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Saturday November 20, 2010

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* Pterosaur Ptake-off * Apprehending Anti-atoms * Feline Physics of Cat Lapping * Can't CO2 the Trees for the Forest * Drunken Bats * Fact or Fiction: Great Wall from Space *

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Pterosaur Ptake-off

Pterosaurs ruled the skies for more than 150 million years. These flying reptiles grew far larger than any bird, the largest of the group weighing on the order of 250kg with a wingspan of more than 10 meters - as large as a small plane.  On the ground, they would have looked a giraffe in the eye.  Many paleontologists have wondered how, even if, these massive creatures could have gotten off the ground.  Studies of modern birds have, indeed, suggested that no bird that size could ever have managed to launch itself into the air.  Dr. Michael Habib, a professor of biology at Chatham University in Pittsburgh, thinks that his studies of the pterosaur have revealed its secret.  The pterosaurs had an advantage over birds that allowed them to grow bigger and still get into the air, and it was the fact that they could use the strength of four legs, rather than just two, to leap into the air.

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Apprehending Anti-atoms

alpha-detector.jpg ALPHA annihilation detector, courtesy ALPHA

This week, a team including several Canadian scientists succeeded in a physics first: they were able for the first time to trap and hold antimatter atoms.  At a laboratory at CERN in Geneva, the ALPHA team was able to create and then capture a few dozen atoms of anti-hydrogen.  Antimatter is a form of matter that immediately is destroyed upon contact with normal matter.  Physicists have been working with anti-matter in the form of sub-atomic particles, the anti-proton and anti-electron, or positron, for decades now.  These particles are relatively easy to control because they are electrically charged, and thus can be contained by electrical fields, so that they don't encounter normal matter and annihilate with it.  However, anti-atoms are electrically neutral and so have been very difficult to capture and contain.  According to Dr. Scott Menary, a professor in the department of Physics and Astronomy at York University, the team trapped the anti-atoms by cooling the ingredients to just above absolute zero, and then capturing newly formed atoms with powerful magnetic fields.  They now hope to study them to see in what ways they may differ from normal atoms of hydrogen.

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Feline Physics of Cat Lapping
cat lapping.jpg Phtoto courtesy Pedro Reis, Micaela Pilotto and Roman Stocker
After watching a cat lapping up milk from a bowl, a team of scientists from the Massachusetts Institute of Technology began wondering about the fluid mechanics of this common occurrence.  Because the cat laps so fast, Dr. Pedro Reis, a Professor of Civil, Environmental and Mechanical Engineering at MIT, had to use high-speed imaging to see exactly what was happening.  It turns out that a cat curls its tongue backwards, like the letter 'J', so that only the top surface touches, but does not break the surface of the water.  It then draws the liquid up into a column that grows by inertia.  Before gravity takes hold of the column, the cat closes it mouth around the liquid in a process of fluid mechanics called 'pinch-off'.  With an instinctive understanding of the physics involved, the cat knows how fast to lap and when to 'pinch-off' the column in order to maximize the amount of liquid it drinks.

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Can't CO2 the Trees for the Forest.
tree_rings.jpg Copyright Arnoldius, cc-by-sa-2.5
It is well known that trees soak up carbon dioxide, and can grow faster as a result. But they are not the major greenhouse gas vacuum cleaners they were thought to be.  This is according to a new study by Dr. Ze'ev Gedalof, a Professor of Geography at the University of Guelph.  By studying over 2,300 archived tree rings, representing over 100 species of trees from forests all over the world, the study expected to find a general rule about the relationship between tree growth and the amount of C02 being soaked up.  Instead, it found that C02 resulted in faster tree growth in only about 20 percent of sites worldwide; and that 20 percent was puzzlingly random.  An astonishing 80 percent of the world's forests showed no C02 induced growth.  The findings suggest that trees not be counted on to counter C02 emissions, as they have been.

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Drunken Bats
drunk-bats.jpg A Pallas's long-tongued bat, courtesy Dr B. Fenton
Bats may be best known for their ability to find prey in the dark, through echolocation.  Now it seems tolerance for alcohol can be added to the bat's list of amazing abilities.  University of Western Ontario Masters student Dara Orbach discovered that as bats in Belize eat fermenting fruit and nectar, they consume levels of ethanol that would induce inebriation in humans.  The bats in her study were given sugar water with 1.5% ethanol and then put through a flight chamber, in which their flight paths and echolocation were recorded.  No significant difference in either was noted, suggesting that regular exposure to fermenting fruit and nectar has resulted in an evolutionary tolerance to high levels of ethanol. For bats, at least, drinking and flying are not prohibited. 

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Fact or Fiction: Great Wall of China From Space
This is another episode of our occasional feature, Science Fact or Science Fiction. From time to time, we present a commonly held idea or popular saying - and ask a Canadian scientist to set us straight on whether we should believe it or not. And today's popular belief is - "The Great Wall of China is the only man-made object you can see from space." 

To help us with this matter, we contacted Canadian astronaut Chris Hadfield, who is currently training in Russia.  He was the first Canadian to walk in space, he's a veteran of two Space Shuttle missions, and in 2012 will become the first Canadian Commander of the International Space Station.  He says it is science fiction.   


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Theme music bed copyright Raphaël Gluckstein, Creative Commons License by-nc-nd-2.0


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