As telescopes got better, more and more faint fuzzy blobs, called "nebulae" could be seen. The French astronomer Charles Messier compiled a catalogue of these fuzzy blobs or "nebulae" so he could distinguish which fuzzy blob might be a new comet which was what he was interested in finding. His catalogue numbers are still in use, M.1, M.2 etc.
Caroline Herschel and her brothers William and Alexander who were also searching for comets, got a copy of Messier's catalogue in 1781. They discovered a fuzzy blob that turned out to be a planet, later called Uranus. (See the Telescope Revolution). The Herschels called the planet after George III and thus got funding for a 48 inch reflector telescope. The biggest in the world, until William Parson, 3rd Earl of Rosse, built his in Ireland. This showed that some of the small oval nebulae had a spiral structure.
William Herschel's son, Caroline's nephew, John Herschel also become an astronomer. (He really wanted to be a lawyer but his father and aunt needed help as they got old - William was 54 when his son was born, Caroline was 42). He invented the word photography and pioneered the application of photography to astronomy. Cameras had been used by astronomers to observe the Sun for at least two thousand years By the end of the 17th century cameras like the ones still in use in the 1950s were made. All that was needed was a way to fix the image projected by light, instead of tracing it. The problem was not just producing a picture on a film of light sensitive chemicals, but of fixing that picture permanently. A number of methods were discovered about the same time in the early 19th century.
One of John Herschel's first photographs that could be printed from a negative (so it had an advantage over the Daguerreotypes which became popular) was of the family 48 inch telescope in Slough, just before it was demolished in 1839.
Even the earliest photographic methods revealed far more than the eye could see. Long exposure times enabled faint objects to be seen. The wavelengths of light that the photographic plates were sensitive to had a different range (further to the blue) than that of the eye so more was seen. And of course it was recorded permanently and more efficiently than a drawing. And this made it much easier to find new objects. Photos taken of the same part of the sky over a period of time could be compared to see if there were any changes.
CCDs have replaced photographic plates as more effective at collecting photons. Also there is a proportional ratio between the number of photons and the detected electron currents which enable an object to be separated from its background.
In radio astronomy the photon detector is the receiver. The photons are focussed by the surface of the dish onto a waveguide horn and probe which feeds down a converter to a detector which converts them into weak electrical currents which are then amplified. The results are collected and stored as computer data to be examined in detail in various ways on the computer.
Fraunhofer Lines tell us what stars are made of
Joseph Fraunhofer was the son of a glazier. Orphaned at 11, and apprenticed to a glass cutter in Munich on 21 July 1801. But the building collapsed. Fraunhofer was the only survivor pulled out of the ruins. Plucky little lad was visited in hospital by the Elector of Bavaria, Maximillan Joseph who gave him a present of 18 ducats so he could set up his own business.
Fraunhofer mapped the lines found in the spectrum of the sun and found identical lines in the spectra of the moon and planets (since they shine by reflected sunlight). But the spectral lines from the stars were different. Fraunhofer died June 7th 1816 aged 39 of TB.
In 1849, Leon Foucault in Paris and W. A. Miller in London, found bright lines that corresponded with Fraunhofer's dark lines. One evening Gustav Kirchoff and Robert Bunsen (inventor of Bunsen burner) used a spectroscope on a massive fire ravaging the city of Mannheim ten miles to the west of them. They detected lines indicating barium and strontium in the spectra of the flames. This proved their experiments that the patterns of the lines were produced by different chemical elements. So they thought they could detect the elements in the spectrum of the sun.
By 1861 Kirchoff identified sodium, calcium, magnesium, iron, chromium, nickel, barium, copper and zinc in the sun. In London, William Huggins applied the method to analysing stars. He fitted a spectroscope to the Clark telescope at his private observatory in Upper Tulse Hill in London. He identified iron, sodium, calcium, magnesium, and bismuth, in the spectra of the stars Aldebaran and Betelgeuse. This was the first proof that stars are made of the same substances that we find here in the solar system.
Then Huggins in 1864 looked at a nebula. He found only a single line. It was a gas. From this he reached the mistaken conclusion that all the nebulae were clouds of gas.
A spectrograph focuses the light from the main telescope mirror through a slit, then lenses, to turn it into a parallel beam before it hits the prism, when the diverging colours are focussed onto a photographic plate to be recorded. Modern optical spectroscopes use a diffraction grating which splits the colours immediately. The light is then focussed and recorded either on a VDU or charge coupled device (CCD). Spectrographs are also used with radio telescopes but electronic devices are now used in an auto correlator and the radio signals are processed to differentiate the strengths of radio signals at different frequencies.
the Cause of Spectral Lines
When a gas is heated, the atoms move about more and collisions between atoms take place which push electrons to orbits at higher energies than their ground state. As they jump to these higher energy levels they absorb photons of energy. These show as dark lines or gaps in the spectrum. Each electron then drops back in stages (as it only exists in certain energy levels) to its ground state, giving off photons of energy on the way which show in the spectrum as bright lines. As the electrons of the atoms of each element only exist at certain energy levels and are never found between, the spectrum of each element shows a characteristic pattern of lines which identify the element as the lines will always been at the same places at the same energy levels of each element.
For example the electron of a hydrogen atom may be "excited" to jump up to a higher energy level, it will then drop back as the hydrogen gas cools down. If it falls back to ground level, then high energy photons are given off, making lines in the spectrum called the Lyman series which fall in the ultraviolet part of the EM spectrum. If the electron only drops as far as the second level, less energy is given off, the lines are called the Balmer series and fall in the visible part of the spectrum.
Calcium atoms give rise to absorption lines at wavelengths of 396.8nm and 393.3nm and these are called the H and K lines.
H-R diagram
In 1915, Annie Jump Cannon, a computer (they were people then) at Harvard, noticed that most stars belonged to about six distinct spectral classes. A deaf spinster, she had the job of looking through the photographic plates and cataloguing the stars, indexing the spectra of each star.
Annie classified the stars by colour. The classifications had to be constantly altered, spoiling her original neat alphabetical labelling system, so the classes now sorted by their spectra, eventually became O,B,A,F,G,K & M. with colours from blue/white through yellow G type stars like our sun to the red M stars.
Antonia Maury was another computer working on the spectra of stars. In 1911, Danish engineer, Ejnar Hertzsprung analysed Annie's and Antonia's data for the stars in two clusters, the Hyades and the Pleiades, knowing that the stars in each cluster would be about the same distance from Earth. This way he could see if there was a relationship between the actual brightness and colour of stars. There was.
Other astronomers then applied Hertzprung's method to stars where the distance could be measured by parallax and found then that the distances of other stars with similar spectra could be measured and their absolute magnitudes found.
Henry Norris Russell of Princeton, USA, plotted the absolute magnitudes of a few hundred stars against their colours and found that most plotted into a curve. This was in 1913. When it was seen that the two diagrams were much the same, it was called the Hertzprung-Russell Diagram.
Henrietta Leavitt
and the Harvard astronomers:
Henrietta Leavitt, 1868-1921, born in Lancaster Massachusetts was one of seven children. Her father was a Congregationalist minister. Miss Leavitt remained religious and puritanical throughout her life. She was deaf.
She studied astronomy at what is now Radcliffe College and got her AB degree in 1892. Later she joined the Harvard college Observatory as one of several women who were working there, including Williamina Fleming and Annie Jump Cannon (who was also deaf).
Miss Leavitt was interested in variable stars. She was one of the first astronomers to study photographic plates to notice changes. Miss Leavitt discovered 2,400 variable stars. Her most important discovery was the period luminosity relation for Cepheid variables which could be used to measure distances.
In 1912, Henrietta Leavitt had the task of examining the many photographic places taken through Harvard's 24 inch refractor in Peru, of the southern skies. She had to compare star images on plates taken on different dates, looking for variations in the brightness of certain stars. Thus she discovered the regular variations in the type of stars called Cepheids.
She discovered that this type of star oscillates in brightness, growing dim, brighter, then dim in a regular cycle. She analyzed a group of Cepheids that were clustered about each other and thus known to be at the same distance. In a cluster of stars which means all the stars would be about the the same distance from us, a star that appeared brighter would actually be more luminous.
Miss Leavitt found that the time for a Cepheid to complete one brightness and dimness cycle was related to its luminosity. A Cepheid 1,000 times as luminous as our sun completed a light cycle every three days. Cepheids 10,000 times as luminous completed their cycle in thirty days.
When this was measured and noted for close Cepheid stars of known distance and luminosity, it could be used to measure the distance to more remote Cepheid stars.
By measuring the cycle time recorded on the series of photographic plates, one would know its luminosity. Then comparing the star's luminosity to its observed brightness, it was possible to calculate its distance.
Miss Leavitt discovered Cepheids in the Magellanic Clouds, it was not then known that these were other galaxies outside the Milky Way. Miss Leavitt calculated from the Cepheids that the Magellanic Clouds had to be at a very great distance.
