SOHO Spacecraft visualisation and during build. The satellite weighs in at ~?2,032 kg? (2 tons) and spans 7.62 m (25 ft) across with its solar panels extended. SOHO was launched in December 1995 via the launch facility SAEF-2 of the Kennedy Space Centre, pad 36B, atop an Atlas Centaur AC-121 rocket; and became operational in March 1996.

  SOHO, the Solar & Heliospheric Observatory, is an international collaboration between ESA and NASA to study the Sun, with instruments to probe the solar core, its outer corona and the solar winds. Engineering was provided by over 200 international investigators. NASA is responsible for the launch systems and mission operations. Mission control is based at the Goddard Space Flight Centre, Maryland, USA.

  SDO - The Solar Dynamics Observatory is a solar observing platform with updated capabilities on the previous SOHO (1996) and complimentary to the STEREO (2006) solar observer missions.

Understand, driving towards a predictive capability, the solar variations that influence life on Earth and humanity's technological systems by determining

• How the Sun's magnetic field is generated and structured
• How this stored magnetic energy is converted and released into the heliosphere and geospace in the form of solar wind, energetic particles, and variations in the solar irradiance.

  Some of the SDO's updated instrumentation is quoted as being:
  AIA (Atmospheric Imaging Assembly) - The Atmospheric Imaging Assembly images the solar atmosphere in multiple wavelengths to link changes in the surface to interior changes. Data includes images of the Sun in 10 wavelengths every 10 seconds. Alan Title; Lockheed Martin Solar Astrophysics Laboratory.
  EVE (Extreme Ultraviolet Variability Experiment) - The Extreme Ultraviolet Variability Experiment measures the solar extreme-ultraviolet (EUV) irradiance with unprecedented spectral resolution, temporal cadence, and precision. EVE measures the solar extreme ultraviolet (EUV) spectral irradiance to understand variations on the timescales which influence Earth's climate and near-Earth space. Tom Woods; Uni of Colorado.
  HMI (Helioseismic and Magnetic Imager) - The Helioseismic and Magnetic Imager extends the capabilities of the SOHO/MDI instrument with continual full-disk coverage at higher spatial resolution and new vector magnetogram capabilities. Phil Scherrer; Stanford Uni.
  The 2 high-gain antennas are Earth-tracking, maintaining as best contact with Mission Control, where-ever the spacecraft; as the craft, despite rotating in sync with the Earth, adopts a steady sun-pointing attitude.

  SDO launched on 11th February 2010, 10:23am EST, after a days delay due to weather; on an Atlas V that lifted from area SLC 41 at Cape Canaveral, Florida, USA. A large satellite by any standard, SDO massed at launch; spacecraft 1,300 kg (2,870 lbs), instruments 300 kg (660 lbs) and nav-fuel 1,400 kg (3,090 lbs); totalling 3,000 kg (6,620 lbs, 2.95 tons). Its 6.6 sq-m (71 sq-ft) solar arrays deliver 1,500 W at an efficiency of 16%, and extend 6.25 m (20.5 ft) across.

  The spacecraft was eventually boosted to a very near circular (eccentricity 0.00025) geosynchronous Earth orbit located over 102° W longitude, inclined at 28.5°.

The estimated population of Africa is 1.267 Billion or 16.41% of the total World population (7,578,909,220).
Africa ranks as number 2 (1, China, 1.411 Billion, 18.67%) ordered by population numbers for world regions designated as 'Continents'.
Data: www.worldometers as of Saturday, 4th November 2017, based on the latest United Nations estimates.

Protostars glow dissipating the gravitational energy of formation as their gas is heated by the compression of collapse. This is called the Kelvin–Helmholtz contraction phase, named after Lord Kelvin (William Thomson - 1862) and Hermann von Helmholtz (1856), both European physicists, who provided calculations based around the gravitational compression of gasses and the cooling of a molten earth, in an initial attempt to calculate the age of the earth.  An argument that had all been started by one of the worlds most famed idiots, the Archbishop James Usher of Armagh, Ireland, in 1650; suffuse with dogma and clouded in ignorance, declared that the universe was created in 4004 BC, on such a day and at such time worth forgetting; least the number 5,654 years ago (@ 1650). A very poor guess. It was a vexing and perplexing problem, as the ages thoughtful calculations offered were falling far short of the preliminary estimates coming in from the geologists and palaeontologists of the day, who were theorising from their standpoint of their understanding of the processes for sedimentary deposits; and from the evidence of the materials and fossils they were collecting in the field. Gravitational collapse, and even chemical burning, could not provide the energy for a glowing sun for the estimated 100’s of millions of years, and at that time just moving into the billion, that the budding science of planetology required. More frustratingly, there was as yet no known process by which geological time could be reliably estimated.

 There began one of the most intense and exciting periods of scientific enquiry, that in its first phase of a short 40 years or so, propelled the planet from a sedentary classical Newtonian view of the mechanical universe, to evolve into the dubiously promising, continually mismanaged, but necessary age of the atom. Chemistry was to be explained as a phenomenon of electricity, and a new world of quantum probability was to be borne.

In a hurried retrospective we may recall that the English philosopher-physicist Isaac Newton began to conceive in 1666 the laws of refraction of light, and an explanation for the dispersion of light into the colours of the rainbow. He released his findings to the Royal Society in 1672; but because of much criticism, did not allow the publication of the rules of optics that he had devised, titled Opticks, until 1704. Newton, putting it a little more kindly than perhaps he deserves; was at once a genius of the first rank and also the first ‘geek’ of physics, disorganised, and an eccentric recluse; the proverbial example of the street-dumb ivory tower ‘Don’. Also beginning in 1666, when he was at his mothers home in the country for two years, to avoid the bubonic plague that ravaged the cities, he devised in secret, what he called Fluxions, what we now call derivative calculus, to support his work on gravitational attraction that he had then begun to develop. He got into another row with the mathematician Gottfried Wilhem Libniz whom Newton could not believe had independently also derived derivative calculus when Libniz version was published in 1676. The then heavyweight British establishment acceded in Newtons favour, so that this branch of mathematics is now accredited  to both Newton and Libniz. Newtons pinnacle contribution to science; his laws of motion, enlarging on the understanding of the 1632 works of the Italian Galileo Galilei, considered by many as the founding father of experimental science; his laws on gravitational attraction, explaining the laws of elliptical orbits, so crucial to astronomy, as proposed by the German mathematician Johannes Kepler in 1594; may have remained buried in the Cambridge archives for another century, had Newton not been harried from the outside.

 To settle an argument between the architect Sir Christopher Wren, physicist Robert Hook and the astronomer Edmond Halley (later of cometary fame); in 1684 Halley came from London to Cambridge to consult Newton. Asked what he thought the course of the planets would take around the sun, if the force of attraction was inversely proportional to the square of the distance between them, Newton quickly answered in his customary way, ‘been there, done that’ and the answer is ‘elliptical’. Incredulous to the rapidity of the response, Halley asked where was the proof? It took three years for Newton to write, after much badgering and even financing from Halley, and included the solutions to much else, before Halley finally handed the completed Principia to the president of the Royal Society, Samuel Peppys, in 1687. That the work was sensational, would be an understatement; its laws underpinned the industrial revolution of the planet and survived for over 200 years, before needing modifications to accommodate the laws for objects moving near the speed of light, and for a better understanding of light itself, when the concept of space-time was to arrive in 1905.

 
Another outstanding precursor to this new age, out of many others that were however necessary in foundation like, Michael Faraday the electrical hardware man, was the complimentary work of the Scots mathematician James Clarke Maxwell, who unified electricity and magnetism in 1860 with what are now known as Maxwell's field equations. It rigorously postulated that an electric field, orthogonal (at 90 degrees) to a magnetic field, oscillated together in a sinusoidal way to produce electromagnetic waves that propagated at a calculable speed. The strength of any new theory is in its ability to predict measurable results. Maxwell's field equations went way beyond this simplistic criteria; as to some observers, the elegance of the mathematics also accomplished an inherent beauty that approached art; and that the manipulation of the mathematics produced much more than just one startling result. The result that the speed of electromagnetic waves turned out to be around 300,000 km/s (≈ 186,000 mi/s); which just happens to be the measured speed of light en vacuo, would have been sensational enough to mark the achievement as 'epic'. The tying of light to a narrow wave-band lying within that enormous range of the electromagnetic spectrum that encompasses kilometre long-wave radio waves at one end and the short fempto-meter gamer-rays at the other. But no, that was just the beginning of what followed.

Maxwell's field equations are the bases for communications and transmittable (& receptable) energy engineering; their astute manipulation predicting all the necessary control algorithms within the disciplines of AM, FM, TV, micro-wave and RADAR, just to highlight a few of the better recognised within this vast field of work; which also purveys into astrophysics and astronomy. Simply in scope, Maxwell's field equations define the term 'awesome'.

The new age of discovery centred around the effort to understand the composition of the atom, which comes from the Greek ἀ- (a-, "not") and τέμνω (temnō, "I cut") or collectively ἄτομος (atomos), which means "indivisible"; and by default, molecules. Although chemists had for years successfully manipulated elements and their molecular constructions, they still remained at a loss to understand the underlying processes that quantified the behaviour of the elements they were dealing with. It was now the turn of the physicist and theoreticians to provide the useful answers.

Ernest Rutherford visits the Curies in Paris in the summer of 1903, on the same day that Marie receives her doctorate. At the end of the evenings celebrations, he is shown a vile coated in zinc sulphide, containing concentrated salts of their newly discovery radium. The vile enchantingly glows brightly white, in scintillation to the stream of radiation exciting it. It is bright enough for Rutherford to later comment that he observed, in its light, that Pierre Curies hands were scared and reddened by such activity. Ever observant, as was his character; little did he realise at the threshold of this science, the dangers to which they were all subject. Mem. Marie Skladowsha Curie would later die of leukaemia (4th July 1934); and all her laboratory papers and other memorabilia, consigned to lead containers for posterity. [The medical sciences that were to eventually qualify the true extent of radiological hazards to biological systems, would take a further 50 years to be properly developed.]

