Saturday, April 30, 2011

Connecting the dark with the light

Just this month, the CDF experiment at Fermilab saw a bump in their data at an energy of 140-150 GeV suggesting that they had seen a new type of particle. But does it really exist and, if so, what is it?

The result was at the 3.2 sigma level, which in statistics means that it is about three standard deviations away from the null hypothesis--or about a 6 in 10,000 chance that the signal is just a statistical fluctuation. That's a small chance but particle physicists have high standards when it comes to this sort of thing.

In particle physics, a 3 sigma result is often described as "evidence" for something but it takes a 5 sigma result to claim "discovery." The trouble is, there are lots of 3 sigma results in particle physics that go away with more data, usually because of some unsuspected systematic error. That doesn't change the likelihood that this result is correct but says that 3 sigma is not actually a discovery, just a promising hint.

[Photo courtesy of Echo Romeo.]

So now we've dealt with the idea that this might not be anything, let's play with a fun speculation advanced by Fermilab's Dan Hooper at today's plenary session at the American Physical Society April meeting.

One thing that physicists know is that it isn't the Higgs particle. But Hooper suggested that the bump could be a new particle representing a new type of force. The particle would generally be described as a Z' (pronounced Z prime) or, equivalently, the force could be called a fifth force, different from electromagnetism, gravity, the weak force, or the strong force.

To make sense, the particle must interact modestly with quarks and extremely weakly with leptons--a so-called leptophobic Z'. But if that is the case, it needs a bunch of other exotic particles to exist or else the Standard Model of particle physics goes haywire. One of those particles would have the properties of a dark matter particle. Furthermore, it would have a mass and cross section just where a bunch of other experiments hint (see our previous story about this).

One role for this Z' could be to mediate between dark matter and the matter we can see--between the dark and the light, so to speak. And that opens up a whole new world of exploration.

Remember that this is just speculation about what the particle could be if it exists but that isn't guaranteed. Expected at the end of the summer is a new analysis that will include about four times the amount of data and that should make the situation much clearer. But wouldn't it be cool if we found a gateway to dark matter in the final year of running of the Tevatron?

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Hinting at dark matter

We haven't seen dark matter yet. We haven't, right? Sitting in a plenary talk at the APS April meeting today I started to have my doubts.

Dan Hooper from Fermilab gave a great overview discussion of the attempts to detect dark matter covering the three major techniques: direct detection, where you see dark matter particles collide with nuclei; indirect detection, where you use telescopes to observe the gamma rays produced by dark matter annihilating; and collider detection, where you create the dark matter in something like the Tevatron or the Large Hadron Collider.

[Photo courtesy of Echo Romeo]

In the discussion, Hooper pointed out the various experiments which have seen hints of dark matter. Of these, only one is claiming to have definitively seen dark matter--the DAMA collaboration, which looks for seasonal variance in a signal representing the amount of dark matter hitting the Earth. Nobody doubts they have seen a signal, there is just debate about whether it is due to dark matter or some other, so far unexplained, effect.

However, there are other experiments which have seen hints of something. That includes CoGeNT, an underground experiment, and the Fermi Gamma-ray Space Telescope. There's even an intriguing hint of how the Tevatron might shed light on the dark matter (see our next post). But where it gets really interesting is that the properties of dark matter in each of these cases is the same. They all seem to have a mass of about 5-10 GeV (a proton is about 1 GeV). Also, their cross sections--the likelihood that they will collide with something--is about the same in each case. The next piece of evidence that would help is if CoGeNT sees a seasonal variation in its results--that data is expected to be released soon.

There is also some suspicions of dark matter observations from the PAMELA satellite but that would not be consistent with these other measurements and has a few potential explanations that don't need dark matter. Then there are experiments like XENON100 which claim to rule out the dark matter explanation for DAMA and CoGeNT.

So what is the situation? We have one claim of dark matter, which hasn't been replicated in other experiments, and two or three other hints that might be dark matter, all coinciding in mass and cross section. Then there are experiments which claim to rule out some of those experimental results. Any of the experimental results by itself can be explained away but taken in concert, the picture looks a bit different.

Just what would discovery of dark matter look like? Well, with all these different experiments looking for it, you'd expect to start to see hints of its existence in them potentially before any could claim discovery. In other words, it would look just like this.

We can't say that we've seen dark matter but might we be able to see say we are seeing the first hints of it? Time will tell and Hooper says that within 5-10 years we will know definitively whether dark matter exists (at least in the form of cold dark matter particles) and have found it if it does.

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Friday, April 29, 2011

Quantum Man

If you happen to be near Anaheim, CA on Monday, you'll get a chance to sit in on a free lecture featuring Lawrence Krauss discussing the life and science of Richard Feynman.



Krauss, one of the country’s leading physicists and science authors, provides a unique perspective on the Nobel Laureate, visionary, and self-described curious character that was Professor Feynman. The lecture takes place Monday, May 2, 7:00 p.m. - 9:00 p.m. at the Hyatt Regency Hotel in Anaheim, California.

More than twenty years after his death, Feynman remains one of the most legendary people in science. His collected lectures and books have inspired a generation of scientists and nonscientists alike with profound insights, humor and awe-inspiring predictions that have expanded the boundaries of science and technology.

Lawrence Krauss is director of the Origins Project at Arizona State University and author of seven books including the wildly popular Physics of Star Trek. His latest book, Quantum Man: Richard Feynman’s Life in Science, offers fresh insight into Feynman’s revolutionary contributions bridging the gap between two of the most powerful theories in physics – special relativity and quantum mechanics.

