Dig pinpoints Stonehenge origins

By James Morgan Science reporter, BBC News

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The excavation is documented in a BBC Timewatch special

Archaeologists have pinpointed the construction of Stonehenge to 2300BC - a key step to discovering how and why the mysterious edifice was built.

The radiocarbon date is said to be the most accurate yet and means the ring's original bluestones were put up 300 years later than previously thought.

The dating is the major finding from an excavation inside the henge by Profs Tim Darvill and Geoff Wainwright.

The duo found evidence suggesting Stonehenge was a centre of healing.

Others have argued that the monument was a shrine to worship ancestors, or a calendar to mark the solstices.

A documentary following the progress of the recent dig has been recorded by the BBC Timewatch series. It will be broadcast on Saturday 27 September.

Date demand

For centuries, archaeologists have marvelled at the construction of Stonehenge, which lies on Salisbury Plain, Wiltshire.

Mineral analysis indicates that the original circle of bluestones was transported to the plain from a site 240km (150 miles) away, in the Preseli hills, South Wales.

This extraordinary feat suggests the stones were thought to harbour great powers.

Professors Darvill and Wainwright believe that Stonehenge was a centre of healing - a "Neolithic Lourdes", to which the sick and injured travelled from far and wide, to be healed by the powers of the bluestones.

They note that "an abnormal number" of the corpses found in tombs nearby Stonehenge display signs of serious physical injury and disease.

And analysis of teeth recovered from graves show that "around half" of the corpses were from people who were "not native to the Stonehenge area".

"Stonehenge would attract not only people who were unwell, but people who were capable of [healing] them," said Professor Darvill, of Bournemouth University.

"Therefore, in a sense, Stonehenge becomes 'the A & E' of southern England."

Modern techniques

But without a reliable carbon date for the construction of Stonehenge, it has been difficult to establish this, or any other, theory.

Until now, the consensus view for the date of the first stone circle was anywhere between 2600BC and 2400BC.

To cement the date once and for all, Professors Darvill and Wainwright were granted permission by English Heritage to excavate a patch of earth just 2.5m x 3.5m, in between the two circles of giant sarsen stones.

The dig unearthed about 100 pieces of organic material from the original bluestone sockets, now buried under the monument. Of these, 14 were selected to be sent for modern carbon dating, at Oxford University.

The result - 2300BC - is the most reliable date yet for the erection of the first bluestones.

Strictly speaking, the result was rounded down to "between 2400BC and 2200BC" - but 2300BC is taken as the average.

An even more precise date will be produced in the coming months.

"It's an incredible feeling, a dream come true," said Professor Wainwright, formerly chief archaeologist at English Heritage.

"We told the world we were going to date Stonehenge. That was a risk, but I was always confident," said Professor Darvill.

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The archaeologists reveal the first accurate carbon date for Stonehenge

Intriguingly, the date range ties in closely with the date for the burial of the so-called "Amesbury Archer", whose tomb was discovered three miles from Stonehenge.

Some archaeologists believe the Archer is the key to understanding why Stonehenge was built.

Analyses of his corpse and artefacts from his grave indicate he was a wealthy and powerful man, with knowledge of metal working, who had travelled to Salisbury from Alpine Europe, for reasons unknown.

Post mortem examinations show that he suffered from both a serious knee injury and a potentially fatal dental problem, leading Darvill and Wainwright to conclude that the Archer came to Stonehenge to be healed.

But without an accurate date for Stonehenge, it was not even clear whether the temple existed while the Archer was alive.

His remains have been dated between 2500BC and 2300BC - within the same period that the first stone circle was erected.

"It's quite extraordinary that the date of the Amesbury Archer is identical with our new date for the bluestones of Stonehenge," said Professor Darvill.

"These two things happening within living memory of each other for sure is something very, very important."

Earliest occupation

Professor Wainwright added: "Was the Amesbury Archer, as some have suggested, the person responsible for the building of Stonehenge? I think the answer to that is almost certainly 'no'.