 Rutherford, together with Frederick Soddy the chemist, went on in 1903 to describe the spontaneous disintegration of radioactive elements and developed the theory of radioactive decay and its inherent time marker of ‘half-lives’. Soddy used the term isotopes , a descriptor ascribed to one Dr. Margaret Todd, to distinguish between mass differences of the same element, that would themselves demonstrate different ‘half-lives’. They went on, in the infancy of the science, to glean the remarkable range of time differences in the ‘half-lives’ of various ‘decay products’ of radioactive elements; from fractions of seconds, to a staggering 4.5 billion years for an isotope of uranium. Their investigations handed the elusive grail of ‘time’ to the geologists and, when used the other way around, ‘half-lives’ to identify specific elements, or indeed new elements, for the chemists. Much of the investigative work that was to follow, well into the late 1930’s, on new elements and their isotopes, created by their bombardment with nuclear emissions, was based on ‘half life’ detection; and then tracing the minute quantities of the elements thus formed; through various chemical separation stages that would then identify the resulting elements.

 
Between 1904 and 1905 Albert Einstein, a Swiss patent office clerk, published four papers. The first, on Brownian motion, and the second, his doctorial thesis in which osmosis is investigated; used classical statistical mechanics that allowed investigators to establish the size of atoms and molecules. The third paper, for which he received a Nobel prize in 1922, explained the Photo-Electric effect in quantum mechanical terms; as the duality of light to be both a particle and a wave, where the wave is a photon, and the photon a discrete quantum unit of energy, and the energy of the quantum unit is proportional to the frequency of light, leading photo-voltaic effects to be proportional to light frequency, rather than light intensity. The forth paper, on Special Relativity, conceived around the perceivings of two observers placed at different points relative to each other within the frame of reference; that changed the perception for the laws of motion of a particle in a straight line; where that the speed of light is a constant and the maximum speed at which only light can travel, where space-time, the fabric of the universe, uses time as its 4th dimension; where for an observer approaching the speed of light, the time slows, lengths shrink and mass increases. It was so esoteric, that it would take the scientific community a while to digest that their world had changed. Further surprises were in store. In 1907 he presented a paper in which the duality of energy and matter is explained; deriving that yet to be, after 1919, the most famous equation of the 20th Century, e = mc², the equation of energy-mass equivalence.

 
In 1908 Rutherford received a Nobel prize for his investigations. It was for chemistry, and not physics; a skewed distinction of merit that much amused him. During his speech at the academy, he announced that he had recently confirmed that alpha (α) particles were in fact nucleons of helium.

Invented in 1911 at the Cavendish laboratory, Cambridge, C.T.R. Wilson constructs a glass cloud chamber. Inside an upright glass cylinder with a glass top for viewing and sitting in a water tank to saturate the air inside with water vapour; floats another capped inverted cylinder, of specific dimensions, with its bottom open to the water, acting as a piston. Up the middle of the tank and into the piston cylinder, is a tube connected to a vacuum system. On activation of the vacuum system, the piston slams to the bottom of the tank, expanding the air in the main tank by adiabatic volumetric expansion to the required order of 1.31 to 1.38. Energetic particles (from a radioactive source, say) are injected into the saturated vapour chamber from the side, and the activity viewed through the top. Only if the source particles and any daughter particles that may result from experimental collisions, are of the type to ionise (remove an electron) from the molecules of air; their track within the chamber become a vapour trail trace of tiny drops of water, coming out of saturation, formed around the ionised air. From photographs; measurements of track lengths and angles of diversions following collisions yield data on momentum, energy and infer the type of particles that formed the (or intermittently did not) traces. When placed in a magnetic field, charged ionisation particles curl in opposite directions, dependant on their charge. The Wilson cloud chamber did ‘Stirling’ work in the earlies’. Its successor, Glaser’s bubble chamber of 1951, along similar principals, uses fluids instead, and liquefied gasses like hydrogen, and generates tracks of bubbles; and are suited to higher energy particle experiments using particle accelerators; liquid density infers shorter tracks from higher energies, that would otherwise overwhelm a gas device.

 Using data from experiments provided by his assistants Henri Geiger (who would later work with Müller to develop the Geiger-Müller tube and GM particle counters) and Ernest Marsden, in which they found that a thin foil of gold bombarded by alpha particles not only diverted the particles by a small angle at the other side of the foil; but also bounced the particles back off the foil like a “fired shell”. Rutherford with electro-magnets on pendulums modelled the results, and concluded that the nucleus must be very small and very dense. From this evidence, in 1911 Rutherford, borrowing an old model from astronomy first set by Copernicus (1543), described the atom as comprising a positively charged nucleus around which orbited the negatively charged electrons. Thompson’s homogenous ‘plumb pudding’ of particles now morphed into Rutherford’s ring of electrons circling mostly empty space, in the centre of which lay the positively charged nucleus of the atom.

But what needs to be understood here, are the subtleties of the change in this visualised model. The Thompson’s homogenous ‘plumb pudding’ model visualised a ball of mixed particles at the position of the atom. The Rutherford model visualised a cloud of electrons spinning around a small nucleus; so now at the position of the atom; was at first a cloud of electrons, then some empty space, then a small positively charged ball at the nucleus. How much empty space, and the size of the ball, no one really knew. It was this space and the ball of the nucleus, that became the puzzle to be sorted out. The ball was positively charged, the ball was heavy, what was in it? Was it a ball at all?

 
Although a constructive, useful and a convenient first step in visualising the structure of the atom, the Rutherford model immediately ran into a problem that ‘classical’ physics of the day could not handle. Although the countering analogy itself is somewhat flawed; the idea of charged electron particles busily whizzing around the nucleus invoked a requirement, through the conservation of energy; that they radiate energy, thereby loosing momentum, and in consequence, would eventually crash into the nucleus. That atoms do not normally glow, and that normal atoms appear stable; is proof enough that the mathematical constructs of the day were inadequate to explain the observations.

In 1911, the Danish theoretician Niels Bohr using Planks quantum theory redefines Rutherford’s atom as a +ve nucleus surrounded by a number of –ve electrons; that the electrons reside in specific quantum states of energy levels. That the electrons excited by incoming photons will only absorb the energy in specific units of quanta that allow them to reside in a different, but specific energy level, determined by multiples of Planks constant, h. That by absorbing photons, the atom is excited, where the electrons move up to higher energy levels; and conversely, by emitting photons, fall back to lower energy levels. For an unexcited atom, the electrons occupy the lowest state of energy excitation, being defined as the ground state for the electrons. 

The Bohr-Rutherford model (as it was later called) was however limited to the description of the simplest atom, hydrogen with 1 electron, as it could not adequately explain the behaviour of atoms with more electrons, needing further developments of quantum theory to do so. However, it immediately explained the underlying principals of Spectroscopy, where absorption lines show the frequency of the photons, in units of quanta, as the electrons absorb the in-coming energy and jump to higher permitted energy levels. Where emission spectra show the reverse; where the emitted photons, out-put energy at frequencies related, in quantised units, to the lower permitted energy level to which the electrons fall. So the multiplicity of spectral lines for each element, represent the movement of electrons from any permitted energy state to another, provided that there is no electron occupying that state in the first place. Hence each element has its own specific spectral signature.

 Bohr’s quantum treatment of the atom allowed him to calculate, from first principles, a constant that had been determined previously by experimental physics called Rydberg’s constant; it also derived the spectral equations of hydrogen that had been laboriously produced from experiment and named after their discoverers; the Paschen (infra-red), Balmer (visable) and Lyman (ultra-violet) series.

After 1913, Bohr and others applied further quantum refinements to his model, and with the adaptation of Pauli’s exclusion principal, it then began to explain further, the behaviour of the elements. That for each specific element, where the number of protons is matched by an equal number of electrons to balance the charge; as the proton/electron count rises, the electrons begin to occupy quantised energy shells, around the atom, which are first filled, and are then required to fill a higher energy shell, an so on, all the way up to the heaviest elements known. And all shells filled in relation to some quantum order. Bohr’s adapted model of the atom defined where an element would reside in an extended version of the Russian chemist Dmitri Ivanovich Mendeleev’s (1871) Periodic Table of the Elements; as the columns are defined by the successive steps in filling of the quantised shells; and the rows defined by the number of filled shells. Physical chemistry is thus explained as the behaviour of the outer shell electrons of one atom – the valency - interacting with the electrons of another atom, or a collection of atoms (atoms of the same or different elements does not matter here), seeking to balance their energy distribution to the lowest possible quantum state accorded for the outer shell, by shearing each others electrons.

In 1914 Albert Einstein began to make a serious effort towards completing his theory of General Relativity, but he needed better mathematics than he understood at the time to do so. His early mathematics lecturer Hermann Minkowski had in 1908 applied a geometrical treatment to the theory of Special Relativity that Einstein had studied in admiration; but for the concepts in his head, he felt he needed different tools. That year he turned to his childhood friend, Marcel Grossman who had made exemplary notes of lectures that Einstein borrowed after the times he went truant, now a professor of mathematics; and asked him for his help. Grossman worked with him and his half completed General Relativity by introducing him to the mathematics of Bernhard Riemann of non-Euclidean curved geometry; and to tensor calculus as pioneered by Bruno Christoffle, Gregorio Ricci and Tullio Levircivitá. After a further year of effort, Einstein had completed his next masterwork.

 General Relativity is a theory of gravity; and by default, also provides a model for the universe. Special Relativity is a sub-set, or special case, of General Relativity as it only deals with matter at rest, or moving in a straight line. General Relativity deals with matter in motion, changing direction, accelerating, gravity fields.

 General Relativity rests on the premise of another idea of equivalence that Einstein conceived. It is based on the idea of a falling object, like a man falling in a lift, who is accelerated by the force of gravity; but who is also weightless. So the accelerating force and the force of gravity are equal and equivalent. So acceleration is equivalent to gravity. So the idea builds another thought experiment. If a man (excuse the sexism) shines a light on one side of a weightless lift, the light will strike the opposite wall in a straight line. If the lift is now however on a planets surface, it is now in an accelerating field, everything in the lift is affected by gravity; the man and the light. So the man stands apposing the force of gravity on one side, and the light falls in an arc to hit the wall lower on the other side. General Relativity set out to prove this. The resulting construct is of curved space applied to the space-time of Special Relativity. Gravity, acceleration, bends space-time.

