Tag Archives: Einstein

Failed GPS satellites to test Einstein’s theory

Making lemonade from lemons: Scientists are going to repurpose two GPS satellites — launched into wrong orbits and thus useless for GPS — to conduct a test of Einstein’s theory of general relativity.

The satellites, operated by the European Space Agency (ESA), were mislaunched last year by a Russian Soyuz rocket that put them into elliptical, rather than circular, orbits. This left them unfit for their intended use as part of a European global-navigation system called Galileo.

But the two crafts still have atomic clocks on board. According to general relativity, the clocks’ ‘ticking’ should slow down as the satellites move closer to Earth in their wonky orbits, because the heavy planet’s gravity bends the fabric of space-time. The clocks should then speed up as the crafts recede.

On 9 November, ESA announced that teams at Germany’s Center of Applied Space Technology and Microgravity (ZARM) in Bremen and the department of Time–Space Reference Systems at the Paris Observatory will now track this rise and fall. By comparing the speed of the clocks’ ticking with the crafts’ known altitudes — pinpointed within a few centimetres by monitoring stations on the ground, which bounce lasers off the satellites — the teams can test the accuracy of Einstein’s theory.

There actually is little uncertainty here. No one expects this experiment to disprove Einstein’s theory, but the failed spacecraft provide a great opportunity to measure things at an accuracy never previously attempted, which in turn will help improve future GPS design.

Scientist proposes that the superluminal neutrinos are merely measuring the true speed of light

On Thursday physicist Susan Gardner of the University of Kentucky proposed in a preprint on the Los Alamos astro-ph website that the neutrinos measured at CERN that appeared to be going faster than light were merely giving us a much more accurate measure of the speed of light.

This is only one of a plethora of papers published this last week on astro-ph discussing and attacking the CERN neutrino results. I expect the scientists will solve this mystery before too long.

Faster than light?

Can neutrinos travel faster than light? After three years of gathering data, an experiment at CERN says they do, though by only a tiny amount.

[Physicist Antonio] Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometre trip between CERN and its detector to within 20 centimetres. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma — the physicists’ way of saying it is certainly correct.

You can download and read a preprint of their paper here.

What I find intriguing about this result, other than its exciting groundbreaking possibilities, is how it illustrates sharply the contrast between normal and healthy science, and the sad and sick state of the field of climate science.
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