More recently, physicists have been theorizing the possibility of lower dimensionality, in which the universe has only two or even one spatial dimension(s), along with one dimension of time. The theories suggest that the lower dimensions occurred in the past when the universe was much smaller and had a much higher energy level (and temperature) than today. Further, it appears that the concept of lower dimensions may already have some experimental evidence in cosmic ray observations.

Now in a new study, physicists Jonas Mureika from Loyola Marymount University in Los Angeles, California, and Dejan Stojkovic from SUNY at Buffalo in Buffalo, New York, have proposed a new and independent method for experimentally detecting lower dimensions. They’ve published their study in a recent issue of Physical Review Letters.

In 2010, a team of physicists including Stojkovic proposed a lower-dimensional framework in which spacetime is fundamentally a (1 + 1)-dimensional universe (meaning it contains one spatial dimension and one time dimension). In other words, the universe is a straight line that is “wrapped up” in such a way so that it appears (3 + 1)-dimensional at today’s higher energy scales, which is what we see.

The scientists don’t know the exact energy levels (or the exact age of the universe) when the transitions between dimensions occurred. However, they think that the universe’s energy level and size directly determine its number of dimensions, and that the number of dimensions evolves over time as the energy and size change. They predict that the transition from a (1 + 1)- to a (2 + 1)-dimensional universe happened when the temperature of the universe was about 100 TeV (teraelectronvolts) or less, and the transition from a (2 + 1)- to a (3 + 1)-dimensional universe happened later at about 1 TeV. Today, the temperature of the universe is about 10^-3 eV.

So far, there may already be one piece of experimental evidence for the existence of a lower-dimensional structure at a higher energy scale. When observing families of cosmic ray particles in space, scientists found that, at energies higher than 1 TeV, the main energy fluxes appear to align in a two-dimensional plane. This means that, above a certain energy level, particles propagate in two dimensions rather than three dimensions.

In the current study, Mureika and Stojkovic have proposed a second test for lower dimensions that would provide independent evidence for their existence. The test is based on the assumption that a (2 + 1)-dimensional spacetime, which is a flat plane, has no gravitational degrees of freedom. This means that gravity waves and gravitons cannot have been produced during this epoch. So the physicists suggest that a future gravitational wave detector looking deep into space might find that primordial gravity waves cannot be produced beyond a certain frequency, and this frequency would represent the transition between dimensions. Looking backwards, it would appear that one of our spatial dimensions has “vanished.”

The scientists added that it should be possible, though perhaps more difficult, to test for the existence of (1 + 1)-dimensional spacetime.

“It will be challenging with the current experiments,” Stojkovic told PhysOrg.com. “But it is within the reach of both the LHC and cosmic ray experiments if the two-dimensional to one-dimensional crossover scale is 10 TeV.”

Lower dimensions at higher energies could have several advantages for cosmologists. For instance, models of quantum gravity in (2 + 1) and (1 + 1) dimensions could overcome some of the problems that plague quantum gravity theories in (3 + 1) dimensions. Also, reducing the dimensions of spacetime might solve the cosmological constant problem, which is that the cosmological constant is fine-tuned to fit observations and does not match theoretical calculations. A solution may lie in the existence of energy that is currently hiding between two folds of our (3 + 1)-dimensional spacetime, which will open up into (4 + 1)-dimensional spacetime in the future when the universe’s decreasing energy level reaches another transition point.

“A change of paradigm,” Stojkovic said about the significance of lower dimensions. “It is a new avenue to attack long-standing problems in physics.”

More information: Jonas Mureika and Dejan Stojkovic. “Detecting Vanishing Dimensions via Primordial Gravitational Wave Astronomy.” Physical Review Letters 106, 101101 (2011). DOI: 10.1103/PhysRevLett.106.101101

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A study of the Royal Society’s archives reveals that women played a far more important role in the development and dissemination of science than had previously been thought, says Richard Holmes

In December 1788, the astronomer royal, Dr Nevil Maskelyne FRS, wrote effusively to 38-year-old Caroline Herschel congratulating her on being the “first women in the history of the world” to discover not one, but two new comets. No woman since renowned Greek mathematician Hypatia of Alexandria had had such an impact on the sciences. Her celebrity would, as the director of the Paris Observatory, Pierre Méchain, noted, “shine down through the ages”.

Nevertheless, observed Dr Maskelyne with jocular good humour, he hoped Caroline did not feel too isolated among the male community of astronomers in Britain. He hoped she would not be tempted ride off alone into outer space on “the immense fiery tail” of her new comet. “I hope you, dear Miss Caroline, for the benefit of terrestrial astronomy, will not think of taking such a flight, at least till your friends are ready to accompany you.” Or at least until her achievements were recognised by his colleagues in the Royal Society. Curiously, no such recognition was immediately forthcoming.

All this year, and all round the globe, the Royal Society of London has been celebrating its 350th birthday. In a sense, it has been a celebration of science itself and the social importance of its history. The senior scientific establishment in Britain, and arguably in the world, the Royal Society dates to the time of Charles II. Its early members included Isaac Newton, Edmond Halley, Robert Hooke, Thomas Hobbes, Christopher Wren and even – rather intriguingly – Samuel Pepys. But amid this year’s seminars, exhibitions and publications, there has been one ghost at the feast: the historic absence of women scientists from its ranks.

Although it was founded in 1660, women were not permitted by statute to become fellows of the Royal Society until 285 years later, in 1945. (An exception was made for Queen Victoria, who was made a royal fellow.) It will be recalled that women over the age of 30 had won the vote nearly 30 years earlier, in 1918. Very similar exclusions operated elsewhere: in the American National Academy of Sciences until 1925; in the Russian National Academy until 1939; and even in that home of Enlightenment science, the Académie des Sciences in France, until 1962. Marie Curie was rejected for membership of the Académie in 1911, the very year she won her second Nobel prize.

It is also true that by the turn of the 21st century, there had been more than 60 distinguished women fellows of the society. Many have become household names, such as the brilliant crystallographer Dorothy Hodgkin, who famously won a Nobel prize in 1964, and whose whirling portrait by Maggi Hambling (1985) now hangs in the National Portrait Gallery. Her heroic life – she mapped the structure of penicillin and then dedicated 35 years to deciphering the structure of insulin – is told in a superb, biography by Georgina Ferry.

Yet in Victorian Britain, the very idea of women doing serious science (except botany and perhaps geology) was widely ridiculed and even botany (with its naming of sexual parts) could be regarded as morally perilous. Mary Anning (1799-1847), the great West Country palaeontologist, struggled for years to have her discoveries – such as the plesiosaurus – recognised as her own.

In March 1860, Thomas Henry Huxley FRS, famed as “Darwin’s bulldog”, wrote privately to his friend, the great geologist Charles Lyell FRS: “Five-sixths of women will stop in the doll stage of evolution, to be the stronghold of parsonism, the drag on civilisation, the degradation of every important pursuit in which they mix themselves – intrigues in politics and friponnes in science.”