 
The theory of General Relativity was first presented in three lectures at the Prussian Academy of Science, in Berlin, around the 25 November 1915. The lectures were presented as “The field equations of Gravitation”. In his presentation Einstein commented as to his assessment of how far he thought his commitment to this project had gone, with “…finally the general theory is closed as a logical system.” So there it was, finished. It was later published in 1916. The emergence of one of the worlds greatest mathematical tools in 240 years had little impact, except to a handful of enquiring minds, because after all, it was complicated and rather esoteric; and Germany was at war (1915 to 1918). However, General Relativity was now subject to proof.
 

Returning to his theoretical work using quantum theory, in 1917 Einstein expanded the theory on the behaviour of electrons, using a simplified Bohr model, where the electron becomes excited by a quantum of energy, the photon. He considered that it would behave in three ways. On excitation, the electron would jump to a higher energy level, provided the frequency of the photon matched an available higher energy level of the atom. But the de-excitation could happen in either of two ways. Either the electron would fall spontaneously to a lower energy level, releasing the absorbed photon to go off in a random direction; or the electron could be immediately de-energised into stimulated emission by the arrival of a photon of the same frequency, in which case the photon would leave in wave synchronisation and direction of the stimulating photon. This was the fundamental theory that was to be applied some 50 years later in the application of LASERs (Light Amplification by Stimulated Emission of Radiation).

The British astronomer, Sir Frank Dyson, in 1917 was aware that the bending of light by the sun would offer proof of General Relativity; and suggested that a solar eclipse, due in 1919, would be the ideal opportunity to test it. Dyson determined that the best view for this eclipse would be on Principe Island, off the west coast of Africa; and to have a back-up in case of poor weather, Sobrol in northern Brazil. With a war on, funds were short; but he started plans for an expedition.

 Luckily, the war appeared ended with the Armistice of November 1918 which had halted the fighting, and political thoughts, as usual presumptuous, considered a British effort to prove a German physicists theory, good ‘brownie point’ propaganda for Britain; and if the theory correct, extra ‘brownie points’ for a defeated Germany; funding was found for the project.

 The Cambridge astronomer Arthur Stanley Eddington would lead the Principe group, and the Greenwich Observatory would send C.R. Davidson and team to Sobrol. Six months before the eclipse, a photographic survey of the area of the sky in which the sun would lie during the eclipse, was made for reference. Both teams had good viewing, and the solar eclipse of 29th May 1919 was successfully photographed from both locations.

 The photographs were developed abroad, and by the 3rd June Eddington, who would have taken reference plates with him, knew that Einstein was right. He telegraphed to The Royal Society with the news. It spread like wildfire; as a consequent message from the mathematician Littlewood of the R.S. to the philosopher mathematician Bertrand Russell records:

 “Completely confirmed: Predicted 1”.72. Observed 1”.75 ± 0.06.”

 
Before any public announcement, all the data had to come in from the field, and further measurements made to dispel any errors. Also the war was not yet officially over. However, The First World War ended on the 28 June 1919, 8 months after the Armistice of 10th November 1918.  A release of the news would bring some cheer to a battle worn Europe.

 So virtually a year after the Armistice, on the 6th November 1919, at a joint meeting of the Royal Society and The Royal Astronomical Society at Birlington House, London, with a Times correspondent in attendance; the announcement was made in the proportions of ‘a Greek drama’, as described by the philosopher Alfred Whitehead who attended. To a packed hall awaiting in silence, J.J. Thompson the president of the Royal Society, rose to make the address, pausing to glance up at the portrait of Newton that hung above them. Thompson began “One of the greatest achievements in the history of human thought.” Using euphemisms of Empire “It is not the discovery of an outlying Island, but a whole continent of new scientific ideas.”

 The Astronomer Royal, Sir Frank Dyson, then rose to outline the results from the Eddington and Davidson teams. In verification of Einstein’s theory, he stated that the bending of light by the gravitational effect of the sun did not tally with the theory of Newton, but was in full accord and near exact agreement with Einstein’s theory of General Relativity.

 
A lively debate then followed, as not everyone was in agreement; but it was clear that some heads of science were thoroughly convinced. J.J Thompson was noted to add that he was “confident that the Einstein theory must now be reasoned with, and that our conceptions of the universe must be fundamentally altered.” At that point, the respected astronomer Sir Oliver Lodge, walked out of the meeting.

 To the press, bending of light by gravitation, upstaging Newton, was news indeed. The 7th November 1919 headlines of The Times read REVOLUTION IN SCIENCE. The worlds press then go on the bandwagon and Einstein became a world celebrity. The year following, 1920, may be regarded as the year of ‘Einstein hysteria’, in which the essence of General Relativity and widely distorted and absurd versions about it, sprang up all over the place to heated debate, socio-didactic slang and satire. Einstein became a household name. By the end of the year, the only people who disagreed with it were; the unfortunate ignorant, the philosophically challenged, jealous physicists and radical anti-Semitic political opponents.

 
Scientists were satisfied with a working theory. And although it is well noted that Einstein added a physical constant called ‘the cosmological constant’ to make his model fit with the then current understanding of the ‘static’ size on the known universe; when the American astronomer Edwin Hubble proved that the existing universe was larger than the Milky Way Galaxy, extended to millions of galaxies beyond, and all of which were accelerating away in an expanding universe; Einstein relented in having “made the greatest mistake in my life”. Had he been less cautious, and not included his fiddle-factor, his model would have predicted Hubble’s discovery. Apologia aside, the Big Bang cosmological model, be it expanding or contracting, adjusted with new cosmological constants of varying polarity, still remains rooted in General Relativity.

 A succinct summary of Einstein’s achievements was penned by the Salk Institute biologist and science author J. Bronowski in 1973 with “In a lifetime, Einstein joined light in time, and time to space; energy to matter, matter to space, and space to gravitation”. What a wonderful legacy to share with the world.

Using radium as a source for alpha particles, Ernest Rutherford in 1919 irradiated the gas nitrogen and discovered that hydrogen had been formed. Nitrogen is changed to hydrogen! Sensationalised in the press as ‘splitting the atom’; it was in fact more a transmutation than a split; the first recorded artificial transmutation of an element. What had actually occurred, and in terms of the new atomic-chemistry that was to follow; when an alpha particle, of atomic weight 4, manages to overcome the repulsive forces within the nucleus of nitrogen, of atomic weight 14, the collision transmuting nitrogen into an isotope of oxygen, of atomic weight 17, with the release of a hydrogen nucleus, of atomic weight 1. 

The hydrogen nucleus of atomic weight 1, with a single +ve charge, that was released by the nuclear reaction, as nucleic process would be called, was named a proton by Rutherford in 1920.

 
Francis William Aston returned to the Cavendish laboratory in 1919 with an idea of how to measure the mass of individual isotopes, in response to a question put to him by J.J. Thompson, for whom he was assistant, about the ratio of the masses of the isotopes of neon-20 +ne-22. His work for J.J., started in 1910, had been interrupted by the intervention of the First World War, during which time he had been working on improving doping for air-frames at the Royal Aircraft Establishment, Farnborough. By the end of 1919, Aston had improvised the first mass-spectrometer, initially limited to ionised gasses, and had begun to produce data on the mass of gaseous isotopes, relative to the mass of hydrogen-1, by measurements on scintillation screens and later on photographic paper. By 1920 he began improvements to his instruments, to include liquids and solids, and his results began impacting on the scientific community; and began giving credence to the Rutherford-Bohr atom. Some of these early results were in slight error, the atomic mass of helium being set too high, and would impact as blind allies of research for early investigations for fissionable materials, carried out by Leo Szilard and others, who were trying to make the first atomic bomb. The error would be corrected by 1935, as with better instrumentation, Aston resurveyed the elements between 1927 and 1935. Aston is credited, over around 20 years of research and development, of having identified some 212 of the [then known] 281 (75.4%) naturally occurring isotopes of the elements. Having previously determined the isotopic abundance ratios of neon, of atomic mass 20.2, by an arduous process of gaseous diffusion; Aston now presented the isotopic ratio of ne-20 +ne-22 from his mass-spectrometer data, to be 9 to 1 respectively, this satisfied J.J.

 Aston championed the work of Prout (1815) who had hypothesised the whole number rule; that atomic weights of the elements (now with their isotopes) would be whole numbers of the atomic weight of hydrogen. Aston was in an ideal position to do so, as his mass-spectrometer was now filling up the tables with unhithertofore accurate measures of atomic weight. Where at first the atomic weight of hydrogen was enumerated as 1, a new standard of weights was established, using the atomic weight of the isotope oxygen-16 as 16.00000; (All to be changed again, later to Carbon-12 as 12.00000). Notwithstanding these technical adjustments; the whole number rule still applies for thoughtful investigation. Aston then catalogued a mass defect that applied across the range of elements; best illustrated with the atomic weights of hydrogen and helium: H = 1.008; and He = 4.002; He = 4 x H nucleons, should be 4.032. Now 4.032 – 4,002 = 0.030 which is the mass defect for helium. That 0.79% of the expected mass is missing, somehow needs accounting. Aston attributed this missing mass to energy needed to hold the helium nucleus together, what today is termed the binding energy, and used Einstein’s energy-mass equivalence formula, e=mc², to account for it. In order to more easily visualise the mass defect across the whole range of elements, Aston devised a clever graph of Packing-Fractions to show it. The table that the physicist Lise Meitner would hold in her head in 1938. His formula takes the mass defect divided by the elements atomic mass x 10,000, and plots the results against rising atomic mass.

 To Aston, the plot is a measure of the stability of the elements, with the lowest, iron (⁵⁶₂₆Fe), being the most stable; and to the extremes, hydrogen (¹₁H) to the left and uranium (²³⁵₉₂U) to the right, having the most bound up, or releasable, energy; a quick account of the energy needed, or released, to transmute one element into another. To us today, it shows the elements of nuclear fusion to the left of iron, and the elements of nuclear fission to the right.

For the astronomer; a large star starts from the left by fusing hydrogen into more massive elements, that it then starts to fuse for the next stage, in steps, and so on, may-be missing a few steps, as the steps are usually in multiples of the helium nucleon, until it arrives at iron; where fusion stops. But because of serendipities in mass needed to form stars in the first place, the iron implodes under the high density conditions prevailing into neutrinos, and other things, in supernovae; the shock from which most all the other elements to the right of iron are now synthesised, and then scattered, together with all the left-over detritus of the elements previously synthesised to the left of iron, to the interstellar medium to merge into new-generation star systems of which sol-earth is an example. We find, and can then play with, the elements to the right of iron; and fission these in our nuclear toys; reactors and atomic bombs. Of course, we also choose to adorn ourselves with the confusion of gold; another, but non-radioactive, to the right of iron, by-product of supernova. Life itself, being a by-product of mostly the elements to the left of iron, and iron itself.

