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| So you're into sci fi? But what about sci fact? Sometimes fact is stranger than fiction... Each month our very own Voyager Science Queen* will bring you interesting, quirky and downright bizarre tasty morsels from the world of science. And its all completely, totally, 100% true! March Sci-Facts |
The Dark Side This month, let us delve into the dark side of physics and astrophysics. There are so many strange and wonderful concepts, fascinating and marvellous phenomena. I am presenting three this month. The Casimir Effect The Casimir Effect is a small attractive force which acts between two parallel uncharged conducting plates when they are held close together. The effect was theorised by Hendrik Brugt Gerhard Casimir, a Dutch physicist, and he formulated experiments to prove its existence in 1948. The actual experiments, that confirmed the existence of effect, were performed in 1996. You can do this experiment at home. Dribble two drops of oil into a dish of water. Watch as they float towards each other: they will suddenly seem to ‘rush’ towards each other and merge. This is due to the water pressure; as the drops drift close they create a narrow gap of water that can not exert the same pressure as the greater amount of water surrounding the oil drops, and so oil drops are pushed together. A similar effect is created with the two parallel plates, except the forces working upon the plates are due to quantum vacuum fluctuations of the electromagnetic field. This negative energy field creates several interesting possibilities. Regions of negative energy density are thought to be essential to a number of hypothetical faster-than-light propulsion schemes. The Casimir Effect may be a way of ‘breaking’ the light speed barrier, by removing the ‘pressure’ of the intervening vacuum, and so may be one way of creating a FTL space drive. Of course, it is all conjecture for now... Dark Matter Most of the stuff in the universe is dark, too cool to glow or shine brightly. Scientists believe most of the matter in the universe is dark matter, that it cannot be detected by any light or electromagnetic emissions. The dark matter has to exist to explain the gravitational effects of the ‘visible’ matter of the known universe. Dark matter creates enough gravitation effects to prevent objects like galaxies and star clusters from spinning apart. There is hot dark matter and cold dark matter. Whether the dark matter is considered hot or cold depends on their respective masses and speeds; hot dark matter travels at high speed. Dark matter was first postulated in 1933. A select team, seventy scientists and astronomers from around the world, used the Hubble space telescope to build a picture of the dark matter in an enormous region of space, in the January of this year. The scientists used a phenomenon known as gravitational lensing to investigate the presence of dark matter. Gravitational lensing occurs when light from distant galaxies is bent by the gravitational influence of matter as it passes on its journey through space. The scientists used the technique to collect light from half a million galaxies, and then mathematically constructed a representation of the invisible mass of the universe. Dark Energy Like dark matter, the exact nature of this dark energy is only guessed at by scientists. It should be homogeneous, nebulous, and only can be detected by its interactions with gravity. Dark energy is part of the structure of dark matter, and helps explain the missing, invisible mass of the universe. The universe shouldn’t be able to expand without it. I find this all a bit iffy. Is this philosophy or physics? |
| *The Voyager Science Queen is also known as Lynne Green So, who is this woman who attempts to entertain us with Science? Well, I really am a scientist. I have a Bachelor of Science degree from the University of Queensland, in Zoology. And, at the moment, I am working in a Pathology laboratory. I have always been intensely curious about every aspect of our universe, from the teeny tiny workings of the gene right up to the mind-bending forces that are twisting and knotting inside a blackhole. So, now I am sharing a brain stuffed full of trivia...and hopefully entertaining people at the same time. As well, I write Fantasy stories and novels. One day, I hope to have a book published, but don't hold your breath. Reading is my other major love, and my favourite authors are Terry Pratchett and Isaac Asimov, though I could list hundreds of others. If I had one wish, I ask for more time to write! Read previous Sci-Facts: Strange Objects Looking for more scientific oddities? Have you checked out Dr Steven Juan's website? He is, quite literally, the wizard of odds! |
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