Category: Hellraisin’
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Dark energy and the bitterest pill
It’s hard to get your head around dark energy, this universe-accelerating stuff that is supposed to fill the cosmos. Dark energy was invented to explain measurements that seem to show that the most distant supernovas all appear to be accelerating away from us. The thinking is that something must be pushing them away and…
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If invisibility cloaks don’t work, try the invisibility sheet
When it comes to invisibility cloaks, nobody has done more to advance the field than John Pendry, a theoretical physicist at Imperial College, London. It was he who suggested the idea in the first place and mapped out how one could be built in theory. He even got his hands dirty by collaborating with the…
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How many pedestrians can squeeze through a corridor?
There’s chaos in the corridors at the labs of Michael Schreckenberg and colleagues at the University Duisberg-Essen in Germany. Schreckenberg specialises in the physics of traffic and transport and has been fascinated by a particular question: how much pedestrian traffic can you squeeze into a shopping mall during the peak shopping hours? This question has…
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The latest social network: binge drinking
Binge drinking is “the rapid consumption of large amounts of alcohol, especially by young people, leading to serious anti-social and criminal behavior in urban centres,” say Paul Ormerod, an economist at Volterra Consulting in London, also linked to the University of Durham. Binge drinking is a growing problem in city centers in the UK, with…
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How to build a quantum eavesdropper
In the cat and mouse game of preparing and eavesdropping on secret messages, quantum encryption trumps all. At least, that’s what we’ve been told. The truth is a little more complex. Quantum key distribution, the quantum technique by which a classical encryption key can be transferred, is perfectly secure in theory. In practice, there are…
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Let the SPIT wars begin
If SPAM arrives in your inbox at 4am, the chances are your antispam software will catch it. But even if it doesn’t, you won’t lose much sleep over its arrival. But it’ll be a different story with SPIT (spam over internet telephony). Junk phone calls at 4am are going to drive you mad because the…
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Western Europe warming much faster than expected
There’s little doubt these days over whether the planet is heating up. Temperature measurements clearly show the trend and in recent years, computer models of the Earth’s climate have been able to reproduce these increases pretty accurately when carbon dioxide is injected into their virtual atmospheres. Where climate models fall down, however, is in predicting…
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Which way does antimatter fall?
The force of gravity on antimatter has never been directly measured but a growing number of physicists believe that such an experiment is within their grasp. Today, a group attempting to design an experiment called AEGIS (Antimatter Experiment: Gravity, Interferometry, Spectroscopy) outline their plans to measure this force. In some ways it’s an ambitious plan.…
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VoIP threatened by steganographic attack
Steganography is the art of hiding message when they are sent, in a process akin to camouflage. In cryptography, on the other hand, no attempt is made to hide the message, only to conceal its content. Today, Wojciech Mazurczyk and Krzysztof Szczypiorski of the Warsaw University of Technology in Poland explain how VoIP services are…
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Solving the faint young Sun problem
We know by studying ancient rocks that liquid water existed on the surface of Earth at least 3.7 billion years ago. That implies that the surface temperature at that time was at least 273K. We also know by studying stars similar to ours that the Sun must have been significantly less bright than it is…