Category: Changin’ the world
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The cosmic ray revolution
Cosmic rays, the high energy protons and helium nuclei that constantly bombard the Earth, have puzzled astronomers for the best part of one hundred years. Where do they come from and how are they accelerated to energies in excess of 10^20 eV—that’s about the energy that Roger Federer gives a tennis ball during a serve?…
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Saturn’s anomalous orbit flummoxes astronomers
One of the first tests of Einstein’s theory of general relativity was to explain the precession of the perihelion of Mercury, which had long bamboozled astronomers. Newton’s law of gravity simply cannot account for it. But relativity does. Now it’s Saturn’s turn to flummox astrophysicists. The Russian astronomer Elean Pitjeva, who heads the Laboratory of…
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Here come the quantum robots
Quantum robots were first investigated in the late 1990s by Paul Benioff, a remarkably original thinker at Argonne National Laboratory in Illinois. Benioff is currently occupied in holding a candle for a theory of everything based on quantum numbers (more or less single handedly). So a team of Chinese physicists led by Daoyi Dong at…
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And the number of intelligent civilisations in our galaxy is…
31573.52 No really. At least according to Duncan Forgan at the Institute for Astronomy at the University of Edinburgh. The Drake equation famously calculates the number of advanced civilisations that should populate our galaxy right now. The result is hugely sensitive to the assumptions you make about factors such as the number of planets that…
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Entangled photons to produce better quantum images
A while back, we saw how quantum imaging had been put on a firmer theoretical footing, thanks to some new thinking by Seth Lloyd at MIT. Quantum imaging involves sending one of a pair of entangled photons towards an object while holding on to the other. For a long while nobody was quite sure what…
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How to test the many worlds interpretation of quantum mechanics
The many worlds interpretation of quantum mechanics holds that before a measurement is made, identical copies of the observer exist in parallel universes and that all possible results of a measurement actually take place in these universes. Until now there has been no way to distinguish between this and the Born interpretation. This holds that…
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How alien Earths will reveal their secrets
The European Space Agency has set itself an ambitious goal: to recognise the biomarkers on Earth-like planets orbiting other stars. The first step in such an endeavour is work out to look for, which the goal that Lisa Kaltenegger at the Harvard-Smithsonian Center for Astrophysics in Cambridge and Franck Selsis at the Laboratoire d’Astrophysique de…
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Periodic Pioneer anomaly points to modified general relativity
The Pioneer anomaly grows ever more fascinating. Here’s the background: Pioneer 10 and 11 were launched in 1972 and 1973 respectively and, after sweeping past a number of the outer gas giants, have been heading out of the solar system ever since. NASA has been accurately tracking their position and speed using Doppler tracking measurements…
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How supermassive black holes help galaxies evolve
It’s easy to imagine that our understanding of the way galaxies form and evolve is more or less complete. After all, we’ve been fitting missing pieces into the jigsaw at an alarming rate in recent years with all this data from WMAP etc about the structure of the early universe, a better understanding of the…
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Supernova over south pole caused Ordovician mass extinction
About 444 million years ago, more than half of all marine invertebrates were wiped out at the end of the Ordovician era in the third worst mass extinction in history. A couple of years ago, Brian Thomas at the University of Kansas pointed out that this holocaust could have been caused by a nearby supernova…