For beginners: You will get a good survey of modern physics/chemistry in R. Nave'sHyperPhysics: and its historical background in- Fowler, Michael: Galileo and Einstein.A contemporary introduction to the universe is UCSD Astronomy Tutorial (Smith and Rappoport);
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98 Neutrinooscillation
Zeilinger
Go for E=mc2 this was tele portation for everybody, are you now curious in 97 Quantum teleportation
Quantum teleportation is the transmission and reconstruction of the state of a quantum system — an idea that was demonstrated experimentally by Dik Bouwmeester and colleagues in 1997. As their principal teleportation resource, the team used a pair of entangled photons; to effect the teleportation, they initiated a measurement involving one photon of the pair and a third photon. As a consequence of this interaction, the state of polarization of the third photon was transferred perfectly to the second photon of the entangled pair. In principle, this process should work even if the teleportation takes place over an arbitrarily large distance.
Nature390, 575–579 (1997)
95 The discovery of an exoplanet
In 1995, Michel Mayor and Didier Queloz made the first discovery of a planet outside our Solar System, in orbit around a Sun-like star in the constellation of Pegasus. Despite controversy over similar, earlier claims, Mayor and Queloz's discovery has withstood the test of time. Their Jupiter-sized planet completes its orbit every 4.2 days — placing it at a distance from its star, 51 Pegasi, that is much less than the Sun–Mercury distance.
Nature378, 355–359 (1995)
93 Superconductivity — rising temperatures
The discovery in 1986 of the first copper oxide superconductor stimulated an explosion of research activity that continues to the present day. The early years of high-temperature superconductivity were characterized by the rapid discovery of many new materials with increasingly high transition temperatures. The record now stands at ~133 K, attributed to a mercury-containing compound reported by Schilling et al. in 1993, although the dream of achieving room-temperature superconductivity has yet to be fulfilled.
Nature363, 56–58 (1993)
92 Pulsar planets
The utility of the clock-like pulses emitted by pulsars (see The first pulsar) did not end with the insights they have yielded into the properties of neutron stars, and hence of high-density matter. In 1992, Wolszczan and Frail reported precise pulsar timing measurements which exhibited periodic variations. Unlike similar observations reported in the previous year (cited as ref. 3 in the paper), these variations were not an artefact, but revealed the presence of two or more planet-sized objects orbiting the neutron star — the first such objects to be detected outside the Solar System.
Nature355, 145-147 (1992)
|91Synthesis of carbon nanotubes
On 7 November 1991, Sumio Iijima announced in Nature the preparation of nanometre-size, needle-like tubes of carbon — now familiar as 'nanotubes'. Used in microelectronic circuitry and microscopy, and as a tool to test quantum mechanics and model biological systems, nanotubes seem to have unlimited potential. Ten years on, new research with nanotubes appears regularly in the pages of Nature and other journals.
Nature354, 56–58 (1991)
90 A new form of carbon
For five years after its discovery in 1985 (see Curious carbon — the 'buckyball'), the buckminsterfullerene molecule, C60, remained something of a curiosity. The development by Krätschmer et al. of a technique for synthesizing C60 as a bulk solid brought fullerenes into the realm of materials science and condensed-matter physics, with rewards that are still being reaped today.
Nature347, 354–358 (1990)
90 Polymer LEDs
By 1990, the development of solid-state light-emitting diodes (LEDs) had come a long way. Efficient LEDs based on inorganic semiconductors had already found widespread application. Molecular organic semiconductors were also coming to the fore — not only were they available in a range of colours but, unlike their inorganic counterparts, they could be readily made into flexible, large-area displays. But physicists were encountering problems with the long-term stability of the organic films. Then Jeremy Burroughes and colleagues produced the first polymer LED: moving from molecular to macromolecular materials solved the stability problem and meant that high-quality films could be made easily.