"But did he travel there to be healed? Did he limp, or was he carried, all the way from Switzerland to Wiltshire, because he had heard of the miraculous healing properties of Stonehenge? 'Yes, absolutely'.

"Tim and I are quite convinced that people went to Stonehenge to get well. But Stonehenge probably had more than one purpose, so I have no problem with other people's interpretations."

Among other key finds, the team uncovered organic material that indicates people inhabited the Stonehenge site as long ago as 7200BC - more than 3,500 years earlier than anything previously known.

They also found that bluestone chippings outnumbered sarsen stone chippings by three to one - which Wainwright takes to be a sign of their value.

"It could be that people were flaking off pieces of bluestone, in order to create little bits to take away... as lucky amulets," he said.

The duo are preparing to publish an academic report of their excavation, and will announce their findings to their peers next month, in a lecture at London's Society of Antiquaries.

Ongoing debate

Experts on Stonehenge said the new date was a major milestone in understanding Britain's most famous monument.

Dr Andrew Fitzpatrick, of Wessex Archaeology, said: "This is a great result - a very important one.

"The date of Stonehenge had been blowing in the wind. But this anchors it. It helps us to be secure about the chronology of events.

"The theory that it was a centre of healing is certainly a plausible one, but I don't think we can rule out the other main competing theory - that the temple was a meeting point between the land of the living and the dead.

"I am not yet persuaded that the Amesbury Archer came to Stonehenge to be healed. I favour the interpretation that he was one of the earliest metal workers, who travelled to the area to make a living from his skills.

"In any case, it is still not clear if his burial predated Stonehenge."

Dave Batchelor, Stonehenge curator at English Heritage, said: "We are pleased that the professors' precision in targeting that small area of turf and their rigorous standards in archaeological excavations have produced such a rich collection of physical evidence.

"We are looking forward to seeing the results of the full analysis, but from what we understand so far, we believe they have added valuable information to the chronology of Stonehenge."

The BBC Timewatch special is broadcast on BBC Two at 2005 BST on Saturday 27 September

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/7625145.stm

Published: 2008/09/21 23:01:34 GMT

© BBC MMVIII

LA QUADRATURE DU NET

http://www.laquadrature.net/fr/pourquoi-la-quadrature-du-net

L'illusion du pouvoir n'est que le fantasme de l'impuissance

Black hole star mystery 'solved'

Astronomers have shed light on how stars can form around a massive black hole, defying conventional wisdom.

http://news.bbc.co.uk/2/hi/science/nature/7574255.stm

Scientists have long puzzled over how stars develop in so extreme conditions.

Molecular clouds - the normal birth places of stars - would be ripped apart by the immense gravity, a team explains in Science magazine.

But the researchers say that stars can form from elliptical discs - the relics of giant gas clouds torn apart by encounters with black holes.

They made the discovery after developing computer simulations of giant gas clouds being sucked into black holes like water spiralling down a plughole.

"These simulations show that young stars can form in the neighbourhood of supermassive black holes as long as there is a reasonable supply of massive clouds of gas from further out in the galaxy," said co-author Ian Bonnell from St Andrews University, UK.

Ripped apart

Their findings are in accordance with actual observations in our Milky Way galaxy that indicate the presence of a massive black hole, surrounded by huge stars with eccentric orbits.

The simulations, performed on a supercomputer - and taking over a year of computing time - followed the evolution of two separate giant gas clouds up to 100,000 times the mass of the Sun, as they fell towards the supermassive black hole.

The simulations show how the clouds are pulled apart by the immense gravitational pull of the black hole.

The disrupted clouds form into spiral patterns as they orbit the black hole; the spiral patterns remove motion energy from gas that passes close to the black hole and transfers it to gas that passes further out.

This allows part of the cloud to be captured by the black hole while the rest escapes.

In these conditions, only high mass stars are able to form and these stars inherit the eccentric orbits from the elliptical disc.

