Major Scientific Discoveries - Timeline

[madbadgalaxyman (Robert)]

TIMELINE OF THE MOST IMPORTANT SCIENTIFIC DISCOVERIES
by Robert Anthony Lang

See also: Notes, later in this thread.

PART 1 - Until 1900

• Accurate cartography of land areas much greater than that of a town, using recognized scientific principles :: (probably Ancient Greece)(e.g. Eratosthenes , 3rd Century BC) (1)
• Heliocentric model of the Solar System :: (Aristarchus, 3rd Century BC)
• Calculation of Circumference of the Earth :: (Eratosthenes, circa 240 BC)
• First star catalog :: (Hipparchus, 129 BC)
• Astrometry & the mathematical description of Planetary Motions :: (Eudoxus & Aristarchus & Ptolemy (et al.) ; 4th to 1st centuries BC) (2)
• Atlas of human anatomy :: (Vesalius 1543) (3)
• First accurate description of magnetism :: (Gilbert 1600)
• Elliptical orbits are discovered, mathematically confirming the correctness of a heliocentric model of the Solar System :: ( Kepler 1609) (4)
• Craters of the Moon & Jupiter's four largest moons are discovered :: (Galileo 1610)
• Circulation of the blood :: (Harvey 1628)
• Laws of Motion & Gravity :: (Galileo 1638 , Newton 1687)
• Boyle's Law :: (Boyle 1662)
• Discovery of Plant cells :: (Hook 1665)
• Discovery of Single-celled organisms :: (Leeuwenhoek 1676 )
• Plant structure (morphology) is accurately characterized :: (Nehemiah Grew, 1682)
• Sexual Reproduction in Plants is proved by experiment :: (Rudolf Camerarius, 1694)
• Classification of Organisms - Taxonomy & Systematics :: (Linnaeus 1751)
• Law of conservation of mass :: (Lavoisier 1774)
• Quantitative Chemistry (Stoichiometry), chemical nomenclature, Theory of Combustion, Discovery of Oxygen & Hydrogen, discovery that water is a compound & not an element :: (mainly Priestley & Lavoisier, 1770s & 1780s) (5)
• Catalog of 2500 non-stellar astronomical objects :: (William Herschel, 1786-1802) (6)
• Stratigraphy, the rock cycle (erosion+deposition), tripartite classification of rocks, and uniformitarianism :: (William Smith 1790-1810 ; James Hutton 1788 ; Charles Lyell 1830-1833 )
• Understanding of Electromagnetism :: (Ampere & Faraday 1820-1831)(Maxwell 1860s) (7)
• Discovery that all mammals develop from an ovum, and the establishment of the science of embryology :: (Karl Ernst von Baer 1827, also: von Baer 1828 & 1837 )
• First reliable parallax distance of a star :: ( Bessel 1838) (8)
• Strong indication that all animals & plants are made up of cells :: (Schleiden 1838, Schwann 1839 )
• Second Law of Thermodynamics (Kelvin)(Clausius)(1850 - 1854)
• Discovery of Deep Time and of the true antiquity of the Earth ::(age estimates of >= 20 Myr by mid 19th C.)(radiometric dating from 1905 onwards)
• Wide-area multi-station quantitative weather data : : (mid 19th C.) (9)
• Theory of Evolution by natural selection :: (Wallace 1858, Darwin 1858 )
• Photosynthesis : : (broad understanding as a process by early 1800s ;; the photosynthesis equation - 1864)
• Neanderthals shown to be a separate and unique evolutionary lineage (William King, 1864)
• Laws of heredity :: (Mendel 1865)
• Periodic Table of the Elements :: (Mendeleev 1869 )
• Statistical Mechanics :: (Boltzmann, 1871?)
• Radio Waves are discovered :: (Hertz 1887)
• Soil Science :: (Dokuchaev, Late 19th C)
• Proof that Bacteria cause infections and infectious disease :: (Pasteur & Koch, 1860-1890)
• Homo erectus is discovered (Dubois 1891)
• Observational evidence that the Brain and Nervous System are composed of neurons and axons and dendrites :: (Ramon y Cajal, 1894 ) (10)

