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Sunday, December 8, 2013

Sam Harris on Free Will

http://www.youtube.com/watch?v=pCofmZlC72g

Wind turbines trash the landscape for the benefit of billionaires

Energy policy is chaotic and incoherent. The myth that wind power is 'free' has driven Britain's politicians mad
Simon Jenkins         

The Guardian,
Illustration: Satoshi Kambayashi
'George Osborne finances a tiny group of extremely wealthy men to let someone else put up wind turbines on their land, or at least he did until Thursday.' Illustration: Satoshi Kambayashi
Is it fair for the chancellor to cut pensions for the poor while offering a million pounds a year to the Duke of Roxburghe for letting the wind blow? Is it fair to offer half a million to the Earl of Moray, a third of a million to the Earl of Glasgow, and a quarter of a million to the Duke of Beaufort, Sir Alastair Gordon Cumming and Sir Reginald Sheffield, the prime minister's father-in-law? Is it fair to promise a reported £1bn to Charles Connell over the next 25 years?
I am not particularly egalitarian. I support austerity in the public finances and accept that this may require a bit of smooth with the rough. But George Osborne is going beyond smooth.
British energy policy is chaotic. It is intellectually incoherent, lurching from fashion to fad with each lurch breeding a pile of taxpayer cash and a carnival of lobbyists out to protect it. Never in the history of public subsidy can so much have been paid by so many to so few.
The chancellor's well-trailed announcement that money for onshore turbines will be cut in favour of offshore is welcome in part, but it makes no sense. While less intrusive on the eye, offshore turbines are even more expensive and inefficient than onshore ones. The bizarre plan to erect 240 down the middle of the Bristol Channel has already been abandoned as uneconomic, despite Osborne's subsidy. The huge East Anglian field may cost billions. It all makes nuclear seem a bargain.
I have sympathy with the wind lobby in one respect. Its members are trying to turn an honest penny and must plan ahead. Just a couple of years ago they were told by wind's most fanatical subsidiser, Chris Huhne, to plan for 10,000 onshore turbines. Contracts were promised. Public money was unlimited. Offshore wind alone would "generate 20,000 British jobs". It was rubbish. The giant Sheringham field is so Norwegian that the country's crown prince was invited to declare it open.
There are almost no British jobs. The German firm Siemens makes most British turbines and sensibly does not rely on British government policy for its investment. It builds on the continent. Its competitor Vestas has pulled the plug on a plant in Kent, and South Korea's Doosan has done likewise in Glasgow. The energy required to mine the turbines' rare minerals and build, import and erect them makes a mockery of their "greenness".
The industry lobby, RenewableUK, on Thursday deplored what it suspected was a "political decision" to cut subsidy, and it was right. The switch reeked of Downing Street's obsession with Ukip, which has shrewdly opposed wind turbines. But an industry that is effectively a state subcontractor must accept such whims. The golden goose would never last.
I have spent two years traipsing Britain in search of the finest views. It is hard to convey the devastating impact of the turbines to those who have not seen them, especially a political elite that never leaves the south-east except for abroad. Fields of these structures are now rising almost everywhere. They are sited irrespective of the wind, since subsidy is paid irrespective of supply, even if there is none. It makes EU agricultural policy a paragon of sanity.
Turbines are to surround Cornwall and stretch along the north Devon coast. They will form a wall off the Dorset shore. They will line Offa's Dyke from Gwent to Shropshire, with a single giant on Clyro Hill looking down the Wye Valley like Rio's Christ the Redeemer. The once desolate Cambrian Mountains are on the way to being an estate of 840 turbines filling views in every direction.
The shires of Northampton, Nottingham and Cambridge are already gathering turbines. Heckington Fen in Lincolnshire may have ones higher than Lincoln cathedral. They are to appear in the Forest of Bowland in Lancashire, in the Brontë country of Yorkshire and on Spurn point off the Humber.
The wildest coastline left in England, in Northumberland, is being flanked by 70 turbines. In Scotland the Roxburghe array of 400 turbines has turned the once lovely Lammermuir Hills into a power station. Inverness and Caithness are to lose their open vistas, as are the Shetlands and the islands off Argyll. Scottish aristocrats have not seen such a turn in fortune since the Highland clearances.
Britain's landscape has never before been subject to such visual transformation. Human hands have always refashioned the country, urban and rural alike, but they have not industrialised its appearance on remotely this scale. Roads, railway lines, quarries, even towns and cities, are inconspicuous compared to wind turbines. Few of Britain's greatest views will be free of the sight of them.
Mostly the gain is footling. Turbines seldom produce their declared capacity. The one that towers over the M4 at Reading generates just 16% of its capacity. What they really generate is money, up to £30,000 a year each in subsidy. The billions poured into wind would have been far better spent – as energy professor Dieter Helm, the consultants KPMG and others have long argued – in pursuing lower emissions through energy efficiency and cleaner carbon.
Yet the myth that wind is "free" has driven politicians mad. They have chased the length and breadth of the land showering quantities of public money on a tiny handful of the rich. Britain's modern landscape is their memorial.