The discovery of Cepheids in the spiral nebulae enabled the distances to be measured and confirmed that these were separate galaxies of stars distant from our own galaxy.
(photo from "She is an Astronomer")
In the Californian sun
Harlow Shapley at Mount Wilson saw the discovery of the regular Cepheid cycle by Miss Leavitt as a means of finding the size of the galaxy which he thought was the whole universe - he did not believe the Magellanic clouds and other nebulae were separate galaxies. Shapley came up with a huge size for the Milky Way of 300,000 light years diameter. This is three times bigger than it now thought to be. But now we know it is only one of uncountable numbers of galaxies. To Shapley this seemed big enough for him to conclude it was the size of the whole universe.
However in 1917, George Ritchey at Mount Wilson, and Heber Curtis at Lick, had searched though old photographic plates and discovered there had been several novae in the spiral nebulae and these were not in the centres, but in the outer spiral arms. This did not accord with the hypothesis that these must be solar systems in the making, with a sun in the middle and planets forming round it. While one or two novae found in the centre of these spiral nebulae would not have contradicted the hypothesis, these were many and in the outer reaches of the spiral arms.
George Ellery Hale (1868-1938) was an astronomer from Chicago who was interested in studying the Sun. He came from a very rich family so he had very good contacts for raising the necessary funds for larger and better telescopes.
One day when he was 42, an elf appeared to him and gave him some useful advice. The elf continued to visit him and offer advice. By 1922, Hale's doctor told him his health could benefit from a holiday abroad. Hale took his family to Egypt for a Nile cruise. While he was there he visited the tomb of Tutankhamen which had just been discovered.
Hale was bowled over by the treasures and splendors of Tutankhamen's tomb. It blew his mind completely. On his return home, he built his own Egyptian tomb and spent the rest of his life in it.
Hale did not live to see the completion of his largest telescope which has a 200 inch aluminiumized Pyrex mirror. It was finally installed at Mount Palomar in 1948.
Edwin Powell Hubble
(1889-1953),
was born in Missouri, USA. Studied law in Chicago and then as a postgraduate at Oxford. Worked as lawyer until 1914 when he got a job at Yerkes Observatory studying nebulae. Then he enlisted as a soldier in the 1st World War in Germany. After the war he got a job at the Mount Wilson Observatory, Pasadena, California.
In 1924, Hubble used Hale's 100 inch telescope to photograph the Andromeda Spiral and discovered a Cepheid variable. From this he estimated a distance of one million light years. This is about half of the current estimate of its distance but far enough to show it was outside our own galaxy. Hubble went on to identify Cepheids, novae and giant stars in other nebulae, proving they were other galaxies, ours was just one of many. Hubble classified the nebulae according to appearance. He thought this showed an evolutionary sequence. He was wrong. But Hubble's classification is useful for identifying galaxies on a photograph.
Hubble was helped by Milton Humason who started work at Mount Wilson looking after the mule trains that took the gear up the mountain then. He became janitor, then assistant, then an astronomer.
While muleteers could use the telescopes, women astronomers could not. Even in the 1950s - Margaret Burbidge got in to do her research, only by taking her husband Geoffrey along as the official user of the telescope.
The Director of the Royal Greenwich Observatory was also always the Astronomer Royal - until Margaret Burbidge was appointed in the early 1970s, the first woman Director.
Relativity
E = mc² and Poincaré
Jules Henri Poincaré (1854-1912) was an engineer and mathematician who anticipated chaos theory and relativity.
Following Newton and until Poincaré it was thought all problems of moving bodies and orbits could be easily solved mathematically. Poincaré published his first paper in Nouvelles Annales de Mathematiques in 1873 when 19. By the time he died in 1913 he had written more than thirty books and five hundred technical papers. He believed in popularising science. In his book "The Value of Science" he says "If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living". He was elected a member of the literary section of the Institute Français.
In 1889, Poincaré showed that Newton's laws only applied to two bodies. When one tried to analyse the motions of a three body or more system, an exact solution cannot be found by mathematical analysis. Newton had written "Nature is pleased with simplicity and affects not the pomp of superfluous causes". But Poincaré commented "A century ago it was frankly confessed and proclaimed abroad that nature loves simplicity but nature has proved contrary since then on more than one occasion."
Poincaré's Return is a theorem which shows that any isolated system (ie the universe) will return to its initial state, and in an unlimited amount of time will infinitely do so. The recurrence time of the universe is calculated at present as about 1010 years.
Poincaré in his lectures at the Sorbonne in 1899, on the experiments on the problem of the Earth's velocity in space (the aether) and of the ratio of the Earth's velocity to the speed of light stated that he regarded it as very probable that the optical phenomena depended only on the relative motions of the material bodies, luminous sources, and optical apparatus, and that this is true not merely as far as qualities of the order of the square of the aberration but rigorously. Poincaré by 1899 believed that absolute motion is undetectable in principle.
Others working on relativity in the 19th century, were Hendrik Lorentz and George Francis Fitzgerald. They were trying to explain the Michelson-Morley effect (light at a constant speed) in terms of a physical contraction of objects moving through the aether, using the Lorentz transformation formulae. This allowed for light to be independent of the relative speed of the observer.
At the International Congress of Physics in Paris in 1900, Poincaré also questioned the actual existence of the aether, saying that he believed more precise observations would reveal nothing more than relative displacements. He said that a new principle would be introduced into physics which would resemble the 2nd Law of Thermodynamics in as much as it asserted the impossibility of doing something - in this case the impossibility of determining the velocity of the Earth relative to the aether.
In 1900, Poincaré suggested that electromagnetic energy might posses mass density equal to (1/C²) times the energy density, that is to say E=mc²where E is energy and m is mass. In a lecture to the Congress of Arts and Science at St.Louis, USA, on 24th September 1904, Poincaré defined this principle and gave it a name The Principle of Relativity. According to the Principle of Relativity he said, the laws of physical phenomena must be the same for a "fixed" observer as for an observer who has a uniform motion of translation relative to him. So that we cannot possible have any means of discerning whether we are or are not carried along in such a motion. He concluded that from all these results there must arise an entirely new kind of dynamics which will be characterised above all by the rule that no velocity can exceed the velocity of light.
and Lorentz
Hendrik Lorentz (from Holland) and George Francis Fitzgerald, tried to explain the Michelson-Morley effect (light moves at a constant speed) in terms of a physical contraction of objects moving through the aether, using the Lorentz transformation formulae.This allowed for light to be independent of the relative speed of the observer. Jules Henri Poincaré questioned the aether. In 1904 he codified a "principle of relativity". (see Poincaré and E=Mc²)
Willem de Sitter in 1913 confirmed the constant velocity of light from his observations of double stars. Direct laboratory verification did not come until 1963.
and Einstein, - Albert or Mileva?
In 1911, Einstein then living in Prague with his first wife Mileva, who did most of the mathematics, and their two young sons predicted that the stronger the gravitational field the more slowly a clock ticks relative to one further from the source of the gravitational field. So the stronger the gravity the slower the oscillations of charged atoms - or ions, and they will radiate at longer wavelengths - red shift.
The effect can be seen on Earth. eg. an atomic clock at the National Bureau of Standards in Boulder, Colorado 1650 metres above sea level gains about 5 microseconds each year relative to an identical clock kept at the RGO at 25 m. above sea level. The nearer to the centre of the Earth, the stronger the gravitational field. Also there were experiments in the 1970s with hydrogen maser and caesium clocks in the air and on the ground.
Gravitational Lensing
Newton had proposed that light rays behaved like a stream of minute particles. As a ray of light streamed past a massive body it would be attracted to it and its path bent.
To Einstein, light rays travelled along paths (geodesics) in space and time. But as space-time became warped by the gravitational field of a massive body, the geodesic bent too.
In 1913, Einstein asked George Ellery Hale to suggest a way of detecting the deflection of light from a star as it passed the Sun. Normally it is not possible to see the stars in the part of the sky near the Sun as it is too bright. Hale suggested this could be done during a total solar eclipse.
An attempt was made to test the hypothesis in 1914 by a team from the University of Berlin, where Einstein was now working. Erwin Finlay-Freundlich led the expedition to observe the the light from the stars appearing near the Sun during the eclipse of the Sun in the Crimea in summer 1914. After they arrived, the First World War started and they were arrested and jailed in Odessa. In September they were returned home in exchange for some Russian prisoners, having missed the eclipse and the chance to make their observations.
Brits have a go
British astronomer Arthur Eddington had heard of Einstein's work through Willem de Sitter in the Netherlands. He arranged an expedition to Principe Island in the Gulf of Guinea, to test Einstein's theory using the eclipse of 1919 to observe the stars near the Sun. On his return Eddington declared at a RAS dinner (in the style of the Rubayat of Omar Khayyam):
Oh, Leave the Wise our Measures to collate
One Thing at least is Certain, Light has Weight
One thing is certain and the rest debate-
Light Rays, when near the Sun, do not go straight!
