Tuesday, November 26, 2013

Earthquakes Statistics Get Help from Forest-fire Models

Natural disasters like forest fires and earthquakes have more than just havoc-reeking, destructive natures in common, according to scientist Eduardo Jagla of the National Atomic Energy Commission in Argentina. In a paper to appear in the APS journal, Physical Review Letters, Jagla found that a statistical model describing the behavior of forest fires could be used to characterize the decay rate of earthquakes.

The number of earthquakes that can occur in a given region over a period of time follows a surprisingly simple logarithmic scale expressed by the Gutenberg-Richter Law. The law takes into account the magnitude of an earthquake, the seismicity rate of the region in question and a constant, called the b-value. Although the b-value hovers around one (give or take 0.5) for most regions, scientists do not fully understand why one is the magic number.

The b-value satisfies observational experiments that follow the GR law, but its origin remains unknown. Jagla proposed that aftershocks are, in part, the reason behind the b-value. This conclusion emerged when Jagla discovered that he could obtain the appropriate b-value by applying the GR model to a scenario of a forest fire spreading from tree to tree.

Credit: Eduardo Jagla who describes: "The attached figure can be interpreted in two different ways: each black pixel can represent a tree in a forest, or intensity of gray can represent the local stress of a tectonic fault."

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Monday, November 25, 2013

Dancing Droplets

The American Physical Society's annual Division of Fluid Dynamics Meeting is well underway in Pittsburgh this week, and it's showcasing a slew of gorgeous videos contending for prizes in the Gallery of Fluid Motion.

We've featured a few of these videos in the past few weeks, and we've got another beautiful example today. Today's video covers the spontaneous motion of dyed liquid droplets as they interact with one another.

Surface tension causes the droplets to dance, kiss, and stride along flat glass surfaces. In the video, researchers Nate J Cira and Manu Prakash (Stanford) show off just what surface tension can do: it can sort different liquids automatically, cause droplets to chase one another in a circle, and much more. Check it out!

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Friday, November 22, 2013

New Evidence Supports Asteroid Origin Of Martian Moon

Study uses reflected light to compare chemical makeup of moon and other asteroids.

Phobos, with Mars in the background. jihemD via wikimedia commons, rights

New research suggests that Mars' larger moon, Phobos, is likely an errant asteroid trapped by the planet's gravitational pull. Astronomers matched the chemical makeup of Phobos' surface to a meteorite that struck Canada, concluding that the Martian moon likely started out as a carbon-rich, "D-type" asteroid that drifted too close to the red planet.

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Thursday, November 21, 2013

Benford's Law: Can it Negate Cheating?

Imagine that you begin your day at an auction, purchasing a myriad of equipment for your laboratory. You then spend the afternoon recording data on the radioactive half-life of uranium, and you end the evening by looking at your tax return. The prices you paid for the auction items, the values comprising your research data and the depressing numbers on your tax return all follow a pattern called Benford’s law.

Benford’s law describes the frequency of leading digits. Lower numbers such as one or two appear as the first digit more often than higher numbers, and the fall-off frequency follows a logarithmic scale. Meaning that more than 50 percent of the prices you paid for the auction items will likely begin with the number one, two or three. Research indicates that the same rule applies to large samples of numbers describing radioactive half-lives, tax returns, statistical physics distributions, geological stream-flow rates and more.

Credit: Alberto G.

Numerous numerical datasets follow Benford’s law. A team of scientists at Trent University and Brock University in Ontario, Canada specialize in multiple-choice test assessment. They began to wonder if Benford’s Law could be used to gain an unfair advantage during undergraduate test taking, specifically in physics. Could Benford’s law offer students the next best strategy to “When in doubt, choose C”?

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Wednesday, November 20, 2013

Podcast: Gauss's Missing Brain

Carl Friedrich Gauss, one of the greatest mathematicians of all time, died in 1855. His brain has been resting at the University of Gottingen for the last 150 years—but under the wrong label.