This can be taken as typical of certain Victorian assumptions, including the idea that physiologically the female brain simply could not cope with mathematics, experimental proofs or laboratory procedures. Certainly compared with their literary sisters, the scientific women of the 19th century still appear invisible, if not actually non-existent. What female scientific names can be cited to compare with Jane Austen, Fanny Burney, the three Brontë sisters, George Eliot or Harriet Martineau?

Yet my re-examination of the Royal Society archives during this 350th birthday year has thrown new and unexpected light on the lost women of science. I have tracked down a series of letters, documents and rare publications that begin to fit together to suggest a very different network of support and understanding between the sexes. It emerges that women had a far more fruitful, if sometimes conflicted, relationship with the Royal Society than has previously been supposed.

It is at once evident that they played a significant part in many team projects, working both as colleagues and as assistants (though hitherto only acknowledged in their family capacities as wives, sisters or daughters). More crucially, they pioneered new methods of scientific education, not only for children, but for young adults and general readers. They also played a vital part as translators, illustrators and interpreters and, most particularly, as “scientific popularisers”.

Indeed, the Royal Society archives suggest something so fundamental that it may require a subtle revision of the standard history of science in Britain. This is the previously unsuspected degree to which women were a catalyst in the early discussion of the social role of science. More even than their male colleagues, they had a gift for imagining the human impact of scientific discovery, both exploring and questioning it. Precisely by being excluded from the fellowship of the society, they saw the life of science in a wider world. They raised questions about its duties and its moral responsibilities, its promise and its menace, in ways we can appreciate far more fully today.

The first woman to attend a meeting of the Royal Society was Margaret Cavendish, the Duchess of Newcastle, in May 1667. There were protests from the all-male fellows – Pepys recorded the scandal – and the dangerous experiment was not repeated for another couple of centuries. But Margaret could take advantage of her position, being the second wife of William Cavendish FRS, a member of one of the great aristocratic dynasties of British science. She knew many of the leading fellows, such as Robert Boyle and Thomas Hobbes. On this occasion, she witnessed several experiments of “colours, loadstones, microscopes” and was “full of admiration”, although according to Pepys, her dress was “so antic and her deportment so unordinary” that the fellows were made strangely uneasy. But this may have been for other reasons.

Margaret later raised issues that have become perennial. She mocked the dry, empirical approach of the fellows, violently attacked the practice of vivisection and wondered what rational explanation could be given for women’s exclusion from learned bodies. She questioned the Baconian notion of relentless mechanical progress, in favour of gentler Stoic doctrines, in her polemical Observations on Experimental Philosophy (1668). She wrote a lively Memoir, in which she gave an interesting definition of poetry as “mental spinning”, being useful to the scientific mind. She also produced arguably the first-ever science-fiction story, The Blazing World (1666), which considered the alternative futures of science. All this earned her the sobriquet “Mad Madge”.

The idea of animals having rights within any humane society was recognised early by female scientists. Anna Barbauld, the brilliant young assistant to Joseph Priestley FRS, the great 18th-century chemist, noticed the distress of his laboratory animals as they were steadily deprived of air in glass vacuum jars, during the experiments in which he first discovered oxygen (1774). Accordingly, she wrote a poem in the voice of one of Priestley’s laboratory mice and stuck it in the bars of the mouse’s cage for Priestley to find the next morning. She entitled it: “The Mouse’s Petition to Dr Priestley, Found in the Trap where he had been Confined all Night“.

For here forlorn and sad I sit,
Within the wiry Grate,
And tremble at the approaching Morn
Which brings impending fate…

The cheerful light, the Vital Air,
Are blessings widely given;
Let Nature’s commoners enjoy
The common gifts of Heaven.

The well-taught philosophic mind
To all Compassion gives;
Casts round the world an Equal eye,
And feels for all that lives.

The notion that animals and, indeed, all life-forms on Earth, had a right to “the common gifts of heaven” can be seen as the first stirrings of the whole environmental movement and the demands it now makes upon science and industry.

By contrast, the first original paper that might be considered as part of a scientific research programme conducted by a woman and published in the Royal Society’s journal, Philosophical Transactions, concerned extraterrestrial phenomena. It was by Caroline Herschel in August 1786, gravely entitled “An Account of a new Comet, in a letter from Miss Caroline Herschel to Mr Charles Blagden MD, Secretary to the Royal Society”. Caroline was sister to William Herschel FRS, the great Romantic astronomer who discovered Uranus and first proposed the existence of galactic systems, such as Andromeda, beyond our own Milky Way. But Caroline’s speciality was discovering new comets, of which she found eight at a time when fewer than 30 were known. Her brother was immensely proud of her, built her special telescopes and helped her to obtain the first state salary for a female astronomer in Britain.

Even so, William carefully annotated Caroline’s historic paper: “Since my sister’s observations were made by moonlight, twilight, hazy weather, and very near the horizon, it would not be surprising if a mistake had been made.” But it had not. Caroline also kept an observational journal for more than 30 years. This gives not only astronomical data, but emotional data too: it’s an invaluable early view of a brother-sister scientific team at work, including their many trials and heartaches. It is one of the earliest records of how science actually gets done, its secret tribulations as well as its public triumphs.

Women also saw the educational possibilities of science in a broader context than their male colleagues. Jane Marcet, encouraged by her husband, Alexander Marcet FRS, published the first truly bestselling scientific populariser for young people in 1806. Breezily entitled Conversations in Chemistry, in which the elements of that science are familiarly explained and illustrated by Experiments, it eventually sold as many books as the poetry of Lord Byron (also an FRS). One of its 15 later editions inspired the great 19th-century physicist Michael Faraday FRS to begin his career in science. He started reading the book in 1810, while still working as an apprentice bookbinder and later recalled: “I felt I had got hold of an anchor in chemical knowledge and clung fast to it.”

Marcet reinvented the dialogue form as a series of imaginary scientific lessons between a teacher “Mrs B” (possible based on a famous astronomer tutor, Margaret Bryan) and her two young women pupils. Emily is observant and rather serious, while Caroline is mischievous but inventive (useful qualities for a young scientist). Caroline continually tempts Mrs B into the more imaginative aspects of science.

While discussing the composition of water, Mrs B points out that oxygen has “greater affinity” for other elements than hydrogen. Caroline instantly grasps the romantic possibilities of this: “Hydrogen, I see, is like nitrogen, a poor dependent friend of oxygen, which is continually forsaken for greater favourites.” Mrs B starts to reply — “The connection or friendship as you choose to call it is much more intimate between oxygen and hydrogen in the state of water” – then sees where this is going and hastily breaks off: “But this is foreign to our purpose.”

With a suppressed giggle, Caroline has discovered “sexual chemistry” and the reader will remember forever the composition of a water molecule: two hydrogen atoms in unrequited love with an oxygen atom (H₂O). Caroline adds suggestively: “I should extremely like to see water decomposed…” Jane Marcet went on to develop the “Conversations” brand in a series of other books on physiology, botany, natural philosophy and other scientific topics of the day.