Nature347, 539–541 (1990)
87 Flux quantization in high-Tc superconductors
In copper oxides, the transition temperature to superconductivity (Tc) is unusually high. A year after the discovery of this phenomenon, C. E. Gough and colleagues measured the quantization of magnetic flux in a superconducting copper oxide and got a value of h/2e (where h is Planck's constant and e is the electron charge). According to Gough et al., their results imply that, in high-Tc materials as in conventional superconductors, "the charge carriers of superconductivity are electron pairs". But although the Bardeen–Cooper–Schrieffer theory has successfully described conventional superconductivity, the exact mechanism for high-Tc superconductivity remains a mystery.Nature326, 855 (1987)
|87A Neutrinos and neutrino mass from a supernova
In 1987, a supernova exploded in the nearby Large Magellanic Cloud. Bahcall, (Tegmark; Sloan)Dar and Piran were quick to point out in Nature that a neutrino burst from the collapsing star should have reached Earth and that, if detected, it would provide "a unique opportunity to test the theory of neutron star formation in Type II supernova explosions". A note added in proof to their 'Scientific Correspondence' confirmed that the Kamiokande neutrino detector in Japan had indeed picked up a signal. The Kamiokande data also afforded the first opportunity to determine the mass of the electron neutrino from astronomical data. A few weeks later, in a letter to Nature, Bahcall and Glashow had set an upper limit on the electron neutrino mass at 11 eV.
Nature326, 135–136; 476–477 (1987)
86 Gravitational microlensing
In 1986, Bohdan Paczynski suggested that dark, compact objects in the halo of our Galaxy — the local cousins of similar objects conjectured to contribute dark matter to the haloes of other galaxies — could be detected on Earth, as their gravitation might occasionally amplify the light arriving from more distant stars. In 1993, in surveys of several million stars in the Large Magellanic Cloud, C. Alcock et al. and E. Aubourget al. observed several candidate events. In total, the two groups detected three stars for which the brightness increased by two magnitudes over an interval of roughly one month.
Nature365, 621-623 (1993) and Nature365, 623-625 (1993)
|85 Curious carbon — the 'buckyball'
Before 1985, it was generally accepted that elemental carbon exists in two forms, or allotropes: diamond and graphite. Then, Kroto et al. identified the signature of a new, stable form of carbon that consisted of clusters of 60 atoms. They called this third allotrope of carbon 'buckminsterfullerene', and proposed that it consisted of polyhedral molecules in which the atoms were arrayed at the vertices of a truncated icosahedron. In 1990, the synthesis of large quantities of C60 (see A new formof carbon) confirmed this hypothesis.
Nature318, 162–163 (1985)
79 Gravitational lensing
In 1979, Walsh, Carswell and Weymann reported the observation of two quasistellar objects that looked suspiciously similar. Known as 0957 + 561 A and B, and separated in the sky by only 5.7 arc seconds, the two sources had nearly identical magnitudes, redshifts and detailed spectra. "Difficulties arise in describing them as two distinct objects," the researchers pointed out. Gravitational lensing, they suggested, offered a more likely explanation: light from a single source, after travelling along distinct, bending paths through the gravitational field of some large intervening object, was arriving at the Earth from two different directions.
Nature279, 381–384 (1979)
74 Black-hole evaporation
It is often said that nothing can escape from a black hole. But in 1974, Stephen Hawking realized that, owing to quantum effects, black holes should emit particles with a thermal distribution of energies — as if the black hole had a temperature inversely proportional to its mass. In addition to putting black-hole thermodynamics on a firmer footing, this discovery led Hawking to postulate 'black hole explosions', as primordial black holes end their lives in an accelerating release of energy.
Nature 248, 30–31 (1974)
|73 MRI — a new way of seeing
In 1973, Paul Lauterbur described an imaging technique that removed the usual resolution limits due to the wavelength of the imaging field. He used two fields: one interacting with the object under investigation, the other restricting this interaction to a small region. Rotation of the fields relative to the object produces a series of one-dimensional projections of the interacting regions, from which two- or three-dimensional images of their spatial distribution can be reconstructed. Application of this technique as magnetic resonance imaging is now widespread.
Nature242, 190–191 (1973)
71 t`Hooft vi
69 An astrophysical water maser
In 1963, Harold Weaver and colleagues observed unusual emissions from the Orion nebula. The radio frequency suggested the presence of hydroxyl (OH) groups, but the line intensities were wrong. The explanation? Weaver et al. suggested that these were not ordinary thermal emissions, but that clouds of OH gas were emitting by maser action, being pumped by infrared light from nearby star-forming clouds. Six years later in Nature, Cheung(now X-rays) et al. reported the discovery of another class of astrophysical maser — spectacularly bright 22-GHz water masers — observations of which are now widely used to probe the dynamics of their environments.
Nature221, 626–628 (1969)
Nature134, 494–495; 880 (1934)
68 The first pulsar
1968 saw the first report of a curious class of astronomical radio sources, distinguished by their rapid and extremely regular pulsations. Hewish et al. associated them with unusually stable oscillations in compact stars. They are now understood to be rapidly rotating, magnetized neutron stars, or pulsars.
