Operatic Atom Bombs

I'd wager the average person rarely (if ever), spends a Friday evening indulging in Die Meistersinger von Nurnberg, but operas aren't always long-winded scenes of voluptuous, ornately dressed characters bellowing incomprehensibly.

Producer John Adam's Doctor Atomic is a two-act opera about the making of the Atom Bomb, the nuclear weapon that was eventually dropped on Hiroshima and Nagasaki near the end of World War II.

The setting is the summer of 1945, in the desert of Los Alamos, New Mexico, where J. Robert Oppenheimer and a team of scientists gathered to build and test the bomb for the first time.

The opera focuses on renowned physicist Robert Oppenheimer and his scientific and moral dilemma surrounding the Los Alamos project-with lots of science thrown in. Created from various sources ( including declassified government documents), the text or libretto of the opera is littered with discussions on uranium and plutonium, the TNT equivalency of the bomb, and whether or not a test explosion might set the atmosphere on fire-an indisputably bad scenario.

In addition to being a brilliant theoretical physicist (he received his PhD at age 22), Oppenheimer loved the arts and culture; it is widely know that he decided to learn Sanskrit in order to read the Bhagavad Gita. He was appointed scientific director of the Manhattan Project after years of contributions to quantum mechanics, nuclear physics, spectroscopy, and astrophysics. He was first to publish a paper in the 1930s suggesting the existence of what now call black holes.

Atomic energy is created by the splitting (fission) or joining (fusion) of atoms- but only by using specific isotopes of uranium or plutonium can a massively destructive explosion be reached. The two atomic bombs detonated over Hiroshima and Nagasaki relied on fission.

Elements undergoing fission ( for example uranium) release neutrons. Some neutrons are scooped up by other uranium nuclei leading to more fission, while others escape the process altogether. If the expected number of neutrons which trigger new fissions is less than 1, a nuclear chain reaction may occur but the size will decrease exponentially.


If the expected number of neutrons is greater than 1, the chain reaction will increase exponentially. The term 'critical mass' describes the point at which the expected number of neutrons causing fission is 1 or more, thus becoming a self-sustaining chain reaction.

The bomb released over Hiroshima used TNT to blow subcritical masses of uranium 235 together, resulting in a 10 kiloton explosion. "Fat man", the bomb used against Nagasaki was a subcritical mass of plutonium 239 squeezed to bit by TNT and causing a 20 kiloton explosion.

If you find yourself in the mood for an operatic pondering of nuclear fusion and fission, Dr. Atomic will finish a run at the Metropolitan Opera in New York Thursday November 12, ad then travel to London at the English National Opera.

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Mysteriously Speedy Dolphins: Gray's Paradox Solved

Remember Gray's paradox? In 1936 the eponymous British zoologist James Gray couldn't reconcile his observations of dolphins swimming at speeds of over 20 miles per hour with his calculations, which demonstrated that dolphin muscles simply weren't built to produce enough acceleration to overcome drag. He ended up blaming this drag violation on dolphin's skin, postulating that it must have drag-reducing properties.

Fast forward decades later to this year's Annual Meeting of the American Physical Society (APS) Division of Fluid Dynamics in San Antonio, Texas, where professor Timothy Wei of Rensselaer School of Engineering announced that he and a team of researchers had solved Gray's paradox- and no, skin has nothing to do with the speediness of these adorable sea mammals.

Wei and his team are the first to provide solid evidence illustrating that dolphins actually do produce enough force to overcome drag. "The scientific community has known this for a while, but this is the first time anyone has been able to actually quantitatively measure the force and say, for certain, the paradox is solved, said Wei in a Rensselaer Polytechnic Institute press release.

Using combined force measurement tools developed for aerospace research with Digital Particle Image Velocimetry (a video-based measurement technique that captures 1,000 video frames per second), Wei tracked two bottlenose dolphins, Primo and Pula, as they swam through water heavily populated with tiny air bubbles.

The color-coded results showed the speed and direction of water flow around and behind the each dolphin, enabling the researchers o calculate precisely how much force was produced.

Turns out they produce way more force that Gray ever imagined- approximately 200 pounds of force is created by tail flapping ( in contrast, Olympic swimmers only generate 60-70 pounds of force at top speed). Good thing dolphins are considered harmless!

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Snake Power

Anyone who’s ever tried to defend a sand castle against the onslaught of a rising tide will have some notion of the enormous energy carried by the waves crashing onto our shores. It has been estimated that wave power could supply a quarter of UK energy demand, yet converting it into electricity is more difficult than it looks.

Current research efforts have branched out into many directions, each seeking to tame the ocean into an efficient commercially viable energy source. One such approach is Anaconda, an innovative wave power system invented by physicist Francis Farley and engineer Rod Rainey.