Here's how Publishers Weekly feels about Quantum Man: Richard Feynman’s Life in Science

“Physicist Richard Feynman has a reputation as a bongo-playing, hard-partying, flamboyant Nobel Prize laureate for his work on quantum electrodynamics theory, but this tends to obscure the fact that he was a brilliant thinker who continued making contributions to science until his death in 1988. He foresaw new directions in science that have begun to produce practical applications only in the last decade: nanotechnology, atomic-scale biology like the manipulation of DNA, lasers to move individual atoms, and quantum engineering. In the 1960s, Feynman entered the field of quantum gravity and created important tools and techniques for scientists studying black holes and gravity waves. Author Krauss (The Physics of Star Trek), an MIT-trained physicist, doesn't necessarily break new ground in this biography, but Krauss excels in his ability, like Feynman himself, to make complicated physics comprehensible. He incorporates Feynman's lectures and quotes several of the late physicist's colleagues to aid him in this process. This book is highly recommended for readers who want to get to know one of the preeminent scientists of the 20th century.”

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Thursday, April 28, 2011

Royal Weddings in Space!

This article made me laugh when I read it last week. I was lamenting the fact that TV viewers might have to choose between watching the royal wedding or the space shuttle launch tomorrow. Then a colleague of mine pointed out that people who watch one might not necessarily watch the other. What a shame, I thought. How can we remedy that? There's only one solution: Royal weddings in space!

[What Prince William & Kate Middleton's nuptials aboard the International Space Station might look like.]

What might be different about a royal wedding in space? First off, the princess-to-be wouldn't have to worry about whether to arrive by car or carriage: She would arrive by space shuttle! (Or Soyuz capsule.)

Instead of walking gracefully down the aisle, Kate and her bridesmaids could float from one module of the International Space Station (ISS) to the other.

If the wedding is 90 minutes long, the ISS will complete one orbit around the Earth and the whole world can be a part of the ceremony.

The groom better not get nervous. If he drops the ring, it's not just a simple matter of bending down and picking it up. It could be lost forever.

A post-wedding kiss in the cupola is so much better than on a balcony.

If they go outside to toss the bouquet and no one catches it, it would go into orbit.

A post-wedding toast might be difficult. Do they make champagne in those little orange juice pouches?

The paparazzi would have a tough time snapping pictures...they would need telescopes.

Carrying the bride over the threshold would be much easier.

[What the official wedding portrait might look like.]

The royal wedding takes place early in the morning on the East Coast of the U.S. - 6 a.m. EDT. STS-134 is set to launch tomorrow at 3:47 p.m. EDT. Why not watch 'em both? In case the royal wedding or the idea of launching on top of a rocket makes you sick, don't worry, there's something for you too!

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Wednesday, April 27, 2011

Small insects paddle through air

Just as a kayaker uses a paddle to push his or her kayak through the water, small insects use their wings to push themselves through the air, using the force of drag. Unlike birds who use the force of lift to fly through the air, insects swim through the air, pushing it behind them like a fish pushes aside water.


[High speed video (8000 images a second or 40 frames per wing beat) of free-flying mosquitoes; filmed at Cornell University in 2009.]

Birds and airplanes use lift - the pressure difference between the top and bottom of a wing - to fly through the air. Most animals going through water, though, use the force of drag to propel themselves along: they reach out and push the water behind them.

To small animals, like tiny flying insects, the air that makes up Earth's atmosphere can feel thick and heavy like water feels to humans. They need more of a push than lift alone to move through the thick atmosphere.

Researchers Leif Ristroph, John Guckenheimer, Z. Jane Wang and Itai Cohen, of Cornell University, and Attila J. Bergou, of Brown University, analyzed 140 movies of fruit flies (Drosophila melanogaster) moving in forward flight.

What they found is that small insects push air aside with their wings as a kayak paddle pushes aside water. Imagine a kayak paddle entering the water at a low angle of attack - fairly horizontal relative to the water. Then imagine the kayaker pushing it backwards: it becomes more vertical in the water, pushing more water aside. Small insects' wings do the same thing, changing their angle of attack to push themselves through the air.

The wing's movement forward is at a low angle of attack, and there is little drag produced. Once it moves back, however, it changes to a higher angle of attack, producing more drag and pushing away more air.

The angle can also be changed to produce the same amount of drag going both backward and forward enabling the insect to hover like a swimmer uses his or her arms to tread water. The scientists created a computer model of the insect's wings and saw the same behavior reproduced on the computer.

Just for good measure, they also used their computer model to see how the density of the fluid surrounding the insect would affect its flight, simulating flight through water and through the Martian atmosphere. Martian air is less dense than air on Earth while water is a thousand times more dense than air.

Because density affects both the forward movement and the drag forces equally, the velocity was relatively unchanged for both scenarios. Flight speeds through the Martian atmosphere were about the same as on Earth and flight through water was slightly slower.

The authors argue that this research is evidence there may be an evolutionary link between modern insects and their swimming ancestors. They theorize the insects' swimming behavior in air may be left over from their predecessors' swimming behavior in water.

This research was published yesterday in the APS journal Physical Review Letters.

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Tuesday, April 26, 2011

More Superconductivity at the March Meeting

[In this Physicsworld.com video, Nobel Laureate Frank Wilczek talks about superconductors, topological insulators, quantum computers and more at the 2011 APS March Meeting.]

Nobel Laureate Frank Wilczek, of the Massachusetts Institute of Technology, talks with Physicsworld.com's Hamish Johnston at the 2011 APS March Meeting about the crossover between various physics disciplines. They also discussed the difficulties in solving problems with high temperature superconductors.

"It's hard to know what's going on in high temperature superconductivity," Wilczek said. "People have ideas that seem entirely disconnected from each other." Wilczek shared the 2004 Nobel Prize for Physics with David J. Gross and H. David Politzer for their discovery with the quantum field theory called quantum chromodynamics.

The centennial of the discovery of superconductivity was celebrated at the March Meeting. For more, check out the original Physicsworld.com article.
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Monday, April 25, 2011

Higgs?

"We know everything about the Higgs boson," Rolf-Dieter Heuer said. "We just don't know if it exists." The director-general of CERN (the European Organization for Nuclear Research) spoke confidently to a group at the University of Maryland April 12 about the hunt for the elusive particle that keeps the Large Hadron Collider (LHC) busy. Over the weekend, rumors surfaced that the ATLAS particle detector at the LHC may have detected the Higgs for the first time.

