naval Observatory Flagstaff Station (NOFS) in Flagstaff, Arizona on October 29, 1964, by American astronomer
Elizabeth Roemer.
1964 Hepatitis B virus • The Hepatitis B virus was discovered in 1965 by
Baruch Blumberg, while working at the National Institutes of Health.
1965 Aspartame • Aspartame is the name for an artificial, non-saccharide sweetener, aspartyl-phenylalanine-1-methyl ester; that is, a methyl ester of the dipeptide of the amino acidsaspartic acid and phenylalanine. Aspartame was discovered in 1965 by
James M. Schlatter, a chemist working for G.D. Searle & Company. Schlatter had synthesized aspartame in the course of producing an anti-ulcer drug candidate.
1965 Pulsating white dwarfs • A pulsating white dwarf is a
white dwarf star whose luminosity varies due to non-radial gravity wave pulsations within itself. The first pulsating white dwarf was discovered by
Arlo U. Landolt when he observed in 1965 and 1966 that the luminosity of
HL Tau 76 varied with a period of approximately 12.5 minutes.
1968 Up quark • The up quark is a first-generation quark with a charge of +(2/3)
e. The existence of up quarks was first postulated when
Murray Gell-Mann and
George Zweig developed the quark model in 1964, and the first evidence for them was found in deep inelastic scattering experiments in 1968.
1968 Down quark • The down quark is a first-generation quark with a charge of −. It is the second-lightest of all the six of quarks, the lightest being the up quark. Down quarks are most commonly found in nucleons. Its protons contains one down quark and two up quarks, while neutrons contain two down quarks and one up quark. Down quarks were theorized by
Murray Gell-Mann and
George Zweig when they discovered the quark model in 1968. '''1969
Mosher's acid''' • Mosher's acid, or α-methoxytrifluorophenylacetic acid, discovered by
Harry S. Mosher in 1969, is a carboxylic acid which was first used as a chiral derivitizing agent.
1969 Interstellar formaldehyde • Interstellar formaldehyde was first discovered in 1969 by Lewis Snyder, David Buhl, B. Zuckerman and Patrick Palmer using the
National Radio Astronomy Observatory. Formaldehyde was detected by means of the 111 - 110 ground state rotational transition at 4830 MHz.
1970 Reverse transcriptase • In biochemistry, a reverse transcriptase, also known as RNA-dependent DNA polymerase, is a DNA polymerase enzyme that transcribes single-stranded RNA into double-stranded DNA. It was discovered by
Howard Temin at the University of Wisconsin–Madison, and independently by
David Baltimore in 1970 at Massachusetts Institute of Technology.
1972 Opiate receptors • Opioid receptors are a group of G protein-coupled receptors with opioids as ligands. The endogenous opioids are dynorphins, enkephalins, endorphins, endomorphins, and nociceptin. The opioid receptors are ~40% identical to somatostatin receptors (SSTRs). Opiate receptors were discovered in 1972 by the American neuroscientist and pharmacologist named
Candace Pert.
1974 Australopithecus "Lucy" at Mexico City. Lucy is the common name of AL 288–1, several hundred pieces of bone representing about 40% of the skeleton of an individual Australopithecus afarensis. Lucy is reckoned to have lived 3.2 million years ago. This
hominid was significant as the skeleton shows evidence of small skull capacity akin to that of non-human
apes and of
bipedal upright walk akin to that of
humans, providing further evidence that bipedalism preceded increase in brain size in human evolution. While working in collaboration with a joint French-British-American team, Lucy was discovered in
Hadar, Ethiopia on November 24, 1974, when American paleoanthropologist
Donald Johanson, coaxed away from his paperwork by graduate student Tom Gray for a spur-of-the-moment survey, caught the glint of a white fossilized bone out of the corner of his eye, and recognized it as hominid. Later described as the first known member of
Australopithecus afarensis. Dr. Johanson's girlfriend suggested she be named "Lucy" after the Beatles' song "
Lucy in the Sky with Diamonds" which was played repeatedly during the night of the discovery.
1974 J/ψ mesons • The J/ψ is a subatomic particle, a flavor-neutral meson consisting of a charm quark and a charm anti-quark. Mesons formed by a bound state of a charm quark and a charm anti-quark are generally known as "charmonium". Its discovery was made independently by two research groups, one at the Stanford Linear Accelerator Center, headed by
Burton Richter, and one at the
Brookhaven National Laboratory, headed by
Samuel Ting at Massachusetts Institute of Technology. They accidentally discovered they had found the same particle, and both announced their discoveries on November 11, 1974.
