Last week I was asked by some school students about the nature of gravity. What is it? Isaac Newton, and a whole pile of textbooks following him, treat gravity as an attractive force between two objects. It’s a force that is proportional to the product of the masses of the two objects, and is inversely […]
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In August 1999, I had the opportunity to travel from the U.K. to Varna, Bulgaria, on the Black Sea coast, to view the European Total Solar Eclipse. Just why we ended up in Varna, as opposed to a plethora of other possibilities in Europe, is a bit of a long story, but a substantial part […]
Continue reading…No, it isn’t something everyone smokes… But it is common in machine mechanisms. The universal joint is a neat way of turning rotation in one plane into rotation in another. A common use is on driveshafts where you want the direction of the shaft to bend. There’s a neat animation on Wikipedia of how the […]
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First the low-tech: The conjunction of Venus (the brighter one) and Jupiter as recorded by my very lousy cellphone camera just after sunset yesterday. Now the high-tech: A day before that Pluto occulted a star. It moved in front of the star, rather like an eclipse. The significance of the event was that it allowed […]
Continue readingSome of us are rather looking forward to getting to 22 June. That's when the days get longer again. Yes, the reality is that no-one's really going to notice much difference for a while, but it's encouraging to think that the days will be getting lighter again, if only by a little bit. Don't confuse […]
Continue readingIn the last few weeks holes have been popping up all over Cambridge. They are being dug by 'ditch-witches' – pieces of machinery designed for making small-diameter tunnels for cabling – as part of the installation of fibre-optic cables for the much vaunted ultra-fast broadband. A ditch-witch is about the ultimate in machinery-obsessed-toddler heaven. We've […]
Continue readingNo, nothing to do with carrots and vitamin A I'm afraid. With dark evenings and mornings with us now :(, Benjamin's become interested in the dark. It's dark after he's finished tea, and he likes to be taken outside to see the dark, the moon, and stars, before his bath. "See dark" has become a […]
Continue readingAt the recent NZ Institute of Physics conference, we were treated to a wonderful description of the earth's magnetic proceses, by Gillian Turner. What makes up the earth's magnetic field? What effect does it have? How is it changing? At first glance the magnetic field of the earth is pretty straightforward. There's a magnetic north […]
Continue readingWe've just had our first session at the NZ Institute of Physics Conference. The focus was on astrophysics, and we heard from Richard Easther about 'Precision Cosmology' – measuring things about the universe accurately enough to test theories and models of the universe. We ablso heard about binary stars and supernovae, and evidence for the […]
Continue readingFriday is the last opportunity to view a solar eclipse in New Zealand for a long time (till 2021 – or 2025 if you don’t count anything of a few percent or lower). I say ‘view’, but the reality is that such a smidgen of sun is going to be covered that you’re going to […]
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