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

Zoltán Dienes

Palgrave Macmillan, May 13, 2008 - Philosophy - 170 pages

ttp://books.google.dk/books/about/Understanding_psychology_as_a_science.html?id=LY5WAAAAYAAJ

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 William W. 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

 

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?

By: Natalie Wolchover

October 31, 2013

     

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.

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.”

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.

From Time One: Discover How the Universe Began

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. http://ow.ly/ruwgN

 

New Experiments to Pit Quantum Mechanics Against General Relativity |...

ow.ly

Physicists have devised experiments that can probe the interface between quantum mechanics and general relativity.

Billions and Billions

I wasn't really a Cosmos fan, but I found Sagan's mind a writings remarkable, if you were a fan you'll probably enjoy this:

http://www.youtube.com/watch?v=HZmafy_v8g8&feature=youtu.be

Supernovae may Drive Evolution on Earth

Posted on December 7, 2013 at 6:00 am
By Joe Garland

                         

Image credit: ESO

On Earth, we have an almost incomprehensible array of life. It comes in millions of different forms (the best estimate puts the figure at 8.7 million species, not counting bacteria). What’s more, these organisms are only an addition to the species that have long been extinct. What causes such diversity?

The answer seems rather simple — seemingly random genetic mutations drive evolution. These mutations are the raw materials of genetic variation; without them, evolution could not occur. But what actually drives these random mutations? Well, this is where things get a little complicated; however, new light has been shed on one possible factor – supernovae.


Cosmic rays are an assortment of sub-atomic particles that reach Earth travelling at great speeds (sometimes near the speed of light). These fast moving particles continuously bombard the Earth, and they are thought to primarily come from supernovae explosions.

As these cosmic rays reach our atmosphere they collide with other molecules, producing a shower of other particles that rain down on the surface of Earth. Most of these pass harmlessly through an organism, but some researchers think that some of the the particles may strike through the genetic material inside biological cells and slightly alter their codes. This may produce a direct mutation in the living organism, or produce a mutation in any descendants that it may produce. If this theory is true, then cosmic ray particles will be one of the biggest drivers of evolution, not just on Earth — but everywhere in the Universe!

However, this unusual relationship between distant stellar explosions and evolution on Earth doesn’t end here. In the words of Henrik Svensmark, who heads the research into the relationship between supernovae and evolution, “The biosphere seems to contain a reflection of the sky, in that the evolution of life mirrors the evolution of the Galaxy.” The findings – based on geological and astronomical data – suggest that nearby supernovae have strongly influenced the development of life over the last 500 million years.

Svensmark began by studying open star clusters where there is intense star formation and supernovae activity. He was able to map when supernovae occurred near the solar system over time, and when he compared this with the geological record, he found a remarkable correlation. It seems that when the Sun passed through the spiral arms of the Milky Way, where large stars are most common, life appeared to prosper. Combined with the tectonic activity, these two factors appear to correlate with nearly all of the variations in the diversity of life of the past 500 million years.

Marine fossils (typically invertebrates such as trilobites, as well as plants and microbes) are a very good indicator of what conditions were like, and the diversity of any life that existed at a certain point in time. When the rate of nearby supernovae is high, the level of carbon dioxide is low, and this points to the thought that plant life may have been very high – as it would use up the carbon dioxide. But plants also ‘dislike’ carbon 13, and they leave it behind. This isotope can be seen in the geological record, and the changes in the level of which further provides quantitative data to back up the theory.

There has also been a match between the patterns of particular geological periods – as they start and end with either an increase or decrease in the supernovae rate. Supernovae are thought to cause sea levels to drop, as they appear to coincide with ‘ice ages’ or glacial periods. During this time, a lot of water is stored on the land as snow and ice – so the sea level stops (we call these changes glacial-eustatic). As a result the species that dominate a certain period (be it warmer or colder) changes as each passes.

Overall, the data supports the idea that cosmic-rays are linked to climate change in the long term, and it is these climatic alterations that lead to the biological effects. The link is actually even larger than that between our climate and our own Sun’s activity! It goes to show the extent to which the Universe is intertwined; just because objects are situated many light-years away from one another, they can still have an impact in extremely significant ways.