In actual fact it had been cloudy, and results were a little fudged. But they were confirmed by observations made during an eclipse three years later.
Einstein had predicted that if two stars were aligned with an observer, the light from the more distant star would be visible as a ring around the nearer star, as the gravity of the nearer star has bent the light about it. This is called "Einstein's Ring". If the stars are not in perfect alignment just two arcs opposite each other can be seen. If the alignment is less exact still, one arc will be bigger and brighter than the other. Even less exact and the image of the star is slightly deflected rather than bent into a circle.
The Einstein ring is unlikely to be seen with stars as their angular size is so small but in 1937, Fritz Zwicky (who was Swiss and worked in the USA) suggested that the effect could be seen with galaxies. This idea was dismissed until the end of the 1970s.
In 1978 twin quasars were discovered by Dennis Walsh (British). Soon after a large dim galaxy, the centre of a cluster of galaxies was discovered acting as a lens which was much nearer than the quasar according to the different red shifts. This had doubled the quasar's image. Many more instances of gravity lensing have been found since them. One is called the Einstein Cross after Einstein, a galaxy has caused four images around it of a distant quasar. Lensed galaxies can be recognized because their redshift is different from that of the galaxy or galactic cluster showing the light is coming from further away.
The Hubble Space Telescope has given us a dramatic picture of the gravitational lenses in the cluster Abel 2218. The distant galaxies can be seen as distorted arcs. The lensing not only reveals the galaxies, it brightens them, so we can see the distorted images of galaxies that would otherwise be too faint to be visible.
Alexander Friedman
Russian theoretical physicist, from St. Petersburg 1888-1925, his father was a ballet dancer. In 1923, he wrote a popular book "The World as Space and time" and a textbook. Friedman offered a complete analysis of the solutions of Einstein's cosmological field equations that went beyond the solutions of Einstein and de Sitter as it included non-static solutions. One of his intentions was "to demonstrate the possibility of a world in which the curvature of space in independent of the three spatial coordinates, but does depend on time". This was pure theory, and not linked with actual observation. He describes his model of the universe: "The variable type of universe represents a great variety of cases; there can be cases of this type when the world's radius of curvature....is constantly increasing in time; cases are also possible when the radius of curvature changes periodically. The universe contracts into a point and then increases its radius from a point up to a certain value, then again,....transforms itself into a point.
This brings to mind what Hindu mythology has to say about cycles of existence and it also becomes possible to speak about "the creation of the world from nothing" but all this should at present be considered as curious facts which cannot be reliably supported by the inadequate astronomical experimental material."
the Doppler effect
Christian Johann Doppler (1803-53) was a professor in Prague. He was interested in the changing pitch of the sound of a train as it moves past. He though that as the train approached the frequency of the sound waves were shortened, and as the train moved away, the frequency of the waves was lengthened. He tested his theory by filling a train with a brass band and employing musicians to record what they heard as the train passed them at various speeds. Doppler realised that this would also apply to light waves and would be useful for astronomers. If a star was approaching the Earth, then the frequency of its light would be higher and the light would be shifted towards blue, if it was moving away, the frequency would be lower and shifted towards red.
Red Shift & Hubble's Constant (Ho)
In 1899, J. Scheiner found absorption lines in the spectrum of M.31, but could not measure their wavelengths. In 1912, V. M. Slipher at Lowell Observatory used a camera attached to a 24 inch refracting telescope to measure the wavelengths of the absorption lines in M.31. He found them displaced towards the blue.
By 1928, Slipher had examined forty one other spectra of nebula and found the others tended to shift towards the red end of the spectrum. This, it was realised could be the Doppler effect. A red shift if the object is moving away from the observer, a blue shift if towards. For small shifts z (the shift) is simply the ratio of the speed of recession to c (the speed of light).
By 1929, Edwin Hubble, with Milton Humason, had realised that the distances of the nebula meant they had to be other galaxies of stars. They noticed the greater the distance, the greater the red shift. They deduced that the universe must be expanding and the speed of its recession could be measured. Hubble expressed this:
a Velocity Equals H times distance l/H is "Hubble's Constant" (Ho) and this is "Hubble's Law".
The model usually given of the expanding universe is that the galaxies and stars are like raisins in a cake being baked. As the cake cooks, it expands and the distance between the raisins increases. It is not the stars and galaxies which are moving but space that is expanding.
It is this expansion which is thought to solve Olber's Paradox "Why is the sky dark at night instead of lit up by the light of the stars?". But we now know that the stars and galaxies are all on the move, and are not scattered through space like the raisins in a fruit cake, but in related clusters, clumps and sheets with great voids between.
Despite this, this expansion model of a cake or of a balloon is still given. Einstein did not accept the idea of the expansion of the universe, and instead used a "cosmological constant". Thought once to have been mistaken, he is now vindicated as a new cosmological constant is considered. The old model of the expanding universe does not fit current observational data.
If you know the Hubble Constant which is the rate of the expansion of the universe, you can calculate not only the distances of the galaxies but the age of the universe. For if the universe is expanding, it must have once been smaller. It was assumed that the universe must have originated at one point in time and space. The Big Bang Theory. This is not a new idea. It is very old, and is found in many creation myths. For example in the Rig Veda from about 3,000 years ago, in bronze age India - "in the beginning neither non-Being existed nor Being....Nothing else existed but Brahman which derived from heat...desire was the first seed of consciousness".
Finding the age of the universe has not been as easy as once thought. Hubble calculated the Hubble Constant as 500 kilometres per second which made the universe 1,800 million years old. When it was found that the age of our solar system as determined by the decay of Uranium 235 is about 4,500 million years, it became clear that this figure was wrong.
Data was fudged to get better results. Later estimates varied from 10,000 million years to 20,000 million years with a Hubble constant between 50 and 60. If the Ho is 50 kilometres a second then the universe would be 17,000 million years old. Astronomers were happy with this figure in the 1980s.
The latest and most accurate estimates of the Hubble Constant have given a value for the Hubble constant of at least 80, which means that galaxies are closer than had been thought, but also that according to the Big Bang theory, the universe must be only 8,000 million years old. This conflicts with evidence that some stars in our galaxy are 19,000 million years old. And some stars are older than that.
You can estimate the age of a star or a cluster of stars or a galaxy by the amount of heavy metals ("metal" is used for all the elements in stars). The more heavy metals, the more the material from old exploding stars has been recycled. The elements in our sun and and solar system show it must be the product of at least three or four generations of stars which had in their time aged, exploded, forming the debris in which new stars were born.
Recent results have been as much as Ho =150 making the age of the universe even younger.
The problem is measuring the distances of galaxies. The nearest ones can be determined by the Cepheids - the pulsating yellow supergiants - but these do not show the red shift of an expanding universe, in fact some, like Andromeda have a blue shift because they are moving towards us.
the e-m spectrum electro-magnetic radiation is a strong force made of photons with a maximum speed of 3x108 m/s
Uranium 235 - so useful
The age of the solar system was dated with Uranium 235. It turns into lead - Pb.206 with a half life of one thousand million years. Meteorites and moon rock give an age of 4.55 thousand million years which could be the age of our sun and solar system including the Earth. But this is not the age of the uranium itself, which was formed before our sun and its solar system, in the explosion of a star as a supernova, which created the cloud of material in which our sun formed. In a supernova a large amount of neutrons are emitted from inside which are captured by atoms in the outer layers, so lighter atomic nuclei are changed into heavier ones and the heavier elements are produced, like uranium 235 and 238. Some elements, like technetium are only found on stars like red giants and not found on Earth in a natural state.
Nuclear fission occurs which a nucleus of Uranium 235 acquires an extra neutron. It unstablizes it. It splits resulting in:
- some new elements like barium and krypton
- 3 x 1011 joules of energy, which is also the kinetic energy of the released
- spare neutrons which can shoot off to attach to other Uranium 235 atoms, thus splitting them, and causing a chain reaction - great efforts have to be made at nuclear power stations to see this does not occur.
Fortunately the isotope Uranium 235 is rare in nature, and the more usual Uranium 238 can absorb an extra neutron without splitting.
the atom bomb
In July 1945, the world's first atom bomb was tested in New Mexico. It was placed on a 100 ft metal tower. At 5.30 am Major General Leslie R. Groves, the man in charge of the organisation of the atom bomb project gave the order to let it off. Brigadier General Thomas F. Farell, Grove's deputy described the explosion: "...the lightning effects beggar description. The whole country was lighted by a searing light with the intensity many times that of the midday sun. It was golden, purple, violet, gray and blue. It lighted every peak, crevasse and ridge of the nearby mountain range with a clarity and beauty that cannot be described.... thirty seconds after the explosion came first the air blast pressing hard against the people and things to be followed almost immediately by the strong, sustained awesome roar which warned of doomsday and made us feel that we puny things were blasphemous to dare tamper with forces hitherto reserved to the Almighty".
It woke people (who had been told nothing) more than 150 miles away who saw the flash like a second sun appearing in the dawn sky.