[The ATLAS experiment as it appeared in November 2005.]

Heuer spoke to a crowd in the large physics lecture hall at the University of Maryland. He gave a status update of everything going on at CERN and explained why the Higgs is such a big deal.

"The cornerstone of the standard model is missing," Heuer said. "We don't know how to generate mass."

The standard model of particle physics says there are 17 elementary particles that make up matter. Sixteen have been observed but one, the one that explains why matter has mass, the one known as the Higgs boson, has yet to be found.

The ATLAS experiment, one of four particle detectors at the LHC, records collisions between particles smashed together in the collider.

On Thursday, an anonymous poster known as "Higgs?" posted an internal ATLAS note in the comments section of the blog Not Even Wrong suggesting ATLAS had found something that could be the Higgs. The note describes the possible detection of the Higgs at an energy where it was not expected to appear.

The note and speculation about it spread like wildfire on the Internet over the weekend, with some thinking 'This is it - the Higgs has been found!' and others saying this is nothing but a routine memo.

CERN hasn't put out any official statements that I can find, but James Gillies, a CERN spokesman, told WIRED Magazine that, "
It’s way, way too early to say if there’s anything in it or not," adding that, "The vast majority of these notes get knocked down before they ever see the light of day."

We'll have to wait and see what comes of it. An internal note is a long way from being a confirmed result, so there is still a long road ahead. Stay tuned...

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Friday, April 22, 2011

Happy Earth Day!

Happy Earth Day! Don't we live on a beautiful planet?

[Earth: The Water Planet. Photo credit: NASA]

Of all the (eight, sadly) planets in our solar system, ours is the only one parked at just the right distance from the sun to support life. This distance is called the Goldilock's Zone - where it's not too hot (close to the sun) and it's not too cold (far away from the sun) but instead (you guessed it) just right for supporting life.

The Goldilock's Zone, also known as the less exciting "habitable zone," is the distance from a star where a planet like Earth can keep liquid water on its surface without it freezing or boiling away, enabling it to support carbon-based life like that on Earth. This zone exists both within a planetary system, like our solar system, and also within a galaxy.

The Zone is not the same for every planetary system. A star that shines 25 percent as brightly as the sun will have a habitable zone that's twice as close to the star as we are to the sun. Planets in that smaller-star system have to be closer to the star to receive enough warmth to keep water in a liquid state. The opposite is true for stars larger than the sun, where planets would need to be further away to prevent water from boiling and evaporating away.

An example of a planet thought to be in a Goldilock's Zone is Gliese 581 g. It orbits the star Gliese 581, part of the constellation Libra, 20.5 light-years away. In 2008, a group from the social networking site Bebo sent a "Message from Earth" in the form of a digital time capsule to Gliese 581 g. The messages were converted into binary code - a series of zeros and ones - and were sent towards the planet by a radio telescope in the Ukraine. The messages zipped by the moon after just 1.7 seconds and Mars after four minutes. It will pass by Gliese 581 g in 2029. Another message, "Hello from Earth" was sent in 2009. Other messages attempting to alert other potential life forms to our presence have been sent out as well.

Both planets and moons are considered when it comes to heavenly bodies that can support life within a Goldilock's Zone. How many planets or moons that could support life have been found thus far? In February, it was announced that NASA's Kepler satellite, which hunts for planets, had found over 1,200 planets, 54 of which could be in the Goldilock's Zone. As exciting as this is, the scientists say it will take years to confirm whether or not these 54 candidates are actually planets. We'll have to wait and see.

Oh, and those messages sent to Gliese 581 g? Don't hold your breath waiting for a reply. If the messages are received and intelligent life does respond, we won't hear back for another 40 years - the time it takes for our message to be received (20 years) and the time it would take for a return message to arrive (another 20 years). In the meantime, you might want to thank your lucky stars that you're on the one known and proven planet that supports life as we know it - Earth.

[The infamous original portrait of Earth, as seen by Apollo 17. Photo credit: NASA]


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Thursday, April 21, 2011

Michele Dufault

It's always sad to hear about tragedy within your community, especially when it involves someone young and promising. We at PhysicsBuzz and Physics Central are very saddened by the death of Yale University physics and astronomy undergrad Michele Dufault.

Dufault, a senior at Yale, was working alone on her senior project in a chemistry laboratory late at night on April 12 when her hair apparently became caught in a lathe - a rotating machine that shapes wood or metal. It is believed she was pulled into the machine and died of asphyxia. She was discovered in the lab by other students and emergency workers arrived sometime near 2:30 a.m.

Dufault was very involved in several physics groups and had worked on projects for the Woods Hole Oceanographic Institution, where she worked on underwater robotic vehicles, and NASA,
where she worked on a plasma physics experiment.

The lab where Dufault was working, Sterling Chemistry Laboratory, was closed for a time following the accident and the Occupational Health and Safety Administration is investigating the accident.

Our thoughts go out to the families, friends and colleagues of Dufault and to the entire Yale community at the time of this tragic loss.
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Wednesday, April 20, 2011

Microclimates: Managing Weather From Street To Street

Considering cities -- not just individual buildings -- improves energy-efficient design.



Walk through a city and the weather may change from block to block, often in startling ways.

Step into a canyon of tall buildings and sunlight disappears. Winds arise seemingly from nowhere. The air smells completely different on a balcony and in the street.

City buildings create their own microclimates. Ignoring these variations can make life uncomfortable for inhabitants and prevent buildings from achieving true energy efficiency, according to Evyatar Erell, a professor of architecture at Israel's Ben-Gurion University of the Negev.

"Even when architects design a green building, it may not make the best use of the environment because other buildings get in the way," he said.

Erell is the lead author of a new book, "Urban Microclimate: Designing the Spaces Between Buildings", that shows how to apply climatology to create greener, more livable cities.