In the period 1924 to 25 theoretical physics was to experience a quantum leap of its own with the structuring of mathematical tools of such staggering diversity and imagination that the exotic would now appear mundane. The German theoreticians Werner Heisenberg and Max Born would develop matrix mechanics, stimulated by Niels Bohr. The French theoretician Louis de Broglie would contribute to wave-particle theory, and together with other accomplishments; using the ideas from quantum mechanics proposed by Planck and Einstein, with wave frequency f, Planks constant h, energy E, and momentum in the previous form p = E/c; derived quantised momentum p, which reduced to p = hf/c; and where c/f = λ (lambda) the wavelength, became pλ = h. The Austrian (and later Irish) physicist Erwin Schrödinger would further develop wave-mechanics. The English mathematician Paul Dirac would prove that the treatments of Heisenberg, Born and Schrödinger were all in fact different expressions of the same thing; which much upset the esoteric Schrödinger; who would later involve Einstein in deliberations of quantum probability with the famous Schrödinger’s Cat, dead and alive, superposition of states paradox. Einstein would support the statistical probability mathematics of the Indian physicist Satyenda Bose, and work together with him to develop a branch of quantum physics called the Bose-Einstein statistics. Much of the early 21st Century theoretical physics is based on these earlier mathematical foundations.

 In around 1925 Cecilia Payne-Gaposhkin, an assistant at the Harvard College Observatory, determined that stars were composed mostly of hydrogen and helium, and not terrestrial types of matter, as was then thought to be the case. Her assessment challenged the male dominated community of science of her era, and took a while to sink in; but she correctly gave her slighted sisters and the stars, fuel with which to brightly shine.

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1926 – J. Robert Openheimer
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On the 2nd January 1931 Ernest Orlando Lawrence an American experimental physicist and his assistant M Stanley Livingston, using Lawrence’s development of an idea borrowed from a Norwegian engineer Rolf Wideröe that was effectively a prototype for a linear particle accelerator, that Lawrence had cleverly compacted into a 4.5 inch circular particle accelerator, operating between the jaws of a huge electromagnet, accelerated protons to 80,000 volts. [Quick note on principle of operation] It was the dawn of particle accelerators, artificially induced and controlled spears of energy, that would be needed to investigate the constituents of the atom. Lawrence and Livingston had brought the first cyclotron on-line.

According to the theoretical physicist Hans Bethe, the history of nuclear physics only began in 1932 after Chadwick’s discovery. After reading a report by the Joliot-Curies about an experiment stated to have been conducted by bombardment with gamma rays, and discussing the results with Rutherford, who replied “I don’t believe it”, James Chadwick agreed with Rutherford, that for the results obtained, the bombarding rays could not have been gammas, but were something else entirely. Chadwick had an idea what they were, and set-up a series of experiments conducted at the Cavendish laboratory, Cambridge, between the 7th and 17th February 1932, to find them. When he had done, he had found that long elusive particle that Rutherford had speculated about back in his 1920 Bakeran Lecture, that massive particle with no charge, that left no trace in a cloud chamber because of it, ignorant to magnetic fields, that at the experiments intensity travelled through 40 cm of air, that whizzed through 2 cm of lead, that was the nuclear ‘hammer’ of physics that Hans Bethe was to later wax-lyric about; the explanation for an isotope, as heavy as a proton, the neutron. Chadwick credited Walther Bothe, Herbert Becker, H.C. Webster and the Joliot-Curies for their help and insights leading to his discovery.

 1933 Leo Szilard – The loose neutron of 20th Century nuclear science.  One is at first tempted to compare Szilard to the near mass-less neutrino that escapes through everything, on that shattering and creatively violent moment that a large mass star shines the brightest, in a type II supernovae explosion that releases the neutrino, that then goes on to penetrate near half the universe, unhindered, passing many mysteries along the way, before being captured in the twilight maze of an atomic nucleus, to expire in a spray of multidimensional exotic entities. On second thoughts, Szilard, whose character still appears unhindered and whom would have undoubtedly enjoyed the mysteries, is more related to that chain reaction, propagated by neutrons, the particle that he himself had wished for, that changed the world; the world that, singlehandedly, he had set out to save. Understanding Szilard’s character is not the object lesson here, others have made better note of that, but it is the knock-on effect that this Hungarian physicist started, that puts him in a category all of his own, as the master shaker of the technological world; with no less tangential a might than Genghis Kahn or Alexander the Great. Leo Szilard hastened the coming of the atomic age, was the first to envisage the reality of the atomic bomb on Tuesday, 12th September 1933, patented the process then gave it away to the British Admiralty, set about to insure its creation, and succeeded. World atomic power was a by-product.

 At the Radium Institute in Paris, Irêne and Frédéric Joliot-Curie, the inseparable pair of radio-chemists, Irêne being the daughter of the famous Marie Curie, and hence conferring the famous name to the pair who become affectionately known to the scientific community as the Joliot-Curies; in early January 1934, conduct an experiment that earns them a Nobel prize for chemistry. They radiate aluminium with alpha particles, and detect a ‘daughter’ element with a 3 minute half-life, which they chemically isolate and identify as a radioactive isotope of phosphorous. Their report published on the 15th January, provided the first chemical proof of the ‘transmutation’ of the elements by nuclear bombardment; the alchemists dream realised.

Enrico Fermi skipped the part of the young child, but was a progeny none the less. Following the trauma of his brothers death, he started the first half of his early education in self taught study at the age of 14; and the other half unusually supplied by an engineer and other attentive family members. He acquired a skill for complex mathematics and a one-track penchant for physics. At the University of Pisa, what he wrote in his scholarship entrance exam, in other circumstances, would have equated sufficient for a doctorial thesis. He concluded his stay there by teaching his teachers. One of his strengths was General Relativity. An odd moment in career development occurred in 1923, when on fellowship to Göttingen, Germany, to study under Max Born; where he met Wolfgang Pauli, Werner Heisenberg and theoretician Pascal Jordan, among others, he was ignored and no spark of enthusiasm or insights resulted; his tasks were ordinary. A following brief fellowship to Leiden however, under Paul Ehrenfest, had him sparkling. From later collected descriptions; Fermi appears as a no-nonsense character with a touch of humour; but to the job in hand, straight to the point, the facts, nothing foggy; his equipment toys of purpose, he was the quintessential, and probably the first, ‘hands-on’ quantum engineer. His Italian colleagues fondly nick-named him the ‘Pope’. Fermi became Professor of theoretical physics at the University of Rome.

 The director of Rome’s physics institute, Orso Corbino, together with Fermi, wishing to bring Italian physics out of the doldrums and intent to build an institute of world standing, thought they should investigate the atomic nucleus. So they began to train and collect talented physicists and necessary equipment for a laboratory in Rome. The team of Rome would eventually include; Emlio Sergè sent to Amsterdam, then trained with Otto Stern in Hamburg; Franco Rosetti sent to Caltech, then to train with physicist Lise Meitner at the KWI in Germany and Edoardo Amaldi who trained with physical chemist Deter Debye in Lipzig. They assembled a cloud-chamber, a radium source and had KWI technical training in temperamental Geiger counters. The laboratory was set up in Rome’s Saritià Pubblica – Health Department – of the institute. 

In that period Fermi completed a definitive work on beta decay, a theoretical treatment of the high energy expulsion of electrons from a decaying nucleus. He introduced a new type of force, the ‘weak interaction’, that acted at inter-nucleic distances.

To start the laboratory, Fermi’s next project was to use, he insisted, neutrons to irradiate all the known elements; to determine if they transmuted under nuclear bombardment. He knowingly went into competition with the Joliot-Curies to enhance the reputation of the Italian institution and was also determined that his team would make new discoveries themselves. Starting first with the light elements of the periodic table, and methodically working upwards in atomic number, he was on his way. He reported a 12 minute half life for aluminium on 25th March 1934, different from the Joliot-Curies earlier discovery, and continued up the table.

 Around mid April 1934 the Rome group had arrived at Uranium. They were beginning to return some results and building radio-chemistry rules in the process; so added a radio-chemist trained at the Rue Pierre Curie in Paris, Oscar D’Agostino, to the team.

The Rome group reported that light elements generally transmuted to lighter elements by either ejecting a proton (p) or an alpha particle (⁴₂H = 2p + 2n). 

 A heavier nucleus has more protons and thus a heavier charge. With more neutrons, the binding energy is also larger. The heavier nucleus is more difficult to get out-of because of these forces. So what the Rome group report was as the nucleus got heavier, it captured a neutron and radiates gamma photons; thus with no charged particle emitted, it becomes a heavier isotope. 

 But they also reported that something else would happen. After a delay, it would emit a –ve beta, which is a positron. And to get a positron they considered a neutron changed to an proton with the release of a +e, transmuting the element into a heavier element. 

 As they were observing delayed –ve beta decay with uranium, Fermi thought, by the same process, that they were transmuting to a heavier element than uranium, as yet undiscovered. It would be the first transmutation into an artificial man made element. This was new territory. 

 Interesting, but as yet without proof, the Rome group reported by 10th May 1934, that they had found activities induced in uranium, with half-lives of 1 and 13 minutes + others of longer durations as yet to be specified.

 
Looking at this induced series further, it was found that they were all beta emitters and D’Agostino had managed to separate the 13 minute activity with a manganese carrier. 

With the debate that it could be heavier than uranium, D’Agostino set out to try to prove that is was not lighter than uranium, by checking with the known heavy elements. The chemistry proved it was not Lead-82, Bismuth- 83, it excluded Radon-86, Francium-87, Radium-88, Actinium-89, and Thorium-90.

On the other hand, Polonium-85 was un-checked and [Astatine]-85 was (then) unknown. 

At that point, the Rome group were still polarised in thought towards a heavier element than uranium-92, x-93, as the source of the 13 minute activity. They reported their screening activities and made cautions thoughts on x-93 in June 1934.
 