Robert Oppenheimer, the chief scientist working on the project said that it made him think of the words from the Bhagavad Gita:
"If the radiance of a thousand suns
were to burst at once into the sky
that would be like the splendor of the mighty one...
I am become death
the shatterer of worlds."
Groves ordered "We must keep this thing quiet".
The Russian atom-bomb had to follow very soon. (1949)
And the cold war stand-off era began.
The Great Universal Theory and Big Bang
In the chart showing the electro-magnetic spectrum it was not possible to fit in one of the most important items. This is our electric power which is provided at 50 Hz. Extremely low frequency. But still not absolute zero Kelvin as there is no radiation at absolute zero.
Now look at the other end of the scale - the hottest. There is a limit to how hot matter can get before it becomes unglued and falls apart into the tiniest particles of which it is composed. A "quark soup". With the discoveries of these tiny particles of which atoms are composed by the 1980s, it was hoped to combine all the new discoveries in quantum physics, astronomy, and mathematics into one model, a Great Universal Theory or GUT. A Great Universal Theory has been attempted before. By Aristotle, for example and Ptolemy.
The name "Big Bang Theory" was invented by Fred Hoyle. He is one of the scientists that has not been in favour of this popular theory that the universe started as one sudden glitch in space which is still expanding as our entire universe.
As you can see from the chart in the front of this book, cosmological theories tend to follow new technologies. The Big Bang is linked to the same scientific work which led to the atom bomb. And the atom bomb gave the idea an image.
Conditions at 10-44 seconds after the Big Bang had to be very very hot as the energy has been estimated as 1019 GeV. This hot electro-magnetic radiation could not exist, or anything else that forms the matter of our present universe. According to this magnetic force must have existed as separate monopoles instead of with north and south poles.
As things cooled so gravitation came into force. At 10-36 seconds old and down to 1015 GeV you have a quark-lepton soup and interaction of particles and antiparticles. And the strong force appeared. The weak force appears when energy is down to 102 GeV after 10-10 seconds from starting time. And the electro magnetic forces appear. All this happens by the time the universe is one second old, and the energy levels are down to one MeV.
It is now cool enough for electrons to combine with protons to make a primitive form of hydrogen atom. It clears as atoms are formed and photons can move about. This is decoupling. By three minutes from take off, the universe is beginning to look like home. Stars can start forming. By the time it is 105 years and 4000 K. galaxies are taking shape. Now the background temperature is 2.7 K.
the missing monopoles
The GUT predicts that magnetic monopoles should exist with energies of 1016 GeV. When Maxwell's equations of electricity and magnetism were formulated fully, it became apparent that isolated magnetic poles cannot exist in nature. With an electric current you can have positive or negative charges, but a magnetic field always has both north and south poles. If monopoles exist they must be around to be discovered, but if free monopoles did exist they would have killed any large-scale magnetic fields. And they might have made the early universe so dense it could not have gone on expanding until now but have already collapsed into a singularity. So there are conflicting ideas about magnetic monopoles.
The existence of monopoles fits into the Grand Unified Theory or GUT and the Big Bang. The GUT monopoles would be quite large particles, as big as atoms, with great magnetic fields. Monopoles would be accelerated by magnetic fields as electrons are by electric fields. They would sop up energy from the magnetic field and thus deplete it. So if there is a strong magnetic field, there can't be a monopole around. So there are unlikely to be many in our solar system.
Monopoles were searched for by a detector. This was built of a superconductor - a coil of wire, cooled down until its electrical resistance has gone. A moving monopole has a ring shaped electrical field. so it will accelerate the electrons in the coil and generate a surge of current which will continue to flow as it is a superconductor. This has only happened once so far, 14th February 1982, just before 14.00, local time, at Stanford University, California. Although it might prove the rarity of monopoles this was not enough evidence yet to prove their existence. Or not.
In a paper of 1957 called B2FH after the authors Margaret Burbidge, Geoffrey Burbidge her husband, William Fowler and Fred Hoyle, Fred Hoyle had suggested that heavy elements formed from nuclear reactions in stars. But only Fowler got the Nobel Peace Prize for this work and not until 1983. This was thought to be because the Burbidges and Hoyle complained when Jocelyn Bell (Burnell) did not get the Nobel prize for her discovery of pulsars, instead it went to her supervisor Martin Rees at the Mullard Radio Astronomy Observatory Cambridge.
From hydrogen to helium to carbon, silicon, up to iron. Fred Hoyle solved the problem of A=8 isotopes as none found. Be 8 is very unstable, so there is a gap between 7 and 9. Hoyle thought the reaction Be 8 and He 4 happens very fast - a resonance reaction.
When two nuclei collide and stick together, the new nucleus carries the combined energy of the two nuclei. The new nucleus wants to settle on one of the steps on its own energy ladder and if its new combined energy is not just right the excess has to be eliminated as kinetic energy or as an excess particle from the nucleus. This means that two colliding nuclei rarely do make it together. If conditions are right the new nucleus is created with exactly the energy that corresponds to one of its natural levels. This settling of energies to one of their appropriate levels is called resonance and it depends on the structure of the nuclei involved in the collision.
In 1954, Fred Hoyle realized that the only way to make enough carbon inside stars is if there is a resonance involving helium 4, beryllium 8, and carbon 12.
The mass energy of each nucleus is fixed and cannot change. The kinetic energy that each nucleus has depends on the temperature inside a star. Hoyle said that since we exist, carbon must have an energy level at 7.6 MeV. Then the experiments were carried out and the energy level measured and it worked out. Hoyle worked on the way stars form elements from hydrogen and helium with Willy Fowler (a nuclear physicist) and Geoffrey and Margaret Burbidge. Fowler got a Nobel Prize for his work.
If the resonance had not been as predicted but slightly different, then more Oxygen 16 than Carbon 12 would have been made - and we would not exist as we are at all!
Primordial nucleosynthesis cannot be continued beyond 42 He in any significant way. A few light nuclei like d. 31 H (triton) 32He, 7Li, and 11Be are formed, but in much smaller fractions than the Y = 1/4 for the 42He nucleus. This is because the nuclei after helium - lithium, beryllium etc. are not stable and revert to helium soon after they are formed. The stabler nuclei like carbon, oxygen etc. which lie beyond this gap of unstable nuclei, cannot be reached by this process of addition of neutrons and protons. It is in principle, possible to produce carbon from 3 helium nuclei and first pointed out by Fred Hoyle in 1954.
But in the first three minutes of the Big Bang Theory, the universe could not have been hot enough to bring about carbon production this way. But the process was shown by Hoyle to be possible inside stars and to hold the key to further nucleosynthesis of heavier nuclei in stars. This was the basis of the first steady state theory.
the Steady State Theory
was first proposed in 1948 by Hermann Bondi, Tommy Gold and Fred Hoyle. They preferred a scenario for the origin of the universe which could be readily tested, as Fred Hoyle said "I think it is very unlikely that a creature evolving on this planet, the human being is likely to possess a brain that is fully capable of understanding physics in its totality. I think this is inherently improbably in the first place, but, even if it should be so, it is surely wildly improbable that this situation should just have been reached..."
The theory is based on the premiss that the overall physical conditions in the universe do not chance (the PCP or Perfect Cosmological Principle). This does not mean a static universe infinitely old. But they had to explain how the background microwave radiation and the light nuclei came about without the hot conditions of the Big Bang. A clue is provided by the fact that if all the observed helium was synsthesized in stars the amount of star light so generated when converted to black body radiation would give a microwave background of about 3K. The photons from stars would bounce back from the needle shaped grains of iron dust in the interstellar medium.
Hoyle's approach was not though a principle like the PCP but by wishing to provide a physical theory for the creation of matter. In the standard Friedman scenario the creation of the universe at the Big Bang is a singular event which cannot be studied as a physical phenomenon. What if the matter in the universe were not created in one go at one time but is continually created.
the Background radiation - 1
In the late 1940s, after the War, George Gamow, Ralph Alpher and Robert Herman, said that if the Big Bang theory was right there should be radiation left over from the early hot (10,000 million K) Universe at one second old, and estimated it at 5-7 K. In 1964 Arno Penzias and Robert Wilson discovered background microwave radiation at 2.7 K. They at first thought it was due to pigeons nesting on the antenna. This, with other new discoveries in astronomy and physics, appeared to solve the BIG BANG v. STEADY STATE dispute in favour of the Big Bang.
Big Bang and Ptolemy Effect
But the Big Bang theory became subject to the "Ptolemy Effect". Ptolemy, who worked in Alexandria, Egypt, in the 2nd century AD, maintained the belief that all motion in the heavens must be circular by a system of epicycles round epicycles going round points off the centres of the circles until he got the right mathematical results. But because the mathematical system worked very well, (and would have produced the correct results for any shaped orbit), later astronomers using his work also accepted Ptolemy's model of the universe which he had based on Aristotle's cosmological system. Aristotle had been tutor to Alexander the Great in the 3rd century BC. He stated that the Earth was immobile in the centre of the universe and everything else rotated about it fixed onto solid spheres. Into this he fitted his ideas of physics and the elements. Earth was the heaviest element so it sunk to the centre. Above it came water, air and fire in that order. Aristotle had been a pupil of Plato and believed that the heavens were perfect, composed of special material in perfect spheres. It was possible to make a model showing the structure of this universe and the movements of the heavenly bodies around the Earth.