[madbadgalaxyman (Robert)]

PART 2 - The 20th Century

• Discovery of Biological Nitrogen Fixation by bacteria that are associated with plants :: (M.W. Beijerinck 1901) (11)
• Proof that atoms exist :: (Einstein 1905, Perrin 1909)
• Relativity :: (Einstein 1905, Einstein 1916)
• Proof of glacial-interglacial cycle (evidence for rapid non-anthropogenic climate change) :: (Penck & Bruckner 1901-1909) (12)
• Superconductivity :: (Onnes 1911)
• Bohr model of the atom :: (Bohr 1913 ) (13)
• Discovery that two atoms of the same element that are chemically indistinguishable can, however, have different atomic weights. (Frederick Soddy, 1913)
• Structure of the Earth - discovery of Crust, Mantle, inner Core, outer Core :: (1900-1936)
• Size of the Milky Way & the Sun's position within it :: (Shapley, 1918-1919) (14)
• Quantum Mechanics :: (Planck, Einstein, Bohr, de Broglie, Heisenberg, Schrodinger, Born, Dirac,1900-1928)
• Proof that stars are mainly Hydrogen & Helium, and that Hydrogen is the most abundant element in the universe :: (Payne-Gaposchkin , 1925) (15)
• Biogeochemistry & the study of whole Earth systems :: (Vernadsky 1926)
• Bees shown to communicate with each other using symbolic language (von Frisch, 1927)
• Proof that the Milky Way is not the only galaxy in the universe :: (Hubble, 1929) (16)
• "Hubble Law" & The Expansion of the Universe : (Lemaitre 1927, Hubble & Humason 1931) (17)
• The Neutron is discovered :: (Chadwick, 1932)
• Dark Matter :: (Zwicky 1933)
• Theory of general-purpose computing devices; the ability of a single machine to compute anything which is computable (Turing 1936-1937 ; ; Church 1936)
• Nuclear fission discovered :: (Hahn & Meitner & Frisch , 1938) (18)
• Black Hole shown to be the result of the collapse of a massive star at the end of its life :: (Oppenheimer & Snyder, 1939) (19)
• Energy-Producing Mechanism of the Sun :: (Bethe 1939 ;; von Weizsacker 1938)
• Planetary Atmospheres are characterized :: ( >1940)
• Ediacaran fossil assemblage is discovered :: (Sprigg 1946)
• Big Bang theory :: ( Lemaitre 1931, Gamow & Alpher 1948 )
• First Identification of a disease as due to a specific molecular abnormality :: (Pauling, 1949)
• First amino acid sequence of a protein :: (Sanger 1952) (20)
• DNA :: (Watson and Crick, 1953) (21)
• Calvin-Benson Cycle (the reactions by which plants utilize CO2 in photosynthesis) :: (Melvin Calvin & Andrew Benson, 1946 to 1954)
• First full structure of a protein :: (Kendrew 1958)
• Nucleosynthesis in Stars :: (Burbidge & Burbidge & Fowler & Hoyle, 1957)
• Australopithecus boisei is discovered :: (Mary Leakey, 1959)
• Oceanography :: (> 1960)
• Standard Model of Particle Physics :: (1960)
• First realistic theory of Galaxy Formation :: (Eggen & Lynden-Bell & Sandage, 1962)
• Quasars proved to be extremely distant & much more luminous than a large galaxy :: (Schmidt 1963)
• The Quark model :: (Gell-Mann 1964, Zweig 1964)
• Cosmic Microwave Background is observed :: (Penzias & Wilson , 1965)
• Plate Tectonics & Continental Drift are proved :: (mid 1960s)
• Pulsars - theory that they are rotating neutron stars (Gold, 1968) (22)
• Australopithecus afarensis is discovered (Donald Johanson, 1974)
• Archaea (Woese & Fox, 1977)
• Life discovered near Deep Sea hydrothermal vents :: (1977)
• Cretaceous-Tertiary mass extinction - evidence for an asteroid impact (Alvarez & Alvarez & Asaro & Michel , 1980)
• Largest-Scale Structures in the Universe are mapped (> 1980) (23)
• Symbiotic theory for origin of Eukaryotic cells :: (Margulis, 1981) (24)
• Characterization of gene control networks and the proteome :: (>1990 )
• Hubble Deep Field - research on primeval galaxies comes of age :: (1996)
• Observational proof of "dark energy" :: (1998) (25)
• Extragalactic distances become known to an accuracy of 10-20 percent, finally resolving the controversy over the value of the Hubble Constant :: (HST Key Project on Extragalactic Distance Scale; final report in 2001)
• Apparently explosive Cambrian evolutionary (diversification) event with the rapid appearance of most metazoan phyla, is characterized :: (20th C.) (26)
• Understanding of Animal Behaviour and Cognition :: (20th C)