By using dialogue, the “Conversations” brought science popularising a step closer to fiction. Indeed, the most universal of all science fiction novels, Frankenstein, or the Modern Prometheus, was largely inspired by the chemical lectures of Sir Humphry Davy FRS. It was written by a teenage Mary Shelley, who attended Davy’s lectures at the newly founded Royal Institution (which encouraged women members) when she was only 14. Published six years later in 1818, this extraordinary novel of ideas first raised the question of scientists’ social responsibility for their discoveries and inventions.

Its cruder and more sensational stage adaptations, starting in the 1820s, also popularised the idea of the “mad scientist”, one of the most powerful of all stereotypes. Equally, the term “Frankenstein’s monster” is still frequently used to refer to any scientific advance, particularly in medicine or biology, that is thought to threaten humanity (stem cell research or GM crops). This is a double-edged propaganda weapon, inciting hysteria as much as rational caution and discussion. But Mary Shelley’s creation has proved how vital it is for science to engage with public fears, as well as fantasies.

The work itself inspired at least one remarkable scientific spin-off, Jane Loudon’s witty novel The Mummy!, published in 1827. Though the title, complete with exclamation mark, gives away the basic plot, the novel is far from anti-scientific. Paradoxically, it celebrates a brilliant array of futuristic inventions and technologies, such as centrally heated streets, cheap, compressed-air balloon travel, houses moved by railway and gas-illuminated safety hats for ladies. After this “wild and strange story”, as she called it, Jane Loudon went on to find more conventional fame as the playful author of The Young Naturalist, the first of many scientific books for children.

At the very time these novels were making their impact, astronomer John Herschel FRS, the son of William, and a future secretary of the Royal Society, was writing a series of historic letters on a new but crucially related field: the public understanding of science. Unusually, his correspondent was a woman, Mary Fairfax Somerville. Their subject was the possibilities of “popularising” the new cosmology of the great French astronomer Pierre-Simon Laplace, whose work, Mécanique céleste, was regarded as second only to Newton’s Principia.

Born in 1780, Mary Somerville was the brilliant and charming Scottish wife of William Somerville FRS. She moved freely in Victorian scientific circles and was a friend of the Herschels, Faraday, Charles Babbage FRS, Jane Marcet and Ada Byron. Ada, incidentally, was the poet’s beautiful, headstrong daughter, a considerable mathematician in her own right. She had first explored the theories of Babbage concerning his famous “analytical engine”, by adding her own highly original but technical commentary to a review of his work (which she translated from the French). Though rightly credited with a share in inventing the modern computer, Ada never risked producing a piece of popular science of the sort Mary Somerville was considering.

During an unhappy first marriage, Mary had taught herself mathematics and had studied both astronomy and painting. She first visited the Herschels’ telescopes at Slough in 1816. She described herself as “intensely ambitious to excel in something, for I felt in my own breast that women were capable of taking a higher place in creation than that assigned to them in my early days, which was very low”. Her first plan was to be a painter.

In 1828, she was challenged by Lord Brougham to produce a popular summation of the new French astronomy for his philanthropic Society for the Diffusion of Useful Knowledge. After immense and covert labour (“I hid my papers as soon as the bell announced a visitor, lest anyone should discover my secret”), she completed an outstanding translation and interpretation of Laplace’s difficult astronomical book on the structure and mathematics of the solar system, retitling it The Mechanism of the Heavens (1830). Her unscientific friend, novelist Maria Edgeworth, described Mary admiringly: “She has her head in the stars, but feet firm upon earth… intelligent eyes… Scotch accent… the only person in England who understands Laplace.”

The translation had originally been intended as a much shorter and simpler work. But now, John Herschel encouraged Mary to continue with the full text, but recommended an extended and popular introduction. “The attention of many will be turned to a work from your pen, who will just possess enough mathematical knowledge to be able to read the first [introductory] chapter, without being able to follow you into its applications… were I you, I would devote to this first part at least double the space you have done… I cannot recommend too much, clearness, fullness and order in the exposé of the principles,” he wrote to her in February 1830. Shrewdly, Herschel urged her to continue to think like a painter, to sketch in firm “outlines”, to “illustrate” vividly, to consider the overall composition: “As a painter you will understand my meaning.”

This long, fluent introductory essay, “A Preliminary Dissertation”, virtually free of any mathematical notation, used brilliant explanatory analogies and metaphors to describe how our solar system was formed and controlled by gravity. While the main translation became the standard textbook for science postgraduates at Cambridge (unheard-of for a woman author), the “Preliminary Dissertation made her famous with a general reading public. Again encouraged by Herschel, she republished it separately in 1832 and it continued to be widely read for the next 50 years.

Maria Edgeworth singled out its exemplary quality as popular science. “The great simplicity of your manner of writing, I may say of your mind, particularly suits the scientific sublime – which would be destroyed by what is commonly called fine writing. You trust sufficiently to the natural interest of your subject, to the importance of the facts, the beauty of the whole, and the adaptation of the means to the end…” Mary’s sense of wonder made every reader “feel with her”.

Mary Somerville then set out to write a completely original book, On the Connexion of the Physical Sciences in 1834. In it, she surveyed the whole field of contemporary sciences – chemistry, astronomy, physics – and drew attention to the unity of their underlying principles and methodology. Nothing like this had previously been attempted. As a result of a positive review by William Whewell FRS, the future master of Trinity College, Cambridge, the inclusive term “scientist” was coined. Amazingly, the word had not existed before 1834. This book ran to 10 editions and shaped the progressive idea of science for more than half a century. Physicist James Clerk Maxwell FRS wrote in 1870: “It was one of those suggestive books which put into definitive, intelligible and communicative form the guiding ideas that are already working in the minds of men of science, so as to lead them to discoveries, but which they cannot yet shape into a definitive statement.”

Mary Somerville went on to write books about the new geography and the ever-expanding world of the microscope: Physical Geography in 1848 and Molecular and Microscopic Science in 1869 (written in her late 80s). Her autobiography, Personal Recollections, was published posthumously in 1873. Throughout her life, she supported women’s suffrage (her signature was the first on JS Mill’s petition to Parliament), campaigned against vivisection and against slavery in America.

She is now largely remembered because she had an Oxford college named after her in 1879. But in her time she was the greatest of all 19th-century women science writers, known as “the Queen of science” and elected honorary fellow of the Royal Astronomical Society (1835) along with Caroline Herschel. If she never entered into the Royal Society in person, her fine marble bust by Chantrey did so. It was first installed in the Great Hall and now resides in the research library of the Royal Society, flanked by Faraday and Darwin.

Most important, Mary Somerville became an outstanding model for a later generation of younger women in science. This was notably true of the first great American woman astronomer, Maria Mitchell. Born in 1818 on the remote whaling-station of Nantucket, Maria had a Quaker upbringing, where her scientific interests were encouraged by her schoolmaster father. Three years after her discovery of a new comet in 1847, she was elected first woman member of the American Association for the Advancement of Science, aged only 32.

Modestly revelling in her newfound celebrity, Maria then toured all the great observatories of Europe, subjecting their various astronomers to her candid, Nantucket eye and salty humour. She visited Greenwich Observatory and the Royal Society, bringing with her as a calling card the first known photograph of a star. For the most part, she was enthusiastically received, especially by the kindly John Herschel, though she was “riled” by Whewell’s chauvinist teasing while dining at Trinity College high table. She was also amazed to be told by Sir George Airy FRS, the British astronomer royal: “In England, there is no astronomical public and we do not need to make science popular.”