"What we're seeing with this book is an appreciation of architectural scales beyond a building's individual plot. This is very topical, because when you talk about mitigating greenhouse emissions, buildings are a big slice of the pie," noted James Voogt, a professor of geography at University of Western Ontario, in London, Canada.

Erell began working with microclimates in 1986, when he joined Ben-Gurion's Sede Boqer campus in the middle of the Negev Desert. He was part of the team that built Neve Zin, the first Israeli settlement designed from scratch to manage the community's own microclimate.

The architects and planners laid out Neve Zin to handle summer daytime temperatures above 100 degrees F, much cooler nights, and winter frosts. Residents built homes with large southern windows. These let in the low winter sun and passively heat the house. During summers, residents close the window's external blinds to block the sun and prevent overheating.

The solar approach worked because planners positioned buildings so that no home could throw a shadow on its neighbors' southern windows. Winding streets slowed cars and prevented desert dust from blasting down their length. High, vine-covered concrete walls defined paths and protected pedestrians from the summer sun.

Those pathways have their urban counterparts, the deep canyons formed by tall buildings. Skyscrapers not only block direct sunlight for all but a few hours per day but also create vortices, the corkscrew circulation of air in a fixed area.

"Sometimes you'll see a vortex with dried leaves spinning around and around and not going anywhere. This trapped wind affects just about every aspect of micrometeorology, from air temperature and humidity to air quality," said Erell.

Vortices can also trap pollutants at street level, preventing them from escaping upwards into the atmosphere. This worsens air quality for pedestrians.

The ratio of building height to street width is a good indicator of airflow patterns, Erell explained. Lofty buildings and narrow streets usually reduce air speed and generate vortices. In cold climates, this keeps warmer air recirculating at street level. Yet those same tall buildings can redirect winds at rooftop level down their sides and into the street, creating cold, powerful blasts.

Where buildings are not as tall or streets are wider, air circulates more freely. This allows pleasant breezes to circulate and whisk away pollutants.

While no urban planner is likely to recommend knocking down a street of skyscrapers to improve street comfort, they can use microclimate principles to revitalize neighborhoods.

An example is Singapore's Clarke Quay, a former warehouse district. "The government decided to renovate the shops and restaurants, and improve the microclimate instead of building an enclosed shopping mall," Erell said.

The site is tropical, hot and humid under a blazing sun with torrential downpours during the rainy season. The designers added trees and large steel frames with umbrella-like canopies that stretched across the street above the warehouses. These protect shoppers from sun and rain. A mechanical ventilation system creates a gentle breeze.

British architectural engineering firm Arup finalized the design by using mathematical models that predicted how each item would affect the quay's microclimate. This enabled the company to properly size and space both the canopies and air blowers.

"I've walked there during the day, and it is reasonably comfortable – certainly more so than other places nearby – even without air conditioning," Erell said.

Erell believes that models are the future of microclimate planning. They would enable planners to judge how different elements would affect complex projects.

In fact, Erell has designed his own model to predict street temperatures. Yet he is the first to say that it takes more than guidelines and computer models to create a livable environment.

"It's not like having a recipe, where you follow all the steps and get a good cake. We start with principles and tools, but you can put them together in many different ways," he said.

Alan S. Brown
Inside Science News Service

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Tuesday, April 19, 2011

The New School of Superconductors

[Physicsworld.com video about superconductivity from the 2011 APS March Meeting]

In 2008, the discovery of iron-based, high-temperature superconductors excited scientists and a new class of superconductors was created to compete with the old. Laura H Green of the University of Illinois Urbana-Champaign spoke with Physicsworld.com's Joe McEntee at the 2011 APS March Meeting about why so much excitement continues to come out of this discovery.

Physicists celebrated the centennial of the discovery of superconductors at this year's March Meeting held in Dallas.

For more, check out the original physicsworld.com article.
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Monday, April 18, 2011

Snake venom: Groovy, baby!

A team of six scientists from the University of Massachusetts Lowell and the Technische Universit√§t M√ľnchen (the Technical University of Munich, Germany) used biophysics to explain how snakes use grooved fangs to deposit venom in victims.

[These images show grooves (white arrows) on the fangs of (A) a banded snake (Bothryum lentiginosum) and (B) a mangrove snake (Boiga dendrophila) . In (B), the fang is embedded in the tissue of the snake's prey with only the base of the fang visible. The prey's tissue has separated from the fang, creating a venom tube (yellow arrow) with three walls defined by the fang and one wall defined by the tissue.]

Some snakes have tubing inside their fangs that distributes globules of venom in prey like a syringe. Most venomous snakes, however, along with many other reptiles, deposit venom in prey via a groove that runs down the middle of each fang.

Bruce Young, from the University of Massachusetts Lowell and his German colleagues, Florian Herzog, Paul Friedel, Sebastian Rammensee, Andreas Bausch and J. Leo van Hemmen, all of the Technical University of Munich, studied how the viscosity of the venom and the fang-prey interaction affected the venom delivery during a snake bite.

Snake venom is a non-Newtonian fluid, meaning it behaves sometimes more like a solid and sometimes more like a liquid. Examples of other non-Newtonian fluids include ketchup, oobleck - the two parts corn starch, one part water gooey concoction - and Silly Putty.

The flow of liquids is affected by liquids' interactions with surfaces. How quickly they slide against a surface is called viscosity. Water has a low viscosity - it flows quickly over substances. Honey, on the other hand, has a high viscosity. It's stickier and flows more slowly, behaving almost like a solid. Snake venom also has a high viscosity, flowing about 500 times more slowly than water. Even so, it's fast enough to flow down a fang and into a victim at a pace of about one centimeter per second (compared to water which flows as fast as 7,000 centimeters a second).

[Sequential photographs taken over a period of less than 400 milliseconds show a drop of snake venom penetrating a puncture wound in a euthanized lizard.]