As its name suggests, Anaconda’s shape is reminiscent of a giant snake, consisting of a rubber tube 200 m long and 7 m across, filled with water and tethered below the ocean surface. Unlike its reptilian cousin however, its habitat is not the Amazon river but the UK coastline.

‘As a wave goes by and passes over the tube, it instigates another wave inside the tube, called a bulge wave,’ explains Professor Grant Hearn, who has been entrusted with the development of Anaconda along with fellow University of Southampton researcher John Chaplin.

The bulge wave stretches out the elastic walls of the tube and, as the rubber regains it shape, is pushed along its length, exactly like the pulses of blood travelling down your arteries. The energy from this wave could then be converted into electricity, for example by using a water turbine at the far end of the tube.

Thinking outside the box

‘You’re essentially using the natural resonance of fluid to transport energy,’ comments Hearn. In this way, Anaconda offers a startingly fresh approach. ‘All the other structures tend to use articulations of some sort, and you exploit the relative motion due to that articulation,’ he adds. The Salter duck for example, invented in the 1970s, uses the motion of ‘ducks’ bobbing up and down on the surface of the water.

Despite highly efficient conversion rates, other hurdles have kept the Salter duck out of water. Constantly buffeted by waves and immersed in salty water, wave power devices tend to suffer from short life spans. Anaconda neatly sidesteps this issue by having no articulations to wear down or parts to fail. ‘Rubber is a very resilient material, so it’s not likely to suffer fatigue in the same way that concrete or metal might, ’ says Hearn.

Soaring costs are also a major headache for engineers, but Anaconda’s simple rubber structure has the additional advantage of making it relatively cheap to produce.

In many ways Anaconda seems to outsmart rival technologies, but Hearn remains pragmatic about its merits, seeing it instead as just one of many innovations that will be necessary to build the perfect wave power system. ‘Each exploits a different technique, but eventually a mixture of these things will come together,’ he says.

Hearn and his team still have a lot of fine tuning to do to maximise Anaconda’s efficiency, but if all goes to plan the sea serpent might be rearing its head on the English or Scottish coast in five years' time. Looks like Nessie too might be facing some tough competition.

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The Restaurant at the End of the Universe

What will be in astronauts' lunch boxes when they go to Mars? Soggy sandwiches, squishy bananas and crisps are unlikely to make the cut.

‘If we go to Mars, that’s a two and a half year mission, so the food would need a five year shelf life,’ explains Dr Michele Perchonok, a food scientist at NASA’s Johnson Space Center in Houston.

There is no refrigeration on board spaceships, so harmful bacteria will have to be zapped before take-off using high pressure processing or microwave sterilisation. ‘With these emerging preservation technologies, foods have a much higher quality once they’ve been processed. And with higher quality comes higher nutrition,’ adds Perchonok.

Saving space is another major consideration. Visitors to Mars will need to pack light and keeping the contents of the food cupboard down to a minimum is key. ‘We want to make things as compact as possible and as lightweight as possible,’ says Perchonok. An even bigger challenge however is ensuring that the food tastes good.

Staying down to Earth

Space travel may summon up thoughts of strange, futuristic food stuffs, but Perchonok’s team strive to ensure that astronauts’ meals taste like they would back on Earth. ‘As missions have got longer and longer, we’ve started developing foods that are closer to home,’ says Perchonok. So astronauts are more likely to be slurping up spaghetti than downing weird space shakes.

Serving food in zero gravity can still hold a few surprises. ‘The crew get to try the food before departing, but we do receive reports that once in orbit it doesn’t taste the same as on Earth,’ comments Perchonok. ‘One reason is that you are in weightlessness and so hot air does not rise. About 85 to 90% of what you taste is really what you smell so if you can’t smell these aromas you may not taste as much.’

Mars bars

As well as their pick of the standard menu items, homesick astronauts are allowed to bring a stash of their favourite Earth treats, as long as these can be stored and consumed safely. Unfortunately for some, this means no crisps or biscuits. ‘We can’t have any crumbs on board,’ says Perchonok. ‘Crumbs can not only go into the equipment and clog up filters but could also get into your nose or your eyes.’

Despite crisp deprivation, today’s astronauts should still consider themselves lucky compared to their predecessors, who endured sandwiches compressed into bite sized cubes and pureed dishes similar to baby food. ‘Now astronauts have around 160 to 180 unique items which they can choose from,’ says Perchonok.

In coming decades, space crew could be treated to the ultimate luxury on Mars – fresh food. Researchers believe that crops such as mizuna lettuce, wheat or soy beans could be grown on Mars. And who knows, if we do find alien life on Mars, it might even be quite tasty.

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