Undaunted, Maria pressed on to meet Mary Somerville, the great object of her tour, who now lived in Rome. She was disconcerted to find the Vatican observatory closed to women after dark, a distinct setback for a professional astronomer. (“I was told that Mrs Somerville, the most learned woman in all Europe, had been denied admission – she could not enter an observatory that was at the same time a monastery.”) But she was captivated by Mary Somerville, both by her directness and by her fantastic range of interests.

“Mrs Somerville’s conversation was marked by great simplicity, with no tendency to the essay style. She touched upon the recent discoveries in chemistry, of the discovery of gold in California, of the nebulae, of comets, of the satellites, of the planets…” To Maria’s satisfaction, she also “spoke with disapprobation of Dr Whewell’s attempt to prove that our planet was the only one inhabited by reasoning beings…”

Maria later wrote an essay in Mary Somerville’s praise. Like her heroine, Maria identified with the anti-slavery cause and the female suffragist movements. But being a generation younger, Maria Mitchell was far more assertive than Mary Somerville about the vital importance of women actually doing science. In fact, she took the Royal Society’s motto, Nullius in verba (“Take nobody’s word for it”) to have a particular relevance to the value of science for women. Too often, and for too long, those “words“ had been male.

“The great gain would be freedom of thought. Women, more than men, are bound by tradition and authority. What the father, the brother, the doctor and the minister have said has been received undoubtingly. Until women throw off this reverence for authority they will not develop. When they do this, when they come to the truth through their investigations, when doubt leads them to discover, the truth which they get will be theirs and their minds will work on and on, unfettered.”

When appointed first professor of astronomy at Vassar in 1865 aged 47, Mitchell installed a symbolic bust of Somerville in her famous teaching observatory, just as the Royal Society had done, though with more didactic intent. Beneath its gaze she mentored a brilliant circle of devoted female students to take up the baton of astronomy.

For all her gifts, Mary Somerville had denied women’s ability to do original science. In Chapter 11 of her Personal Recollections, she had written ruefully: “I was conscious that I had never made a discovery myself, I had no originality. I have perseverance and intelligence, but no genius. That spark from heaven is not granted to [my] sex… whether higher powers may be allotted to us in another state of existence, God knows, original genius in science at least is hopeless in this. At all events it has not yet appeared in the higher branches of science.”

Maria Mitchell, as a great science teacher, came to think this conclusion was a historic mistake and emphatically told her students why, in her celebrated Vassar lectures: “The laws of nature are not discovered by accident; theories do not come by chance, even to the greatest minds, they are not born in the hurry and worry of daily toil, they are diligently sought… and until able women have given their lives to investigation, it is idle to discuss their capacity for original work.”

With the inspiring examples of both Somerville and Mitchell, the work of popularisation rapidly expanded in Victorian England after 1860. Mary Ward, cousin to astronomer William Parsons FRS, brought out beautifully illustrated books describing the history and function of scientific instruments: The Microscope in 1868 and The Telescope in 1869. Both these books carried extensive advertisements for these instruments, priced from 10 guineas, now within the reach of ordinary families.

Arabella Buckley, who had been assistant to Charles Lyell FRS, used her experience to write one of the earliest general surveys of science for young people, entitled A Short History of Natural Science, and of the Progress of Discovery From the Time of the Greeks to the Present Day (1876). Margaret Gatty, building further on the tradition of scientific tales and wonders, published her semi-fictional series Parables From Nature, which ran to an astonishing 18 editions between 1855 and 1882.

The social impact of Darwin’s On the Origin of Species (1859) produced a mixed response from the women popularisers. On the one hand, there was Agnes Giberne’s Sun, Moon and Stars (1880), which might be described as a work of Romantic revisionism, prefacing each chapter with biblical quotations and emphasising the divine order and established hierarchy in the universe. “When I consider Thy heavens, the work of Thy fingers, what is man that Thou art mindful of him, or the son of man that thou visitest him?” Her book was written hopefully “for children, working men or even grown-up people of the educated classes”.

On the other hand, there was Alice Bodington, the fearless Darwinian author of Studies in Evolution (1890). Her polemical and provocative essays in the radical Westminster Review followed the social and theological implications of Darwin’s theories. In Religion, Reason and Agnosticism (1893), she remarks that the “destruction of old creeds” by science must lead to a new, but necessary scepticism. In this unusually frank essay, she confesses her own loss of faith. “Deep as the microscope can fathom, far as the telescope and spectroscope can take us into the universe, we see evidence of unvarying law… not of the personal interference of the Deity.” Evolution had destroyed the idea of intelligent design, “once regarded as the cornerstone of natural religion”. Without science, Alice Bodington felt, religion was “as a fairy tale or an opium dream, delusive though exquisitely fair, it can give no permanent support, no real comfort”.

Yet, paradoxically, science itself might eventually show that “the extraordinary, the unique instinct of religion” in mankind was itself evolving “from the lowest fetish worship” to some “unimaginable glory”. In this, the progressive understanding of science would lead not to philosophic despair, but to continuous hope and wonder in the universe. “The deathless instinct of religion bids us not despair.”

By the turn of the century, major science was indeed being done by women, just as Mary Somerville had hoped and Maria Mitchell had firmly predicted. In the 1880s, Margaret Huggins, an early expert on stellar photography, began to sign Royal Society papers on spectroscopy jointly with her husband, Sir William Huggins FRS. Hertha Ayrton was producing highly original work on the electric arc. Although rejected as a fellow in 1902 (amid a stormy debate that Margaret Cavendish would have relished), Hertha was the first woman to read her own paper at a Royal Society meeting two years later and was awarded the Royal Society’s Hughes Medal in 1906. Slowly, the tide was turning. The Lost Women of Science were about to be found.

Yet these remarkable women had already added a third dimension to the whole scientific enterprise as originally conceived by Lord Bacon, and by the founding fathers of the Royal Society. The two primary aims of science had long been established as the discovery of the nature of physical reality “by experiment and proof” and the applications of such discoveries “for the relief of man’s estate”. In Bacon’s terms, science should bring “light” and science should bear “fruit”.

The Lost Women had helped to add a third, fundamental imperative. Science should sow “seeds”. Science should broadcast, should disperse the seeds of knowledge to all and as imaginatively as possible. Science, and the scientific method, should become a new means of general education and enlightenment, not merely for the elite. Until scientific knowledge was explained, explored and widely understood by the population at large, the work of scientists would always be incomplete. This third dimension or imperative added a radical new parameter to both the practice and the philosophy of science in Britain.

As Maria Mitchell had put it, with one of her famous smiles: “We especially need imagination in science. It is not all mathematics, nor all logic, but it is somewhat beauty and poetry.”