As a non-Newtonian fluid, snake venom changes its viscosity. When sliding down a fang, the venom has a high viscosity, clinging to the fang as the snake prepares to bite. When a snake sinks its fangs into a victim, however, the three walls of the grooved fang are sealed by a fourth wall - the prey's tissue - forming a hollow venom tube that leads down into the prey's deep tissue. Only in that deep tissue, and not at the surface, can the venom be effective.

The increase in surface area (by the addition of a fourth wall) combined with the friction caused by the fang sliding into the tissue changes the viscosity of the venom in the groove. It becomes less viscous, flowing faster, and accelerates into the prey, usually in less than a second.

Snakes with grooved fangs hold on to and often repeatedly penetrate their prey in order to give the slower-moving venom time to set in. This is in contrast to snakes with tubular fangs that deposit venom rapidly.

The authors' research is due to appear in the APS Physical Review Letters journal.

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Friday, April 15, 2011

Folding paper: How hard can it be?

There's not much to it: Folding paper. So what's the big deal with folding a piece of paper in half umpteen times? It's a very big deal, apparently. Don't believe me? Try it.


[Fifteen students from St. Mark's School in Southborough, Mass., fold 13,000 ft. of toilet paper in half 13 times.]

A group of fifteen high school students from St. Mark's School in Southborough, Mass., claimed to have set a new record when they folded a 13,000 ft. roll of single-ply toilet paper in half 13 times - beating the former 12-fold record. Led by teacher James Tanton, the students worked with the Massachusetts Institute of Technology origami club, OrigaMIT, to help gain access to MIT's Infinite Corridor (an 825-foot-long hallway connecting several campus buildings) where they accomplished their feat.

In the video though, it's hard to tell how well the team actually accomplished the 13th fold. As I watch the video, I can't help thinking, "How hard can it be?" To find out, I folded a piece of printer paper. It didn't go so well...

[8.5" x 11" printer paper folded 6 times]

As you can see from the photos above, I was only able to fold it in half 6 times. So then I tried again with a piece of tissue paper:

[Tissue paper folded 9 times]

This time, I was able to get to nine folds, though you can see by the seventh fold, I had to hold the paper down to maintain the fold.

After that little experiment, it's much easier for me to understand why 13 folds is such a big deal.

Though paper is quite slim - the average slice of printer paper is but 0.1 mm thick - its thickness adds up quickly when folded. Each time a piece of paper is folded in half, its height doubles. By the time paper has been folded 12 times (the previous record), it is 16 inches tall. Double that height by folding it once more (a thirteenth time) and it will be two and a half feet tall.

Imagine being able to fold a piece of paper in half 42 times (just over three times as many folds as the St. Mark's kids managed). It would be tall enough to reach the Moon.

[The St. Mark's group struggling with their 13th fold.]

James Tanton, the students' teacher, said they will try for 13 folds again next year using 24,000 ft. of toilet paper in the hopes of creating a fold that can stand on its own.

All I can think now is that if I had 24,000 ft. of toilet paper, I would never have to go shopping for it again.


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Thursday, April 14, 2011

May the Force be Withheld

The Chinese government has placed a ban on television programming portraying time travel (think of shows like "Dr. Who" and "Star Trek"), saying that going back in time to alter events is against the Chinese spirit. Its State Administration of Radio Film and Television has singled out shows portraying time travel, but the language used could extend to other science fiction staples as well. Which makes us wonder, how will China inspire its young scientists?


Here's a horrible Google translation of one paragraph from the original Chinese guidelines published on March 31:
In recent months, the national report prepared by the general trend is good repertoire, but we also found signs of some incorrect creation: individual declaration of the record through the supernatural drama and drama, random compilation of myths, bizarre plots, bizarre, absurd way, and even rendering of feudal superstition, fatalism and reincarnation, value orientation ambiguity, the lack of significance of positive thinking. In this regard, I hope the correct creative idea production organizations, to carry forward the fine traditional Chinese culture, efforts to improve the ideological and artistic quality drama.

CNN translated it a little better, saying the Chinese are banning "fantasy, time-travel, random compilations of mythical stories, bizarre plots, absurd techniques, even propagating feudal superstitions, fatalism and reincarnation, ambiguous moral lessons, and a lack of positive thinking." It's unclear whether this is in response to one show or what triggered the ban in the first place.

Though most reports focus on forbidding the portrayal of time travel, the wording up top leaves us to wonder how much, if any, science fiction can be portrayed. I don't think anyone can argue with me when I say the Star Wars series included most of the banned material above, particularly "random compilations of mythical stories."

Does that mean no Spike marathons of the Star Wars trilogies in China?

If so, how will young Chinese children be inspired about science? You could argue that many youngsters get interested in science through science fiction. Bill Nye the Science Guy is great, but he's no Obi Wan.

In the same breath that they discourage portrayal of the material above - discourage the portrayal of time travel and altering past events - the state also encouraged creating works that paint a true picture of the Chinese revolution and establishment of the ruling communist party. Truth, though, has long been acknowledged to be open to interpretation to the Chinese:
In accordance with the central spirit, to celebrate the 90th anniversary of the establishment of the Chinese Communist Party at all levels should actively preparing for the TV, to introduce a number of vivid reproduction of the Chinese revolution, construction and reform and opening up historical picture, a true reflection of the party under the leadership of people of all the great rejuvenation of struggle to achieve national good works, for the 90th anniversary of founding gift.
Ultimately, we can only hope that youngsters across the globe will be free to use their imaginations and be inspired to dream up the inventions and ideas of the future. If science fiction helps to create the next Albert Einstein, is that really such a bad thing?

Furthermore, why would China toy with potentially hindering interest in science when it is on track to overtake the U.S. in science output very soon?

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Wednesday, April 13, 2011

Time to Update the Table of the Elements

It seems like something we should do periodically (bada boom).



Brother can you spare some argentum? Maybe you could drop some in my stannum cup. Then I'd be totally aurum. Never heard of any of that stuff? I'd guess you probably have, just not in the words of the long dead Latin language.