These results match the two primary properties of the young stars in the centre of our galaxy: their high mass and their eccentric orbits around the supermassive black hole.

"That the stars currently present around the galaxy's supermassive black hole have relatively short lifetimes of [about] 10 million years, which suggests that this process is likely to be repetitive," Professor Bonnell explained.

"Such a steady supply of stars into the vicinity of the black hole, and a diet of gas directly accreted by the black hole, may help us understand the origin of supermassive black holes in our and other galaxies in the Universe."

Conserver éternellement les arbres remarquables est chose impossible.

Sachons les respecter de leur vivant.

What is collective intelligence and what will we do about it? Thomas W. Malone, Director MIT Center for Collective Intelligence

Edited transcript of remarks at the official launch of the
MIT Center for Collective Intelligence
October 13, 2006

It now falls to me, at this point in the program, to give you an overview of what collective intelligence is, in the first place, and what we’d like to do about it. The working definition of collective intelligence that we’re using is that collective intelligence is groups of individuals doing things collectively that seem intelligent [Q.: mais comment se reconnaissent-ils?].

Now, if you think about it that way, collective intelligence has existed for a very long time. Families, companies, and countries are all groups of individual people doing things that at least sometimes seem intelligent. Beehives and ant colonies are examples of groups of insects doing things like finding food sources that seem intelligent. And we could even view a single human brain as a collection of individual neurons or parts of the brain that collectively act intelligently.

But in the last few years we’ve seen some very interesting examples of new kinds of collective intelligence:

• Google, for instance, takes the collective knowledge created by millions of people making websites for other purposes and harnesses that collective knowledge--using some very clever algorithms and sophisticated technology--to produce amazingly intelligent answers to the questions we type in.
• Wikipidia, at another extreme, uses much less sophisticated technology but some very clever organizational principles and motivational techniques to get thousands of people all over the world to volunteer their time to create an amazing on-line collection of knowledge.
• In just a few minutes, you’ll hear from Alph Bigham the CEO of a company called Innocentive [est-ce vraiement innocent ?] which lets companies with difficult research problems harness the collective intelligence of thousands of scientists in a network all over the world to help solve those problems.
• A lot of companies today--Hewlett Packard, Eli Lilly, Google and others--are now beginning to use things called prediction markets [mais qui paie quoi à qui et comment ?] where people buy and sell predictions about future events (like sales of their products) in ways that leads to more accurate predictions in many cases than traditional market research or polling or other techniques.

Now, I think these examples are just the beginning. With new information technologies—especially the Internet—it is now possible to harness the intelligence of huge numbers of people, connected in very different ways and on a much larger scale than has ever been possible before. In order to take advantage of these possibilities, however, we need to understand what the possibilities are in a much deeper way than we do so far.

So, I think the time has come make collective intelligence a topic of serious academic study. And that is our goal in the Center for Collective Intelligence.

The key question we’re using to organize our work is: How can people and computers be connected so that collectively they act more intelligently than any individual, group, or computer has ever done before?

In order to answer that question, I think at least three types of research are needed. The first is just collecting examples or case studies [Malone : mais tu ne change jamais de méthode ?]. I think there are going to be a lot of natural experiments going on in the next few years, people trying lots of interesting things--with or without us. But I think that we can help the world learn from its experience with all these natural experiments by systematically describing and collecting examples of interesting cases of collective intelligence.

For instance, Eric von Hippel, in the Sloan School, has done some very interesting case studies of how the collective body of users of a product is often a better source of innovation for a company’s products than the company’s own researchers [Ndr : y-avait-t-il vraiement besoin de faire une étude ???]. This kind of case study research is common in business schools, but it is certainly not the only kind of research we need to do.

Another kind of research we need to do is something that is more typical in an engineering school. That is to create new examples of the phenomena we want to study. If you’re an aeronautical engineer, for instance, you wouldn’t just study birds and flying insects, you’d also want to create some flying machines and study how they work. In our case, that means we want to create some new examples of collective intelligence and study how they work.