Richard Holmes’s The Age of Wonder won the Royal Society’s Science Books Prize for 2009; its sequel, The Lost Women of Victorian Science, will be published by HarperCollins and Pantheon USA

There is a growing sentiment that the open web is a fundamentally dangerous place. Recent waves of hacked WordPress sites revealed exploited PHP vulnerabilities and affected dozens of well-known designers and bloggers like Chris Pearson. The tools used by those with malicious intent evolve just as quickly as the rest of the web. It’s deeply saddening to hear that, according to Jonathan Zittrain, some web users have stooped so low as to set up ‘Captcha sweatshops’ where (very) low-paid people are employed to solve Captcha security technology for malicious purposes all day. This is the part where I weep for the inherent sadness of mankind.

“If we don’t do something about this,” says Jonathan Zittrain of the insecure web, “I see the end of much of the generative aspect of the technologies that we now take for granted.” Zittrain is a professor of Internet governance and regulation at Oxford University and the author of The Future of the Internet: and How to Stop It; watch his riveting Google Talk on these subjects.

The Wild West: mainstream media’s favorite metaphor for today’s Internet

The result of the Internet’s vulnerability is a generation of Internet-centric products — like the iPad, the Tivo and the XBOX — that are not easily modified by anyone except their vendors and their approved partners. These products do not allow unapproved third-party code (such as the kind that could be used to install a virus) to run on them, and are therefore more reliable than some areas of the web. Increased security often means restricted or censored content — and even worse — limited freedoms that could impede the style of innovation that propels the evolution of the Internet, and therefore, our digital future.

The web of 2010 is a place where a 17 year-old high school student can have an idea for a website, program it in three days, and quickly turn it into a social networking craze used by millions (that student’s name is Andrey Ternovskiy and he invented Chatroulette). That’s innovation in a nutshell. It’s a charming story and a compelling use of the web’s creative freedoms. If the security risks of the Internet kill the ‘open web’ and turn your average web experience into one that is governed by Apple or another proprietary company, the Andrey Ternovskiys of the world may never get their chance to innovate.

Security Solutions

We champion innovation on the Internet and it’s going to require innovation to steer it in the right direction. Jonathan Zittrain says that he hopes we can come together on agreements for regulating the open web so that we don’t “feel that we have to lock down our technologies in order to save our future.”

According to Vint Cerf, vice president and Chief Internet Evangelist at Google, “I think we’re going to end up looking for international agreements – maybe even treaties of some kind – in which certain classes of behavior are uniformly considered inappropriate.”

Perhaps the future of the Internet involves social structures of web users who collaborate on solutions to online security issues. Perhaps companies like Google and Apple will team up with international governmental bodies to form an international online security council. Or maybe the innovative spirit of the web could mean that an independent, democratic group of digital security experts, designers, and programmers will form a grassroots-level organization that rises to prominence while fighting hackers, innovating on security technology, writing manifestos for online behavior, and setting an example through positive and supportive life online.

Many people are fighting to ensure your ability to have your voice heard online — so use that voice to participate in the debate, stay informed, and demand a positive future. Concerned netizens and Smashing readers: unite!

Despite its relatively short lifespan, IT has had some huge watershed moments. TechRepublic’s Jack Wallen followed the tech timeline to identify the most pivotal events.

It’s unlikely that everyone will ever agree on the most important dates in the history of IT. I know my IT timeline has a personal and professional bias. But I’ve tried to be objective in examining the events that have served to shape the current landscape of the modern computing industry. Some of the milestones on my list are debatable (depending upon where you are looking from), but some of them most likely are not. Read on and see what you think.

1: The development of COBOL (1959)

There are many languages out there, but none has influenced as many others as COBOL has. What makes COBOL stand out is the fact that there are still machines chugging along, running COBOL apps. Yes, these apps could (and possibly should) be rewritten to a modern standard. But for many IT administrators, those who don’t have the time or resources to rewrite legacy apps, those programs can keep on keeping on.

2: The development of the ARPANET (1969)

It is an undeniable fact that the ARPANET was the predecessor of the modern Internet. The ARPANET began in a series of memos, written by J.C. R. Licklider and initially referred to as the “Intergalactic Computer Network.” Without the development of the ARPANET, the landscape of IT would be drastically different.

3: The creation of UNIX (1970)

Although many would argue that Windows is the most important operating system ever created, UNIX should hold that title. UNIX started as a project between MIT and AT&T Bell Labs. The biggest initial difference (and most important distinction) was that it was the first operating system to allow more than one user to log in at a time. Thus was born the multi-user environment. Note: 1970 marks the date the name “UNIX” was applied.

4: The first “clamshell” laptop (1979)

William Moggridge, working for GRID Systems Corporation, designed the Compass Computer, which finally entered the market in 1991. Tandy quickly purchased GRID (because of 20 significant patents it held) but then turned around and resold GRID to AST, retaining the rights to the patents.

5: The beginning of Linus Torvalds’ work on Linux (1991)

No matter where you stand on the Linux versus Windows debate, you can’t deny the importance of the flagship open source operating system. Linux brought the GPL and open source into the forefront and forced many companies (and legal systems) into seeing monopolistic practices as well as raising the bar for competition. Linux was also the first operating system that allowed students and small companies to think in much bigger ways than their budgets previously allowed them to think.

6: The advent of Windows 95 (1995)

Without a doubt, Windows 95 reshaped the way the desktop looked and felt. When Windows 95 hit the market the metaphor for the desktop became standardized with the toolbar, start menu, desktop icons, and notification area. All other operating systems would begin to mimic this new de facto standard desktop.

7: The 90s dot-com bubble (1990s)

The dot-com bubble of the 90s did one thing that nothing else had ever done: It showed that a great idea could get legs and become a reality. Companies like Amazon and Google not only survived the dot-com burst but grew to be megapowers that have significant influence over how business is run in the modern world. But the dot-com bubble did more than bring us companies — it showed us the significance of technology and how it can make daily life faster, better, and more powerful.

8: Steve Jobs rejoining Apple (1996)

Really, all I should need to say here is one word: iPod. Had Jobs not come back to Apple, the iPod most likely would never have been brought to life. Had the iPod not been brought to life, Apple would have withered away. Without Apple, OS X would never have seen the light of day. And without OS X, the operating system landscape would be limited to Windows and Linux.

9: The creation of Napster (1999)

File sharing. No matter where you stand on the legality of this issue, you can’t deny the importance of P2P file sharing. Without Napster, file sharing would have taken a much different shape. Napster (and the original P2P protocols) heavily influenced the creation of the BitTorrent protocol. Torrents now make up nearly one-third of all data traffic and make sharing of large files easy. Napster also led to the rethinking of digital rights (which to some has negative implications).

10: The start of Wikipedia (2000)

Wikipedia has become one of leading sources of information on the Internet and with good reason. It’s the single largest collaborative resource available to the public. Wikipedia has since become one of the most often cited sources on the planet. Although many schools refuse to accept Wiki resources (questioning the legitimacy of the sources) Wikipedia is, without a doubt, one of the largest and most accessible collections of information. It was even instrumental in the 2008 U.S. presidential election, when the candidates’ Wiki pages became the top hits for voters seeking information. These presidential Wiki pages became as important to the 2008 election as any advertisement.

What’s missing?