Very Nice Post on Cosmic Rays

This week’s Ask Ethan has a very nice post on cosmic rays, their origins, and how they interact with the Earth.  Recommended reading.

http://scienceblogs.com/startswithabang/2013/12/06/ask-ethan-14-the-highest-energy-particles-in-the-universe/

Jensen K, Karch A. Holographic Dual of an Einstein-Podolsky-Rosen Pair has a Wormhole. Phys. Rev. Lett. 2013;111(21)

Quoted from Brian Koberlein, Rochestor, NY.

Entanglement is a well-known property of quantum mechanics.  It is perhaps most famously demonstrated through the Einstein-Podolsky-Rosen (EPR) experiment.  Suppose we have a mischievous mutual friend.  She decides to prank us by sending sending each of us one member of a pair of gloves.  She packs each glove in a box and mails one to each of us.  We find out about the prank, so we both know that we’re getting one glove of a pair.  But until either of us open our respective box, neither of us know which glove we have.  Once the box arrives at your door, you open it up, and find you have the left glove.  At that moment you know I must have the right glove.

This is the basic idea of the EPR experiment.  For gloves it isn’t a big deal, because from the get-go the left glove was heading your way.  You just didn’t know you were getting the left glove.  That’s because gloves are not quantum things.  In the quantum regime, things get much more strange.  In quantum theory, things can be in an indefinite state until you observe them.  It would be as if our boxes contained a pair of something (gloves, shoes, salt and pepper shakers, etc.) but it is impossible to know what specific something until one of us opens their box.

In quantum theory we would say the boxes contain a superposition of possible things, and the outcome only becomes definite when the outcome is observed.  Now even though you can’t know what specific object you have, you know that I must have its pair.  So if you open the box to find a red right shoe, you know immediately that I must have a red left shoe.  We both know this without opening the box, so we can say that the outcomes of opening our boxes are entangled.  Knowing the contents of one box tells us the contents of the other.  We’ve actually done this experiment with photons, atoms and the like, and it really works.

Of course this is really hard to wrap your head around.  If I’m thousands of miles away from you, and I open my box to find a salt shaker, I know you must have a pepper shaker.  But your box couldn’t have known that until I opened the box.  How is that possible?  How can the opening of my box instantly affect your box thousands of miles away?  Do the boxes communicate faster than light? (No.)  Is there some secret (hidden variable) so that the boxes know what they will become when observed? (No.)  That is part of what makes entanglement so strange, and the EPR experiment so popular.  The one thing we can say is that entanglement is a very real physical effect in quantum mechanics.  There isn’t anything magical going on, just something we humans find strange.

Wormholes come from general relativity.  Unlike entanglement, there is no experimental evidence for wormholes.  Instead, they are a hypothetical connection between two locations in space.  Normally when people think of wormholes, they think of something out of science fiction (http://goo.gl/nz5SV2) where people use wormholes to travel to distant stars, but the hypothetical wormholes in general relativity aren’t traversible, nor do they have to be large.

This particular paper is looking at how there might be a connection between wormholes and quantum particles.  This idea isn’t new, in fact the idea that fundamental particles could be wormholes dates back to the 1950s, when John Wheeler proposed a model known as geometrodynamics, where everything was empty space and charged particles were the mouths of wormholes.  Wheeler was an excellent physicist known for coming up with a lot of wild ideas, some of which worked, and some of which didn’t.  In the case of geometrodynamics, it never really worked, and after a while interest faded.

But with the rise of string theory, different versions of the idea have gained some popularity.  Hence this new paper.  What the authors did was to look at a specific case of the EPR experiment, dealing with two quark particles.  What they were able to show is that the entangled quarks can be described in two ways.  The first is the standard way in which entanglement is described in quantum theory, but the second (dual) way is as two particles connected by a wormhole.  Both of these descriptions are equivalent.

Does this mean that entangled particles are wormholes?  No.  What it means is that there is an interesting connection between the mathematics of entanglement and the mathematics of quantum wormholes.  Just to be clear, this has nothing to do with any new experimental evidence.   But it is interesting, because it shows a connection between quantum entanglement and general relativity, and that may lead the way toward a better understanding of quantum gravity.

