Cathemeral Thinking

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Monday, September 09, 2002 The speed of gravity How fast does the influence of gravity travel? Ask any physicist and they'll tell you that it travels at the speed of light. However, this has never actually been directly tested with experiments. It is surprisingly hard to tease out the speed of gravity from astronomical observations but some data collected over the past weekend may provide the answer. I first mentioned this in my physics tip sheet back in June and now a few journalists have written the story up in full. Read the New Scientist coverage or the (very brief) ABC (Australia) news report. My tip sheet item from June: 2) Measuring the speed of gravity S. Kopeikin, E. Fomalont 6th European VLBI Network Symposium (To be held June 25-28, 2002, Bonn, Germany) Einstein’s general relativity predicts in theory that the speed of gravity is the same as the speed of light. However, there are ways that the speed of gravity can be tested experimentally. Such a test would provide an independent confirmation of Einstein’s difficult-to-test theory. The authors propose using the passage of a particular quasar past Jupiter on September 8, 2002 to measure the speed of gravity. If signals at the Very Long Baseline Array (VLBA) radioastronomy facility are measured with a precision of a few picoseconds, the speed of gravity can be measured with a precision of about 10%. You can also read the conference preprint at: http://www.arxiv.org/abs/gr-qc/0206022 For those who want some more discussion of the speed of gravity, try the Physics FAQ page. Stay tuned for the results of the experiment over the next weeks/months... Permalink  7:44:40 PM  Your views [] Garlic may protect the heart from damage after surgery The natural antioxidants in raw garlic prevent damage in rat hearts after surgery, says a study in BMC Pharmacology. More details in the press release or read the full paper. Permalink  7:18:54 PM  Your views [] Diamonds aren't forever New research published in Science suggests that the Earth may no longer be making large diamonds. (Non-technical report at BBC Online.) Permalink  7:12:48 PM  Your views [] Physics-violating patent revoked Bob Park reports in his most recent What's New column, Blacklight Power, who seem to have a history of trying to or succeeding in patenting physics-violating devices, have had a group of patents rejected or even revoked. Permalink  7:01:28 PM  Your views [] Truly biodegradable plastic? A new plastic made from soybean proteins and plant-based fibres has been produced in an effort to overcome the problems of past attempts to make biodegradable plastics. In the past, biodegradable plastics have been touted as a solution to many environmental problems ranging from landfill increases to animal entrapment. However, most attempts to create a biodegradable plastic have been flawed. Some only degraded in sunlight, thereby staying intact in landfill dumps. Some only degraded into smaller pieces of plastic, which could lead to other environmental problems and prevented the plastic from being collected in one place. "These new fully biodegradable, environment-friendly green composites have good properties and could replace plastic parts in the interiors of cars and trains, in computers and in packaging materials and other consumer products," says Anil Netravali, a professor of fibre science in the College of Human Ecology at Cornell. "They also provide excellent insulation against heat and noise for use in applications such as cars. Although the plant-based fibers may not be as strong as graphite and Kevlar®, for example, they are low in cost, biodegradable and replenishable on a yearly basis," he says. Many people may not think of soybean and plant matter being made into plastics but the properties of plastics do not necessarily require the environmentally damaging compounds most commonly used. Plastics are often most useful for their mechanical properties and making the long-chain molecules in plastics from plant matter can be made to function well, as this research shows. Of course, a big question is whether or not the new materials will be commercially viable but it would seem they could be - if only they can make it through the initial acceptance and development phases. Good luck! More at Cornell   Permalink  4:42:34 PM  Your views [] I've been away from reporting while working on other projects but expect more of my science news to start appearing here... David Permalink  4:29:41 PM  Your views []

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