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March 19, 2011December 24, 2015

Astronomy Without A Telescope – Doubly Special Relativity

[/caption] General relativity, Einstein’s theory of gravity, gives us a useful basis for mathematically modeling the large scale universe – while quantum theory gives us a useful basis for modeling sub-atomic particle physics and the likely small-scale, high-energy-density physics of the early universe – nanoseconds after the Big Bang – which general relativity just models …

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March 12, 2011December 24, 2015

Astronomy Without A Telescope – Black Hole Entropy

[/caption] An easy way to think about the entropy of black holes is to consider that entropy represents the loss of free energy – that is, energy that is available to do work – from a system. Needless to say, anything you throw into a black hole is no longer available to do any work …

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March 5, 2011December 24, 2015

Astronomy Without A Telescope – Unreasonable Effectiveness

[/caption] Gravitational waves are apparently devilishly difficult things to model with Einstein field equations, since they are highly dynamic and non-symmetric. Traditionally, the only way to get close to predicting the likely effects of gravity waves was to estimate the required Einstein equation parameters by assuming the objects causing the gravity waves did not generate …

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February 26, 2011December 24, 2015

Astronomy Without A Telescope – Knots In Space

[/caption] So finally you possess that most valuable of commodities, a traversable wormhole – and somehow or other you grab one end of it and accelerate it to a very rapid velocity. This might only take you a couple of weeks since you accelerate to the same velocity as your end of the wormhole. But …

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February 19, 2011December 24, 2015

Astronomy Without A Telescope – Black Holes: The Early Years

[/caption] There’s a growing view that black holes in the early universe may have been the seeds around which most of today’s big galaxies (now with supermassive black holes within) first grew. And taking a step further back, it might also be the case that black holes were key to reionizing the early interstellar medium …

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February 12, 2011December 24, 2015

Astronomy Without A Telescope – Plausibility Check

[/caption] So we all know this story. Uncle Owen has just emotionally blackmailed you into putting off your application to the academy for another year – and even after you just got those two new droids, darn it. So you stare mournfully at the setting binary suns and… Hang on, they look a lot like …

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February 5, 2011April 26, 2016

Astronomy Without A Telescope – Situation Cloudy

[/caption] Most people agree that the Magellanic Clouds are in orbit around the Milky Way. What’s not clear is whether it is a bound orbit or just a temporary ‘ships passing in the night’ arrangement. Something which could clarify the relationship is the Magellanic Stream, a 600,000 light year long string of gas dragged through …

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January 29, 2011December 24, 2015

Astronomy Without A Telescope – Gravity Probe B

[/caption] There’s a line out of an early episode of The Big Bang Theory series, where Gravity Probe B is described as having seen ‘glimpses’ of Einstein’s predicted frame-dragging effect. In reality, it is not entirely clear that the experiment was able to definitively distinguish a frame-dragging effect from a background noise created by some …

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January 22, 2011December 24, 2015

Astronomy Without A Telescope – Time Freeze

[/caption] There is a story told about traveling at the speed of light in which you are asked to imagine that you begin by standing in front of a big clock – like Big Ben. You realize that your current perception of time is being informed by light reflected off the face of the clock …

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January 15, 2011December 24, 2015

Astronomy Without A Telescope – Why Carbon?

[/caption] Last week’s AWAT Why Water? took the approach of acknowledging that while numerous solvents are available to support alien biochemistries, water is very likely to be the most common biological solvent out there – just on the basis of its sheer abundance. It also has useful chemical features that would be advantageous to alien …

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