John Lennon RIP



 CCmai7FCCmai7F
 Imagine there's no heaven, it's easy if you try
 CCmai7FCCmai7F
 No hell below us, above us only sky
 AmDmGG7
 Imaginall the people, living for to day. A-ha..
Imagine there's no countries, it isn't hard to do.
Nothing to kill or die for, and no religion too.
Imagine all the people, living for to day. You-u..
 FGCFGCE
 YomasaI'm a dreamer, but I'm not the only one.
 FGCE
 hope some day you'll join us,
 FGC
 Anthe world will be one
Imagine no possessions, I wonder if you can
No need for greed or hunger, a brotherhood of man
Imagine all the people, sharing all the world. You-u..
You may say I'm a dreamer, but I'm not the only one.
I hope some day you'll join us,
And the world will live as one


http://www.youtube.com/results?search_query=john+lennon&sm=3



Philosophy and the Hitchhikers Guide to the Galaxy by Nicholar Joll

http://books.google.dk/books?id=VuAgtqaPBvoC&printsec=frontcover&dq=subject:%22Philosophy%22&hl=da&sa=X&ei=LJSkUsSNFunJsQTqkYLADA#v=onepage&q&f=true

"Philosophy and the Hitchhikers Guide to the Galaxy"

For full details go to the link above.  Sounds utterly fascinating.  I wasn't able to extract any info or pictures to show here.  Another link is http://najoll.wordpress.com/hitchhiker-philosophy/.  I got the following information:

Nicholas Joll, philosopher

Philosophy and THE HITCHHIKER’S GUIDE TO THE GALAXY

Philosophy  Science fiction  Literature  Humour  SatireInvitingly large red button
‘[A] very readable and mind-expanding collection’ – The Guardian, 8/9/2012 (and online here)

News

The slides from my Hitchhiker’s Towel Day talk (at Cambridge Central Library, May 25th 2013).

Reviews

Try and Buy

Buy the Hitchhiker book (in handsome paperback or rather nice e-book) from
Excerpts (try before you buy!)
    1. the book’s front matter (PDF file) including the preface and the contents pages (the latter being separately available as a JPG) (and this whole bundle is the one available via the ‘send to’ link in the sidebar on the right of this page) ©
    2. part of the Introduction (PDF) ©
    3. the book’s index of ‘philosophers, sages, luminaries, and other thinking persons’ (webpage) ©
    4. a larger image of the cover (in a PDF) ©
ILLUSTRATION: The start of Adams's *Restaurant at the End of the Universe* (image hosted by imgur.com)ILLUSTRATION: Getting philosophy out of academe

Understanding psychology as a science: an introduction to scientific and statistical inference

Front Cover
An accessible and illuminating exploration of the conceptual basisof scientific and statistical inference and the practical impact this has on conducting psychological research. The book encourages a critical discussion of the different approaches and looks at some of the most important thinkers and their influence.

The VASIMR Plasma Rocket: Bridging the Gap in Space Travel

by on November 22, 2013
Plasma rocket technology was first introduced to the scientific community in 1977 by Franklin Chang Díaz, a Costa Rican scientist and astronaut. The idea has been developed since then and is now at the stage where it can be implemented into future projects. The technology allows for considerably faster space travel than what the technologies currently employed by organizations such as NASA can do.

What is the VASIMR Plasma Rocket?

VASIMR stands for Variable Specific Impulse Magnetoplasma Rocket, which makes use of argon gas (one of the most stable gasses known to man) and a renewable source of energy found in space, radio waves in the form of light. The main difference with this type of rocket is being able to use mostly renewable energy in the propulsion system, which gives the rocket a greater lifespan than similar, modern-day rocket technologies. The plasma technology has multiple applications such as the cleaning and coating of surfaces in a plasma coating system at nano-level. The uses of plasma, the 4th state of substances, are just being touched on now with recent advances in science.

The new plasma rocket is able to heat the argon gas, creating the plasma which is then focused out electromagnetically to give the rocket its propulsion. A shield protects the machinery from what is known as electrode erosion, which is a major cause of general wear and tear on a plasma rocket.

VASIMR’s Impact on Space Travel

Over the last 36 years, the various shortcomings of the propulsion system have been ironed out. Problems such as wear and tear as well as the total velocity it can achieve have been improved dramatically. This new form of thrust is said to cut space mission times by up to six times. With the use of the plasma rocket, it will be possible to make quick surveys to other planets or even asteroids that may be on a collision course with Earth.

The thing that excites most scientists about the applications of the new rocket is a mission to Mars. The main problems in previous missions to Mars were that it would take too much fuel to allow the spaceship to reach the red planet and make a return journey. Deep space is another area that opens up to space explorers with the abilities of the plasma rocket. Travels to the areas of space that have remained inaccessible are back in the realm of possibility for scientists. Space debris removal as well as in-space resource recovery are also said to be possible with the new plasma rocket technology. Additionally, the magnetic field created by the rocket is thought to create a protective shell for the spaceship, which would help protect it against the radiation in space.