For instance, Mark Klein in the Center for Collective Intelligence is leading a group of people in a nascent project that hopes to harness the collective intelligence of thousands of people around the world to help deal with the problems of global climate change [& l'Opus Dei ? Qu'en fait-on ?]. We have some specific technical ideas about how to combine computer simulation techniques with online ways of representing issues and positions and arguments that we think may be helpful in this process.

In the process of creating new examples, we hope to advance the state of the art and to learn new design principles not just for the technologies, by the way [BTW], but also for the human, the organizational, the social, and the motivational systems that are needed for these systems to work effectively.
But case studies and creating new examples are not the only things we need to do. I think we also need to do systematic studies and experiments. For instance, in some cases, we’ll find examples of things that work well but we won’t know why from just a case study. So we need to do systematic experiments to help figure those things out. This is the kind of research that would be more often done in a school of science or a school of social science. For example, Sandy Pentland (in the Media Lab), Drazen Prelec (in the Sloan School), and Josh Tennenbaum (in the Brain and Cognitive Sciences department) are all doing different laboratory experiments about different ways of helping groups make predictions more effectively [c'est joli la diversité !].

But these three things--case studies, new examples, and systematic experiments--are not the only things we need to do. We also need new theories to help tie all these things together [ça devient compliqué ...]. I think that is especially important in the case of collective intelligence because there’s now a lot of hype and prejudice going around about collective intelligence [de qui parle-t-il ?].

On the one hand, there are people who think that collective intelligence is magic, and if you just add it, it’ll make everything wonderful. For instance, there is a book called The Wisdom of Crowds by James Surowiecki who--by the way--does not believe what I just said. But many people who’ve heard about his book do believe it. They think that just doing things “collectively” will make everything great.

On the other hand, there are people who are prejudiced against the very notion of collectiveness and decentralization. Very recently for instance, there have been a number of people who’ve looked at the success of Wikipedia and pointed out ways in which is not perfect. And then, based on that, they have argued that nothing without central control can ever be successful.

Now, I think both of these extremes are equally wrong. Sometimes collective intelligence is good; sometimes it isn’t. Sometimes it works, and sometimes it doesn’t. A very important part of our goal is to help put a more solid scientific foundation under the claims in this area.

Fortunately, we don’t have to start from scratch [scratch] in doing that. There’s already a lot of good work that has been done in many fields, including psychology, organization theory, artificial intelligence, brain science and others. Part of what we want to do is to help organize the work that has already been done.

But even if we had already organized all of the results of all of the previous research, there would still a lot to learn. New technologies are now making it possible to organize groups in very new ways, in ways that have never been possible before in the history of humanity. And no one yet understands how to take advantage of these possibilities.

We certainly don’t have all the answers yet; we’re just beginning to ask the questions [ça c'est prudentiellement bien prudent, bravo!]. We hope we can make a contribution just by helping to frame the questions better [je suis d'accord : le plus important c'est de poser les bonnes questions ... c'est déjà fini la lecture ...]. We’re pretty [pretty] sure we can have a lot of fun trying. And we hope that in the long run the work we do in this center will help contribute to scientific understanding in many different disciplines and help us understand new and better ways to organize businesses, to conduct science, to run governments, and--perhaps most importantly--to help solve the problems we face as society and as a planet.

L’Albatros

Souvent, pour s’amuser, les hommes d’équipage
Prennent des albatros, vastes oiseaux des mers,
Qui suivent, indolents compagnons de voyage,
Le navire glissant sur les gouffres amers.



À peine les ont-ils déposés sur les planches,
Que ces rois de l’azur, maladroits et honteux,
Laissent piteusement leurs grandes ailes blanches
Comme des avirons traîner à côté d’eux.

Ce voyageur ailé, comme il est gauche et veule !
Lui, naguère si beau, qu’il est comique et laid !
L’un agace son bec avec un brûle-gueule,
L’autre mime, en boitant, l’infirme qui volait !