Although what we now know to be much better cosmological systems were put forward in the centuries before Ptolemy, its possibilities of visualization, its mathematical results, and most importantly, its fit into the cosmological concepts of the major state imposed religions long after Ptolemy's time, made it favoured when other books were burned. Thus although it had to be constantly modified, to suit advances in mathematics and observations, it was never abandoned, and became enshrined dogma until the weight of evidence against it was too much. On November 2nd 1992, the Pope finally accepted the results of a commission he set up 13 years earlier, that the Earth orbits the Sun, and Galileo was wrongly condemned by the Inquisition for asserting this in 1633.
Like Ptolemy's universe before it, the Big Bang combined the latest discoveries in physics with the latest discoveries in cosmology in a nice tidy coordinated package, which fitted without conflict into the traditional cosmological ideals of the world's major religions. The Pope liked it. The Dalai Lama liked it....
Background Radiation -2
When the background radiation was investigated by satellites such as PROGNOZ 9 (Russia), launched 1983, and COBE (USA), launched 1989, it was found to be isotropic. That is after allowing for the bow-wave caused by our galaxy moving through space and other such known disturbances there was no appreciable change in all directions. If radiation had been left by the Big Bang it should be lumpy and uneven to have formed the sheets and clusters of galaxies. If the background radiation is even, except for the bow waves caused by the movement of galaxies through it, it can have no relationship to these structures and could not therefore be relict radiation from a "Big Bang".
In April 1992, George Smoot announced with much media flourish, that results from COBE showed fluctuations in radiation of one thirty millionth of a degree and claimed this was proof of the Big Bang. But his claims have been challenged. The tiny fluctuations are not constant and could have been caused by the instruments themselves on the, by now ageing, COBE, or if real, may be caused by gravity waves, or have other causes - none of which proves the Big Bang theory. The enthusiasm and publicity of Smoot's claims may due to the "Ptolemy Effect" or because his department at NASA was about to run out of funds and they were pushed to prove their worth to continue their work. (A situation scientists frequently find themselves in, see Kepler's quote).
Observations of the background radiation over smaller regions of the sky continue. Satellites are not necessary for this, with modern technology. The Mullard Radio Astronomy Observatory, Cambridge, for example, uses equipment on the ground.
Other ideas have been put forward to explain the microwave background radiation. (There is also background radiation at other wavelengths). In 1968, Hoyle, Wickramasinghe and Reddish showed that if all observed helium were produced in thermonuclear processes in stars, then the resulting star light would be absorbed then re-emitted by intergalactic particles, generating a microwave background at the observed temperature. Cosmic grains - small particles of iron, carbon etc. found in interstellar space, include iron whiskers one millimetre long and one micrometre wide which probably formed in the metallic vapours of the expanding envelopes of supernovae. They absorb wavelengths at 30 micrometres to 10 centimetres and could wipe out any unevenness in the radiation from stars and galaxies. This theory can be found in "The Primeval Universe" by Jayant Narlikar, 1988.
Another factor to be considered is that our solar system is in a cloud of mostly hydrogen but also other molecules, which is bound to affect results as more and more precision is sought after. In an article by Arp, Burbidge, Hoyle, Narlikar, and Wickramasinghe in Nature vol. 346 30 August 1990 The Extragalactic Universe: an alternative view ..."that so far as microwaves are concerned, we are living in a fog and that the fog is relatively local. A man who falls asleep on the top of a mountain and who wakes in a fog does not think he is looking at the origin of the Universe. He thinks he is in a fog."
Quasars
These were first discovered as strong radio sources. The first one to be identified optically was the brightest, 3C273, identified by Maarten Schmidt, Dutch astronomer working at Mount Palomar, California. At first they looked like blue stars with extremely large red shifts.
Hubble's law works well on ordinary galaxies but does not apply to quasars. According to the Big Bang theory, they would be powerfully radiating galaxies on the edge of the finite universe 10,000 million to 13,000 million light years away, seen as they appeared in an early stage of development.
Halton (Chip) Arp discovered in 1971, that the Galaxy NGC4319 and Quasar Markarian 205 were linked up very definitely with a bridge of material. This was confirmed by later, more advanced, photographic technique. According to the Big Bang theory, the greater the red shift the greater the distance, yet these connected objects have greatly differing red shifts. M 205 should have been 12 times the distance of NGC 4319 but they were linked together. Arp has found many other cases since then, where active galaxies have definite links with quasars of great red shift and interaction shown by jets of material and other effects.
Halton Arp and Geoffrey Burbidge found the Quasar 3C273 is interacting with a giant elliptical cloud of hydrogen gas 65,000 light years long in the Virgo Cluster, which it was thought may be a dwarf galaxy in the process of forming. It is shooting out a jet of material along the long axis of the cloud. They are 65 million light years apart.
Quasars have been identified with active galaxies, many first observed by radio telescopes and given various names - Seyfert galaxies, N galaxies, BL Lac objects, blazars, QSOs and quasars. One feature most of them have in common are jets of ionised plasma shooting out, sometimes unevenly from one or more high energy sources. Usually there are two jets in opposite directions. One for example, was found by the 5-metre telescope with a camera sensitive to infrared, on Mount Palomar at the centre of Cygnus A coinciding with the radio source. It was then investigated by the UK Infrared telescope in Hawaii and found the central source lies within a dense cloud of hydrogen about 10 light years across. Such galaxies have been investigated by the HST and other telescopes. Quasars have been found in otherwise quietly normal galaxies. Quasars are now thought to be the result of a galactic collision, which is happening all the time to galaxies. The dense object which may one have been the active engine of a destroyed galaxy can be left embedded in a now settled galaxy.
The picture shows CygnusA. It is normal for galaxies with stars forming around them to have jets from the poles of their hubs. These jets are thought to be coming from the accretion disk of massively dense object - probably a black hole.
The largest objects in the universe are the double radio sources - galaxies with huge clouds of radio emission more than 100 times greater than the visible galaxy and stretching for more than a million light years. The two radio-emitting regions look like twin turbulent clouds on each side of the visible galaxy.
The radio emission arises from the synchrotron process when electrons accelerated to nearly the speed of light spiral through magnetic fields. The electrons would slow down and loose energy over a few million years. But due to periodic interaction with the magnetic field, at the synchrotron frequency, the electrons are constantly being accelerated back to nearly the speed of light. By the late 1970s it was discovered that the electrons are produced in jets, shooting out in opposite directions from the centre of the galaxy at speeds close to the speed of light. When the jets strike the gas molecules in intergalactic space, the fast moving electrons lose their directional motion and form vast clouds of radio emitting gas.
The central engine of a galaxy is a massively dense object like a black hole (several million times the mass of our sun but not much bigger) which is sucking up material towards it. The material dragged towards the black hole is spinning around its equator in an almost flat accretion disk, warped and tilted at the outer edges. It looks red from the dust.
The dust in the accretion disk still holds its own magnet fields. Along those twisted and distorted field lines ionised particles are sent spiralling to stream out in jets at the poles at nearly the speed of light 60 light years or more into space. Until they coalesce into clouds of ionized particles which cools to form new hydrogen atoms. Around the accretion disk there are clouds of gas out to about one light year and and dust out to about 10,000 light years, to the stars of the galaxy. The stars orbiting around the hub of the galaxy stretch out to around 100,000 light years to the edge of the galaxy. The jet from M 67 a large galaxy in the centre of the Virgo cluster is of electrons and positrons streaming at nearly the speed of light from a gas disk - possibly surrounding a black hole.
The picture left shows the black hole in M87. A black hole may also be in the centre of NGC 4261 inside a gas and dust disk. Seyfert galaxy NGC 5728 may also harbour a black hole. In fact it seems that something like a black hole may be powering most galaxies. The picture to the right shows the black hole in NGC4438 - it is feeding.
Near-infrared images of the centre of the active galaxy NGC 1097, obtained with the NACO adaptive optics instrument on ESO's Very Large Telescope in 2005, show a complex central network of filamentary structure spiralling down to the centre of the galaxy. These observations provide astronomers with new insights on how super-massive black holes lurking inside galaxies get fed.
Galaxies collide with each other causing star bursts - the creation of new hot stars and many other effects, including the creation of new black holes. Our neighbour the Andromeda galaxy, the only other large galaxy besides our Milky Way in our local group of galaxies, is not quite the same as the Milky Way as once thought. It has two very bright spots which may be black holes with accretion disks. The stars orbit round the smaller one only. The other may be the remains of another galaxy which was swallowed by the Andromeda galaxy.