The 39-Day Mission to Mars

The rocket will allow for a mission to Mars with a travel period of just 39 days, which is almost 6 times faster than current methods. With speeds estimated at 35 miles a second, the rocket system will make quick work of the distance between Earth and Mars. NASA rates a new system on a scale of one to ten based on its readiness to be deployed. The VASIMR system is at a six currently, which means that it is ready to be tested in space. It would seem that it won’t be much longer before the new rocket system is employed in all space missions.
Image: Wikipedia
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The good news and the bad news

 By Jerry A. Coyne, Ph.D

First, first, I'd like to offer some comments.  When I read Coyne's piece below, it didn't just sound like an attack on New Atheism (I am a little foggy about what this is, admittedly, though I do read my Dawkins and Dennet, etc.), but a disguised form of religious apologism.  They believe that religion isn't all so bad, that we (or many of us) do need at least the "good" parts, and that we should keep it in some forms.  New Atheism does sound like religion is a complete scourge on all mankind that should eviscerated from humanity's soul.  If I exaggerate, please correct me, but -- and I speak as a born and raised atheist and nature/science lover, so it would only be an honest mistake on my part -- at least some people give that impression.  To me.

I remember a Facebook(?) question, by Dawkins(?) to the effect that what would the world be like if religion were to completely disappear -- I don't recall if "suddenly" were in there, but treated it as such.  My reply is that the vast masses of humans would be wondering around aimlessly crying,  "Landrew guide us!"  (If you aren't a fan of the original Star Trek series you might not catch the allusion.)  I suspect most people, though certainly not close to all, really do have a deep, one might say throbbing", need for some "heartfelt" guidance and direction and control.  Nor is it merely taught; there is an evolutionary basis for it, albeit reinforced by social upbringing.  So I suppose religion must gradually (and is) diminish very gradually, with still a lot of its pains still to be endured.  Perhaps New Atheism is compatible with this view, I don't know.

Well, I can say more, but without further ado, Jerry Coyne, whose original post is at http://whyevolutionistrue.wordpress.com/2013/12/08/the-good-news-and-the-bad-news-2/#comment-631306.
 