[madbadgalaxyman (Robert)]

This list gives the years when very major advances in human understanding of the physical world occurred. It excludes technological advances, and it leaves out advances in mathematics. So here are the most important scientific discoveries and the most revolutionary steps forward in human understanding. Included as scientific discoveries are important milestones in cartography & cosmography & astrometry & human anatomy, because the absolute prerequisite for scientific understanding is the accurate observation & description & drawing & measurement of the physical world.

This list is far from being comprehensive. Many discoveries in the exponentially expanding sciences of astronomy and biology were left out due to space limitations (I would like to have included the many discoveries regarding our own Galaxy and its various components!). And my apologies for the lack of chemistry advances, and for leaving out the long & complex history of work on the wave-particle duality. In reality, some of the important scientific discoveries are so new that their 20th Century History has only started to be investigated and recorded.

Some important discoveries aren't suitable for this timeline, as they were made through a very long history of fundamental advances made by many scientists. An example of this sort of scientific advance that is not suitable for a "General Science" timeline is the theory of stellar interiors and stellar evolution; this field was started 160 years ago by Helmholtz (1854) & Kelvin (1861) with a plausible physical theory of the energy source and the age of the Sun..... but stellar astrophysics is still very much under development as of today. The landmark papers on stellar physics and stellar evolution & nucleosynthesis are so numerous that they need their own Very Long timeline!

The discovery dates that are given here are, where possible, the year (or years) of the publication(s) of a major conceptual advance as a connected whole, in the form that eventually convinced the skeptics, rather than the dates when earlier scientists (or even the scientist who published the completed discovery) may have discovered parts of the final information content of a discovery.
I have aimed for accuracy in the the attribution of credit for each discovery, but attribution is quite often a source of ongoing heated controversy; please refer to the notes.

[Steffen]

Interesting list. Wouldn't Becquerel/Rutherford/Curie also qualify (nuclear physics), or Fleming (Penicillin)?

Cheers
Steffen.

[madbadgalaxyman (Robert)]

Originally Posted by Steffen

Interesting list. Wouldn't Becquerel/Rutherford/Curie also qualify (nuclear physics), or Fleming (Penicillin)?
Cheers
Steffen.

As for Rutherford and Curie, I do agree with you, as experimental scientists often get a bad deal in lists of scientific advances (e.g. Boyle's law is almost common knowledge these days, but it was very hard for Boyle to do these experiments in the context of his times). I will see if I can at least slip in Rutherford, as atomic physics would be inconceivable without his experiments.
In the notes that go with this list, which I have not yet published, I refer to the Bohr atom as the Rutherford-Bohr model of the atom. However, I ended up just calling it the Bohr atom in the main list of discoveries.
(in the same vein, the Hubble Constant should be called the Hubble-Lemaitre constant)

As for Penicillin, I think that it was an important advance, but perhaps reliant on other work in biochemistry that may be thought of as more fundamental.
I would probably go for Jenner, the pioneer of Vaccination, in preference to Penicillin.
The problem with medical advances is that there are too many of them to put them all in the list!
Robert Koch was probably the greatest practical microbiologist, at least in the context of his times, as the role of microbes in causing disease was still greeted with scepticism when he was working in the 19th C; yet he proved that several diseases were caused by specific bacteria.