A mix-up that appears to have taken place in the 1860's put Gauss's brain the wrong jar. It wasn't until this year, when scientists from the Max Planck institute were taking fMRI images of the brain for archival purposes, that neuroscientist Renate Schweizer noticed something was amiss. To most people, human brains all look the same. But Schweizer knows one brain from the next, and she realized this couldn't be the brain of Carl Friedrich Gauss—because she'd seen this brain before.

Listen to the podcast to learn how Schweizer identified the impostor brain, and where they found the real one.
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Tuesday, November 19, 2013

Fascinating Flying Fish

It swims in the ocean, dances on water and glides through air, what is it? Not much of a riddle since the solution is in the title, but how bizarre that a single family of fish evolved to achieve three feats of which most animals can perform only one.

Patricia Yang, a graduate student of mechanical engineering at the Georgia Institute of Technology, raises flying fish in a tank in Taiwan. She is one of the few scientists around the world to study flying fish in a laboratory setting instead of their natural environment. In the lab, she could get a close look at the initial steps any fish must make before taking flight. One being breaking the surface-tension barrier between water and air.

Credit: Theron Trowbridge

While the fish were still in their juvenile state, measuring no longer than two centimeters, Yang and a group of scientists from Georgia Tech and the National Sun Yat-sen University in Taiwan trained them to launch into the air on command. Using high-speed videography, the team examined the speed and angle with which the flying fishlings broke the water’s surface.

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Monday, November 18, 2013

MAVEN Launch Live

At 1:28 PM EST today, the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) will blast off from Cape Canaveral en route to study the evolution of the red planet's atmosphere.

While the spacecraft will launch in a matter of hours, this launch date almost had to be pushed back two years due to the U.S. government shutdown in October.

As Universe Today reported earlier today, NASA administrator Charles Bolden had to make the case that continuing to prepare for MAVEN's launch was critical to protecting life and property – a necessary condition that was required for most employees to continue working during the shutdown.

Instead of touting the mission's science objectives, Bolden focused on MAVEN's role as a communications relay for ground missions on Mars. Without MAVEN, Bolden argued, data coming from the Curiosity and Opportunity rovers may have been lost.

Thanks in part to Bolden's efforts, the MAVEN mission is still on for today. You can watch the launch live on NASA TV in the embedded player below.

Live streaming video by Ustream
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Friday, November 15, 2013

Getting Einstein to Say "I Was Wrong"

Einstein in 1931
Image: Wikimedia Commons
What does it take to convince Albert Einstein he was wrong? According to new scholarship and contrary to popular belief, not even the legendary astronomer Edwin Hubble backed up by photos of distant galaxies could convince the wispy-haired physicist to ditch his now-infamous mistaken cosmological fudge-factor.

Historian Harry Nussbaumer's paper argues that Einstein ignored observational evidence his "Cosmological Constant" was wrong, and instead only admitted he was wrong when he personally came to the conclusion that his model of the universe was unstable. Nussbaumer culled through stacks of the physicist's diary entries, drafts of speeches and even newspaper articles, looking for the source of his conversion.

When Einstein was developing the theory of general relativity in 1915, he was faced with a serious problem; His equations indicated that there was no way the universe could exist. At the time, everyone thought the universe was static, that stars didn't move very much and the idea of galaxies was unheard of. According to his equations based on that understanding of the universe's density, gravity should pull everything in the universe together into a single conglomerated mish-mash.

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Thursday, November 14, 2013

Thor: The Dark World, Does it Pass the Bechdel Test?

This past weekend the sequel to Marvel's blockbuster "Thor," "Thor: The Dark World," hit theaters.  Those who have seen either movie know that Thor's love interest, played by Natalie Portman, is an astrophysicist named Jane Foster.  There are too few women in Science, Technology, Engineering and Math (STEM) fields and even fewer in physics specifically.  To use the film's popularity to possibly encourage more girls to go into STEM careers, Marvel launched a contest that asked girls to meet local women in STEM careers and make a video about their experiences.  The makers of the best videos would then be flown to Hollywood to meet Natalie Portman and several successful women in STEM fields.   As someone who does outreach professionally I thought the contest left much to be desired both in terms of advertising and lasting effects.  In some ways it was a wasted opportunity on Marvel's part, but more than that, I have seen women "scientists" in movies like Thor before (Denise Richards, Jennifer Love Hewitt) and they are usually just your average damsel in distress with thick glasses and too few clothes.  How could it be ok to then use that as a model to encourage girls to go into science?  So got myself a huge bag of Sour Patch Kids and took my notebook and book light down to the local movie theater and geared myself up for a long winded rant on the blog about representations of women scientists on film.  Wow, was I surprised.