First, the bad news—so that you won’t be left fuming after you get both pieces of news. The two “pieces” are pieces of journalism that just appeared.
For some time now, Salon has been publishing pieces excoriating New Atheism, its Horsemen, and other atheists. I’m not sure why this is so, but it’s definitely been noticed.  And its most recent article, “What Hitchens got wrong: Abolishing religion won’t fix anything.” by journalist Sean McElwee, continues the tradition. It’s dreadful, and fails on four counts: it is gratuitous (a postmortem attack on Hitchens—do we need another one?), it says nothing new, it is mean-spirited, and many of its claims are wrong.  Because of that, I won’t dissect it in detail, but we need to see what kind of attacks keep on coming. Here are the main points (indented quotes are from McElwee):
1. New Atheists think that all suffering comes from religion.
The fundamental error in the “New Atheist” dogma is one of logic. The basic premise is something like this:
1. The cause of all human suffering is irrationality
2. Religion is irrational
3. Religion is the cause of all human suffering
That syllogism is obviously wrong, even logically, and we all know it. But who among atheists has said religion causes all human suffering? Name one person!  Our contention is, of course, that it causes a great deal of human suffering, but that some suffering will remain even when religion is gone. That will be caused because some humans are malicious or uncaring, because there are inequities in society, and because some “evil” is simply the workings of nature. But who can deny that areligious societies like Sweden or Denmark have less suffering than, say, Yemen or Saudi Arabia?
2. Hitchens was a hypocrite because he supported a war promulgated by a religious American president.  I kid you not:
But then [in the 2003 Gulf War] Hitchens decided that, in fact, bombing children was no longer so abhorrent, because these wars were no longer neocolonial wars dictated by economics and geopolitics but rather a final Armageddon between the forces of rationality and the forces of religion. The fact that the force of rationality and civilization was lead by a cabal of religious extremists was of no concern for Hitchens.
How many times is Hitchens going to be excoriated for this? Granted, I disagreed with that war, and with Hitchens’s stand, but it’s not the only stand he ever took. Do any people we admire only have opinions we agree with? At any rate, there’s no point in dragging Hitchens around the block for this once again.  And the fact that Bush was religious was irrelevant given Hitchens’s feelings about the Kurds.
3. The problems associated with militant Islam come from politics, not religion.  This contention is so common that it should be given a name. Here’s McElwee’s version:
Is not the best explanation for the Thirty Years’ War more likely political than religious? Might it be better to see jihad as a response to Western colonialism and the upending of Islamic society, rather than the product of religious extremism? The goal of the “New Atheists” is to eliminate centuries of history that Europeans are happy to erase, and render the current conflict as one of reason versus faith rather than what is, exploiter and exploited.
Bernard Lewis writes,
“For vast numbers of Middle Easterners, Western-style economic methods brought poverty, Western-style political institutions brought tyranny, even Western-style warfare brought defeat. It is hardly surprising that so many were willing to listen to voices telling them that the old Islamic ways were best and that their only salvation was to throw aside the pagan innovations of the reformers and return to the True Path that God had prescribed for his people.”
I have to wonder if Hitchens, Dawkins and Harris truly believe that eliminating religion will also make the Islamic world forget about centuries of colonization and deprivation. Without religion, will everyone living in Pakistan shrug off drone strikes and get on with their lives?
First of all, eliminating religion won’t fix the problems of the Middle East, though it will certainly help.  Those problems stem not only from dysfunctional theocratic types of government, but also oppressive dictators (viz., Assad), corruption, and so on. Those factors often have nothing to do with Western oppression.
But they also stem from the issue that Hitchens always singled out as critical in making a society dysfunctional: the economic disempowerment of women. That, of course, is embedded in Muslim doctrine. My own view is that we should argue against religion directly, for one can convert believers and those on the fence, but ultimately one must also try to create a more just and caring world, for it is people’s lack of security and their own dysfunctional situation that makes them religious. And working orking on both fronts has a salubrious feedback effect, for religion itself creates as well as stems from dysfunctional societies. Hitchens, of course, recognized that (I believe he used Marx’s famous “opium of the people” quote), and was doing his bit to oppose dictatorship and foster equality whenever he could.
But the main problem here is that most Islamic violence is directed not at colonialist oppressors, but at other Muslims (e.g., Sunni vs. Shia). Or against Islamic women.  Or it comes from a religiously-motivated hatred of Jews: another religious motivation.  Yes, colonialism plays some role, but if you read Lawrence Wright’s absorbing book The Looming Tower: Al-Qaeda and the Road to 9/11 (highly recommended, and it won a Pulitzer Prize), you’ll see that the origins of Al-Qaeda and its predecessor the Muslim Brotherhood trace back not to colonialism by Western powers, but to resentment of the “secular” government of Egypt and the desire to spread Islam throughout the world. I wish more people who play the “it’s-all-politics” card would read that book!
In fact, McElwee goes further, arguing that:
4. No war was ever about religion; they were all “political.”
Religion has a tendency to reflect political and economic realities. Hitchens, in fact, has made ample use of this Marxist analysis, questioning religious experts whether it was Constantine or the truth of Christ’s words that were largely responsible for its breakneck spread. Constantine was, and his proclivities shaped the church. The doctrine of the Trinity was not decided exclusively by decades of intense debate; the whimsy of Constantine and political maneuvering between by Arius and Athanasius had a significant influence on the outcome.