Silver (argentum), tin (stannum) and gold (aurum) are pretty familiar materials to most of us, and if you've taken chemistry you've likely used the Latin abbreviations Ag, Sn, and Au without worrying too much about the odd choices for the shortened handles of these and and a few other elements like iron (Fe for ferrum), potassium (K for kalium) or lead (Pb for plumbum).

But I've had just about enough of this silliness. All roads may have once lead to Rome (plumbumed to Rome?), but no more. It might mean reprinting a few chemistry texts, but we'll need to do that as we work to eliminate Avogadro's constant anyway.

Just to get things rolling here are my suggestions for abbreviations for the Latin-named elements.

Sodium - So

Potassium - Pm Ps

Iron - Io

Copper - Cp

Silver - Sv

Tin - T

Antimony - At An

Tungsten - Tg

Gold - G

Mercury - Mc

Lead - L

There, that wasn't so hard!

Some of the new abbreviations are kind of awkward because the more sensible versions were taken by other elements. The fact that we have I for iodine, Ir for iridium, and In for indium left only Io for Iron. I would prefer for Io to stand for Iodine and I for Iron. Making that switch, however, would be risky because there would be no obvious way of knowing which element you're talking about, if you don't know when or where the chemical formula you're dealing with was first written down.

Oh well, nothing's perfect, but we can at least try to make things better. And an updated periodic table would definitely be better!


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Tuesday, April 12, 2011

100 Years of Superconductivity

[Physicsworld.com video about superconductivity from the 2011 APS March Meeting]

Paul Michael Grant was a physicist working for IBM when his colleagues in Zurich discovered the first high-temperature superconductor in 1986. Grant, who worked for IBM's Almaden labs in California, has become a proponent of using superconductors for electricity distribution since leaving IBM in 1993.

Physicsworld.com's Hamish Johnston spoke with Grant at the 2011 APS March Meeting in Dallas about the commercial applications of superconductors. The centennial of the discovery of the superconductor was celebrated at this year's meeting.

For more, check out the original physicsworld.com article.
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"First Orbit" Shows Man's First Voyage Into Space

Fifty years ago today, Yuri Gagarin became the first human to travel to space. To share his voyage with the world, one filmmaker has made an experimental documentary - "First Orbit" - to share with the world:

[First Orbit available for free on YouTube]

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Monday, April 11, 2011

Yuri Gagarin & the First Orbit

Yuri Gagarin was the first human to ever enter space on top of a rocket, simultaneously becoming the first man to go into space and the first to ever go into orbit. Unfortunately, he made for a poor tourist, having no video camera on that first historic voyage. Fifty years later, one filmmaker is helping the world to see what Gagarin might have seen a half century ago.


[First Orbit Trailer]

Chris Riley, co-director of "In the Shadow of the Moon" has collaborated with the European Space Agency (ESA) to produce the experimental documentary "First Orbit" - a compilation of video shot from the International Space Station (ISS) and original Soviet video from Gagarin's flight.

"I just kind of suddenly thought 'Wouldn't it be great to film a view that Gagarin had?'" Riley said in a BBC interview. "I always remembered the sad reality of there not being any footage of it."

Italian astronaut Paolo Nespoli - already an accomplished space photographer - was recruited to film Gagarin's journey from the newly-installed cupola aboard the ISS. Permission was obtained to use 15 minutes of the astronaut's time to set up and tear down the camera that filmed the same 90 minute orbit Gagarin would have seen.

"It became a maths problem," Riley said in his interview, describing the challenge of tracing the cosmonaut's original path. He had to consider the orbit, the inclination of the orbit and the differing altitudes.

The ISS cruises at an altitude that varies from about 219 to 221 miles above the Earth's surface. On his flight, Gagarin's altitude varied from 105 to 203 miles. Though Gagarin never flew quite as high as the ISS, the orbital altitudes were still pretty close, a difference of a few miles making little impact on the view from space.

Being close to the right inclination was another concern for the director. The orbital inclination is the angle between a reference plane - in this case, a flat disc defined by the equator - and an axis, like the one running from the North Pole to the South Pole through the center of the Earth. Spacecraft don't always orbit over the equator or pole-over-pole. Instead, they often orbit at a path that might go across the southern tip of South American and then back up across Egypt and into Siberia, as Gagarin did.

If you drew a line on a globe representing his flight path you would see that it crossed the equator twice, heading near each of the Poles but never quite reaching them. Gagarin was on an orbital inclination of 65 degrees, taking him near, but not quite to, each of the Poles. The ISS's inclination is nearer to 52 degrees, keeping it on a circular path around the Earth that sticks closer to the equator than Gagarin did.

Even so, the ISS's inclination was close enough to Gagarin's to allow the director to film almost exactly what Gagarin saw. Because the ISS's orbit varies, Riley had the chance to film the Gagarin orbit about once a week. But the director also wanted to film an orbit at the same time of day Gagarin would have seen on his flight. That orbit, it turned out, came around only once every six weeks.

Riley got his shot, and after some back and forth with the Russian government, got a copy of the audio from Gagarin's flight. The emotion in the cosmonaut's voice, Riley said, really makes the film come together.

Lastly, Riley was able to do it all for free, making the film free to the world. That was the plan from the beginning, Riley said, to give away the film "for all mankind" to celebrate the world's first manned flight into space.

The film premiers tomorrow, on the 50th anniversary of the Vostok 1 flight. It will be broadcast on YouTube when the clock strikes midnight at the International Date Line. It will also be broadcast at Yuri's Night events around the globe.

[Gagarin's Vostok 1 capsule on display at the RKK Energiya Museum near Moscow.]

For details on attending a Yuri's Night event, click here.
For details on how to watch the video on YouTube, click here.

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Friday, April 08, 2011

Music Review: Resonance: Music from the ATLAS Experiment

If music is audible mathematics, then it makes sense that people who studied a lot of math would connect through music. That's what happened at the ATLAS experiment in Switzerland where physicists, technicians, and engineers spent their free time in jam sessions when away from the world's largest particle collider (the LHC).