Were there other important events in the timeline of IT? Sure. But I think few, if any, had more to do with shaping modern computing than the above 10 entries. What’s your take? If you had to list 10 of the most important events (or inventions) of modern computing, what would they be? Share your thoughts with fellow TechRepublic members.

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Larry Dignan is Editor in Chief of ZDNet and Smart Planet as well as Editorial Director of ZDNet sister site TechRepublic. See his full profile and disclosure of his industry affiliations.

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By DENNIS OVERBYE

Published: April 2, 2010

Yes, the collider finally crashed subatomic particles into one another last week, but why, exactly, is that important? Here is a primer on the collider – with just enough information, hopefully, to impress guests at your next cocktail party.

Let’s be basic. What does a particle physicist do?

Particle physicists have one trick that they do over and over again, which is to smash things together and watch what comes tumbling out.

What does it mean to say that the collider will allow physicists to go back to the Big Bang? Is the collider a time machine?

Physicists suspect that the laws of physics evolved as the universe cooled from billions or trillions of degrees in the first moments of the Big Bang to superfrigid temperatures today (3 degrees Kelvin) — the way water changes from steam to liquid to ice as temperatures decline. As the universe cooled, physicists suspect, everything became more complicated. Particles and forces once indistinguishable developed their own identities, the way Spanish, French and Italian diverged from the original Latin.

By crashing together subatomic particles — protons — physicists create little fireballs that revisit the conditions of these earlier times and see what might have gone on back then, sort of like the scientists in Jurassic Park reincarnating dinosaurs.

The collider, which is outside Geneva, is 17 miles around. Why is it so big?

Einstein taught us that energy and mass are equivalent. So, the more energy packed into a fireball, the more massive it becomes. The collider has to be big and powerful enough to pack tremendous amounts of energy into a proton.

Moreover, the faster the particles travel, the harder it is to bend their paths in a circle, so that they come back around and bang into each other. The collider is designed so that protons travel down the centers of powerful electromagnets that are the size of redwood trunks, which bend the particles’ paths into circles, creating a collision. Although the electromagnets are among the strongest ever built, they still can’t achieve a turning radius for the protons of less than 2.7 miles.

All in all, the bigger the accelerator, the bigger the crash, and the better chance of seeing what is on nature’s menu.

What are physicists hoping to see?

According to some theories, a whole list of items that haven’t been seen yet — with names like gluinos, photinos, squarks and winos — because we haven’t had enough energy to create a big enough collision.

Any one of these particles, if they exist, could constitute the clouds of dark matter, which, astronomers tell us, produce the gravity that holds galaxies and other cosmic structures together.

Another missing link of physics is a particle known as the Higgs boson, after Peter Higgs of the University of Edinburgh, which imbues other particles with mass by creating a cosmic molasses that sticks to them and bulks them up as they travel along, not unlike the way an entourage forms around a rock star when they walk into a club.

Have scientists ever seen dark matter?

It’s invisible, but astronomers have deduced from their measurements of galactic motions that the visible elements of the cosmos, like galaxies, are embedded in huge clouds of it.

Will physicists see these gluinos, photinos, squarks and winos?

There is no guarantee that any will be discovered, which is what makes science fun, as well as nerve-racking.

So how much energy do you need to create these fireballs?

At the Large Hadron Collider, that energy is now 3.5 trillion electron volts per proton — about as much energy as a flea requires to do a pushup. That may not sound like much, but for a tiny proton, it is a lot of energy. It is the equivalent of a 200-pound man bulking up by 700,000 pounds.

What’s an electron volt?

An electron volt is the amount of energy an electron would gain passing from the negative to the positive side of a one-volt battery. It is the basic unit of energy and of mass preferred by physicists.

When protons collide, is there a big bang?

There is no sound. It’s not like a bomb exploding.

In previous trials, there was an actual explosion.

All that current is dangerous. During the testing of the collider in September 2008, the electrical connection between a pair of the giant magnets vaporized. There are thousands of such connections in the collider, many of which are now believed to be defective. As a result the collider can only run at half-power for the next two years.

Could the collider make a black hole and destroy the Earth?

The collider is not going to do anything that high-energy cosmic rays have not done repeatedly on Earth and elsewhere in the universe. There is no evidence that such collisions have created black holes or that, if they have, the black holes have caused any damage. According to even the most speculative string theory variations on black holes, the Large Hadron Collider is not strong enough to produce a black hole.

Too bad, because many physicists would dearly like to see one.

An earlier version of this article misstated that the Earth began to cool in the aftermath of the Big Bang.

http://www.nytimes.com/2010/04/04/weekinreview/04overbye.html

Read more: Found: Hawking’s initials written into the universe

THE subtle signal of ancient helium has shown up for the first time in light left over from the big bang. The discovery will help astronomers work out how much of the stuff was made during the big bang and how much was made later by stars.

Helium is the second-most abundant element in the universe after hydrogen. The light emitted by old stars and clumps of hot pristine gas from the early universe suggest helium made up some 25 per cent of the ordinary matter created during the big bang.

The new data provides another measure. A trio of telescopes has found helium’s signature in the cosmic microwave background (CMB, pictured), radiation emitted some 380,000 years after the big bang. The patterns in this radiation are an important indicator of the processes at work at that time. Helium affects the pattern because it is heavier than hydrogen and so alters the way pressure waves must have travelled through the young cosmos. But helium’s effect on the CMB was on a scale too small to resolve until now.

By combining seven years of data from NASA’s Wilkinson Microwave Anisotropy Probe with observations by two telescopes at the South Pole, astronomers have confirmed its presence. “This is the first detection of pre-stellar helium,” says WMAP’s chief scientist, Charles Bennett.

These observations are in line with earlier measurements, although less accurate. “I think CMB measurements will surpass them eventually,” says team member David Spergel.

More accurate numbers could reveal how quickly the early universe expanded. Helium forms from the interaction between protons and neutrons. This is constrained by the number of available neutrons, which would have dropped during the time the brand new universe was expanding as they decayed into protons. So the amount of helium that formed places important limits on how quickly this expansion took place. That could help test theories that postulate extra dimensions or as-yet-unseen particles.

Better data should be available in the next few years. The European Space Agency’s Planck satellite, which launched last year, is poised to measure the amount of helium even more precisely.

DRIVING through the countryside south of Hanover, it would be easy to miss the GEO600 experiment. From the outside, it doesn’t look much: in the corner of a field stands an assortment of boxy temporary buildings, from which two long trenches emerge, at a right angle to each other, covered with corrugated iron. Underneath the metal sheets, however, lies a detector that stretches for 600 metres.

For the past seven years, this German set-up has been looking for gravitational waves – ripples in space-time thrown off by super-dense astronomical objects such as neutron stars and black holes. GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.

For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time – the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into “grains”, just as a newspaper photograph dissolves into dots as you zoom in. “It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time,” says Hogan.

If this doesn’t blow your socks off, then Hogan, who has just been appointed director of Fermilab’s Center for Particle Astrophysics, has an even bigger shock in store: “If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram.”

The idea that we live in a hologram probably sounds absurd, but it is a natural extension of our best understanding of black holes, and something with a pretty firm theoretical footing. It has also been surprisingly helpful for physicists wrestling with theories of how the universe works at its most fundamental level.

