Category: Seein’ the light
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Loop quantum cosmology: a brief overview
Abhay Ashtekar, a physicist at the Pennsylvania State University is one of the founders of loop quantum cosmology and also a part-time populariser of science. Today, he uses both of these attributes to produce a fascinating overview of loop quantum cosmology that non-specialists will find enlightening. A recommended read. Ref: arxiv.org/abs/0812.0177: Loop Quantum Cosmology: An…
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Two new SETI searches see first light
The Search for Extraterrestrial Intelligence is picking up steam. The folks over at the Berkeley SETI group now have 7 separate searches underway at infrared, visible and radio wavelengths. Today, Andrew Siemiona and pals outline the two newest programs which have recently seen first light and are hunting for pulses just a few hundred nanosceonds…
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And here is the sunspot forecast…
Astronomers have been monitoring sunspot numbers since 1700 and using them as an indicator of solar cycles since 1913. Today we know that peaks in sunspot numbers have an important influence on the Earth, increasing the amount of drag on satellites and contributing to telecoms and and power outages. Accurate forecasts of sunspot activity could…
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Why PAMELA may not have found dark matter
This is the one we’ve been waiting for. For months, the astrophysical world has been abuzz with rumors that the orbiting observatory PAMELA has found evidence of dark matter. Various people have speculated on the nature of this dark matter but the PAMELA team has been cautious, refusing to release the data until they are…
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On the origin of Saturn’s rings
One of the outstanding mysteries of our Solar System is how Saturn’s rings formed. We know they rings are made of water ice with very few contaminants. We know they are different to the rings around Jupiter, Neptune and Uranus which are much smaller and probably the result of the surface erosion of nearby moonlets.…
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The amazing powers of silicon carbide
Silicon carbide is one of those workhorse materials that can do almost anything. Because it has a high melting point, it is used in high performance brake discs, as a the matrix for particulate filters in engines, and because it is a semiconductor in high temperature and high voltage applications. Come to think of it,…
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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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The physics of skin vision
Most animals use optical systems to form images but a substantial number rely on optics-less cutaneous vision or skin vision. And while computer scientists have spent a good deal of time and effort trying to reproduce the former, how many will even have heard of skin vision? So a systematic investigation of this kind of…
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The Casimir conundrum
When it comes to the Casimir force, physicists are in an embarrassing position. “Weak intermolecular forces have a truly pervasive impact, from biology to chemistry, from physics to engineering. It may therefore come as a surprise to know that there still exist, in this well established field, unresolved problems of a fundamental character. This is…
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The magnetic magic of liquid mirrors
Liquid mirror telescopes are amazing contraptions. They start life as a puddle of mercury in a bowl. Set the whole thing spinning and the mercury spreads out in a thin film up the sides of the bowl. The result is a fabulously cheap mirror that can be used for a variety of astronomical surveys.…