["The ATLAS Boogie" by the Canettes Blues Band music video]

Rock, blues, classical, heavy metal and folk: These are just a handful of the musical genres represented on the two "Resonance: Music from the ATLAS Experiment" CDs.

The CDs were recorded by employees working on the ATLAS project on the Large Hadron Collider (LHC) at CERN, the European Organization for Nuclear Research, in Geneva, Switzerland.


[Behind the scenes video on the making of 'Resonance"]

Musical numbers include both original songs and covers recorded by 19 different artists and groups including Squirrelheads in Gravy, The Collider Trio, and even piano soloist Fabiola Gianotti, the head of ATLAS.

The CDs are a collection of recordings arranged alphabetically by artist, so the songs jump from heavy metal to classical to rock and back to classical. In other words, it's not the kind of CD you would normally pop into your stereo and just listen to.

Still, the music is great and the eclectic gumbo of songs makes for a sensuous sampling of the cultural mash-up that is the ATLAS group.

What's more, proceeds from the CD go to charity, specifically to the Happy Children's Home in Nepal. The recently-constructed orphanage is already home to four children and is getting ready to welcome four more, according to their website.

The ATLAS experiment (the project at the LHC, not the one in the recording studio) is a particle detector looking for signs of new physics that could help us understand better how our Universe was formed.

ATLAS records collisions between particles smashed together in the LHC. It could one day detect the legendary Higgs boson - the hypothetical elementary particle that the standard model of particle physics says must exist. In the standard model, the Higgs boson is the particle that gives all other elementary particles mass. Finding it would revolutionize physics. So far the Higgs has eluded scientists. (According to a recent NYTimes story, it might have just been found, though the consensus says otherwise).

To buy the CDs and accompanying DVD, go to the Resonance website. There, you can preview each of the 36 songs, including the hilarious and sadly true "Points of Order" on CD1, and order the CD-DVD set. The CD set (but not the DVD) can also be downloaded online from iTunes, amazon.co.uk and a few other websites.

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Wednesday, April 06, 2011

European Settlers Not The First To Alter American Landscape

Native Americans on the East Coast dramatically changed the landscape by farming well before the first Europeans arrived.

(ISNS) -- One of the great American myths claims that before Europeans colonists settled in North America, Native Americans existed in total harmony with nature, surviving on the renewable bounty that the continent's natural environment provided and altering little of the surrounding landscapes. They were America’s first environmentalists and the land they lived in remained unspoiled.

But that is not entirely true.

Research by scientists at Baylor University, the Smithsonian Institution, and Temple University has found that the Native Americans who lived in the Delaware Valley, the river valley that separates New Jersey from Pennsylvania, dramatically altered its terrain with their farming. They cleared forests and increased the number of floods.

“From the period 1000-1600 A.D., a few hundred years before European colonization, there was this episode of strong, more frequent flooding that coincides with increase in prehistoric land use,” said Gary Stinchcomb, a doctoral student at Baylor and lead author of the study. “We also find increasing [numbers of] maize kernels and we also find more grasses at the site.”

While the alteration in the landscape was hardly in the league with what the colonists did later -- the pre-colonial population was never very large -- the impact was not insignificant and the alterations continued until the Native Americans left the valley in the early 18th century.

Another myth is that the Eastern part of North America, particularly the mid-Atlantic states and the Northeast, were completely forested. That is also likely not true as the Native Americans had to clear the forest to make way for their crops, and corn was grown almost everywhere along the East Coast.

The paper appears on-line in the journal Geology.

The Native Americans in the area were called Delawares by Europeans, called them-selves Lenni Lenape and are now virtually extinct. They moved out of the area before the American Revolution, leaving behind only place names. The few remaining Le-nape have gone to Canada or been absorbed into the Cherokee Nation in Oklahoma, and the last native speaker died decades ago.

Stinchcomb said the researchers analyzed a range of material as part of their study, including: maize kernels deposited by the floods at archeological sites in the area, carbon dating, geochemical signatures of carbon, artifacts and bodies called phytoliths or plant stones which are small silica bodies found in many plants, especially grass and maize. The phytoliths give researchers a picture of what types of plants were in the area.

The researchers found that during the period archeologists call the Late Woodland, the 500 or so years before the European colonization, the number of agricultural sites in the valley grew dramatically as the Native Americans greatly increased land use.

While a population increase could account for some of the expansion, a more likely scenario is increased agriculture.

According to Dean Snow, professor of archeological anthropology at Pennsylvania State University, the Lenape depended on deer hides for clothing, which motivated hunters to follow the wanderings of deer throughout the valley. They always returned to their villages, where the crops were being raised. If the deer moved, the Lenape and their farms and villages moved with them.

The researchers also looked at sedimentation rates or flooding in the river valley and flood plain. They found an increase in the same time period, Stinchcomb said, and that appeared to be true all along the river valley.

Correlation does not equal causation, but Stinchcomb said that “this data suggests that as Native Americans practiced more intensive farming, they increased the magnitude and frequency of flooding in the river valleys.”

That the Lenape affected the environment was known before -- Native Americans did not always act as good stewards of the land as asserted by mythology -- but the discovery of the increased flooding was new, Snow said.

To plant their crops, the Lenape had to chop down trees, and anecdotal evidence supports that conclusion. Early colonists reported finding huge tracts of land in the river valleys that had apparently been cleared. They, of course, then proceeded to clear the rest.

The finding also helps resolve an old debate among anthropologists -- now somewhat muted -- over just how agricultural the Lenape were. According to this finding, agriculture was a major factor in their lives, Snow said.

The impact of the Lenape’s farming however has a broader, semantic result.

“Our streams prior to European colonization are not, by definition, natural. They probably have been tampered with,” Stinchcomb said.

By Joel N. Shurkin
Inside Science News Service

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Monday, April 04, 2011

Why is it so hard to find flight 447's black boxes?