In many cases, it is even difficult to assign credit for work done, but I have done a more accurate job on giving accurate dates and in attributing work properly, than you will find in many other timelines on the internet.

[madbadgalaxyman (Robert)]

Here are the numbered explanatory notes, and some commentary, regarding some of the discoveries in the timeline.
Cheers, Robert Lang

NOTES

(1) Very very few maps have survived from Ancient Greek times. As with the astronomical observations of the Greeks, the accuracy of their mapping continued to increase with the passing of the years. Eratosthenes (circa 275-194 BC) certainly had that knowledge of astronomy & geometry & mathematics which is necessary for the production of an accurate map of large parts of the surface of the Earth. Lamentably, his work is only known from secondhand accounts rather than from the original texts! It seems that the Sumero-Akkadians, probably the oldest civilization that has directly passed on many of its fundamental ways of thinking and organizing to modern Western Civilization, were already capable of making accurate plans of buildings and accurate town plans. But it seems that accurate smaller-scale (wider area) maps may have been beyond them. This e-book has chapters about ancient cartography:

http://www.press.uchicago.edu/books/HOC/index.htm
(2) The scribes & astrologers of the ancient Babylonian Empire also engaged in astrometry of the moon and planets. I have no idea how accurate they were.
(3) A lot of experts say that Leonardo da Vinci was the first accurate anatomist, but these experts tend to be from an arts background. How accurate, really, were Leonardo's anatomical drawings?
(4) Galileo is widely credited with heroically proving the heliocentric system, and the story of his interrogation by the Inquisition and his subsequent house arrest is well known, but the Cardinals were not fools and they knew that he did not have in his posession a mathematical proof of the correctness of a Sun-centred solar system.
(5) Antoine Lavoisier seems to be the first person who was doing exact chemical science in the modern sense, using concepts and procedures and nomenclature that we would recognize today. However, I have not assessed whether or not the credit for some of his discoveries should really be shared with other workers.
(6) Herschel's sky surveying and cataloging of non-stellar objects laid the essential groundwork for Galactic and Extragalactic astronomy, so it qualifies as a major advance in science.
(7) I have only listed Michael Faraday and Andre-Marie Ampere as discoverers of major advances in electromagnetism in the 1820s. But this was truly a golden decade for discovery in this field, and there were many other workers making important discoveries at this time, e.g. Ohm, Oersted, Arago, Biot, Savart, Poisson, etc. Here is a remarkably detailed and comprehensive timeline of advances in electricity and magnetism, not that I can vouch for its accuracy:http://www.magnet.fsu.edu/education/tutorials/timeline/
(8) Several other parallaxes were published by other workers in the same year. However they were wrong!
(9) The invention of the telegraph had made this feasible.
(10) Any kind of exact knowledge of human and animal brains is at most 120 years old! Neurobiology, like molecular biology, is a very recent science.
(11) What is nitrogen fixation? And why will I die if I don't know about it? See this article:
http://www.nature.com/scitable/knowl...ation-23570419
(12) The existence of the last Ice Age had become evident during the 19th C., but Penck and Bruckner provided abundant geological evidence to back up a plausible chronology for multiple glaciations and deglaciations. (13) The Bohr model of the atom is also justifiably called the Rutherford-Bohr model.
(14) Kapteyn's now obsolete model of the Milky Way was that of a small galaxy with the Sun conveniently located near to its centre. While Harlow Shapley's model (in a series of papers between 1918 and 1919) greatly overestimated the diameter of our own Galaxy, it established the correct picture of our Milky Way Galaxy as a gigantic stellar system with the Sun's position a long way out from its centre.
(15) Cecilia Payne-Gaposchkin's 1925 PhD thesis is arguably the best in the entire history of astronomy, proving that the stars are made up of mainly hydrogen & helium. Even schoolchildren know that Newton discovered the laws of motion and Darwin discovered evolution, but it is not well known that Payne-Gaposchkin showed that hydrogen is the most abundant element in the universe.
(16) Harlow Shapley had taken the position that the Milky Way is the entire universe, a view that was still tenable in the early 1920s. However, a 1929 paper by Edwin Hubble officially announced the first totally convincing resolution of the Andromeda Galaxy into stars & star clusters. Hubble also announced the discovery of many Cepheid variable stars within M31, and he used the Cepheid P-L relation to calculate that M31 was at 8.5 times the distance of the SMC. While Hubble had already (in 1925 & 1926 papers) found some evidence that the "spiral nebulae" are likely to be vast stellar structures similar to our Milky Way Galaxy, his landmark 1929 paper about the Andromeda Galaxy convinced even the skeptics that this is the case. See for example:
http://adsabs.harvard.edu/abs/1999ApJ...525C.212C
In fact, Hubble certainly had not proved his case in 1923, though you will find this misinformation repeated again and again on the internet! It took a long time for astronomers to get comfortable with the idea that the universe contains multiple super-giant stellar systems comparable to the Milky Way. In fact, there was already hard evidence for this in the 19th Century; for example, William Huggins found that the spectrum of the Orion Nebula contained primarily emission lines from low-density gas and the spectrum of Messier 31 contained primarily absorption lines.....which have to be from cool gas in front of incandescent gas......stellar photospheres!