M 51, has two discs crossing each other in its centre, which may also be the result of a galactic collision. The Cartwheel galaxy is now thought to have its distinctive appearance as a result of a smaller galaxy passing right through it causing a shock wave making new stars on its outer edge.
Black holes are now seen to be an integral part of star creation. Not only do they form a central core of a galaxy of stars but the powerful jets of plasma coalesce into clouds of new stars - eventually forming new galaxies.
When a star collapses under its own gravity during a supernova explosion, it can form a Neutron Star, a Black Hole, or a Magnetar. Magnetars are also small and very dense - a teaspoon-size amount of it would have a mass around about a billion tonnes. But Magnetars also have extremely powerful magnetic fields. And they release vast quantities of gamma rays when they have a starquake, caused by the massive stresses in their outer crust.
Red Shift and Gravity
According to Einstein (Relativity - English translation 1920) "An atom absorbs or emits light of a frequency which is dependent on the potential of the gravitational field in which it is situated."
The frequency of an atom situated on the surface of a heavenly body will be somewhat less that the frequency of an atom of the same element which is situated in free space (or on the surface of a smaller celestial body).....thus a displacement towards the red ought to take place for spectral lines produced at the surface of stars as compared with the spectral lines of the same element produced at the surface of the Earth.
Einstein's calculations that gravity produces a shift to the red in the spectrum has been demonstrated as real. A body with a strong gravitational field would have a greater red shift than a body at the same distance but weaker gravity.
Red Shift and Mach
In 1990, Chip Arp, Fred Hoyle, Chandra Wickramasinghe, Geoffrey Burbidge and Jayant Narlikar, met in Cardiff and published their Cardiff Manifesto, published in Nature August 1990, to consider alternatives to the Big Bang and explain the red shifts of quasars.
Hoyle and Narlikar have produced a theory to explain the red shifts of quasars based on Mach's principle - "the inertia of matter arises from its interaction with other matter in the universe and may increase with the age of matter."
Any particle just created starts with zero inertial mass. It picks up mass as it grows older by interacting with more and more particles in the Universe. Because the effect is universal a hydrogen atom of young matter will have a smaller inertial mass and so its spectral lines will have longer wavelengths. Thus its lines will be shifted to the red as compared with those of an old hydrogen atom.
This could explain why some quasars have much larger red shifts than their galactic partners. The quasar could have been ejected from the older galaxy. As the quasar grows old, the discrepancy in red shift decreases. It does not fully explain the clusters of galaxies interacting with each other which have different red shifts. The picture shows Stephan's Quintet, one of Arp's examples of an associated group of galaxies with different redshifts.
the clumpy universe
The basic assumption of the Big Bang model assumed a smooth isotropic universe. But the universe has been discovered not to be like that at all. Galaxies are not dotted about like raisins in a cake. They are in clumps, orbiting and affecting each other gravitationally. These smaller clusters are part of larger clusters.
The cluster of galaxies in which our Milky Way belongs is being pulled towards the larger Virgo cluster and other clusters like Puppis have an effect too.
The larger clusters form a structure, which if it could be viewed from a distance, would look rather like a sponge or the cellular structure of an organism with the clumps of galaxies forming sheets round great voids 50-200 million light years across.
In 1953 Gerard de Vaucouleurs discovered that galaxies within about 200 million light years of the Virgo cluster of galaxies, which included our Milky Way, were part of a giant disk of galaxies.
Vera Rubin thought galaxies could move in other ways that outward from expansion after the Big Bang. She collected together data on galaxies in 1954 which showed that galaxies were moving in a different way to that which fitted the idea of expansion. It took her a very long time but her calculations showed the galaxies moved into clumps with large voids of empty space between.
Vera Rubin was the first woman given permission to use the Palomar Observatory, and then she worked at the Carnegie Institution in Washington with W. Kent Ford. They were measuring the redshifts of the newly discovered quasars. Then Vera Rubin decided to study nearby galaxies. Very few astronomers had noticed a poor correlation between the redshifts of galaxies and their observed distances.
In the 1970s Vera Rubin and Ford measured the motions of the nearby galaxies and in 1975 they discovered that the Milky Way had a velocity of about 500 kilometres per second that also had nothing to do with the expansion of the universe. These observations were not accepted by the astronomical establishment.
During the 1970s further discoveries were made on the structure of the universe, the super clusters and voids between. In a cluster, galaxies can be found every few million light years. In a void such as the one found in 1981 in the constellation of Bootes, about 200 million light years across, there is almost nothing.There are also long chains of galaxies like the Perseus-Pisces chain, some 100 million light years long.
In 1977 balloons were sent aloft with instruments to measure minute variations in the background radiation. They found that the radiation was shifted towards the red end of the spectrum on one side of the sky and to the blue in the other. This meant that the Milky Way was indeed travelling in the direction of the blueshifted background radiation, They had found the bow-wave of the galaxy and that it was travelling even faster than Vera Rubin thought, 600 kilometres per second (about 2 per cent of the speed of light).
Not in the same direction as she had thought though. It was found that all the local galaxies were rushing towards something. Our local group of galaxies was being pulled mainly towards the larger Virgo cluster. But this was also being pulled in the same direction towards something else together with other groups of galaxies. The Virgo cluster was being pulled in the direction of the larger Hydra-Centaurus supercluster about 70 million light years away. But this was also rushing towards something else in the same direction even further away.
The place to which all the galaxies were heading fast, was called The Great Attractor. In 1987 it was found that every nearby galaxy including those in clusters and huge superclusters was rushing at 600 to 700 kilometres per second towards a place that lay some 300 million light years beyond Hydra-Centaurus. The mass of this Great Attractor was estimated as millions of galaxies.
In 1989, Sandra Faber and Alan Dressler found a Great Attractor - two superclusters of galaxies 300 million lights across, beyond Hydra-Centaurus with masses about 20,000 times the mass of the Milky Way. They found that galaxies nearer to this such as those in the Hydra-Centaurus group had a much higher speed than ours, up to 1,000 kilometres per second. But 150 million light years out, the velocities of the galaxies dropped to nearly zero. They had arrived at their destination, and were now part of the Great Attractor. Also a group of Italian astronomers discovered a concentration of galaxies in a place about three times the distance beyond the Great Attractor which might have an affect on galaxies on the other side. Another attractor was found in the Perseus-Pisces supercluster in the opposite direction of the sky which would be pulling us back in the opposite direction. It was realised that galaxies were moving in all sorts of directions in the universe.
In 1986 Margaret Geller, John Huchra and Valerie de Lapparent at the Harvard-Smithsonian Center for Astrophysics, found that galaxies appeared to be located on bubble-like structures about 100 million light years in size with voids in the bubbles. Their survey helped by computer technology was able to show the three-dimensional locations of a sample number of 1,074 galaxies. The distance of each galaxy was assumed by its red shift. Margaret Geller and John Huchra extended their survey to 3,962 galaxies in 1989. This showed a "Great Wall" of galaxies for at least 5000 million light years.
Although the distances of far off galaxies can be assumed only from their red shifts, this does give the broad picture of their relative positions and distances, and thus an image has been built up of the overall structure of the universe. Shown in this picture.
Expanding Universe -2: inflation
The expansion of the universe after the Big Bang did not explain the lumpy structure of the universe. Neither did it fit the timescale. The situation was saved in the 1980s by inflation theory invented by Alan Guth. According to this, the universe suddenly underwent a much faster expansion some time after the Big Bang. It was a fudge to save the theory though. Attempts have continued to uncover the conditions which would have prevailed and caused the expansion of the early universe according to the Big Bang theory.
The picture shows the blast after two gold nuclei have collided in this experiment, it is hoped producing for a brief instant a quark-gluon plasma - a very hot state of matter found in black holes and which should have been the state of the universe after the big bang.
There is difficult in reconciling new observational data with the ideas of any sort of uniform expansion of the universe. Distant objects now appear to be much further than expected while nearby clusters including out own are different to expectations. The unseen unknown Dark Matter is blamed for this.
is the oldest cosmological belief. That the universe has been made for humans to live in. This led to the belief that the configurations of the universe as seen from Earth was meaningful to each person's life. This is called astrology and was dealt a death blow as part of astronomy in the 17th century when the telescope revealed an infinite universe in which the Earth was not the central feature. Until then it had been the most likely source of income for the astronomer.
Here are some Quotes:
Kepler said "The scanty rewards of an astronomer would not provide me with bread if men did not entertain hopes of reading the future in the heavens."
"Many people are aware of the Weak and Strong Anthropic Principles. The Weak one says, basically, that it was jolly amazing of the universe to be constructed in such a way that humans could evolve to a point where they make a living in, for example, universities, while the Strong one says that, on the contrary, the whole point of the universe was that humans should not only work in universities but also write for huge sums books with words like 'Cosmic' and 'Chaos' in the titles." - Terry Pratchett, HOGFATHER, 1996.