Then they had a serious embarrassment when their director Corbino announced, at terms end, over-excited by the presence of the King of Italy, that they had found a new element. It go into the press and went international. But it was the summer holidays; so the embarrassment passed, nearly.

Fermi sailed to the South Americas on a lecture tour, leaving it all behind.

Independence day USA 4th July 1934: Leo Szilard patents the atom bomb on the same day that Mem. Marie Curie dies. Albert Einstein presents the most moving eulogy “of all celebrated beings, the only one whom fame has not corrupted.” (R. Rhodes – pg. 215)

With Fermi away, Emlio Sergè and Edoardo Amaldi visited the Cambridge laboratory, in England, with two problems to discuss. The first was neutron capture; where current theory on the ball nucleus suggested that neutrons whizzing through the nucleus, had about 10^-21 seconds to get through. The Rome team found that by experiment they got gamma emissions after 10^-16 seconds: -21 + 16 = -5: 100,000 times too long. Thus they supposed the theoretical model was faulty. The second problem was that they wanted proof-positive of neutron capture with a gamma emission. Nothing new on the first problem transpired (that would come later from Bohr); But on the second problem; the Cambridge team found the required neutron capture, in sodium, while they were there.

 On their return to Rome, with Oscar D’Agostino’s help, they repeat the sodium proof, and then find a second case with Aluminium, with a half-life of almost 3 minutes. This was around August 1934.

 
A returning Fermi stopped in London at an international physics conference, and having had news from Rome, presented that of the 60 elements radiated by the group of Rome, they had induced activities in 40 of them; placed the radiation capture problem to the forum; cited the Cavendish team sodium results; and then reported Sergé’s and Amaldi’s Aluminium near 3 minute activity results.

 Then there was trouble. Despite great efforts, Amaldi could not repeat the Aluminium near 3 minute results. Fermi got upset and dressed the team down heavily.

 
After Fermi’s chastisement, Bruno Pontecorvo joined the Group of Rome at the time when they were planning to standardise the radiation sources to silver, with a half-life of 2.3 minutes, which should give their results some base-line consistency. But they discovered to their astonishment that different activation tables around the lab, caused different radiative intensities from their silver sources. A certain wooden table near a spectroscope caused the highest radiation when compared to a source on a marble table in the same room.

 They decided to tackle the problem, but lost sight of their investigative faculties in favour of engineering solutions by applying shielding techniques to solve the problem. Starting on the 18th October they began measurements within and without lead shielding, to arrive at the 22nd October 1934 with the bazaar idea to test placing a lead shield between the source and the target. Truly fish out of water, from a historical perspective, and by distorted metaphor; no less than divine intervention hindered fledglings in their work to attend to student examinations that halted their work and brought the ‘Pope’ into the picture. Fermi now had to run the ‘lead’ experiment on that day. The master dithered with subliminal excuses warring in his head, and placed instead a paraffin shield in place of lead. The system roared into activity. The late morning saw pilgrimage to the experiment with noises of “Fantastic! Incredible! Black Magic!” Fermi went home to lunch.

 Fermi came back after a solitary lunch with probable answers and a few testable theories.

 The hydrogen in the paraffin and of the wooden tables, slowed down the neutrons. That took care of the wooden-marble table problem.

The slowed neutrons had more time to be captured by the nucleus. That took care of the sources.

How to test for hydrogen? Water! Corbino’s goldfish pond at the back of the building would do. An entourage of equipment irradiated the goldfish; and it worked as well in water as it did with paraffin.

Now for the effects of slow neutrons. With the paraffin shield; silicon(14), phosphorous(15), zinc(30) – no appreciable effect; aluminium(13), copper(29), iodine(53) – were all activated.

They tried radon without beryllium, as a source, to insure that neutrons and not gamma rays, were being slowed – It was the neutrons.

They used oxygen in place of paraffin as shield – a decrease in intensity; oxygen slowed neutrons less than hydrogen.

 Sergè typed “Influence of hydrogenous substances on the radioactivity produced by neutrons – I” at Amaldi’s house after dinner. Fermi dictated; Rossetti, Amaldi and Pontecorvo shouted. After they left, a house-maid timidly asked if they were all drunk. Yes – with excitement. The paper ended with a note on the just short of 3 minute activity of aluminium; is was enhanced by slow neutrons; but diminutive with fast neutrons and here overwhelmed by other induced activities.

 A codicil to understanding was that Sergè and Amaldi had not failed in their work months before, but had used a marble table, with a null result for the <3 minute activity of aluminium.

 
The groups next task, was to start all over again, now using slow neutrons, to determine any new isotopes and decay products.

 The notion of slow neutrons had arrived. Hans Bethe later commented that they “might never have been discovered if Italy were not rich in marble” prompted from the observation that in America, most lab-tables were wooden. An amusing point; but “delayed” rather than “never” would be more to the truth. Slow or thermal neutrons, would become the activators for ‘power’ and ‘breeder’ reactors; and fast neutrons, the avatars for bombs.

All elements of atomic number > 92, i.e. 93 to 118 (shown in green above), are man-made elements; all of which are unstable - they immediately begin to spontaneously decay.
Find Page update (2017) to recently named elements, atomic number 112 to 118 (above)

Later in 1934, the criticism of the work of the Group of Rome started coming in.

 In a paper by Aristide von Grosse it was argued that the group had created protactinium(91) and not a transuranic X(93) as claimed. The Group of Rome took it as a challenge to push ahead.

 
The Completion Backwards Principle exists largley through a song (The Tubes) 1981; so in its sentiment, this part of the story can be told backwards. 

Leona Woods wrote, answering a question; that Ida Noddack, a German chemist and co-discoverer of rhenium(75)[1925], was ahead of her time; and that Bohr’s liquid-drop model of the nucleus (1937) had not yet been formulated to allow informed estimates about the size and dynamics of the atomic nucleus.

This would mean that Edward Teller’s version that “Fermi performed the calculations – and found the probability was extraordinarily low … so he forgot about it.” Was a good assessment; where Fermi had told Teller, Sergè and Woods that he had done the calculations. The fact is that Fermi’s model was wrong in September 1934; he got wrong answers, but did not know it.

Ida Noddack was ahead of her time when she wrote “it is conceivable that the nucleus brakes up into several large fragments, which would of course be isotopes of known elements but would not be neighbours [i.e. close to uranium in atomic number].” She had reacted with “Fermi therefore ought to have compared his new radioelement with all known elements,” continuing her criticism with “not clear why he chose to stop at lead[82]” referring to “his new beta emitter” about which Fermi stated was not protactinium(91), and nothing down the range of elements to lead(82). Noddack, who was a good chemist, pointed out that any number of elements could be precipitated out of uranium nitrate with a manganese carrier. His “Method of proof” was “not valid” was where she had begun. 

Appearing in The Journal of Applied Chemistry in September 1934; Ida Noddack’s “On element 93” criticised Fermi’s June paper “Probable production of elements of atomic number higher than 92.” Noddack had hit hard with “the reports found in the newspaper” when reflecting on Corbino’s ill-timed announcement. But the message had got through to the intended, if only, recipients; Fermi, and as Emlio Sergè reported, by messages he sent to the Joliot-Curies in France, and to Otto Hann at the KWI in Germany. Its publication in a specialist journal, made low its message and readership. 

Summing up their work in a paper on 15 February 1935, the Group of Rome were still of the opinion that the activities they had induced in uranium; a 15-second;13-minute and 100-minute half-life products; i.e. a series where each was the product of the next stage; were of Ur(92); X(93) and Y(94) of atomic weight 239. 

After displaying some obvious surprising mental cognations while being given a report on some calculations by Hans Beth on the low probability of neutron capture by the nucleus; Niels Bohr summarised his cogitations in a lecture at the Danish Academy on 7th January 1936. Bohr was pressing for theoretical improvements with his “neutron capture and nuclear construction” in which he outlined a change to the model of the nucleus. Dispelling previous suppositions that neutrons sailed through the nucleus; instead of a ball of mixed nucleons, he proposed now a distinct collection of nucleons, a mixture of protons and neutrons closely packed together.

Bohr surmised that neutrons could not pass through this nucleus, that they are captured by the strong force and agitate the nucleons inside. Nothing can escape as the strong force holds all the nucleons together. The excited nucleus now ejects a gamma ray photon to ‘cool-off’, as the nucleus returns to some level of equilibrium; and the element would gain a unit of mass, becoming just another isotope. All confirmed by the Group of Rome’s recent experiments.

The size of the atoms nucleus had now gone from small to tiny. The comparative dimensions of the atom, with respect to ‘empty space’ and the size of the nucleus, still remains by any standards quite staggering; where a calculation that magnifies the construct, reveals a model equivalent to a grain of sand sitting in the middle of the Albert Hall.

It turns out however that Fermi and his Group of Rome team were ahead of the game in 1934, but were misled because they lacked this model for the atomic nucleus, and thus came to erroneous conclusions.

 
Niels Bohr, drawing reference to his doctorial theses on surface tension in fluids, in 1937 proposes in a paper that the nucleus of an atom would behave like a liquid drop. He suggests that the strong nuclear force that binds the nucleus together, acting similarly to surface tension, would be opposed by the +ve charge within the nucleus, which would tend to force it apart. In this state, the nucleus would oscillate like a wobbling liquid drop, if struck by an incoming object. This idea the liquid drop model would become, a year later, central to the preliminary explanation for the splitting of the atom.
 

In 1938 Enrico Fermi received the Nobel prize for his radio-active isotopic and slow neutron discoveries. He used the funds to narrowly escape Italy’s involvement in WW2; and set up with his family a new life in the U.S.A. He contributed hugely to the development of atomic physics in the U.S.
 

THE HANN-STRASMANN PAPER

On the 21st December 1938 the German radio-chemists Otto Hann and Fritz Strasmann discover an error in previous chemical analysis of ‘daughter’ products of nuclear reactions previously conducted in their laboratory at the Kaiser Wilhelm Institute for Chemistry in Germany, and they confirm the ‘daughter’ to be an isotope of barium, not radium as many had previously thought. They remain sceptical, as this appears to be a ‘daughter’ of uranium; an unusually large fragment of the mass of a uranium atom, almost half; a ‘daughter’ of unexpected size, and also thus far unreported by radio-chemists. They communicate with the German physicist Lise Meitner, now in war exile in Sweden, wishing her considered advice in explanation. 