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Wednesday, November 13, 2013

Podcast: No Sign of Primordial Black Holes

Today on the podcast I talk with Kim Griest, a professor of physics at UC San Diego and professional dark matter hunter.

Griest is exploring the possibility that the mysterious gravitational force acting on all the matter in our universe is caused by black holes that formed in the very early universe. Griest and two of his colleagues recently published the results of a search for these primordial black holes using data from the Kepler space telescope (which was designed to hunt for planets orbiting stars other than our sun). The group did not find primordial black holes, but the new results do set a limit on how big the black holes can be: no larger than about one millionth the mass of the moon. Griests says there is still a chance the black holes could appear in the remaining two years of Kepler data he and his colleagues have yet to analyze.

The Large Underground Xenon (or LUX) dark matter experiment also announced a negative result in its search for a new subatomic particle that could explain dark matter.

These negative results aren't as exciting as, say, finding dark matter—but they are an important part of the quest.

Listen to the podcast to hear more about these ancient black holes and the search for dark matter.

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Tuesday, November 12, 2013

Fluid Dynamics Explains Some Traffic Jams

A popular luxury car option might be part of the solution to unexplained traffic jams.

It happens to everyone. You are cruising down the freeway -- at the speed limit, of course -- when suddenly the traffic thickens and slows to a complete stop. When traffic resumes moving you note there was no apparent reason for the halt -- no accident, no detour, no construction.

The phenomenon has been the topic of countless dissertations and theses -- why does the traffic stop? Can gridlock be avoided?

An MIT professor and expert in computer vision thinks that he has the answer.

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Monday, November 11, 2013

Do Not Shave a Fruit Fly’s Eyes

(Clip of a fruit fly cleaning itself slowed by 33x. Credit: Guillermo Amador at Georgia Institute of Technology.)

From a distance, insects can appear smooth and sleek, but get close enough and hundreds of tiny bristles called setae come into focus. Suddenly what once seemed smooth now resembles a porcupine terror.

For certain insect species, setae cover many parts of the body including the legs and eyes. The tiny hairs contain nerves that signal to the insect when dust, pollen, mold or other particles are on its body. Moreover, insects use setae as combs to clean themselves by rubbing the bristles against each other, which flicks debris away.

These are just two examples of the many applications setae serve insects and there are still more to be discovered. A team of scientists at Georgia Institute of Technology recently found another application of setae on the eyes of fruit flies.

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Friday, November 08, 2013

Creepy Soft Robots Could Get Under Your Skin

Robots tiny enough to fit inside your body might someday deliver your medicine from the inside.

From Inside Science TV.
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Thursday, November 07, 2013

Picking the Perfect Punkin for Chunkin

Credit: Punkin Chunkin Website punkinchunkin.com

Last weekend, thousands watched as competitors from around the country competed for the 28th annual World Championship Punkin Chunkin trophy. Trebuchets, resembling something out of a Lord of the Rings film, flung their pumpkins while air cannons, rivaling some cranes in size, fired the helpless gourds toward their inevitable, squashy doom.

American Chunker Inc. launched this year’s farthest-flying pumpkin at a distance of 4,694.68 feet, about 585 feet shy of a mile. The team sent their winning pumpkin flying on the first day of the event when conditions were more favorable for chunkin than the final two days of the competition. The trick to winning Punkin Chunkin relies more on just the machine.