Le Poète est semblable au prince des nuées
Qui hante la tempête et se rit de l’archer ;
Exilé sur le sol au milieu des huées,
Ses ailes de géant l’empêchent de marcher.

Charles Baudelaire
Les fleurs du mal

L'origine della Luce

La lüs a lè nassìda al tèp dei tèp in cèl, intàt che al Padretèrno a gh'ìa scapàt in fàl la prima ögiàda 'n giro per mètes a creàl ! La lüs a l'ia selvàdega e dispetúsa insèm, la sìa metìda sübet a fà balà la lüna col súl e i stèle 'n cèl compàgn d'ü mülinèl ! L'ìa trasfurmàt ol mònt con töt ol sò calùr in d'öna gran furnàs per inventà i culùr de pitürà zò'l cèl con töt ol sò splendùr !

A gh'è ülìt del tèp perchè la se calmès e la troès la pàs in fì a' de'nnamuràs e de fà crès i fiùr con töcc i sò culùr ! La lüs la s'è cambiàda in cèl come öna fàta che'impìa e smòrza zò ol sul come ü falò, de nöcc, la lüna e i stèle coi dìcc facc a fiamèle ! La lüs lè töta amùr, la te dà èta e fiàt e òia a' de campà, la te fà sèmper fèsta perchè l'è'nnamuràda de töcc ì'nnamuràcc !

La lüs l'è sèmper bèla in cèl e sö la tèra e quando la sberlüs la dìs "sò mè l'amùr che scòlda töcc i nì e che fà crès i fiùr ! " La lüs l'è verità, ghe scàpa gna ü pensèr col bè e col màl che s'fà la ghe fà ciàr a töcc de dèt e fò de cà per chi la öl dovrà ! La lüs l'è sèmper giöstra a'sè la par sbagliàda a chi ghe ulta i spale perchè la ghe fà ombra e i sèra i öcc per vèt apèna chèl che i crèt !

La lüs la fà pensà a Chèl che l'à 'nventàda perchè l'è apèna Lü che l'pöl amò smorsàla isce' come là fàcc ai tèp che l'l'à mpiàda ! Ma quando 'l Creatùr l'ismorserà sta lüs, la sarà prònta l'òtra, piö bèla e amò piö fòrta, chèla che l'à decìs de dàm in paradìs !

don Guilio Gabanelli

ON AIME LE PRINCIPE !

Sur cette photo, prise par des observateurs britanniques, on voit nettement des militaires chinois recevoir de leurs officiers des tenues de moines. L'hypothèse de la participation de faux moines dans le déclenchement des actes de violence à Lhassa avait déjà circulé ... . Plusieurs témoignages étaient parvenus dans ce sens. Cette fois, les faits semblent avérés....

Olanda: sì al sesso libero nei parchi

Una bozza di regolamento messa a punto dagli esperti della polizia dei Paesi Bassi - che dovrebbe entrare in vigore dopo l’estate - parla chiaro: appartarsi in un giardino pubblico e lasciarsi andare a libere effusioni, dal petting al rapporto sessuale completo, d’ora in poi non dovrà più essere considerato un comportamento perseguibile. Basta che siano seguite alcune semplici regole: rispettare gli orari, appartandosi solo dal tardo pomeriggio in poi; piazzare la coperta lontano dall’area giochi riservata ai bambini; gettare i preservativi e l’eventuale sigaretta negli appositi cestini.

La polizia invita dunque tutte le più grandi città d’Olanda - da Rotterdam a L’Aja a Utrecht - a seguire l’esempio di Amsterdam, dove già il libero sesso in alcuni parchi pubblici è permesso. Di fronte a coppie o più persone che si appartano - si legge nella bozza di regolamento inviata alle principali amministrazioni comunali - «i pubblici ufficiali non devono nella maniera più assoluta disturbare le attività, fintanto che non arrechino disturbo agli altri». Azioni «correttive» da parte degli agenti potranno essere prese «solo in presenza di comportamenti offensivi visibili da pubblico passaggio».