Meitner, in a holiday discussion with her nephew the German physicist Otto Frisch, on the 24th December (Christmas eve) 1938; conceives an unstable dum-bell shape for the nucleus of uranium, based on Bohr’s idea of the nucleus acting like a water droplet, which would split into two large pieces on absorption of a slow neutron. Meitner and Frisch conclude that it is the charge of the +ve protons, acting in repulsion, in the dum-bell shape, that assists in driving the unstable nucleus apart on incidence with the low energy neutron. This is evidence of splitting of the uranium atom! Using data from Aston’s Packing-Fractions that Meitner had memorised, they calculate that the energy released per nucleon, to be of the order of 200 Meg-eV (electron volts); this is a huge amount of energy. Frisch later calculates that this release from one atom alone, would make a small grain of sand jump. Meitner shortly communicates to Hann her congratulations for his and Strasmann‘s important “an extensive burst” discovery. 

On his return to Copenhagen, Otto Frisch sets up an experiment for evidence of splitting of the uranium atom with slow neutrons. On the 13th, and repeated on 14th January 1939, Frisch succeeds. A visiting American student biologist William A Arnold, observing the experiment with him on the 14th, inspires Frisch to name the process of splitting the atom, by a biological term, fission. Frisch would contact Meitner to confirm this result and they would both present reports, posted on the 16th, using the term fission.
 

At Paupin Hall, Colombia University in New York, Herbert Anderson is the first United States physicist to split the uranium atom on 25th January 1939, having been briefed on the Hann-Strasmann experiment before-hand, by Niels Bohr himself; but unaware of Fisch’s previous success. The news through the grapevine, had been leaked accidentally to the Belgian theoretician Leon Rosenfield by a boat travelling Niels Bohr on his way to a US physics conference in Washington. The grape vine took the news east, and Bohr’s report at the conference on the 26th took it west; whenst it ignited the U.S., Leo Szilard and a worried Fermi into bomb making. The ‘Pope’ had done sufficient noble work to hold laureate, and needn’t have worried; but he shortly appended a note to the Rome paper on transmutations cautioning that the results should be reviewed for reaction products of uranium. In France, the Joliot-Curies chagrined to have so nearly missed the opportunity, having had all the same reports from Europe; split the uranium atom on 26th January 1939.
 

In Göttingen Germany, in the summer of 1927, physicist Fritz Houtermans and visiting British astronomer Robert Atkinson speculated about the energy production of the stars while on a walking tour. British astronomer Arthur Eddington had recently indicated from observations that the sun and stars burn at 10’s of millions of degrees and last lifetimes of billions of years; a prodigious use of energies that was unexplained. Could the nuclear transformations that Rutherford was demonstrating be the source of such power? They worked out a basic theory, that at the high temperatures and pressures in the core of stars that nucleons would have sufficient kinetic energy to penetrate the electronic barriers of a nucleus, an release binding energy; sufficient to power the star. A theory correct in principal but inaccurate in detail. Houtermans and Atkinson would later work with the Russian theoretician George Gamov to correct the detail and further the aspects of the theory; and named such processes thermonuclear reactions, on accord of the high temperatures at which they operate. The German theoretical physicist Hans Bethe in 1939 added to the theoretical model for nuclear fusion; the nuclear combination of lighter elements to form heavier ones, when he unravelled the carbon cycle, termed CNO for short or Carbon-Oxygen-Nitrogen cycle at length; a secondary high temperature fusion reaction of hydrogen into helium, a process step that powers the stars. Bethe was awarded a Nobel for this effort.

See section: Sun – Sol for details of the p-p and CNO reactions.

In 1939 Enrico Fermi set about to prove that nuclear chain reactions were possible. To do this, he had to build experimental reactors from which to deduce the fundamental parameters of not only the materials necessary, but of how to control such systems so that they would not blow up in the process. Later he was tasked by The Manhattan Engineer District (MED) project to prove methods for the high volume production of plutonium, a man-made element, produced by the nuclear bombardment of uranium, and for which a controlled nuclear reactor was necessary. Fermi, the first quantum engineer, would make the first series of historic nuclear reactors to test this technology, the by-product of which would be the nuclear arms industry of the USA and Britain; and the nuclear power industry of the western democratic world. 

An industry develops its own nomenclature. The word ‘pile’, used in ‘nuclear pile’, was derived from Fermi’s struggled translation, into linguistic American, of the word ‘heap’. 

The term ‘exponential’ refers to an exponential term in a scaling factor equation that would upsize the model to a theoretically full blown critical reactor. Activity reproduction factor k:  not critical < 1.00000 > critical.

The German theoretician Werner Heisenberg in 1925 had been shocked that Plato (427-348 BC), one of the Greek Pythagoreans, had visualised such as an atom, in any geometric form; as it could not be seen, it was a mathematical abstraction; Heisenberg preferred abstractions. The 1936 Bohr-Rutherford atom was now however complete as the first working model of the atom. It was visualised as a cloud of light negative electrons surrounding a tiny nucleus composed of a balancing number of heavy positive charged protons, together with, in the main, a similar number of similarly heavy neutral neutrons. The Pythagorean idea that the atom was the smallest indivisible particle of matter allowed, seemed to have at last been described. But the atom was composed of supposedly fundamental particles, the electron, the proton and the neutron; and even these entities were now under siege by experimental discoveries and by the theoreticians, as being sub-components or having some sub-components of their own. The 1936 Bohr-Rutherford atom, although a helpful working construct, was the last atom of a past era.

In difference to historical precedent; the name ‘atom’ survives today, as the smallest unit of a chemical element. The behaviour of its electrons is quantised; and the affinity of charge of the electrons filling the outer quantum shell, leads to physical chemistry. Its behaviour is described by quantum electrodynamics. The atom is however divisible.

In brief; today the last atom is now defined in the Standard Model, a construct of many mathematicians and theoreticians and supported by the results of international experimental physicists, and credited to the work of Sheldon Glashow (1960); Abdus Salam and Steven Weinberg (1967). It supports 61 elementary particles, of which the last, the Higgs boson, in the mass region of around 125-126 Gig-eV, was identified at CERN in a series of experiments carried out through 2011 to 2012, to be declared existent with a statistical significance level of 5 sigma, on 4th July 2012.

In hierarchical classification of the Standard Model, the components of the last atom become:

The electron – A fermion class lepton
The proton – A hydron AND fermion class baryon
The neutron - A hydron AND fermion class baryon

Following his resurvey of the atomic weights of the elements in 1935, in a lecture given by Francis William Aston in 1936, he was aware that once the means was found, atomic energy could be useful for mankind, but in a flush of typical dry British humour, ended his speech with the procaine comment: “… man will realise and control its almost infinite power. We cannot prevent him from doing so and can only hope that he will not use it exclusively in blowing up the next door neighbour.”
Aston died, age 68, on the 20th November 1945, having sad account of Hiroshima and Nagasaki. 

It is with assertive irony for history to record that on Wednesday, 11th October 1941, the last utterances of the economist Alexander Sachs to convince the President Franklin D. Roosevelt, his old friend, to commit the resources of the U.S.A. to an atomic bomb project, would have been a reading of this last paragraph of a transcript from Aston’s address, to which the president replied. 

“Alex,” said Roosevelt, quickly understanding, "What you are after is to see that the Nazies don’t blow us up.”

“Precisely,” Sachs said.

Roosevelt called Watson. “This requires attention,” he said to his aid.

 Rhodes, Richard © 1986; The Making of the Atomic Bomb; p.g. 324

 The letter to the President that Eugine Wigner and Leo Szilard had solicited from Albert Einstein some three months past on 16^th July 1941, and who had signed the final draft later; had been outlined by Sachs, as had Leo Szilard’s covering letter, when he had started his verbal brief to the President. The letters went unread with the file to Watson.

  * - A play on the name of the Si-Fantasy novel Something Wicked This Way Comes, 1962, by Ray Bradbury

1. Enterprise OV-101. The Test Vehicle, never went into space but was a test bed that proved the design, aerodynamics and avionics of the Space Transportation System (STS). She was first flown on the back of a Jumbo jet. She would do 5 free atmospheric flights on her own; the first ALT-12 on 12th August 1977 and last ALT-16 on 26th October 1977. It would take 4 years after this for a re-usable space system to be ready for launch in 1981.
2. Columbia OV-102. The first reusable STS to fly space, STS-1 on 12th April 1981. She would complete 27 return missions. Colombia would fly the fourth of 4 planned service missions for the Hubble Space Telescope (HST); STS-109 on the 1st March 2002, which would also be her last completed space mission of 10 days and 22 hours with a successful return home to base. Colombia would fly her last and 28th space mission, STS-107 on 16th January 2003. Colombia died together with her 7 crew members, when she burnt up on a fiery re-entry, due to a loss of insulation tiles at launch, when returning to land at the Kennedy Space flight Centre, Florida, on 31st January 2003; some 15 days and 22 hours for mission accomplished and a successful launch. The accident would ground the NASA STS programme for 2 years before the next space flight; STS-114 of Discovery on 26th July 2005.
3. Challenger OV-099. First flew STS-6 to space on the 4th April 1983 and would complete 9 missions. The 10 mission, STS-51-L on the 28th January 1986, would last 01m 13s; at which point supporting structures of the main liquid fuel-tank of the booster vehicle were weakened by a hot jet of gas escaping from a leaky synthetic O-seal of one of the strap-on chemical booster rockets, causing the system to break apart under aerodynamic stress, and appear to exploded to create the Challenger Disaster. There was actually no explosion; but rather a spectacular voiding of liquid propellant and oxidant from the ruptured liquid-fuel tank. On view to millions of world enthusiasts on TV, and especially to a great number of young children in the U.S.A. who were eagerly following the mission because of a civilian school-teacher aboard, Christa McAuliffe who had aspired to the rank of mission specialist out of a field of some 11,500 applicants; the Challenger Disaster was a poignant reminder that space flight and the technologies of the day were still in primitive infancy. The Challenger STS, with her 7 crew, were ruled to have died on impact in the Atlantic ocean, a few miles East of the Florida launch coast, some 2.75 long minutes after the vehicle arched away, in ballistic trajectory, from the point of rupture. The Challenger Disaster had two root causes. One, the synthetic seals of the re-usable chemical booster rockets had a flexibility characteristic that was temperature sensitive; they would harden, with sealant loss, at temperatures around the freezing point of water, 0 deg C; the prevailing ground temperature at the time of the wintery vehicle launch. Two, an unkind endemic and epidemic viral societal disease of American society called Market Forces. The accident would ground the NASA STS programme for over 2 years before the next space flight; STS-26 of Discovery on 29th September 1988.
4. Discovery OV-103. First flew STS-41-D to space on 30th August 1984, and completed 39 missions, the highest number of the STS fleet. STS-31 launched on 24th April 1990, Discovery with a crew of 5, on a 5 day 1 hour mission, deployed the optically defective Hubble Space Telescope (HST), a joint NASA venture with the European Space Agency (ESA). Discovery would fly 2 of the 4 planned service missions for the HST; the second STS-82 on 11th February 1997 and the third STS-103 on 19th December 1999. Discovery flew STS-133, her last mission to space on 24th February 2011; to return 12 days & 19 hours afterwards.
5. Atlantis OV-104. First flew STS-51-J to space on 3rd October 1985, and completed 33 missions. Atlantis flew the fifth and only un-planned Hubble Space Telescope (HST) update and repair mission of 12 days and 21 hours with 7 crew, occasioned by public and scientific debate in the U.S.A., during her STS-125 space flight on 11th May 2009; it was also to be the last HST service flight by STS vehicles, intending an extended HST lifespan to 2014. Atlantis flew STS-135; her last mission to space on 8th July 2011; to return 12 days & 18 hours afterwards; the last STS space flight that closed this NASA STS manned flight programme.
6. Endeavour OV-105. First flew STS-49 to space on 7th May 1992, and completed 25 missions. Endeavour flew the first of 4 planned service missions for the HST; STS-61 on 2nd December 1993, which provided the HST with corrective optics, or ‘glasses’, that allowed the telescope for the first time to operate within its design parameters, and to return images of such astonishing clarity, that it would set the Hubble ST as one of the most influential and successful scientific instruments of its class ever deployed by mankind. Endeavour flew STS-134, her last mission to space, on 16th May 2011; to return 15 days & 18 hours afterwards.