1974 Charm quark • The charm quark is a second-generation quark with an electric charge of +2⁄3
e. It is the third most massive of the quarks, at about 1.5 GeV/c2 and roughly one and a half times the mass of the proton. It was predicted in 1964 by
Sheldon Glashow and
James Bjorken and first observed in November 1974, with the simultaneous discovery of the J/ψ|J/ψ meson charm particle at Stanford Linear Accererator Center by a group led by
Burton Richter and at
Brookhaven National Laboratory by a group led by
Samuel C. C. Ting.
1974 Binary pulsars • A binary pulsar is a pulsar with a binary companion, often another pulsar, white dwarf or neutron star. The first binary pulsar, PSR 1913+16 or the "Hulse-Taylor binary pulsar" was discovered in 1974 at
Arecibo by
Joseph Hooton Taylor, Jr. and
Russell Hulse, for which they won the 1993 Nobel Prize in Physics.
1974 Leda • Leda is a prograde irregular satellite of Jupiter. It was discovered by
Charles T. Kowal at the
Palomar Observatory on September 14, 1974.
1974 Seaborgium • Seaborgium is a chemical element with the symbol Sg and atomic number 106. Seaborgium is a synthetic element whose most stable isotope 271Sg has a half-life of 1.9 minutes. Chemistry experiments with seaborgium have firmly placed it in group 6 as a heavier homologue to tungsten. Seaborgium was independently discovered by groups at the
Joint Institute for Nuclear Research and
Lawrence Berkeley National Laboratory in 1974, and was named in honor of the American chemist
Glenn T. Seaborg.
1975 1983 Bok • 1983 Bok is a minor planet discovered on June 9, 1975, by American astronomer
Elizabeth Roemer at
Kitt Peak National Observatory in Arizona. As a minor planet, 1983 Bok was named in honor of
Bart J. and
Priscilla Fairfield Bok.
1975 Themisto • Themisto is a small prograde irregular satellite of Jupiter. It was discovered by
Charles T. Kowal and
Elizabeth Roemer in 1975.
1975 Amarillo Starlight • The Amarillo Starlight is a 16.37-carat white diamond that was discovered in 1975 by W. W. Johnson of Amarillo, Texas while vacationing at the
Crater of Diamonds State Park in Arkansas. The Amarillo Starlight was later cut into a 7.54-carat marquise shape.
1977 Upsilon mesons • The upsilon meson is a flavorless meson formed from a bottom quark and its antiparticle. It was discovered by the E288 collaboration, headed by
Leon Lederman, at Fermilab in 1977, and was the first particle containing a bottom quark to be discovered because it is the lightest that can be produced without additional massive particles. It has a mean lifetime of 1.21×10−20 second and a mass about 10 GeV.
1977 Bottom quark • The bottom quark is a third-generation quark with a charge of −1⁄3
e. The bottom quark was discovered by the E288 experiment at Fermilab in 1977 when collisions produced bottomonium.
1978 Restriction endonucleases • A restriction enzyme is an enzyme that cuts double-stranded or single stranded DNA at specific recognition nucleotide sequences known as restriction sites. Such enzymes, found in bacteria and archaea, are thought to have evolved to provide a defense mechanism against invading viruses. Inside a bacterial host, the restriction enzymes selectively cut up foreign DNA in a process called restriction; host DNA is methylated by a modification enzyme to protect it from the restriction enzyme's activity. The Nobel Prize in Medicine was awarded, in 1978, to
Daniel Nathans,
Werner Arber, and
Hamilton O. Smith for the discovery of restriction endonucleases.
1978 Charon • Charon, discovered by
James W. Christy on June 22, 1978, while working at the
United States Naval Observatory, is the largest moon of the dwarf planet Pluto.
1979 Metis • Metis is the innermost moon of Jupiter. It was discovered in 1979 by
Stephen Synnott in images taken by
Voyager 1.
1979 Thebe • Thebe is the fourth of Jupiter's moons by distance from the planet. It was discovered by
Stephen Synnott in images from the
Voyager 1 space probe taken on March 5, 1979, while orbiting around Jupiter.
1979 Rings of Jupiter • The planet Jupiter has a system of rings, known as the rings of Jupiter or the Jovian ring system. It was the third ring system to be discovered in the Solar System, after those of Saturn and Uranus and was first observed in 1979 by the
Voyager 1 space probe.