NOTES 17 to 26 in Next Post

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[madbadgalaxyman (Robert)]

(17) It was the 1931 paper of Edwin Hubble & Milton Humason that established the velocity-distance relation of galaxies beyond reasonable doubt, not Hubble's 1929 paper (which had really rough data!). It is certain that Georges Lemaitre should also share the credit for discovering the expanding universe. See this paper:
http://arxiv.org/ftp/arxiv/papers/1108/1108.0709.pdf
and this thread: http://www.iceinspace.com.au/forum/s...d.php?t=109083
(18) Otto Hahn won the Nobel for the discovery, but Lise Meitner never received a Nobel Prize for her essential role in this work!
(19) J. Robert Oppenheimer's 1939 paper (J.R.Oppenheimer & H.Snyder, 1939, Phys.Rev, 56, 455) predicted that a hyper-dense object with sufficient gravity to stop all light escaping from it can be formed by the contraction of a sufficiently massive star at the end of its life. This work is considered one of the most important advances in relativistic astrophysics. (A few months earlier, Oppenheimer & Volkoff had published calculations of the conditions under which a neutron star could remain stable under its own gravity, finding that it would be unstable (no static solutions and no equilibrium) above a certain critical value of its total mass!). Oppenheimer & Snyder showed that if a star's gravitationally collapsing core has sufficient mass, then even neutron pressure is still insufficient to prevent its further contraction to a black hole, and that even a neutron star would continue to shrink inexorably towards an eventual fate as a possibly point-like object. To quote from their paper : ".....this contraction will continue indefinitely."(!) . And I further quote: "The star tends to close itself off from any communication with a distant observer; only its gravitational field persists." [ A history of 1930s research on the stability (equilibrium) of neutron stars & ordinary stars, and on the conditions necessary for gravitational collapse, can be found in: "The Attraction of Gravitation"(1993) ed. Earman & Janssen & Norton, part of which is available in GoogleBooks. ]
(20) It is remarkable that before the 1950s, biochemists were unable to figure out the structures of large biomolecules like proteins.
(21) Francis Crick and James Watson, who figured out the correct structure, were entirely reliant on the X-ray crystallography data of Rosalind Franklin.
(22) Pulsars were discovered in 1967 (published in 1968) by Jocelyn Bell Burnell, a PhD student at the time. Unfortunately, her supervisor won the Nobel Prize for her discovery! It took a lot of work for her and the said supervisor to prove that the rapid and evenly-spaced radio pulses that they had detected with their radiotelescope did not actually come from a glitch in the electronics or from radio interference, and the extreme regularity of the pulses even had people thinking that some 'Little Green Men' might have produced them. Bell Burnell was a brilliant observer; but - in my opinion - a more significant advance was actually Thomas Gold's publication in 1968 and 1969 of his theory that a pulsar is a very rapidly spinning neutron star with an extremely strong magnetic field, an idea that is still accepted and which is still consistent with all existing observations.