"It would indeed be fascinating if the Universe did have a purpose. It would probably be pleasant for there to be life after death. However, there is not one scrap of evidence in favour of either speculation. As it is easy to understand why people crave for cosmic purpose and life eternal, and there is no evidence for either, it seems an inescapable conclusion that neither exists. All there is for science to explain is the psychology of brains that maintain them as actualities." - Peter Atkins in "Chemistry & Industry" quoted in the Guardian 23.1.96.
Clues to the shape of the universe:
Belousov-Zhabotinsky Reaction (B-Z reaction)
Boris Pavlovitch Belousov was head of a laboratory of biophysics attached to the Soviet Ministry of Health in the early 1950s. During his research he made up a cocktail of chemicals meant to resemble and therefore throw more light on the Krebs cycle - the metabolic pathway by which living cells break down organic foodstuffs into energy (as molecules of adenosine triphosphate) and C02 gas.
Belousov's mixture contained citric acid which is actually in the Krebs cycle, Potassium bromate to substitute for the biological equivalent of oxidising the citric acid, sulphuric acid and a catalyst of ceric ions to resemble enzymes.
But the solution started to oscillate regularly like a clock between being colourless and being yellow - corresponding to two distinct forms of the charged ceric ion.
He investigated further and saw the formation of spiral patterns of colour.
In 1951, his paper was rejected for publication because no one else had observed such a reaction which appeared to contradict the Second Law of Thermodynamics - order decaying uniformly to disorder.
In fact, the reaction had been observed before and not accepted. William Bray of the University of California, Berkeley, in 1921, discovered an oscillating chemical reaction in the conversion of hydrogen peroxide to water but his work was dismissed as the result of poor experimental procedure.
But during the 1960s, Anatoly Zhabotinsky studied Belousov's oscillation reaction as a graduate student of biochemistry at Moscow State University. He experimented, e.g. replacing the ceric ion with a iron reagent that gave a more distinctive colour change from red to blue. This attracted the attention of others.
In 1973 the model of the chemical reaction system with spatial self organisation was called the Brusselator.
In 1980 Belousov and Zhabotinsky got the Lenin Prize for this discovery, but Belousov had died in 1970.
Since then many more chemical clocks in changing colours have been made.
The B-Z reaction is important because these spiral waves occur in all sorts of organisations in the universe - galaxies, slime moulds, heart attacks, hurricanes.
The picture shows slime mould gathering together.
Feigenbaum's number
There are universal patterns hidden in the erratic behaviour of chaotic dynamical systems. One of them was discovered by Mitchell Feigenbaum, so it is called the Feigenbaum number.
The Feigenbaum number lurks within every period-doubling cascade. Each successive branch gets closer and closer to 1/4.669 times the size of the previous one.
For example: if a small quantity of liquid helium, cooled very close to absolute zero, is heated from below, it forms tiny convection cells, in which the helium circulates and carries heat upward. If the temperature at the bottom is increased a little, then the cells begin to wobble periodically: Wobble-wobble-wobble-wobble over and over again. At a higher temperature, pairs of consecutive wobbles become slightly different: wobble-wobble-wobble-wobble. The period doubles in length; you now have to wait for two wobbles before everything repeats. As the temperature rises still further, the wobbles group into fours- wobble-wobble-wobble-wobble repeated indefinitely.
This doubling of the period by the creation of ever finer differences between consecutive sequences of wobbles is called a period-doubling cascade. Each successive step in the cascade occurs as the result of an ever smaller rise in the temperature. In mathematical models there is a particular critical temperature, and when this is reached, the period has doubled infinitely often, resulting in chaos. The period-doubling cascade is a route from order to chaos. It is important because it is one of the commonest such routes.
Other systems can be seen to behave in this way. For example Water dripping from a tap goes through a similar period-doubling cascade, from drip-drip-drip-drip to drip-drip-drip-drip, to drip-drip-drip-drip as the tap is turned further on, the cascade ends in chaos. Electronic oscillations, models of the interactions between predators and prey, and models of blood-cell production also behave in this manner. The period-doubling cascade is a common feature of dynamical systems.
Feigenbaum discovered a pattern in the models of such a cascade. In terms of the pattern of liquid helium, it would go: The amount by which the temperature must rise, in order to double the period, decreases geometrically as the period gets longer. Each such increment is roughly 3/4.669 times as long as the previous one. For instance, if the temperature has to go up by one degree to increase the period from one to two then it must go up by only 3/4.669 of a degree to increase the period to 4, by 3/4.6692 to increase it to 8 and so on. The precise ratios are not exactly equal to 3/4.669 but as the period gets larger, that value becomes a better and better approximation.
When Feigenbaum tried a different mathematical equation with a period-doubling cascade, he got the same ratio- 3/4.669. The two ratios agreed to twenty decimal places. Obviously not a coincidence. More experiments showed that virtually any mathematical equation with a period-doubling cascade produced the same universal ratio. A new number had arrived in mathematics to keep π company, 4.669 and a bit, or δ
Intermittency
Bursts of noise or chaos then order, then chaos breaks through, then back to order.
for example: The length of the Earth's day is intermittent. Our day is the result of the planet's rotation about its axis in 24 hours. There is a slight wobble in this regularity which takes place over a 5-day cycle. And the structure of the universe is intermittent.
Fractals and Mandelbrot
In 1963 Benoit Mandelbrot introduced the new concept of a "fractal", a geometric form with fine structure on all scales of magnification.
Recycling and the Origin of the Universe?
Jets of ionised particles from the central engines of galaxies cool into clouds and new hydrogen molecules form within the cooling cloud, to become embryonic galaxies in which new stars will form. Other creation events are also observed. Great gamma flares - like the hypothesised big bang.
It is possible that clusters of galaxies could have formed through local creation events - "mini-bangs".
New Galaxies and Clusters and Old Cluster of Galaxies appear to be in the wrong places for Big Bang theory.
New
According to the Big Bang theory, all the galaxies must have been formed at the same time. But surveys by the Infra Red Astronomy satellite (IRAS), and the Hubble Space Telescope (HST) have shown several galaxies that must be young as they are nearly completely hydrogen, with no heavy elements that form only in ageing stars.
There are also young galaxies like these near our own galaxy and orbiting around it. According to the Big Bang theory these new galaxies should only be found at great distances where we are looking back in time to the origins of the universe.
Invisible galaxy
At the end of February 2005, the discovery of a galaxy which had not formed stars, was confirmed by observations made from the optical Isaac Newton telescope on La Palma in the Canary Islands. It was first observed by the vintage Lovell Radio Telescope in Cheshire in 2000. It is in the Virgo cluster some 50 light years from us, the Virgo cluster neighbours our own.
and Old
On 2nd March 2005, ESA released the results of a survey combining observations with ESO's Very Large Telescope and ESA's XMM-Newton X-ray observatory, in which they discovered the most distant, very massive structure in the Universe known so far.
It is a remote cluster of galaxies that is found to weigh as much as several thousand galaxies like our own Milky Way and is located no less than 9,000 million light-years away.
The VLT images reveal that it contains reddish and elliptical, i.e. old, galaxies. Interestingly, the cluster itself appears to be in a very advanced state of development.
Studying XMM-Newton observations targeted at the nearby active galaxy NGC 7314, the astronomers found evidence of a galaxy cluster in the background, far out in space. This source, now named XMMU J2235.3-2557, appeared extended and very faint: no more than 280 X-ray photons were detected over the entire 12 hour-long observations.
Knowing where to look, the astronomers then used the European Southern Observatory's Very Large Telescope (VLT) at Paranal (Chile) to obtain images in the visible wavelength region. They confirmed the nature of this cluster and it was possible to identify 12 comparatively bright member galaxies on the images.
The VLT data measured the redshift of this cluster as 1.4, indicating a distance of 9,000 million light-years, 500 million light years farther out than the previous record holding cluster.
Since the latest estimate for the age of the universe at this time is 13,700 million years old the astronomers were surprised at the results.
"We are quite surprised to see that a fully-fledged structure like this could exist at such an early epoch," says Christopher Mullis. "We see an entire network of stars and galaxies in place, just a few thousand million years after the Big Bang".
Far away galaxies so old that they are filled with very old stars and no apparent new ones are being formed have also been found.
And large galaxies of stars at a distance where they would have to have formed very early in the history of the universe. Even if this is because the larger galaxies are more easily observed they are still there.
Very Old Star in our galaxy and problems of dating stars.
Gamma Bursters
Gamma Ray telescopes have found a distribution of gamma ray flares or bursts occurring all over the universe as well as within galaxies. Some of these bursts, which are the hottest things in the universe, are annihilation events, as anti-matter positrons reaction with electrons to obliterate leaving only the creation of a gamma ray photon. There are clouds of antimatter near the centre of our own galaxy. Other bursts are associated with neutron stars and black holes as material is sucked onto their surface. There are other known causes, but the cause of the massive gamma ray flares - hotter than the estimated Big Bang are still a mystery.
The picture shows a gamma burst one billion light years away which blew its galaxy apart.
