Month: August 2008
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Rot ‘n’ decay (part 2)
More highlights from the arXiv this week: Quantum Computing with Alkaline Earth Atoms Graphene Nanodevices: Bridging Nanoelectronics and Subwavelength Optics Observation of Quantum Capacitance of Individual Single Walled Carbon Nanotubes Inferring Basic Parameters of the Geodynamo from Sequences of Polarity Reversals Can Matter Wave Interferometer Detect Translational Speed?
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Rot ‘n’ decay
The best of the rest from the physics arXiv this week: Gravitational Time Advancement and its Possible Detection How Hard Is Bribery in Elections? On the Stability of Black Holes at the LHC The Flavour of Inflation Dante, Astrology and Astronomy
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Do nuclear decay rates depend on our distance from the sun?
Here’s an interesting conundrum involving nuclear decay rates. We think that the decay rates of elements are constant regardless of the ambient conditions (except in a few special cases where beta decay can be influenced by powerful electric fields). So that makes it hard to explain the curious periodic variations in the decay rates of…
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Why Galileo underestimated the distance to the stars
“Galileo argued that with a good telescope one could measure the angular sizes of stars, and that the stars typically measured a few arc-seconds in diameter,” says Chris Graney at Jefferson Community College in Louisvile in good ol’ Kentucky. That doesn’t sound right. We know today that stars appear as point sources of light, so…
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The sound of a bouncing basketball
“A basketball bounced on a stiff surface produces a characteristic loud thump, followed by high pitched ringing,” says Joanthan Katz at Washington University in St Louis. The question is why and, conveniently, Katz provides the answer on the arXiv today. He assumes first that a basketball is an inextensible but perfectly flexible hollow sphere. From…
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The ultimate black hole size limit
We have a pretty good idea that a supermassive black hole is sitting at the center of our galaxy. By supermassive, astronomers mean about 6 millions times as massive as our sun. That’s pretty big by any standards but how big can black holes get Is there any limit to how big these monsters can…
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Why aluminum should replace cesium as the standard of time
The second is defined as 9,192,631,770 vibrations of a cesium atom and measured in a device known as a fountain clock. These work by cooling a tiny cloud of cesium atoms to a temperature close to zero, tossing it up in the air and zapping it with microwaves as it falls. Then you watch the…
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Rocks ‘n’ comets (part 2)
More highlights from the physics arXiv: Local Causality and Completeness: Bell vs. Jarrett Superconducting Atom Chips: Advantages and Challenges The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres Networks of Quantum Nanorings: Programmable Spintronic Devices The Meccano of Life
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Rocks ‘n’ comets
The best of the rest from the physics arXiv this week: Why it has Become more Difficult to Predict Nobel Prize Winners A Local Scheme Accounting for EPR Quantum Correlations Enhanced Heating of Salty Water and Ice Under Microwaves Phonon-Induced Artificial Magnetic Fields Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets
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How to find another Earth
“We stand on a great divide in the detection and study of exoplanets,” says the Exoplanet Task Force on the arXiv today in describing their plan for finding another Earth orbiting another star. On one side of this divide are the hundreds of known massive exoplanets, they say. And on the other” lies the…