Nature217, 709-713 (1968)
63 The quasar enigma solved
In the early 1960s, astronomers were puzzled by quasars — sources of intense radio emission that seemed to be stars, but had unintelligible optical spectra. In 1963, Maarten Schmidt solved the puzzle by recognizing the Balmer lines of hydrogen, strongly redshifted, in the spectrum of the quasar 3C 273. Schmidt reached the "most direct and least objectionable" conclusion, that 3C 273 was no star, but the enormously bright nucleus of a distant galaxy.
Nature197, 1040 (1963)
62 Cosmic X-ray sourcesGiaconi
60 Stimulating stuff — the first laser
After demonstration in 1954 of the 'maser' principle (microwave amplification by stimulated emission of radiation), systems were sought in which the effect occurred in the infrared and visible spectrum. This goal was reached in 1960 when Theodore Maiman achieved optical laser action in ruby.
Nature187, 493-494 (1960)
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58 X-ray crystallography — the first image of myoglobin
To understand how a protein performs its individual biological function, it is essential to know its three-dimensional structure. As early as 1934, J.D. Bernal and Dorothy Hodgkin (then Dorothy Crowfoot) showed* that proteins, when crystallized, would diffract X-rays to produce a complex pattern of spots. They knew that these patterns contained all the information needed to determine a protein's structure but, frustratingly, that information could not be deciphered. By comparing patterns from crystals containing different heavy-metal atoms, Max Perutz and colleagues devised the approach that was to solve this riddle. In 1958, J. C. Kendrewet al. applied Perutz's technique to produce the first three-dimensional images of any protein — myoglobin, the protein used by muscles to store oxygen.
Nature181, 662–666 (1958)
57B|Bardeen, Cooper and Schrieffer
57A The ponderomotive force
In 1957, Boot and Harvie reported the observation of a force on charged particles in an inhomogeneous electric field, which originated from second-order terms of the equation for the Lorentz force on the particles. Almost immediately it was realized that this 'ponderomotive force' could be used to trap and control electrons. But the force is weak: only with the development of modern laser technology is the ponderomotive force being exploited in new particle-acceleration techniques and inertial confinement fusion. Nature180, 1187 (1957) y.chalmers.se/tp/Network/ 56 Quantum correlations in lightELECTRICAL ANALOGS OF THE HANBURY BROWN TWISS EXPERIMENTGBG Teor-PH Eurostrings
Classical interferometry works by detecting correlations in the phases of two waves. In Nature in 1956, R. Hanbury-Brown and R. Q. Twiss demonstrated another technique that probes quantum-mechanical correlations in the electromagnetic field. Splitting an incoherent light beam, they found that photon detections in the two daughter beams were correlated: the photons were bunching together. This corresponds to a correlation in the intensity of light in the two beams, which Hanbury-Brown and Twiss suggested could be used to infer the angular size of distant stars. Physicists now rely on the effect to probe the quantum character of complex light sources.
Nature177, 27–29; 178, 1449–1450 (1956)Click here for an obituary of Robert Hanbury Brown.
56(27) The neutrino — the mystery and the discovery
In the 1920s, physicists were confused: the phenomenon of b decay (in which an electron is emitted from the atomic nucleus) seemed to violate conservation laws. The energy spectrum of the electrons, or b-rays, is continuous: if energy is conserved, another, variable, amount of energy must somehow leave the system. In 1927, Ellis and Wooster1 tried — and failed — to capture and measure that missing energy. By 1933, Pauli had devised an explanation in terms of another, undetected, particle being emitted by the nucleus; Fermi called it 'the neutrino'. Only in 1956 was the existence of the neutrino proved: Reines and Cowan2 sent Pauli a telegram to inform him of their discovery.
1. Nature119, 563–564 (1927) 2. Nature178, 446–449 (1956)
*Bernal, J. D. & Crowfoot, D. Nature133, 794–795 (1934).