Le paradoxe est le miroir de l'âme !

La nature de la réalité n'entre pas dans les limites de la logique et ne peut donc être expliquée autrement que par des paradoxes.

Chögyal Namkhai Norbu
Dzogchen et tantra

[IF]

If you can keep your head when all about you
Are losing theirs and blaming it on you,
If you can trust yourself when all men doubt you
But make allowance for their doubting too,
If you can wait and not be tired by waiting,
Or being lied about, don't deal in lies,
Or being hated, don't give way to hating,
And yet don't look too good, nor talk too wise:

If you can dream--and not make dreams your master,
If you can think--and not make thoughts your aim;
If you can meet with Triumph and Disaster
And treat those two impostors just the same;
If you can bear to hear the truth you've spoken
Twisted by knaves to make a trap for fools,
Or watch the things you gave your life to, broken,
And stoop and build 'em up with worn-out tools:

If you can make one heap of all your winnings
And risk it all on one turn of pitch-and-toss,
And lose, and start again at your beginnings
And never breath a word about your loss;
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on!"

If you can talk with crowds and keep your virtue,
Or walk with kings--nor lose the common touch,
If neither foes nor loving friends can hurt you;
If all men count with you, but none too much,
If you can fill the unforgiving minute
With sixty seconds' worth of distance run,
Yours is the Earth and everything that's in it,
And--which is more--you'll be a Man, my son!

Rudyard Kipling

Conoscenza del Sé

La conoscenza del Sé è une cosa facile, la più facile di tutte le cose.

Il Sé è qualcosa di assolutamente reale, anche per un uomo semplice. Si potrebbe dire : un frutto nella mano aperta è al suo confronto un'illusione.

Il Sé che risplende nel cuore come sole, è reale e onnipervasivo. Si rivela non appena il falso immaginare si disperde e non resta più macula alcuna. L'immaginazione é infatti il motivo per cui appaiono forme illusorie : il mondo e l'Io, che sembrano cosi reali come il Sé, il quale solo davvero dura, immutabile e vero. Se il Sé risplende, le tenebre si disperdono; il dolore svanisce, resta solo beatitudine.

Il pensiero 'Io sono il corpo' è il filo attorno al quale, come perle, si infilano rappresentazioni di ogni genere. Se pero ti immergi nel profondo domandando : 'Chi sono io e da dove vengo ?', allora le rappresentazioni svaniscono e irrompe splendente la conoscenza del Sé come'IO-IO' nella caverna del cuore. Questo è paradiso, quiete, dimora di beatitudine.

A che giova sapere tante cose e non sapere nulla del Sé ? Che cosa resta da conoscere per uno che ha conosciuto il Sé ? Da chi ha se stesso riconosciuto il Sé come reale, l'unico Uno spontaneamente risplendente nella miriade di Sé, dall'intimo brilla in costui la luce del Sé. Questa è reale manifestazione della grazia, fine dell'Io e inizio di beatitudine suprema.

Per sciogliere le catene del destino insieme a tutte le sue relazioni e liberarsi dal terribile ciclo di nascite e morti questa via è incomparabilmente più facile delle altre. Percio stabilisciti nella quiete e intima a lingua, mente e corpo di tacere. Allora quel che da te stesso risplende sorgerà in te. Questa é l'esperienza suprema. Ogni paura svanisce. Questo è il mare infinito della perfetta beatitudine.

'Annamalai' il monte insormontabile, l'Uno trascendente in tutti noi, é l'occhio nascosto nell'occhio della mente. Osserva l'occhio e tutti i sensi, che a loro volta illuminano il firmamento e tutti gli elementi intorno. E il firmamento spitituale al cui cospetto compare il firmamento della mente. Risplende all'interno del cuore, che é privo di ogni moto e pensiero, e davanti allo sguardo costantemente quieto resta rivolto all'interno come QUELLO. Annamalai splende di luce propria, tuttavia la grazia del maestro é soprattutto necessaria. Abbandonati allora fiducioso al Sé, e beatitudine sarà il tuo guadagno.