(23) Successive and ever-deeper imaging surveys of the sky, showing the distribution of galaxies over the face of the apparent sky (that is, as seen from Earth), had shown that the galaxies seem to be distributed very unevenly; the distribution of luminous matter is not isotropic. The strong clumping of galaxy redshifts, in most lines-of-sight, was another early indicator that galaxies are not evenly distributed in space, that the universe contains many strong overdensities and underdensities of galaxies. Maps of the sky distribution of galaxies have not provided evidence for the homogeneity ("evenness") in the space distribution of galaxies and matter that had been predicted by the cosmologists! For instance, the two-dimensional distribution of the galaxies in Fritz Zwicky's CGCG (1961-1966), when plotted on a sky map, showed clusters and superclusters of galaxies, with the galaxies arrayed in a bubbly & foamlike structure that included "holes" where there seemed to be few galaxies . However, the nature of the actual three-dimensional distribution of galaxies in space, at the very largest scales, remained poorly known even in the mid-1970s , though clusters of galaxies were already known, as was the tendency of several galaxy clusters to group together into a supercluster. Fortunately for astronomers, instrumental advances beginning at the end of the 1970s gradually allowed ever-increasing numbers of galaxy spectra to be obtained, and therefore the making of distance estimates for ever larger numbers of galaxies, thereby allowing three-dimensional maps to be made of how the galaxies are distributed in the universe; in particular, the CfA1 and CfA2 redshift surveys were perhaps the first major advance in accurately mapping the space distribution of luminous matter at the very largest scales. Since then, there have been many surveys deriving large numbers of galaxy redshifts (galaxy distances), thus probing the space distribution of the galaxies out to ever larger distances and on ever larger scales, with the fundamental finding of an overall bubble-like and foamy structure that has walls and shells and filaments of multiple galaxies surrounding giant voids which contain very few galaxies. Searches for galaxies in voids have made it very likely that the space density of galaxies in voids really is unusually low, and the universe is now known to contain coherent structures as much as 1.4 billion light years long (e.g. the Sloan Great Wall). As ever more surveys have been made to map the distribution of galaxies, and as the total survey volume has progressively increased, progressively larger structures have been found....... yet cosmologists still seem wedded to the idea of an isotropic and homogeneous universe!
Here is an excellent review of the Large-Scale Structures in the cosmological context:
http://www.sns.ias.edu/pitp2/2011files/nature04805.pdf
(24) Others had also posited that the eukaryotic cell is a composite organism which had its origin in two or more free-living cells, but Lynn Margulis, over several decades, gradually collected a weight of evidence that eventually ended up convincing most biologists. The evidence is now strong that the mitochondria & chloroplasts inside eukaryotic cells are the descendents of free-living bacteria that became incorporated into a larger cell.
(25) Two teams, the Supernova Cosmology Project and the High-redshift Supernova Search Team, observed distant Type Ia supernovae and thereby established that the actual expansion law of the universe is not compatible with previously favoured models of cosmology. (observations of Type Ia supernovae, together with their known luminosities, are commonly used to make credible distance estimates for very distant galaxies). According to professional cosmologists (who are never in doubt, but often wrong......), this work showed that the expansion of the universe is actually accelerating, due to some unknown cause. The poorly-known substance or phenomenon or energy which is responsible for the acceleration of the universe is often called dark energy , or, more accurately, cosmic antipressure. A really clear explanation of all this can be found here:
http://www.slac.stanford.edu/econf/C...perlmutter.pdf