But if there were no religion, there would be no conflict over the Trinity, regardless of the “political maneuvering” involved! Of course not all wars are religious, and there is always a secular element even when religion is involved, but to deny that religious beliefs motivate internecine conflict and war is to deny reality.
I sometimes wonder if there is anything that would convince people like McElwee that religious beliefs contribute to armed conflict. Or will they always find a way to construe things as “political”? I see that tactic as close to theology in its refusal to accept reality and its obsession with confabulating explanations when reality shows its face. If you waffle hard enough, you can even construe the Inquisition as “political”.
5. Atheists and rationalists don’t understand religion, and promulgate a simplistic caricature of it. McElwee quotes the odious Terry Eagleton on this point:
Similarly, within the church there are modernizers and reformers working to quash the Church’s excesses, no Hitchens, Dawkins or Harris needed. Terry Eagleton writes,
“Card-carrying rationalists like Dawkins, who is the nearest thing to a professional atheist we have had since Bertrand Russell, are in one sense the least well-equipped to understand what they castigate, since they don’t believe there is anything there to be understood, or at least anything worth understanding. This is why they invariably come up with vulgar caricatures of religious faith that would make a first-year theology student wince. The more they detest religion, the more ill-informed their criticisms of it tend to be. If they were asked to pass judgment on phenomenology or the geopolitics of South Asia, they would no doubt bone up on the question as assiduously as they could. When it comes to theology, however, any shoddy old travesty will pass muster.”
What McElwee ignores is that many, many atheists were once fervent believers, and understand religion very well. Think of the atheists who were once preachers or fervent Christians: Dan Barker, Jerry DeWitt, Bart Ehrman, John Loftus, Eric MacDonald, and so on. Did those people fail to understand religion? I don’t think so. And many readers of this site have testified to—”witnessed,” as it were—their former deep immersion in religion. (I should also note the recent survey that showed that UK Christians knew less about their faith than did UK atheists).
And why do you have to be a believer to criticize religion? Do you have to be a Nazi to criticize Nazism, or a segregationist to understand and efface the evils of segregation? It seems to me that being an outsider gives one a certain advantage, at least in seeing and publicizing the harms of religion. Those in the asylum are often blinded to their delusion. And, at any rate, we have a distinguished roll of former religionists who are plenty well equipped “to understand what they castigate.”
That bit of obtuseness leads McElwee to his last inane conclusion:
6.  Atheists should shut up about religion because change is best made by the believers themselves.  Yes, that’s what he says:
Of course, I’m entirely aware of the problems in modern American Christianity. I have written an essay excoriating what I see as the false Christianity. But any critique of religion that can be made from the outside (by atheists) can be made more persuasively from within religion. For instance, it would hardly be the theologian’s job to point out that, according to The Economist, “Too many of the findings that fill the academic ether are the result of shoddy experiments or poor analysis. A rule of thumb among biotechnology venture-capitalists is that half of published research cannot be replicated.” I’m sure scientists are well aware of the problem and working to rectify it. Similarly, within the church there are modernizers and reformers working to quash the Church’s excesses, no Hitchens, Dawkins or Harris needed.
This is nonsense.  First of all, nearly all pressure to reform churches comes not from religion or church doctrine itself, but from secular movements outside the church that affect believers. I am absolutely convinced, for instance, that some churches’ acceptance of gays and women’s equality comes from social movements outside of religion. That kind of secular pressure is needed if any reform is to take place.
But, most important, “insiders” aren’t working to reform the most invidious forms of faith.  How many Catholics in the Vatican are undermining its doctrines about sex, divorce, the sinfulness of gays, and the prohibition of birth control? Answer: none that I know of.  How many Muslims in Saudi Arabia and Iran are working to dismantle the pernicious doctrines of Islam? Are we supposed to sit back and let the Vatican fix Catholicism? If so, then we’ll wait a long time!
If McElwee lived in Nazi Germany, he’d probably tell us: “Look, Rommel and von Stauffenberg are working to bring down Hitler. Call off the U.S. and British troops, call off the French Resistance, because any critique of Nazism made from the outside can be made more persuasively by members of the Nazi Party.”
The fact is that the “reform” of religion will occur much faster with pressure from nonbelievers, for many forms of faith have no motivation for changing.  And you don’t have to be a believer to see the harm.  If I were offered a plate of dog feces to eat, I wouldn’t be persuaded by the argument, “You can’t know whether it’s bad until you’ve eaten a lot of dog crap.”
McElwee goes on to espouse a form of NOMA, arguing that we need religion to tell us about the meaning of being human and how to live the good life, and that religion shouldn’t intrude on science. He’s right about the second part but not the first. Religion doesn’t have any more credibility about the meaning of life, and the best way to live  than the exertions of secular, humanistic philosophy in telling us how to live. In fact, religion is the worst guide for life, because it relies on faith rather than reason.
I see I’ve written too much again. But this stuff just keeps coming, and will continue, I suppose, until the memory of Hitchens has faded.