The machine controls the pumpkin’s launching speed and angle and therefore is a major determinant of how far the pumpkin travels. However, there are other components, which affect distance, that chunking competitors cannot control. Wind velocity is a major one. Although they cannot influence the weather, punkin chunkers can attempt to minimize the effect from air and wind by launching the most aerodynamic pumpkin possible. But what would that look like? It depends.

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Wednesday, November 06, 2013

Podcast: Rescue Radar from Dolphin Clicks

When physicist Tim Leighton saw documentary footage of dolphins using bubble nets to catch their prey, he knew something was fishy. How were the dolphins differentiating the bubbles and the fish? Even the most sophistocated man-made sonar doesn't have that ability.

At least, not until Leighton and his colleagues at Southampton University designed Twin Inverted Pulsed Sonar or TWIPS, which can see through bubbles and focus on a true target, like a fish. Leighton's development of the technique was inspired by his curiosity about dolphin sonar abilities. In the October 23 issue of Proceedings of the Royal Society A, Leighton and his colleagues at the University of Southampton announced that they've successfully done with radar what TWIPS did with sonar. TWIPR (twin inverted pulsed radar), as it's called, is particularly apt at detecting electronic circuits, even amid clutter like scrap metal, soil, snow and concrete. The potential applications include searching for hidden explosive devices, like IED's, or covert listening devices. TWIPR could also be used to locate people in disaster areas (like collapsed buildings) by seeking out the circuitry in their cell phones.

This week on the Physics Central Podcast I talk with Leighton about how TWIPR works it's magic and whether or not he's solved that pesky dolphin problem.

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Tuesday, November 05, 2013

Kepler News Sparks Media Headline Mayhem

It’s all over the news: A team of scientists at UC Berkeley and University of Hawaii used Kepler data to gain one step closer to determining the abundance of potentially habitable extra-solar planets within the Milky Way Galaxy.

In their paper, published yesterday in the journal Proceedings of the National Academy of Sciences, the team states: “We find that 22% of Sun-like stars harbor Earth-size planets orbiting in their habitable zones.”

Although the statistic is simple enough, the media are playing a number flinging game to see who can produce the most earth-shattering headline. Consequently, readers are caught in the midst of confusing, misguiding headlines such as:

“Kepler Space Telescope data suggests up to 40 billion Goldilocks planets”SlashGear

“8.8 billion habitable Earth-size planets exist in Milky Way alone”NBCNews

“Two billion planets in our galaxy may be suitable for life”The Guardian

But my personal favorite is a press release issued by the W.M. Keck Observatory: “One in Five Stars has Earth-sized Planet in Habitable Zone.” To their credit, the authors redeem themselves in the first sentence by specifying Sun-like stars. The University Herald earns no such redemption with their take titled “Kepler Telescope Researchers Estimate One in Five Stars in the Universe Has an Earth-Like Habitable Planet.”

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Monday, November 04, 2013

Pittsburgh’s Abandoned Atom Smasher

The derelict Westinghouse Atom Smasher, one of the oldest (and biggest) artifacts from the dawn of the Nuclear Age, awaits its fate atop a hill outside Pittsburgh. 

The world’s first industrial particle accelerator sits rusting away in the Pittsburgh suburb of Forest Hills, its future unclear. It was cutting edge technology when it was built in 1937, but when the company retired it in 1958, it was a relic of an obsolete technology. Six months ago, a D.C. real estate developer with a penchant for history bought the site and has been doing what he can to preserve the giant silver teardrop. If all goes according to plan, he’ll convert the old atom smasher into an education center while turning the rest of the property into rental units.

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Friday, November 01, 2013

Snakelike Zaps To Flowing Air Can Improve Vehicle Aerodynamics

Serpentine electronics could improve performance of cars and planes
Experiments in wind tunnels can provide insights into aerodynamics that can improve vehicle performance. Image credit: Georgepehli. Rights info 
The way air flows over surfaces can slow cars down and make airplanes loud when they fly over homes. Now scientists find that it's possible to reduce this drag by using curved electronic devices to generate electrically charged particles that control the flow of air over the surfaces of vehicles. 

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