The four 13-metre telescopes called the High Energy Stereoscopic System (HESS) in Namibia completed the first large survey of the Milky Way at very high energy gamma ray wavelengths. (HESS searches the night sky for streaks of ultraviolet light produced when the gamma rays slam into Earth's atmosphere.) HESS discovered eight new sources in its scan of the inner 30,000 light years of the disc of the Milky Way. All show an unusually high number of very energetic gamma rays and appear to be a few tens of light years across - the size expected for supernova remnants. Three are actually associated with nearby supernova remnants, while three others appear near pulsars.
But two sources are not linked with either type of object. And furthermore, they do not seem to emit either X-rays or radio waves, which are produced when electrons are accelerated to high speeds.
That suggests these could be "dark" objects that may - for some unknown reason - accelerate only protons.
SGR J1550-5418, which rotates once every 2.07 seconds, holds the record for the fastest-spinning magnetar. This image is from the Swift telescope. Published 11th February, 2009.
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Gamma-Ray Fireworks Now Erupting from Rare Stellar Object
Dark matter in the galaxy cluster CL 0152-1357, mapped in purple. The yellowish galaxies are the visible cluster member galaxies forming a filamentary structure, possibly in the process of merging. This was mapped from archived Hubble images. The two clusters involved each contain more than 400 galaxies. Although dark matter which is estimated to make up more than 90 per cent of the universe cannot be seen and is collisionless and possibly particle-less - it should be affected by gravity like ordinary matter and therefore can be found where gravity has effect such as galactic clusters with gravitational lensing.
The detection of dark-matter and dark energy is still controversial, as results could have other causes.
Big Bang or Little Pops....
New mathematical models show the universe is fractal, but multi fractal which also indicates many points of origin. The ideas of the universe being created in one point of time is simplistic. It is now known that there is continuous creation of new material from the centres of galaxies as part of a natural cycle of creation and regeneration. It is possible that the gamma ray bursts may be big bang type creation events, they go on all the time and can happen anywhere.
We are not alone
More evidence our universe is one of many all squashed together?
Here is a review of brane theory and the current view that our universe is just one of an infinite number of universes formed in this way (possibly) -
It should be obvious that our perception of the universe will always been limited by our physical capabilities, psychology and technology. But this doesn't stop many from assuming we now have the answer to Life, the Universe and Everything.
More Quotes
From: Lonely Hearts of the Cosmos by Dennis Overbye, 1991 -
"It is probably part of the human condition that cosmologists (or the shamans of any age) always think they are knocking on eternity's door, that the final secret of the universe is in reach. It may also be part of the human condition that they are always wrong."
From: Quasars, Redshifts and Controversies by Halton Arp, 1987. (on how the hypothesis of the Big Bang had become enshrined dogma)..."This dogma simply states-At this golden moment in human history, we know all the important aspects of nature that we will ever know. In spite of a long record of fundamental revolutions in human thought, there are now no surprises, there is now an end to this history".
From The Extragalactic Universe: an Alternative View: Arp, Burbidge, Hoyle, Narlikar & Wickramasinghe, Nature, August 30, 1990.
"Cosmology is unique in science in that it is a very large intellectual edifice based on very few facts. The strong tendency is to replace a need for more facts by conformity..."
From "The Collapse of Chaos" by Jack Cohen and Ian Stewart, 1994:
"Cosmologist are confident that they knew what was happening from the first few microseconds of the Big Bang onward - though they admit they're a little unsure of the precise details before that.
But Voyager taught us that we didn't even know what was happening on Saturn, right in our own backyard. So the cosmologists' confidence seems misplaced. They don't think so, however, because their ....story....fits the available evidence, such as the expansion of the universe, the cosmic background radiation, and the relative abundance of the chemical elements.
The problem is, it's an incredibly ambitious story to erect on such tiny foundations. The relativistic models of the universe that are used, for example, contain no stars. They are just huge-scale approximations in which the grainy gravitational fields of stars and galaxies are smoothed out into a general overall curvature. That curvature is closely related to a single quantity Ω (omega), the average density of matter. If Ω is less than 1, the universe expands forever, if Ω is greater than 1 it eventually collapses again. For a whole lot of reasons, mostly to do with quantum mechanics, theorists expect our universe to have the value Ω = 1, poised right on the boundary between expansion and contraction.
Unfortunately, experiments generally lead to a value closer to Ω = 0.25."
which brings us to
the Ptolemy Effect
From "Was Ptolemy a Fraud?" in The Eye of Heaven by Owen Gingerich, 1993...."In some of the manuscripts, the Almagest begins with the epigram, 'I know that I am mortal by nature, and ephemeral; but when I trace at my pleasure the windings to and fro of the heavenly bodies I no longer touch earth with my feet: I stand in the presence of Zeus himself and take my fill of ambrosia, food of the gods.'
The epigram seems to place Ptolemy within the long series of scientists who have tasted the intoxicating pleasure of a splendid theory."
In "The Crime of Claudius Ptolemy" by Robert Newton, 1977, Newton states that the Almagest "has done more damage to astronomy than any other work ever written and astronomy would be better off if it had never existed."
From: Archaeology Yesterday and Today, by Jaroslav Malina and Zdenek Vasicek, Cambridge University Press, 1990, pp.242-243.
"Successors to Ptolemy managed to explain all the planetary movements unforeseen by his theory thanks only to their practice of adding any number of epicycles to planetary revolutions. Ptolemy's Effect means then that a wrong theory can explain anything if its basic erroneous propositions are altered and modified by a plethora of qualifications. The basic beliefs can in this way remain unchanged, while at the same time appearing to explain all the facts, which are qualified in advance anyway by the flexible application of terminology within a given ideology".
In their book "Fearful Symmetry", 1992, Ian Stewart and Martin Golubitsky show that Ptolemy's epicycles could produce accurate data for square orbits or any other shape.
Search for Dark Materials continues
Down Boulby Mine in Yorkshire lurks the ZEPLIN-III.
This picture from the Hubble space telescope shows galaxies at red shift 8.5, which means their light has taken about 13 billion years to reach us, so far away, that according to the Big Bang theory, the universe was only 600 million years old - (but the galaxies would had taken very many millions of years to evolve to this stage). And many stars have been discovered this far away, which contain heavy metals - they are older stars like our sun, recycled a number of times, possibly like the star mentioned below, in its final throes.
One of John Herschel's first photographs that could be printed from a negative (so it had an advantage over the Daguerreotypes which became popular) was of the family 48 inch telescope in Slough, just before it was demolished in 1839.
The picture shows CygnusA. It is normal for galaxies with stars forming around them to have jets from the poles of their hubs. These jets are thought to be coming from the accretion disk of massively dense object - probably a black hole.
The picture left shows the black hole in M87. A black hole may also be in the centre of NGC 4261 inside a gas and dust disk. Seyfert galaxy NGC 5728 may also harbour a black hole. In fact it seems that something like a black hole may be powering most galaxies. The picture to the right shows the black hole in NGC4438 - it is feeding.
This could explain why some quasars have much larger red shifts than their galactic partners. The quasar could have been ejected from the older galaxy. As the quasar grows old, the discrepancy in red shift decreases. It does not fully explain the clusters of galaxies interacting with each other which have different red shifts. The picture shows Stephan's Quintet, one of Arp's examples of an associated group of galaxies with different redshifts.
The picture shows the blast after two gold nuclei have collided in this experiment, it is hoped producing for a brief instant a quark-gluon plasma - a very hot state of matter found in black holes and which should have been the state of the universe after the big bang.
Boris Pavlovitch Belousov was head of a laboratory of biophysics attached to the Soviet Ministry of Health in the early 1950s. During his research he made up a cocktail of chemicals meant to resemble and therefore throw more light on the Krebs cycle - the metabolic pathway by which living cells break down organic foodstuffs into energy (as molecules of adenosine triphosphate) and C02 gas.
The picture shows slime mould gathering together.
At the end of February 2005, the discovery of a galaxy which had not formed stars, was 
On 2nd March 2005, ESA released the 
The picture shows a gamma burst one billion light years away which blew its galaxy apart.
21st March 2008 - 
Dark matter in the galaxy cluster CL 0152-1357, mapped in purple. The yellowish galaxies are the visible cluster member galaxies forming a filamentary structure, possibly in the process of merging. This was mapped from archived Hubble images. The two clusters involved each contain more than 400 galaxies. Although dark matter which is estimated to make up more than 90 per cent of the universe cannot be seen and is collisionless and possibly particle-less - it should be affected by gravity like ordinary matter and therefore can be found where gravity has effect such as galactic clusters with gravitational lensing.
This picture from the Hubble space telescope shows galaxies at red shift 8.5, which means their light has taken about 13 billion years to reach us, so far away, that according to the Big Bang theory, the universe was only 600 million years old - (but the galaxies would had taken very many millions of years to evolve to this stage). And many stars have been discovered this far away, which contain heavy metals - they are older stars like our sun, recycled a number of times, possibly like the star mentioned below, in its final throes.