1980 Oncogene • An oncogene is a gene that is mutated or expressed at high levels, and thus helps turn a normal cell into a tumor cell. In the late 1970s,
Robert Weinberg and his team of researchers began the search for a human oncogene. Using gene transfer techniques, researchers in his lab inserted DNA from human bladder tumor cells into normal animal cells. When the animal cells turned cancerous, Dr. Weinberg's associates began inserting smaller pieces of DNA into the normal cell. By 1980, they found a single fragment that turned the normal cell cancerous. This gene was found to belong to a sub-family of related genes, called
ras, that was later discovered to play a role in causing bladder, lung, and colon cancer in both rats and humans. More results emerged in 1982 when Dr. Weinberg's laboratory discovered that a single, subtle genetic glitch in this oncogene topples the delicate balance between a bladder cell's normal and cancerous states.
1980 Pandora • Pandora is an inner satellite of Saturn. It was discovered in 1980 from photos taken by
Voyager 1, and was provisionally designated S/1980 S 26.
1980 Prometheus • Prometheus is an inner satellite of Saturn that was discovered in 1980 from photos taken by
Voyager 1. It was provisionally designated S/1980 S 27.
1980 Atlas • Atlas is a moon of Saturn that was discovered by
Richard Terrile in 1980 from Voyager photos and was designated S/1980 S 28.
1981 Larissa • Larissa, also known as Neptune VII, is the fifth-closest inner satellite of
Neptune. It was first discovered by
Harold J. Reitsema, William B. Hubbard, Larry A. Lebofsky, and
David J. Tholen based on fortuitous ground-based stellar occultation observations on May 24, 1981, and given the temporary designation S/1981 N 1, being announced on May 29, 1981.
1983 Pneumococcal polysaccharide vaccine • Pneumococcal polysaccharide vaccine, also known as Pneumovax, is a vaccine used to prevent Streptococcus pneumoniae infections such as pneumonia and septicaemia. It was discovered by American scientists at Merck & Co. in 1983. '
1984 Whydah
wreckage' '' which sank in 1717, near
Cape Cod. The red X marks the spot. First launched in 1715 from London, England, the
Whydah was a three-masted ship of galley-style design measuring in length, rated at 300 tons burden, and could travel at speeds up to . Christened
Whydah after the West African slave trading kingdom of
Ouidah, the vessel was configured as a heavily armed trading and transport ship for use in the
Atlantic slave trade, carrying goods from England to exchange for slaves in
West Africa. It would then travel to the Caribbean to trade the slaves for precious metals, sugar, indigo, and medicinal ingredients, which would then be transported back to England. Captained by the English pirate
Samuel Bellamy, the
Whydah, on April 26, 1717, sailed into a violent storm dangerously close to
Cape Cod and was eventually driven onto the shoals at
Wellfleet, Massachusetts. At midnight she hit a sandbar in of water some from the coast of what is now Marconi Beach. Pummelled by -an-hour winds and 30 to waves, the main mast snapped, pulling the ship into some of water where she violently capsized, taking Bellamy, all but two of his 145 men, and over 4.5 tons of gold, silver and jewels with it. After years of exhaustive searching, it was in 1984 that world headlines were made when American archeological explorer
Barry Clifford found the only solidly-identified pirate shipwreck ever discovered, the
Whydah. Two-hundred thousand artifacts and sunken treasures were discovered in the shipwreck as well.
1985 Puck • Puck is an inner satellite of
Uranus. It was discovered in December 1985 by the
Voyager 2 spacecraft. '
1985 RMS Titanic
wreckage' The RMS
Titanic was an
Olympic class passenger liner owned by the
White Star Line and was built at the
Harland and Wolff shipyard in Belfast, in what is now Northern Ireland. At the time of her construction, she was the largest passenger steamship in the world. Shortly before midnight on April 14, 1912, four days into the ship's maiden voyage,
Titanic struck an iceberg and sank two hours and forty minutes later, early on April 15, 1912. The sinking resulted in the deaths of 1,517 of the 2,223 people on board, making it one of the deadliest peacetime maritime disasters in history. After nearly 74 years of being lost at sea on the bottom of the ocean floor, a joint Franco-American expedition led by American oceanographer
Dr. Robert D. Ballard, discovered the wreckage of the RMS
Titanic beneath the waves of the
North Atlantic on September 1, 1985. Ballard was then forced to wait a year for weather conditions favorable to a crewed mission to view the wreck at close range. In 1986, Ballard and his two-man crew, in the
ALVIN submersible, made the first two-and-a-half-hour descent to the ocean floor to view the wreck first-hand. Over the next few days, they descended again and again and, using the
Jason Jr. remote camera, recorded the first scenes of the ruined interior of the luxury liner.