  Ubiquitous to astronomers, conceived as the most convenient way to visualise the evolutionary life of stars, individually and en-mass; the Hertzsprung–Russell diagram (H-R) displays stars in the relation of their power output (the stars real luminescence compared to the sun (Sol = 1 unit) against a plot of their measured surface temperature (degrees Kelvin).

POPULATION I & II STARS
  Binney and Merrifield astronomers and authors, whose main interests are focussed on Galactic astronomy, provide an appealing historical account on the development of the H-R diagrams and their relation to the matter of star populations; which will be related here. They note that astronomers Lindbold and Oort, who were developing theories of the kinematics (the motions) of stars in galaxies, had proposed that spiral galaxies could be better understood if they were considered as comprising two differing components that comprised the galaxy; a spheroidal group of stars and a group that made up the disk. Each of these components suggested that the stars in them were examples of two distinct stellar-type populations.
  The American astronomer Walter Baade, taking advantage of wartime (WWII - 1944) city blackouts in the Los Angeles area, using the 100 inch Mount Wilson telescope, was able to resolve stars within the inner regions (associated with the ‘halo’ or spheroidal component) of some nearby spiral galaxies; and stars from nearby elliptical galaxies. On analyses of their colour and brightness, Baade realised that these bright stars were red-giants, and quite different from the bright stars found in spiral arms, which were blue super-giants. Baade concluded that he was observing two different star populations; Population I contained the bright blue super-giants in the dusty and gaseous regions of the spiral disks; and Population II contained the red-giants in the dust free regions of spiral and elliptical galaxies. So open-clusters and spiral disks contain Population I stars and globular-clusters, galactic spheroids and elliptical galaxies contain Population II stars.
  In the 1920’s, Ejnar Hertzsprung of Denmark and Henry Norris Russell of the U.S.A. independently discovered that if a plot was made of stars luminosity (power) against their colour (temperature), the plot began to reveal patterns of position within the diagram, and that they were not scattered randomly within it. These plots were named after their discoverers and became widely known as Hertzsprung–Russell (H-R) diagrams. Present day astronomers more usually call them colour-magnitude (C-M) diagrams in everyday use; because they use the colours they detect, or selected filtered differences, to plot directly on their graph. It is more convenient to do so; where it is inferred that the colours represent the temperature of the stars anyway. However we shall use the old H-R name, in this section, just for the moment.   Early H-R plots of stars from open-clusters and from globular clusters revealed different patterns, giving better weight to the idea of differing star populations. After much examination of the diagram, it became apparent that what was being displayed were evolutionary trends in the life cycles of stars. Between the mid 1940’s and the mid 1960’s, the emerging technology of computers began to have a strong impact on the understanding of stars, as mathematical modelling began to bring convergence between theories and observations. Further application of reverse-engineering, by use of proposed theoretical models of star composition and age, plotted on the H-R diagram, began to reveal what these groupings represented. And so the dual tools of observation and theoretical modelling, after years of effort, brought an understanding of the evolutionary life cycle of stars. So the H-R diagram became a convenient way to visualise, or plot, a stars life; as it progressed through millions or billions of years of its evolutionary life-cycle, from birth to death.
  The principal strength of the H-R diagram is its ability to display, at a glance, the similarities and differences between different types and groups of stars observed. The principle feature of the H-R diagram is its location of the Main Sequence (MS) stars. Main Sequence stars are those that have evolved to the point of just starting their nuclear ‘burning’. They have just changed from being a mass of hot glowing gas, to a true nuclear fired ‘star’. This is the point at which the star has started to burn (fuse) hydrogen into helium in their cores by thermonuclear synthesis.
  After accretion, a star will shine under the influence of gravitational compression, moving along what is now called the Hayashi track (see later) at the end of which it starts thermonuclear ignition to become a main sequence star; and then later moves away from the main sequence, to evolve into different types of star.
  The H-R diagram displays the main sequence trend as a curved band that is heavily dependant on the original mass of the young MS stars. This band is sometimes called the ‘Zero Age Main Sequence’, or ZAMS plot, and positions the stars according to increasing mass. The relation that has been found is that; low mass stars reside at the bottom; and high mass stars at the top of the MS plot. All further analysis then follows, by comparison of where a star, or a group of stars, may lie in relation to the MS plot.
  From these relationships, the type of star, its age, the age of a group or cluster of stars, and other features of interest may be determined.
  It was through these H-R plots that it was discovered that stars from open clusters represented young stars, of Population I; and that globular clusters represent old mature and dyeing stars, of Population II.
  It is not a trivial exercise to place a star on the H-R diagram, as a star needs careful analyses of its characteristics before being plotted. The H-R diagram requires an accurate determination of a stars power output, or luminosity as astronomers prefer to term it; a characteristic which is related to a stars surface temperature (colour) and its size. But as it is not easily practical to measure a stars size directly, this will be inferred from the stars temperature; by using bands of different frequencies (colours) and measurements of their intensity; and that relationship is calibrated from the known black-body radiation plots specific to a particular temperature. This colour relation ( hence colour-magnitude (C-M) ) however still needs to be referred to a standard to have any comparative meaning; so the standard chosen is the luminosity of our local star, the sun (LSol=1). An accurate order of the stars distance is also required for the calculations, this can be pains taking to do. Once determined however, stars thus plotted on the H-R diagram may then be given a classification number that denotes, at a glance, the type (colour; size) and inferred age of the star.
  When clusters of star are analysed and plotted on an H-R diagram, the age of the cluster may then be determined from examination of the resultant placing and grouping of the stars on the diagram. Where it is assumed that all stars in the cluster were accreted at around the same time; the stars of the group would each have then evolved in a way characteristic to their starting mass. The maturity of the population now viewed, will display their current evolutionary status on the H-R diagram, from which the age of the population can de determined by examination of the point along the MS where the stars are just old enough to initiate helium burning, to start to ‘turn off’, away from the MS. At the ‘turn off’ point, the spectral class of the stars at the tip of the turn is determined; as we already know at what age that spectral class of star will begin to start helium burning, the age of the whole cluster will then follow as that age.

METALLICITY
  Where it has earlier been indicated that stars form from generally two different populations; Population I for young stars and Population II for old stars; the significance of the differences in population has now been found to be related to a parameter termed the metallicity of the stars. In a slightly confusing legacy leftover term from historical astronomy; it is the Population II stars that are actually the first type of stars to have been formed. The theory postulates that they were formed from primordial hydrogen and helium, that was the first of a small number of the light elements to precipitate out, between 2 and 17 minutes after the Big Bang creation of the universe. As the universe cooled further after the event, ionised then molecular atoms froze out of the primordial particle soup to represent a significant amount of the matter-nuclei of the universe. The abundance of dark-matter that was also precipitated, presumably at the same time, is outside of our scope of concern for this discussion; is not well understood and remains an area of active research. This era of primordial nucleosynthesis, marks a period known as the atomic epoch. This era is theorised to have been followed, roughly over the next billion years, by an era termed the galactic epoch. It was in this period that the first stars were formed in galactic conglomerates, originating the Population II stars of low metallicity, comprising mostly of hydrogen and helium. These stars would then evolve and die (not all, some of the lower mass variety are still evolving today) to have performed further nucleosynthesis of the heavier elements in and around their cores, from which astronomers have another legacy habit to call anything heavier than helium ‘metals’. These ‘metals’ roughly represent some 90 elements, Lithium-3 to Uranium-92, that are the ‘natural’ elements noted in the periodic table of elements. (We recall that any element of number 93 and above; are man-made). Any second or further generation (n-th) stars born out of debris of these first generation stars, now become Population I stars of higher metallicity. Again, our local star, the sun, is used as a benchmark of a star with medium metallicity; having been made from material of the n-th generation of stars formed in the disk of the Milky Way galaxy. Stars of similar type, but of higher metallicity, are noted to have spectra shifted slightly more towards the red than low metallicity stars.

CAUTION: Just a mild caution that in the H-R diagrams shown here, the tracks shown for star evolution are somewhat simplified in representation, as real stars and their currently understood models, are actually a little more complex in behaviour.