(26) The apparently sudden appearance of many of the basic body plans (= phyla) of animals in the fossil record , was already appreciated by Charles Darwin, who lamented that the apparently explosive nature of the event was hard to fit in with his theory of gradual biological evolution. However, the serious study of the nature of the so-called "Cambrian explosion" occurred in the 20th century, prompted by the collection of ever more Cambrian & Precambrian fossils, with the extremely rare fossils of soft-bodied animals being key data points in the ongoing arguments. The time frame of this evolutionary radiation, the nature of the soft-bodied antecedents of the Cambrian organisms in the fossil record, and the question of exactly which phyla are represented in the Cambrian rocks, are all subjects of ongoing debate What can be said for sure is that easily fossilizable multicellular animals (that is, those with hard parts) first appeared in the Cambrian Period.


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[AstralTraveller (David)]

That's a very interesting list Robert, which I will pore over later. Thanks for putting in the time and effort. It certainly is a useful reference and there is stuff in there that I was unaware of.

Of course everyone is going to say 'what about xxx' and I'm no different! My first though was that there is little (nothing?) about spectroscopy, and you don't need me to tell you how important that discovery was. I would expect to see names like Bunsen, Kirchhoff and Fraunhofer on the list. The second omission seems to be Plate tectonics, although I concede that in that case a definitive discoverer and discovery date are harder to isolate. Thanks again.

[Steffen]

Continental Drift and Plate Tectonics is there, may be worthwhile tagging it with Alfred Wegener's name (after all, he was the one who got laughed at for his theory), but there were many other's of course.

Regarding Marie Curie, she's got twice as many Nobel Prizes as Albert Einstein, I reckon she deserves a mention

Cheers
Steffen.

[AstralTraveller (David)]

Originally Posted by Steffen

Continental Drift and Plate Tectonics is there,..

Oops, my bad.

[madbadgalaxyman (Robert)]

Originally Posted by AstralTraveller

Of course everyone is going to say 'what about xxx' and I'm no different! My first though was that there is little (nothing?) about spectroscopy, and you don't need me to tell you how important that discovery was. I would expect to see names like Bunsen, Kirchhoff and Fraunhofer on the list.

Originally Posted by Steffen

Continental Drift and Plate Tectonics is there, may be worthwhile tagging it with Alfred Wegener's name (after all, he was the one who got laughed at for his theory),
Cheers
Steffen.

Thanks very much, David and Steffen, for your interesting input.

As far as Wegener is concerned, his inclusion or exclusion in the "Major Discoveries list" is the sort of question I faced all the time, for many of the discoveries:
- do you include the pioneer of the field who was far-sighted and ahead of the game, and who perhaps saw things intuitively that were far ahead of his or her time, but who had no real proof.
OR
- Do you include the person or persons who did all the hard work of actually proving that something is really occurring

I do take Steffen's point about Rutherford's importance in atomic theory, in this regard, as he did the hard yards of difficult experimental work.

My own preference, in compiling the list of dates and discoverers for this list of the top discoveries, was quite often to give a later year and/or author for a discovery, at the time when the discovery was put in the form that was eventually accepted, rather than to name the pioneer of the field.
(e.g. Galileo was a brilliant advocate for the heliocentric theory, and Copernicus rewrote Ptolemaic reasoning but with the Sun at the centre, but Kepler was the one who turned it into an elegant mathematical form that actually predicts the observables)
(e.g. Evolution was not discovered by Darwin, but by others......such as the now much villified Jean-Baptiste Lamarck)
(e.g. I gave the kudos for proving the atomic theory to Einstein and Perrin, instead of to John Dalton a hundred years earlier. The story of the 19th century fight over the atomic theory is interesting. Maybe Dalton and Einstein should both be on the timeline for the atomic theory, but a timeline is supposed to give only one year for a discovery!)
(e.g. Hubble's original 1929 paper on the expansion of the universe, included remarkably poor observational evidence. So I gave the prize to Hubble and Humason in 1931.)

In the matter of continental drift and plate tectonics, Wegener's ideas , as we know, were often ridiculed, so he is easy to slot into the "brave hero who was before his time" category.