Shrî Ramana Maharshi

We propose a complete change of point of view and a real characterizati- on that solve that problem; in this framework, being non-monotonic for a relation is equivalent to being a proper extension of a consequence relation, a precise structural condition binding those two relations.

Il meurt lentement

En souvenir de mon fils Carlo qui est mort brutalement le 9 décembre 2005, quelques heures seulement après m'avoir souhaité un bon anniversaire ...

Il meurt lentement
celui qui ne voyage pas
celui qui ne lit pas
celui qui n'écoute pas de musique
celui qui ne sait pas trouver grâce à ses yeux

Il meurt lentement
celui qui détruit son amour propre
celui qui ne se laisse jamais aider

Il meurt lentement
celui qui devient esclave de l'habitude
refaisant tous les jours le mêmes chemins
celui qui ne change jamais de repère
ne se risque jamais à changer la couleur de ses vetements
ou qui ne parle jamais à un inconnu

Il meurt lentement
celui qui évite la passion
et son tourbillon d'émotions
celles qui redonnent la lumière dans les yeux
et reparent les coeurs blessés

Il meurt lentement
celui qui ne change pas de cap lorsqu'il est malheureux au travail ou en amour
celui qui ne prend pas de risques pour réaliser ses rêves
celui qui, pas une seule fois dans sa vie, n'a fui les conseils sensés

Vis maintenant !
Risque-toi aujourd'hui !
Agis tout de suite !
Ne te laisse pas mourir lentement !
Ne te prive pas d'être heureux !

Jacques Derrida

KulturSPIEGEL

"We now know the Solar System doesn't just evolve due to gravitation."

Light puts asteroids into a spin

Jonathan Fildes Science and technology reporter, BBC News

The shower of solar particles can make asteroids spin faster

The constant bombardment of billions of tiny particles from the Sun is shaping the Solar System, studies have shown.

As the fine solar shower rains down on objects, such as asteroids, it can steadily alter their orbit and spin.

Although the mechanism that describes the effect has been known for many years, it has never been seen.

Now, separate studies published in the journals Nature and Science have observed and measured the tiny stellar shoves on two spinning asteroids.

They reveal that both are gradually starting to spin faster and faster, which could eventually create new Solar System landmarks.

"If we can spin up an asteroid so fast, there's a really good chance that these objects will fly apart," said Dr Stephen Lowry, a planetary astronomer at Queen's University Belfast and lead author of one of two Science papers.

In this case, the fragments could form a binary asteroid where two objects orbit each other, he said.

"This is a phenomenon that gradually affects the evolution of the Solar System," said Dr Mikko Kaasalainen of the University of Helsinki, who is an author of the Nature paper.

Random spin

The Yarkovsky-O'Keefe-Radzievskii-Paddack (Yorp) effect is named after the astronomers who made key observations that led to the theory.

It describes the torque, or rotational force, created when light particles hit the surface of an object, causing it to heat up.

As the asteroid rotates, its brightness increases and decreases, which is directly related to how fast it's spinning Stephen Lowry

"As the heat is re-emitted it exerts a gentle recoil effect," said Dr Lowry.

"An analogy would be if there was a child and they threw a ball forward, there would be a slight recoil effect."

The theory was proposed in order to explain various Solar System phenomena which show peculiar regular behaviour.

For example, astronomers looking at a cluster of asteroids known as the Koronis family, which is located in the main belt between Mars and Jupiter, noticed that the larger fragments spun in two distinct alignments.

The cluster was thought to have been the result of a catastrophic collision more than two billion years ago which would have blown erratically spinning fragments throughout the surrounding area.

Without the Yorp effect realigning the objects, this random motion would still be seen today.

The existence of other phenomenon like binary asteroids can also be explained by YORP.

Tiny changes

But although astronomers had several clues to the effect's existence, no direct evidence had ever been seen.

Now, two teams have analysed separate distal spinning asteroids and have been able to quantify how much their spin is changing. They have also been able to predict the possible future fate of the rocky lumps.