Physicists Eye Quantum-Gravity Interface

 
Gravity curves space and time around massive objects. What happens when such objects are put in quantum superpositions, causing space-time to curve in two different ways?
Courtesy of Dirk Bouwmeester
Gravity curves space and time around massive objects. What happens when such objects are put in quantum superpositions, causing space-time to curve in two different ways?
  
It starts like a textbook physics experiment, with a ball attached to a spring. If a photon strikes the ball, the impact sets it oscillating very gently. But there’s a catch. Before reaching the ball, the photon encounters a half-silvered mirror, which reflects half of the light that strikes it and allows the other half to pass through.
What happens next depends on which of two extremely well-tested but conflicting theories is correct: quantum mechanics or Einstein’s theory of general relativity; these describe the small- and large-scale properties of the universe, respectively.
In a strange quantum mechanical effect called “superposition,” the photon simultaneously passes through and reflects backward off the mirror; it then both strikes and doesn’t strike the ball. If quantum mechanics works at the macroscopic level, then the ball will both begin oscillating and stay still, entering a superposition of the two states. Because the ball has mass, its gravitational field will also split into a superposition.
But according to general relativity, gravity warps space and time around the ball. The theory cannot tolerate space and time warping in two different ways, which could destabilize the superposition, forcing the ball to adopt one state or the other.
Knowing what happens to the ball could help physicists resolve the conflict between quantum mechanics and general relativity. But such experiments have long been considered infeasible: Only photon-size entities can be put in quantum superpositions, and only ball-size objects have detectable gravitational fields. Quantum mechanics and general relativity dominate in disparate domains, and they seem to converge only in enormously dense, quantum-size black holes. In the laboratory, as the physicist Freeman Dyson wrote in 2004, “any differences between their predictions are physically undetectable.”
In the past two years, that widely held view has begun to change. With the help of new precision instruments and clever approaches for indirectly probing imperceptible effects, experimentalists are now taking steps toward investigating the interface between quantum mechanics and general relativity in tests like the one with the photon and the ball. The new experimental possibilities are revitalizing the 80-year-old quest for a theory of quantum gravity.
“In the final showdown between quantum mechanics and gravity, our understanding of space and time will be completely changed.”
“The biggest single problem of all of physics is how to reconcile gravity and quantum mechanics,” said Philip Stamp, a theoretical physicist at the University of British Columbia. “All of a sudden, it’s clear there is a target.”
Theorists are thinking through how the experiments might play out, and what each outcome would mean for a more complete theory merging quantum mechanics and general relativity. “Neither of them has ever failed,” Stamp said. “They’re incompatible. If experiments can get to grips with that conflict, that’s a big deal.”
Quantum Nature
At the quantum scale, rather than being “here” or “there” as balls tend to be, elementary particles have a certain probability of existing in each of the locations. These probabilities are like the peaks of a wave that often extends through space. When a photon encounters two adjacent slits on a screen, for example, it has a 50-50 chance of passing through either of them. The probability peaks associated with its two paths meet on the far side of the screen, creating interference fringes of light and dark. These fringes prove that the photon existed in a superposition of both trajectories.
But quantum superpositions are delicate. The moment a particle in a superposition interacts with the environment, it appears to collapse into a definite state of “here” or “there.” Modern theory and experiments suggest that this effect, called environmental decoherence, occurs because the superposition leaks out and envelops whatever the particle encountered. Once leaked, the superposition quickly expands to include the physicist trying to study it, or the engineer attempting to harness it to build a quantum computer. From the inside, only one of the many superimposed versions of reality is perceptible.
A single photon is easy to keep in a superposition. Massive objects like a ball on a spring, however, “become exponentially sensitive to environmental disturbances,” explained Gerard Milburn, director of the Center for Engineered Quantum Systems at the University of Queensland in Australia. “The chances of any one of their particles getting disturbed by a random kick from the environment is extremely high.”
Because of environmental decoherence, the idea of probing quantum superpositions of massive objects in tabletop experiments seemed for decades to be dead in the water. “The problem is getting the isolation, making sure no disturbances come along other than gravity,” Milburn said. But the prospects have dramatically improved.
Dirk Bouwmeester, an experimental physicist who splits his time between the University of California, Santa Barbara, and Leiden University in the Netherlands, has developed a setup much like the photon-and-ball experiment, but replacing the ball on its spring with an object called an optomechanical oscillator — essentially a tiny mirror on a springboard. The goal is to put the oscillator in a quantum superposition of two vibration modes, and then see whether gravity destabilizes the superposition.
Ten years ago, the best optomechanical oscillators of the kind required for Bouwmeester’s experiment could wiggle back and forth 100,000 times without stopping. But that wasn’t long enough for the effects of gravity to kick in. Now, improved oscillators can wiggle one million times, which Bouwmeester calculates is close to what he needs in order to see, or rule out, decoherence caused by gravity. “Within three to five years, we will prove quantum superpositions of this mirror,” he said. After that, he and his team must reduce the environmental disturbances on the oscillator until it is sensitive to the impact of a single photon. “It’s going to work,” he insists.
Photo of Markus Aspelmeyer
Courtesy of Markus Aspelmeyer
Markus Aspelmeyer, a quantum physicist at the University of Vienna, is developing three experiments aimed at probing the interface between quantum mechanics and gravity.