1986 Portia • Portia is an inner satellite of
Uranus. It was discovered from the images taken by
Voyager 2 on January 3, 1986, and was given the temporary designation S/1986 U 1.
1989 Proteus • Proteus, also known as Neptune VIII, is
Neptune's largest inner satellite. Proteus was discovered from the images taken by
Voyager 2 during the Neptune flyby in 1989.
1989 Despina • Despina, also known as Neptune V, is the third-closest inner satellite of
Neptune. Despina was discovered in late July 1989 from the images taken by the
Voyager 2. It was given the temporary designation S/1989 N 3.
1989 Galatea • Galatea, also known as Neptune VI, is the fourth-closest inner satellite of
Neptune. Galatea was discovered in late July 1989 from the images taken by the
Voyager 2. It was given the temporary designation S/1989 N 4.
1990 Strawn-Wagner Diamond The Strawn-Wagner Diamond is a rare 3.03 carat diamond that is certified by the
American Gem Society (AGS) as the world's most perfect diamond in terms of its cut and the highest grade possible, the "Triple Zero". The Strawn-Wagner Diamond was discovered in 1990 at the
Crater of Diamonds State Park by Shirley Strawn of Murfreesboro, Arkansas.
1995 Top quark • The top quark is the third-generation up-type quark with a charge of +(2/3)e. It was discovered in 1995 by the
CDF and
D0 experiments at Fermilab and is the most massive of known elementary particles.
1995 Comet Hale-Bopp • Comet Hale-Bopp was arguably the most widely observed comet of the 20th century, and one of the brightest seen for many decades and it was visible to the naked eye for a record 18 months when it passed near planet Earth. Hale-Bopp was discovered by
Alan Hale and
Thomas Bopp on July 23, 1995, at a great distance from the Sun, raising expectations that the comet would brighten considerably by the time it passed close to Earth. Although predicting the brightness of comets with any degree of accuracy is very difficult, Hale-Bopp met or exceeded most predictions when it passed perihelion on April 1, 1997. '
1998 USS Yorktown
(CV-5) wreckage' • The third USS
Yorktown in the
United States Navy, lead ship of the
Yorktown class of aircraft carriers, was laid down on May 21, 1934, at Newport News, Virginia, by the
Newport News Shipbuilding and Drydock Company.
Yorktown was launched on April 4, 1936, sponsored by First Lady
Eleanor Roosevelt, and commissioned at Norfolk, Virginia, on September 30, 1937, with Captain Ernest D. McWhorter in command.
Yorktown was hit by air-launched torpedoes during the
Battle of Midway on June 6, 1942.
Hiryū, the sole surviving Japanese aircraft carrier, wasted little time in counter-attacking. The first wave of Japanese dive bombers badly damaged
Yorktown with three bomb hits that snuffed out her boilers, immobilizing her, yet her damage control teams patched her up so effectively that the second wave's torpedo bombers mistook her for an undamaged carrier. Despite Japanese hopes to even the odds by eliminating two carriers with two strikes,
Yorktown absorbed both Japanese attacks, the second wave mistakenly believing Yorktown had already been sunk and they were attacking . After two torpedo hits,
Yorktown lost power and developed a 26° list to port, which put her out of action and forced Admiral
Frank J. Fletcher to move his command staff to the heavy cruiser Astoria. The second attempt at salvage, however, would never be made. Throughout the night of June 6 and into the morning of June 7,
Yorktown remained stubbornly afloat. By 0530 on June 7, however, the men in the ships nearby noted that the carrier's list was rapidly increasing to port. At 0701, the ship turned over on her port side and sank in of water, her battle flags still flying. On May 19, 1998, the wreck of the
Yorktown was discovered by
Dr. Robert D. Ballard, American oceanographer and discoverer of the wreck of the
RMS Titanic. The wreck of the
Yorktown was found beneath the surface and was photographed.
1998 Embryonic stem cell lines • A breakthrough in human embryonic stem cell research came in November 1998 when a group led by
Dr. James Thomson at the University of Wisconsin–Madison first discovered a technique in order to isolate and grow cells which derived from human blastocysts, could one day lead to major medical advancements in organ transplantation as well as gene therapy and treatment of maladies such as paralysis, diabetes, cancer, and AIDS. ==Twenty-first century==