The holograms you find on credit cards and banknotes are etched on two-dimensional plastic films. When light bounces off them, it recreates the appearance of a 3D image. In the 1990s physicists Leonard Susskind and Nobel prizewinner Gerard ‘t Hooft suggested that the same principle might apply to the universe as a whole. Our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.

The “holographic principle” challenges our sensibilities. It seems hard to believe that you woke up, brushed your teeth and are reading this article because of something happening on the boundary of the universe. No one knows what it would mean for us if we really do live in a hologram, yet theorists have good reasons to believe that many aspects of the holographic principle are true.

Susskind and ‘t Hooft’s remarkable idea was motivated by ground-breaking work on black holes by Jacob Bekenstein of the Hebrew University of Jerusalem in Israel and Stephen Hawking at the University of Cambridge. In the mid-1970s, Hawking showed that black holes are in fact not entirely “black” but instead slowly emit radiation, which causes them to evaporate and eventually disappear. This poses a puzzle, because Hawking radiation does not convey any information about the interior of a black hole. When the black hole has gone, all the information about the star that collapsed to form the black hole has vanished, which contradicts the widely affirmed principle that information cannot be destroyed. This is known as the black hole information paradox.

Bekenstein’s work provided an important clue in resolving the paradox. He discovered that a black hole’s entropy – which is synonymous with its information content – is proportional to the surface area of its event horizon. This is the theoretical surface that cloaks the black hole and marks the point of no return for infalling matter or light. Theorists have since shown that microscopic quantum ripples at the event horizon can encode the information inside the black hole, so there is no mysterious information loss as the black hole evaporates.

Crucially, this provides a deep physical insight: the 3D information about a precursor star can be completely encoded in the 2D horizon of the subsequent black hole – not unlike the 3D image of an object being encoded in a 2D hologram. Susskind and ‘t Hooft extended the insight to the universe as a whole on the basis that the cosmos has a horizon too – the boundary from beyond which light has not had time to reach us in the 13.7-billion-year lifespan of the universe. What’s more, work by several string theorists, most notably Juan Maldacena at the Institute for Advanced Study in Princeton, has confirmed that the idea is on the right track. He showed that the physics inside a hypothetical universe with five dimensions and shaped like a Pringle is the same as the physics taking place on the four-dimensional boundary.

According to Hogan, the holographic principle radically changes our picture of space-time. Theoretical physicists have long believed that quantum effects will cause space-time to convulse wildly on the tiniest scales. At this magnification, the fabric of space-time becomes grainy and is ultimately made of tiny units rather like pixels, but a hundred billion billion times smaller than a proton. This distance is known as the Planck length, a mere 10^-35 metres. The Planck length is far beyond the reach of any conceivable experiment, so nobody dared dream that the graininess of space-time might be discernable.

That is, not until Hogan realised that the holographic principle changes everything. If space-time is a grainy hologram, then you can think of the universe as a sphere whose outer surface is papered in Planck length-sized squares, each containing one bit of information. The holographic principle says that the amount of information papering the outside must match the number of bits contained inside the volume of the universe.

Since the volume of the spherical universe is much bigger than its outer surface, how could this be true? Hogan realised that in order to have the same number of bits inside the universe as on the boundary, the world inside must be made up of grains bigger than the Planck length. “Or, to put it another way, a holographic universe is blurry,” says Hogan.

This is good news for anyone trying to probe the smallest unit of space-time. “Contrary to all expectations, it brings its microscopic quantum structure within reach of current experiments,” says Hogan. So while the Planck length is too small for experiments to detect, the holographic “projection” of that graininess could be much, much larger, at around 10^-16 metres. “If you lived inside a hologram, you could tell by measuring the blurring,” he says.

When Hogan first realised this, he wondered if any experiment might be able to detect the holographic blurriness of space-time. That’s where GEO600 comes in.

Gravitational wave detectors like GEO600 are essentially fantastically sensitive rulers. The idea is that if a gravitational wave passes through GEO600, it will alternately stretch space in one direction and squeeze it in another. To measure this, the GEO600 team fires a single laser through a half-silvered mirror called a beam splitter. This divides the light into two beams, which pass down the instrument’s 600-metre perpendicular arms and bounce back again. The returning light beams merge together at the beam splitter and create an interference pattern of light and dark regions where the light waves either cancel out or reinforce each other. Any shift in the position of those regions tells you that the relative lengths of the arms has changed.

“The key thing is that such experiments are sensitive to changes in the length of the rulers that are far smaller than the diameter of a proton,” says Hogan.

So would they be able to detect a holographic projection of grainy space-time? Of the five gravitational wave detectors around the world, Hogan realised that the Anglo-German GEO600 experiment ought to be the most sensitive to what he had in mind. He predicted that if the experiment’s beam splitter is buffeted by the quantum convulsions of space-time, this will show up in its measurements (Physical Review D, vol 77, p 104031). “This random jitter would cause noise in the laser light signal,” says Hogan.

In June he sent his prediction to the GEO600 team. “Incredibly, I discovered that the experiment was picking up unexpected noise,” says Hogan. GEO600′s principal investigator Karsten Danzmann of the Max Planck Institute for Gravitational Physics in Potsdam, Germany, and also the University of Hanover, admits that the excess noise, with frequencies of between 300 and 1500 hertz, had been bothering the team for a long time. He replied to Hogan and sent him a plot of the noise. “It looked exactly the same as my prediction,” says Hogan. “It was as if the beam splitter had an extra sideways jitter.”

No one – including Hogan – is yet claiming that GEO600 has found evidence that we live in a holographic universe. It is far too soon to say. “There could still be a mundane source of the noise,” Hogan admits.

Gravitational-wave detectors are extremely sensitive, so those who operate them have to work harder than most to rule out noise. They have to take into account passing clouds, distant traffic, seismological rumbles and many, many other sources that could mask a real signal. “The daily business of improving the sensitivity of these experiments always throws up some excess noise,” says Danzmann. “We work to identify its cause, get rid of it and tackle the next source of excess noise.” At present there are no clear candidate sources for the noise GEO600 is experiencing. “In this respect I would consider the present situation unpleasant, but not really worrying.”

For a while, the GEO600 team thought the noise Hogan was interested in was caused by fluctuations in temperature across the beam splitter. However, the team worked out that this could account for only one-third of the noise at most.

Danzmann says several planned upgrades should improve the sensitivity of GEO600 and eliminate some possible experimental sources of excess noise. “If the noise remains where it is now after these measures, then we have to think again,” he says.

If GEO600 really has discovered holographic noise from quantum convulsions of space-time, then it presents a double-edged sword for gravitational wave researchers. One on hand, the noise will handicap their attempts to detect gravitational waves. On the other, it could represent an even more fundamental discovery.

Such a situation would not be unprecedented in physics. Giant detectors built to look for a hypothetical form of radioactivity in which protons decay never found such a thing. Instead, they discovered that neutrinos can change from one type into another – arguably more important because it could tell us how the universe came to be filled with matter and not antimatter (New Scientist, 12 April 2008, p 26).