Main Sequence Mass (Sol = 1M) -- : -- : -- Star evolution by Mass -- : -- : -- Star Type Classification (Sol = G2V)

Famous local Stars -- : -- : -- Nearby local Stars -- : -- : -- Brightest (most luminous) local Stars

The hypothetical evolution, over 10 Giga years, of a star cluster illustrated on the H-R diagram

Star Cluster Evolution
On the assumption that all stars are accreted at about the same time

Plot of globular clusters (like M80 @ 8kpc) -- : -- : -- 1M-Sol Full Track (life-cycle) -- : -- : -- Hipparcos (Space Telescope) Data

Blue Stragglers (from left H-R plot) are stars who's evolutionary life has been altered by acquiring/loosing mass in a close or contact binary environment,
thus altering their evolutionary track as expected for the age of the population of stars under investigation.
The main point being made here is that the 'turn-off' location, the point at which the main group of stars branch away from the main sequence
signifies the age of the star cluster, which here is about mid-way between F and G type stars,
shows an age for the cluster of around 4 to 5 Giga years.

Note: Hipparcos (High Precision Parallax Collecting Satellite) a tortured attempt to honor the ancient Greek astronomer Hipparchus of Nicea, who made the first known star map; a mission by the European Space Agency (ESA) 1989 to 1993. A reduced data set from 20,000 data points of stars within ~200 pc (652 lt-yrs) provides one of the most precise H–R diagrams ever compiled.
The Hipparcos parallax data was about 10 times more accurate than ground based data, at the date of its release in around 1999. The satellite also measured star colours, which transulates to tempreature. The Hipparcos data became the benchmark for distance measurements, and caused a recalibration of most other measuring techniques; and literally, changed the percieved size of the universe. Among other ramifications of its data, and considered by some to be its most significant contributions to astronomy; it recalibrated the Cepheid variables, placed the Large Magellanic Cloud 10% further away; increased the distance of the Andromeda Galaxy by 33%; indicated that the oldest stars are a little younger than was previously thought and reconcilled the embarrassing problem that some stars seemed to be older than the universe itself.

The data set is truncated for low mass stars (bottom of plot), the red dwarfs (failed stars) and brown dwarfs (dead stars), because they were to faint for the electronics to detect.

  In the main, there are about 5 different processes in principal, by which stars are borne; all of which have the prerequisite of sufficient an accumulation of gas and/or molecular dust from which the process of star formation can start.
  Leaving aside for the moment the convoluted detail of arguments arising for the formation of stars into galaxies, from the early cosmological standpoint of a uniform background of matter, that then needs to become clumpy and grainy, in large probability chunks, before it can coalesce into galaxies of stars; we look instead first at other, the more violent of the processes, to begin. As even though the process of primordial galaxy formation is of high and important interest, it will be noted later; however understanding the fundamental processes of single star accretion, is a sub-set and prerequisite for any grand model.

  A tangible view on some of these processes has only relatively recently been available to astronomers and astrophysicists within the last three decades or so; as a plethora of now space borne and new technology ground instruments, probing the universe in virtually all areas of the electromagnetic spectrum, have worked together to provide the observational data, the likes and quality of which has never before been so astutely managed nor so widely accessible. And together with this, among many technologies, the advances in electronic control and computer hardware and software technologies that have enabled data acquisition (e.g. imaging), data storage (e.g. memory), data transport (e.g. telecommunications) and data manipulation (e.g. mathematical modelling) to progress to staggering levels of sophistication and application.
  The details of the fundamental process that occur to actually form a star, are still not fully understood and are in a continual process of review. Astrophysicists attempting to model these processes, assisted by data from observational astronomers, face many complex challenges in producing a diverse array of models to illustrate the characteristic birth of a single star, or for the formation of clusters of stars, and so on.

The Southern Milky Way above Atacama Large Millimeter/submillimeter 66 antennas Array (ALMA); The Chajnantor plateau
@ 5,000 m (16,400 ft), Atacama, Chile. Republic of Chile; ESO; National Radio Astronomy Observatory (NRAO); National Astronomical Observatory of Japan (NAOJ).
By ESO; Babak Tafreshi - TWAN
28 May 2012
ALMA went fully On-Line on 13 March 2013

  Models must face the observational realisation that not all stars are single enteritis, but that around 60% of all stars are binaries, or of associations of a higher order of complexity. That clusters of stars may be closed (remain gravitationally bound), or open (loose gravitational focus). That some stars are primordial (1st generation, as old as the universe itself, and formed from the primordial constituents of matter) and others are of nth generation (formed from material processed in previous generations of stars), thereby being made of material containing ‘metals’, elements produced in the interior of previous generations of stars; so these models should also contain parameters for ‘metallicity’. That on the micro scale, the model should account for the formation of stars and planetary systems; on the small scale, account for the formation of star clusters; on the medium scale, account for the formation of oval and spiral galaxies and their interactions; and on the large scale account for the formation of galactic clusters; and on the cosmological scale, to account for everything contained within what is understood to be the known universe.
  A tall order indeed.

10 - M42 - The Great Nebulae in Orion; a Sketch by the Earl of Rosse (William Parsons) (~ 1845 to 1850); Messrs De la Rue; Cassel & Co Ltd, Lith, London 1890 (scanned image)

The Rosse instrument, the Leviathan of Parsonstown as it was locally called and for credence to the worlds largest optical telescope of its day, is a Newtonian 6ft (72 inch) (1.83 m) brass reflector;
(66% Cu + 33% Sn) of 3 tons ~1845 to 1908.
Birr Castle, Parsonstown, Ireland

Its predecessor, the original Rosse instrument, was a 3ft (36 inch) (0.91 m) brass reflector; 1826 ~ 1845.

10 - M78 - NGC 2068 - A reflection Nebula in Orion @ 1,400 Lt-yr (429 pc) distant.
La Silla 2.2m MPG/ESO telescope; Camera: WFI 8k x 8k mosaic CCD;
Filters: blue, yellow/green and red.
ESO, Post-processing Igor Chekalin, 11th November 2010

The location of M78 relative to the constellation of Orion (right).

An artists impression (left) of a protostar forming within the dark molecular cloud of a Bock Gobule

  NGC 5272 is one of the most intensely studied globular clusters in the MW halo, being in the northern skies, following M13; and being one of the largest and brightest, following Omega Centauri (ω Cen). Discovered by Charles Messier on 3rd May 1764, to be designated M3, and resolved into stars by William Herschel at around 1784. Interest in the cluster grew after the American astronomer Solon Irving Bailey noted from 1913, a larger than usual population of variable stars in the cluster.
  It is now known to contains ~ 274 variable stars; by far the highest number found in any globular cluster. These include 133 RR Lyrae variables, of which about a third display the Blazhko effect of long-period modulation. M3 is considered a metal rich cluster, is the prototype for the Oosterhoff type I cluster, for medium abundance of heavy metals, in the range of –1.34 to –1.50 dex; a logarithmic abundance term relative to that of the Sun; showing an actual metallicity of 3.2 – 4.6%. Its high metallicity suggests that it is not a primordial cluster, being made from nth generation stars, and may have originated in the MW galactic disk before migrating to the halo; or a resultant cluster from a past galactic encounter of the MW galaxy.
  The estimated age of M3 is between 8 to 11.39 Gig-years; the latter being the currently accepted age; this is just ~ 2 Gig-years younger than the currently accepted age of the universe. This just means that the star population of M3 is quite old and mature; as directly indicated in the colour-magnitude (CM or H-R) plot alongside.
  The cluster is 33,900 light-years (10.4 kpc) away, with an apparent visual magnitude of +6.2, placing it at the edge of the limit to naked eye visibility. It is made up of ~ 500,000 stars and is estimated to mass 450,000 MSol in a volume some 180 ly in diameter. M3 is located about 31,600 ly (9.7 kpc) above the Galactic plane and roughly 38,800 ly (11.9 kpc) from the centre of the Milky Way galaxy.

Incert: Omega Centauri by Gordon Mandell.      

  Visible in the main filter-enhanced image are; the low temperature red super giants as red stars; blue stragglers, the A and B-type giant stars as blue; horizontal branch giant stars as orange. The rest of the stars are intermediate F stars moving away from the main sequence and approaching the rising giant branch; they will be the larger of the white stars. The smaller stars; orange, white and red, will be mainly stars still on the main sequence; intermediate between F and G-type, down to the red M-type stars. It is assumed that the H-R plot (or Colour Magnitude - CM - plot as astronomers would want to call it) may not have originated with the high resolution of the HST, and could be ground based, where the band of low luminosity stars down to the M regions of the graph, have not been fully represented.
  In the main, the H-R (CM) plot indicate an age for the cluster of around 4-5 Gig years (at turn off); somewhat at odds with the stated age of some 12-14 Giga years for this ‘old’ cluster.

  The blue stragglers are expected however, as many binary, and higher order star systems, are known to exist in globular clusters; which will rejuvenate stars to stragglers by mass-transfers in these systems.

Observed Structure of The Milky Way Galaxy
Source: 2nd derivative by Rursus 9th June 2007; 1st derivative by YUL89YYZ; Ctachme, Kevin Krisciunas, Bill Yenne The Pictorial Atlas of the Universe, page 145 (ISBN 1-85422-025-X) and µOR

Excited doubly ionised hydrogen (H II) regions are marked as coloured highlights in their respective spiral arms. The three sizes, donate their excitation parameter U:
• Small - U > 200 pc cm-2
• Medium - 200 > U > 110 pc cm-2
• Large - 110 > U > 70 pc cm-2

Stylised face and edge view of the disk of the MY galaxy illustrating the position of the galactic halo stars and the globular clusters found around the galaxy.

  It all started with an engineering graduate of the U.S. Naval Academy of 1940, whom with some arduous service in the U.S. Armed forces, survived WWII to later complete a Ph.D in physics, with instruction from Karl Herzfeld, a mentor of the prodigal mathematician John Wheeler. After a year of actually working with Wheeler and his team, Joseph Weber was well versed in Einstein’s theory of relativity and the properties of gravitational waves.

Joseph Weber (1919 - 2000) in 1975 with his prototype gravitational wave detector made with a 2 meter aluminium bar, 1 meter in diameter, with piezoelectric strain gauges.
By James P Blair, National Geographic Society; Black Holes & Time Warps, Kip S Thorne, Pg 368