55 Hard pressed — the first synthetic diamondsClaims of the conversion of carbon to diamond date back to 1880, but it was not until 1955 that the first reproducible synthesis was reported. Bundy et al. describe the high-pressure, high-temperature apparatus that enabled them to reach the stability field of diamond, and prove that the material obtained was indeed diamond. Ironically, some of the same authors discovered 38 years later that the very first diamond grown by their technique was not synthetic after all, but a fragment of a natural diamond that got into the experiment. Fortunately, however, the technique was sound, and marked the beginning of the present synthetic-diamond industry. Nature176, 151–155 (1955) & 365, 19 (1993)
53 DNA — a new twiston life First steptowards life
The determination in 1953 of the structure of deoxyribonucleic acid (DNA), with its two entwined helices and paired organic bases, was a tour de force in X-ray crystallography. But more significantly, it also opened the way for a deeper understanding of perhaps the most important biological process. In the words of Watson and Crick: "It has not escaped our notice that the specific pairing that we have postulated immediately suggests a possible copying mechanism for the genetic material."Nature171, 737–738 (1953)
51Spiral growth of crystalsMicroscopic spirals often appear on the surfaces of solids grown slowly from solution. In 1949, F. C. Frank proposed an explanation, suggesting that crystal growth could lead to screw dislocations — linear defects oriented normally to the growing surface and forming the core ofa lattice structure locally akin to a spiral staircase. In Nature, four years later, Ajit Ram Verma and S. Amelinckx offered experimental support for the idea. Photos of a solid forming on a surface revealed a growth front spiralling outward around a central point. Measurements confirmed the height of the growing layer as a single unit cell.
Nature167, 939–940 (1951)
51 The hydrogen 21-cm line cgi/content/full/300/5620/745
September 1st marks the fiftieth anniversary of Ewen and Purcell's report in Nature of the discovery of the hydrogen 21-cm line. In fact, they had seen the signal months before, but waited for corroboration by Dutch and Australian astronomers before publishing: Muller and Oort's paper* in the pages following Ewen and Purcell's report includes the text of a cable sent by Pawsey from Australia. Oort had already realized the significance of the discovery — that detection of this spectral line, produced by transitions between hyperfine levels of the ground-state hydrogen atom, would permit measurements of velocities by the Doppler effect. The 21-cm line put radioastronomy on the map, and brought about a revolution in the study of galactic structure.
Nature168, 356 (1951) *Muller, C. A. & Oort, J. H. Nature 168, 357–358 (1951).
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49 Quantum Mechanics As A Statistical Theory Moyal PrCamPhilSoc 45 (1949) 99
48A The invention of holography
The spherical aberration of electron lenses has long been the bane of electron microscopy. Enter Dennis Gabor in 1948 with a proposal for an 'electron interference microscope', which did not rely on traditional optical principles. Instead, interference between the illuminating and scattered electron wavefronts was used to record a three-dimensional representation of the object under investigation. This principle is now known as holography.Nature161, 777-778 (1948)
B The first stored-program computer
The modern computer was born on 21 June 1948, when the University of Manchester's Small-Scale Experimental Machine, nicknamed the 'Baby', successfully executed its first program. Designed and built by F. C. Williams and Tom Kilburn*, the Baby kept only 1,024 bits in its main store, but it was the first computer to store a changeable user program in electronic memory and process it at electronic speed. Nature162, 487 (1948)
*Click here for an obituary of Tom Kilburn.
37Coulson/31PhD Löwdin/29Fischer-Hjalmars/22Pople&Hall/21Ballhausa&Longuet-Higgins
47 Superconductivity defeats gravity
Superconductors have no electrical resistance and are strongly diamagnetic. In the Meissner effect, a superconductor expels a magnetic field. In 1947, in a letter to Nature, Russian physicist V. Arkadiev demonstrated a striking consequence of such diamagnetism. Using a steel magnet and a superconducting lead disk resting in liquid helium, Arkadiev revealed in a photograph how the magnet was "repelled from the horizontal surface with such force" that it hovered in the air with no other support. Today, with liquid nitrogen and modern high-temperature superconductors, Arkadiev's levitation is a common trick in the physics classroom. Nature160, 330 (1947)
47 V-particles — stranger still!
In 1947, Rochester and Butler twice observed that cosmic rays produced peculiar V-shaped tracks in a cloud chamber. These events, they suggested, reflected the decay of unknown particles with masses roughly 1,000 times that of an electron. In 1949 and 1951, Brown et al. and Armenteros et al. offered more extensive corroborating evidence for these 'V-particles', showing that there were at least two different kinds, which produced protons and pions when they decayed. These were the first observations of strange particles — now known as kaons, lambdas, cascades and sigmas — which are produced by the strong interactions, but can only decay by the weak interaction.