However, an awful lot of further geological discovery and measurement had to take place before his theory was finally proven in the 1960s. If you look at how the story panned out after Wegener, it was a very long and hard road for geology to actually measure and observe what is really going on in the Earth's crust and upper mantle. Indeed, the mantle is still not fully understood, to this very day!

There are many examples of people like Wegener who saw patterns that others did not see, using only very limited data, and who eventually turned out to be correct, but we tend to remember those of them whose conceptions were laboriously proved, later on.

David, your point about including the spectroscopists is well taken, and I will give it very serious consideration. Another angle on this is:
- how important or difficult was the work undertaken, in its time, and did it represent a major advance?
vs.
- how important it seems now.

I am somewhat familiar with the very remarkable story of Fraunhofer, so I am trying to assess his achievement in the light of these sorts of questions.

I do agree, The list does need a few more advances in physics and chemistry to be put in. However, there are also a lot of discoveries in astronomy and biology that could compete for a place in this list!

To me it seems that the study of the history of science is very much a work in progress; indeed scientists are more concerned with the ever advancing frontier rather than with who discovered what; the great old stories we like to tell ourselves about the brilliant scientists of the past are often not questioned.

[xelasnave]

Thank you Robert for your wonderful post.
A very ambitious undertaking well done.

[Ric]

A great post Robert.

Thanks for taking the time to compile it, there's a lot of work that has gone into it.

[madbadgalaxyman (Robert)]

This timeline cost me a couple of weeks of work, and it is good enough to be worth republishing here.

- Robert

[rally]

Robert,

Interesting project.

I wonder if the list might be more complete and meaningful by including a small list of those whose contributions to any final proof or theory wouid not have otherwise been possible.

In the theme of " . . . on the shoulders of giants"
ie include all the giants and those who stood upon them !

Maybe with some nomenclature keys/codes that show who published, who first theorised/hypothesised and whose other discoveries/research was key to final discovery.

That might also alleviate the quandary of who do you include and who do you exclude.

In much the same way that an author bibliographically acknowledges his sources and a patentor acknowledges prior relevant art.

Just a thought

Rally

[rrussell1962]

Despite my interest in Astronomy my personal favourites all begin with "A" Antiseptics, Antibiotics and Anaesthetics. Life would be a lot less pleasant, and shorter, without them. I'll add a "V" for Vaccination.

[AlexN]

Well done. Although I don't see the launch of HST, SRO, Spitzer, Cassini, Voyager 1 or 2?
Surely the devices that make discoveries possible deserve a spot on the list.

[Eratosthenes (Peter)]

Robert,

A nice list of achievements that I am certain people could add to. (such as the Antikythera mechanism, dated to ~200 BC and is the worlds first computing device that could predict planetary motion, eclipses etc. Alcmaeon of Croton was the first to carry out eye surgery and postulate that human emotions resided in the brain rather than the heart ~ 400 BC)

(only issue I have is your list's highly western-centric emphasis. There are lots of discoveries that can be traced back to other societies and civilisations, including indigenous Australian peoples - the very first major engineering works, is attributed to Australian aboriginals who lived in Western Victoria and us dated to almost 8000 years ago. Also we have the first seismograph invented in China and is about 2000 years old. The ancient Chinese were also fiddling around with magnetism which enabled the first compass to be invented. The Arab world also made great contributions to human advancement and enlightenment)

[rally]

The Transistor and Integrated Circuit ?

You list Turing for the computer - but what of Babbages 1834 designed mechanical "Analytical Engine".
They only built a small working prototype and not the complete computer but I wonder if his many publications and references did not stimulate Turing and others.
His other device the Difference Engine was also developed and made by others

It had Input (punched cards), output (printer and typesetting), read write memory of 50 digit numbers, a bus where variables could be copied, shuffled between processor and memory and printer, it had sequential and conditional program branching, variables and a processing unit (he called it the Mill) and sub processors !

And all of that designed in 1834 !

[Steffen]

I think Robert's list is for discoveries, not inventions.