Markus Aspelmeyer, a professor of physics at the University of Vienna, is equally optimistic. His group is developing three separate experiments at the quantum-gravity interface — two for the lab and one for an orbiting satellite. In the space-based experiment, a nanosphere will be cooled to its lowest energy state of motion, and a laser pulse will put the nanosphere in a quantum superposition of two locations, setting up a situation much like a double-slit experiment. The nanosphere will behave like a wave with two interfering peaks as it moves toward a detector. Each nanosphere can be detected in only a single location, but after multiple repetitions of the experiment, interference fringes will appear in the distribution of the nanospheres’ locations. If gravity destroys superpositions, the fringes won’t appear for nanospheres that are too massive.
The group is designing a similar experiment for Earth’s surface, but it will have to wait. At present, the nanospheres cannot be cooled enough, and they fall too quickly under Earth’s gravity, for the test to work. But “it turns out that optical platforms on satellites actually already meet the requirements that we need for our experiments,” said Aspelmeyer, who is collaborating with the European Aeronautic Defense and Space Company in Germany. His team recently demonstrated a key technical step required for the experiment. If it gets off the ground and goes as planned, it will reveal the relationship between the mass of the nanospheres and decoherence, pitting gravity against quantum mechanics.
The researchers laid out another terrestrial experiment last spring in Nature Physics. Many proposed quantum gravity theories involve modifications to Heisenberg’s uncertainty principle, a cornerstone of quantum mechanics that says it isn’t possible to precisely measure both the position and momentum of an object at the same time. Any deviations to Heisenberg’s formula should show up in the position-momentum uncertainty of an optomechanical oscillator, because it is affected by gravity. The uncertainty itself is immeasurably small — a blurriness just 100-million-trillionth the width of a proton — but Igor Pikovski, a theorist in Aspelmeyer’s group, has discovered a backdoor route to detecting it. When a light pulse strikes the oscillator, Pikovski claims that its phase (the position of its peaks and troughs) will undergo a discernible shift that depends on the uncertainty. Deviations from the predictions of traditional quantum mechanics could be experimental evidence of quantum gravity.
Aspelmeyer’s group has started to realize the first experimental steps. Pikovski’s idea “provides us with a quite, I have to admit, unexpected improvement in performance,” Aspelmeyer said. “We are all a little surprised, actually.”
The Showdown
Many physicists expect quantum theory to prevail. They believe the ball on a spring should, in principle, be able to exist in two places at once, just as a photon can. The ball’s gravitational field should be able to interfere with itself in a quantum superposition, just as the photon’s electromagnetic field does. “I don’t see why these concepts of quantum theory that have proven to be right for the case of light should fail for the case of gravity,” Aspelmeyer said.
But the incompatibility of general relativity and quantum mechanics itself suggests that gravity might behave differently. One compelling idea is that gravity could act as a sort of inescapable background noise that collapses superpositions.
“While you can get rid of air molecules and electromagnetic radiation, you can’t screen out gravity,” said Miles Blencowe, a professor of physics at Dartmouth College. “My view is that gravity is sort of like the fundamental, unavoidable, last-resort environment.”
Rendering of an optomechanical oscillator.
Christopher Baker and Ivan Favero at Université Paris Diderot-CNRS
In an optomechanical oscillator, the light confined between two mirrors causes one of the mirrors to oscillate on a spring. Experimentalists plan to use such devices to pit quantum mechanics against general relativity.
The background-noise idea was conceived in the 1980s and 1990s by Lajos Diósi of the Wigner Research Center for Physics in Hungary and, separately, by Roger Penrose of Oxford University. According to Penrose’s model, a discrepancy in the curvature of space and time could accumulate during a superposition, eventually destroying it. The more massive or energetic the object involved and, thus, the larger its gravitational field, the more quickly “gravitational decoherence” would happen. The space-time discrepancy ultimately results in an irreducible level of noise in the position and momentum of particles, consistent with the uncertainty principle.
“That would be a wonderful result if the ultimate reason for the uncertainty principle and the puzzling features of quantum physics are due to some quantum effects of space and time,” Milburn said.
Inspired by the possibility of experimental tests, Milburn and other theorists are expanding on Diósi and Penrose’s basic idea. In a July paper in Physical Review Letters, Blencowe derived an equation for the rate of gravitational decoherence by modeling gravity as a kind of ambient radiation. His equation contains a quantity called the Planck energy, which equals the mass of the smallest possible black hole. “When we see the Planck energy we think quantum gravity,” he said. “So it may be that this calculation is touching on elements of this undiscovered theory of quantum gravity, and if we had one, it would show us that gravity is fundamentally different than other forms of decoherence.”
Stamp is developing what he calls a “correlated path theory” of quantum gravity that pinpoints a possible mathematical mechanism for gravitational decoherence. In traditional quantum mechanics, probabilities of future outcomes are calculated by independently summing the various paths a particle can take, such as its simultaneous trajectories through both slits on a screen. Stamp found that when gravity is included in the calculations, the paths connect. “Gravity basically is the interaction that allows communication between the different paths,” he said. The correlation between paths results once more in decoherence. “No adjustable parameters,” he said. “No wiggle room. These predictions are absolutely definite.”
At meetings and workshops, theorists and experimentalists are working closely to coordinate the various proposals and plans for testing them. They say it’s a mutually motivating situation.
“In the final showdown between quantum mechanics and gravity, our understanding of space and time will be completely changed,” Milburn said. “We’re hoping these experiments will lead the way.”
This article was reprinted on ScientificAmerican.com.

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