The French government announced today that more bodies and wreckage from the Air France flight 447 crash off the coast of Brazil had been found almost two years after the crash. The critical pieces of the puzzle, the plane's flight data recorders - or black boxes - are still missing, however. But why are they so hard to find?

[Flight 447's vertical stabilizer (tail fin), recovered in 2009.]

The wreckage from flight 447, which crashed in the Atlantic Ocean off the coast of Brazil in June 2009, is scattered over mountainous ocean floor at depths from 12,500 - 13,000 feet, or around 2.5 miles. Though that doesn't sound very deep, especially when you consider that modern airliners often cruise at three times that height, it's far too deep for scuba divers or naval submarines to explore.

For every 33 feet you descend under water, the atmospheric pressure pushing down on you increases by 100 percent. At the surface, every person and object has 14.7 pounds per square inch of air pressure pressing down on him or her. That pressure feels normal to us, but once it is increased or decreased, it starts to cause problems.

Boyle's law tells us that as the pressure doubles, the volume decreases by half (assuming there's no change in temperature). If, for example, we pulled a party balloon under water, at 33 feet - where the atmospheric pressure is doubled - the balloon would be half as big as it was at the surface. Drag it down another 33 feet and it would shrink in half again. Human's lungs are a lot like a balloon. At around 100 feet, humans reach the limit of how much pressure their lungs can stand.

Imagine what it is like at 12,500 feet, where the wreckage is scattered. Even modern naval submarines can't stand the pressure at that depth. They call it a day at around 1,000 feet where the pressure is over 30 times the surface pressure. Beyond that, they could be crushed like an empty soda can.

At the wreck site, the pressure is almost 400 times the pressure at the surface. To survey the sea floor at 12,500 feet below the surface, a special mini submarine called a submersible is needed. Submersibles have a limited range and can only stay under water for hours at a time so they usually work in conjunction with another vessel - a ship or a larger submarine.

A yellow submersible called Nautile, who previously surveyed the Titanic wreckage, helped originally locate flight 447 wreckage in 2009. (The Titanic wreckage is also at a depth of about 12,500 feet.) A similar sub, called Alvin, was also used to explore the Titanic wreckage when the ship was discovered. Though it seems impossible, the tiny sub is protected by a titanium pressure hull just 2 inches thick. Both subs carry 3 explorers.

The sub that found the latest wreckage was an unmanned sub called a REMUS 6000. The REMUS 6000, with no human occupants, can travel a little faster and a little longer than Nautile or Alvin, but even it can explore for only 22 hours at a time, limited by battery life.

A deep, dark environment and the special tools needed to explore it make searching for anything at 2.5 miles under the sea a difficult task. There's hope, after finding an engine and landing gear, that the black boxes may yet be found, and help solve the mystery of what really happened to flight 447. Even if they are found, it's anyone's guess whether the boxes will have survived two years of crushing pressure in a corrosive seawater environment.

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Friday, April 01, 2011

Low Water Mark for Physics Buzz Team

PhysicsBuzz is sad to report today that several of the physicists who toured the decrepit Superconducting Super Collider in Texas were escorted from the office this morning. Re-posted below is an article detailing what happened:

-----

Apr 1, 10:00 AM EDT

Four Physicists Arrested in National Lab Break-in
By Flora S. Lipo

COLLEGE PARK, Md. -- A team of four physicists was arrested this morning at the headquarters of the American Physical Society (APS) in College Park, MD. Plain-clothed officers from the Department of Homeland Security entered the building around 8:30 a.m. and detained the suspects without incident. The group is charged with breaking and entering a secure government facility, destruction of government property, stealing national secrets and parking illegally.
[Photo taken by a building employee as the suspects were being escorted out.]

During the APS March Meeting held in Dallas, Texas, the individuals traveled 30 miles south to Waxahachie, Texas, and entered the five remaining buildings of the Superconducting Super Collider (SSC).

To gain access to the facility they allegedly tore apart a cargo bay door. Police suspect that scientific equipment, framed photos, signs and a mug shot were all stolen from the site as trophies. The group supposedly took over 300 photos of their exploits, which may used by the prosecution at their impending trial. While they allegedly committed these crimes, their rented minivan was parked in a handicap parking spot resulting in a $250 parking fine. One member of the group said, “Yes, the parking ticket was just rancid icing on this most untasty cake.”

The Department of Homeland Security was alerted to the team’s exploits after their blog post about their adventures became viral. An anonymous source tipped off the department after reading the post, which had been featured on SlashDot, PhysicsWorld, BoingBoing and Reddit.

“I was appalled that that a team of physicists would not only break into a national lab which still houses government secrets but then brag about it! I had to let someone know so that this behavior did not continue and the group would have to answer for their crime," the informant said. Though the Waxahachie police station directly across the street saw some unusual activity on the buildings’ roofs, they chose not to act. “We just thought it was some birds or something. We didn’t think it was that big a deal,” one Waxahachie police officer said before returning to his coffee and jelly donut.

The quartet is currently being housed in the Riverdale, MD, penitentiary to await extradition to Texas. The fifth member of the team remains at large and is suspected to have fled to Arizona. This is the third arrest for one of the team and he may be eligible to be prosecuted under the Texas “three strikes” law, possibly leading to a much longer sentence.

Closed down in 1993, the SSC would have been the largest particle accelerator in the world, even surpassing the Large Hadron Collider (LHC) currently operating in Switzerland. After the accelerator was shut down the buildings became the property of the U.S. Government. They are now used to house thousands of confidential government files.

APS declined to comment on the incident.

Happy April Fool's Day from the Physics Buzz team! <-- No one found this secret clue!

***UPDATE @ 4:01 P.M. EDT***
April Fools! The Physics Buzz team members are each safely tucked into their cubicles and offices here in College Park. We wish everyone a happy April Fools Day and would also like to extend an apology to the Department of Homeland Security for any ill-will that came your way as a result of this post. It was all in good fun!

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