It would be ironic if an instrument built to detect something as vast as astrophysical sources of gravitational waves inadvertently detected the minuscule graininess of space-time. “Speaking as a fundamental physicist, I see discovering holographic noise as far more interesting,” says Hogan.

Small price to pay

Despite the fact that if Hogan is right, and holographic noise will spoil GEO600′s ability to detect gravitational waves, Danzmann is upbeat. “Even if it limits GEO600′s sensitivity in some frequency range, it would be a price we would be happy to pay in return for the first detection of the graininess of space-time.” he says. “You bet we would be pleased. It would be one of the most remarkable discoveries in a long time.”

However Danzmann is cautious about Hogan’s proposal and believes more theoretical work needs to be done. “It’s intriguing,” he says. “But it’s not really a theory yet, more just an idea.” Like many others, Danzmann agrees it is too early to make any definitive claims. “Let’s wait and see,” he says. “We think it’s at least a year too early to get excited.”

The longer the puzzle remains, however, the stronger the motivation becomes to build a dedicated instrument to probe holographic noise. John Cramer of the University of Washington in Seattle agrees. It was a “lucky accident” that Hogan’s predictions could be connected to the GEO600 experiment, he says. “It seems clear that much better experimental investigations could be mounted if they were focused specifically on the measurement and characterisation of holographic noise and related phenomena.”

One possibility, according to Hogan, would be to use a device called an atom interferometer. These operate using the same principle as laser-based detectors but use beams made of ultracold atoms rather than laser light. Because atoms can behave as waves with a much smaller wavelength than light, atom interferometers are significantly smaller and therefore cheaper to build than their gravitational-wave-detector counterparts.

So what would it mean it if holographic noise has been found? Cramer likens it to the discovery of unexpected noise by an antenna at Bell Labs in New Jersey in 1964. That noise turned out to be the cosmic microwave background, the afterglow of the big bang fireball. “Not only did it earn Arno Penzias and Robert Wilson a Nobel prize, but it confirmed the big bang and opened up a whole field of cosmology,” says Cramer.

Hogan is more specific. “Forget Quantum of Solace, we would have directly observed the quantum of time,” says Hogan. “It’s the smallest possible interval of time – the Planck length divided by the speed of light.”

More importantly, confirming the holographic principle would be a big help to researchers trying to unite quantum mechanics and Einstein’s theory of gravity. Today the most popular approach to quantum gravity is string theory, which researchers hope could describe happenings in the universe at the most fundamental level. But it is not the only show in town. “Holographic space-time is used in certain approaches to quantising gravity that have a strong connection to string theory,” says Cramer. “Consequently, some quantum gravity theories might be falsified and others reinforced.”

Hogan agrees that if the holographic principle is confirmed, it rules out all approaches to quantum gravity that do not incorporate the holographic principle. Conversely, it would be a boost for those that do – including some derived from string theory and something called matrix theory. “Ultimately, we may have our first indication of how space-time emerges out of quantum theory.” As serendipitous discoveries go, it’s hard to get more ground-breaking than that.

Check out other weird cosmology features from New Scientist

Marcus Chown is the author of Quantum Theory Cannot Hurt You (Faber, 2008)

A novel formulation of quantum mechanics, the “relative histories” formulation (RHF), is proposed based upon the assumption that the physical state of a closed system – e.g., the universe – can be represented mathematically by an ensemble E of four-dimensional manifolds W. In this scheme, any real, physical object – be it macroscopic or microscopic – can be assigned to the role of the quantum mechanical “observer.” The state of the observer is represented as a 3-dimensional manifold, O. By using O as a boundary condition, we obtain E as the unique set of all W that satisfy the boundary condition defined by O. The evolution of the “wavefunction of the universe” E is therefore determined by the movement of the observer O through state space.

In a sense, the RHF is a specific instance of the consistent histories formulation, in which a single “history” is equated with a single W. However, the RHF can also be interpreted as an implementation of Einstein’s ensemble (or statistical) interpretation, which is based upon the notion that the wavefunction is to be understood as the description not of a single system, but of an ensemble of systems: in our case, an ensemble of W’s. We could, in addition, think of the RHF in terms of Everett’s relative state formulation (i.e., the multiple worlds interpretation (MWI)), in which each “world” is equated with one of the four-manifolds W.

The mathamatical underpinnings of the RHF have been developed to an extent sufficient to demonstrate that the RHF gives rise to quantum statistics. However, the mathematical structure of the RHF is far from complete. At this stage, the primary motivation for the development of the RHF centers on the fact that it offers a constellation of interpretational advantages that are not found in any other single formulation of QM. One of these advantages is its versatility; as discussed above, the RHF is a sort of unification of many other standard formulations of QM, such as the consistent histories formulation, the MWI, Einstein’s statistical interpretation, and the FPI. In addition, the RHF is possessed of the following interpretational features: (1) a clear definition of the observer and of its space of states, and a lack of the fundamental split between observer and system that is characteristic of the Copenhagen Interpretation; (2) movement of the observer through state space that obeys classical notions of locality and probability; (3) a derivation of quantum statistics and quantum nonlocality from classical notions of probability and locality; (4) a demonstration of compatibility with general relativity; (5) an adherence to the notion that “all is geometry;” (6) the absence of a requirement for any extra “unphysical” dimensions of spacetime beyond the four of our everyday experience; and (7) a spacetime structure that is causal on the large scale. In addition, the RHF provides a simple conceptualization of the EPR argument that QM cannot be considered both local and complete. In exchange for these interpretational features, we are forced merely to accept that the structure of spacetime is acausal on the small scale.

As of January 2005, the RHF is summarized in a series of three papers that are available for download from the following site:
RHF papers.

These papers have been formatted using LaTeX to make them as reader-friendly as possible. There are three parts. Part I – Basics.pdf presents an introduction to the basic mathematical elements of the RHF, including the 4-geon model of fundamental particles, and demonstrates in explicit terms that the RHF makes the same predictions as the Feynman path integral (FPI) approach. Since the FPI is an independent formulation of quantum mechanics — for example, the FPI is well-known to provide a basis for the derivation of the Schrodinger equation — the equivalence between the RHF and the FPI implies equivalence between the RHF and quantum mechanics in general. Part II – Interpretation.pdf provides an overview of the interpretational issues surrounding the RHF, as summarized above. Part III – Further Mathematical Development.pdf is not (as of January 2005) yet ready for download and review, as I anticipate that it will undergo significant revision as I learn more about Morse theory and its application to the RHF.

I am currently (as of January 2005) in the process of soliciting an informal “peer-review” of the RHF prior to any attempt at submission for publication, even to arXiv. I anticipate this to be a slow process: the complexity of the RHF technique is about on a par as, say, the Feynman path integral (FPI) technique itself. Furthermore, an understanding of the RHF, especially its interpretational implications, requires a broad knowledge of the foundations of QM — especially regarding the inner workings of the FPI — that even many practicing physicists lack. I welcome any comments, be they from an expert or a layman, which should be sent to my yahoo! email address (straycat_md).

For an online discussion of the Relative Histories Formulation, check out my Yahoo! group: QM_from_GR (http://groups.yahoo.com/group/QM_from_GR)