The team from Finland created computer models of Apollo 1862

A team lead by Dr Lowry and Patrick Taylor of Cornell University used optical and radar telescopes to monitor an asteroid known as 2000 PH5, which makes regular near-Earth passes.

At its closest, the 114m-diameter (374ft) lump comes within 1.8 million km (1.1 million miles) of Earth.

"As the asteroid rotates, its brightness increases and decreases, which is directly related to how fast it's spinning," said Dr Lowry.

By combining four years of optical information with radar to work out the size and shape of the object, the team was able to measure the increasing spin of the asteroid and therefore the size of the Yorp effect acting on PH5.

"It currently rotates every 12 minutes and we detected a change of one millisecond per year," said Dr Lowry. "It's a tiny, tiny effect but it's acting over millions of years."

The team predicts that over the next 15 million to 40 million years the asteroid will gradually speed up until it is turning over every 20 seconds.

At this point, the rocky mass may fly apart forming a cluster of smaller asteroids or a new binary system.

Large implications

A team from Finland has calculated the changes to another asteroid, 1862 Apollo, a 1.4km-wide (0.9 miles) near-Earth object that is approximately 340 million km (210 million miles) away.

I don't want to call it a dawn of a new age of astronomical sciences but it will certainly spark a whole range of new studies Stephen Lowry

Instead of making new observations, the researchers looked at historical snapshots of the object dating back to 1982. From these they were able to extract light information that could be checked against a theoretical model to discount other effects.

The result was also suitably minute.

"The current rotation period is about three hours and the change is only four thousandth of a second per year," said Dr Kaasalainen.

Although both results were almost intangibly small, the implications are much larger, especially for models of the evolution of the Solar System, he said.

"We must include this radiation effect because it can transport asteroids between different orbital states and effect their rotation," he said.

"We now know the Solar System doesn't just evolve due to gravitation."

Dr Lowry also believes it is a key finding for looking back through history.

"Asteroids are the leftovers from the start of the Solar System, so by understanding these asteroids, we may get an idea of what the Solar System was like before the planets formed," he said.

"I don't want to call it a dawn of a new age of astronomical sciences but this detection will certainly spark a whole range of new studies."

USAToday.com Refashions Itself as a Social Network

USA Today is unveiling a massive overhaul of their web site that adds a number of great features. The notable additions include: reader comments on every story, the ability to create a profile page that can be shared with others, citizen journalist photos, story tagging and digg-like recommendation buttons.

This is exactly the direction USA Today needs to follow. However, it doesn't go quite far enough. In addition to building these features, the media need to bridge their communities to the ones where we already spend our time. RSS, widgets and embedded content would help here. For example, USA Today should let us add our blog, Twitter or Facebook feeds or even embedded YouTube vids to our profile pages.

Connecting communities is so easy today with web services and it would go a long way toward making the their site - or any site for that matter - stronger. Hopefully we'll see this happen soon.

Sony unveils its new 3D universe

Playstation 3 gamers will be able to meet, chat and share content with friends inside a 3D universe.

"It's about community, collaboration and customisation," said Sony's Phil Harrison at the Game Developers Conference, in San Francisco.

Gamers can buy furniture and clothes, while publishers and retailers are also expected to offer 3D spaces.

Mr Harrison said the games industry had to learn from the success of the web 2.0 movement.

"We want to start a movement called Game 3.0. It's about emerging entertainment, powered by the audience at the centre of the experience."

Gamers can create avatars - online versions of themselves - and buy new clothes and create their own homes as a 3D social networking service.

Dynamic advertising - including high definition video - can be pushed into the 3D universe.

"There will be individual locations dedicated to game publishers, game developers, and titles. Over time it will extend to non-game brands. The industry is on the threshold of a new era of creativity, collaboration, communication and commerce embedded into an experience to empower games,"

Mr Harrison said.

Darren Waters
Technology editor, BBC News website, San Francisco