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Is it possible for light to travel faster or slower in the distant corners of our universe? The speed of light, like dozens of other so-called fundamental constants, is essential to how physicists understand the cosmos. These numbers even help define our units of measure, such as the meter, the second and,
as of this Monday, the kilogram.
However, there is no scientific consensus as for why the constants must be constant, or fundamental.A new
paper in the journal
Physical Review Letters proposes experiments to
investigate whether these unwavering pillars of physics are, in fact, fluctuating over space-time. If so, scientists will need to reevaluate the current models of our universe -- or at least give these numbers a different name.How fundamental are the constants?"Fundamental constants are essentially just parameters that appear in a theory," said Peter Mohr, a physicist from the National Institute of Standards and Technology in Gaithersburg, Maryland, who was not involved in the new paper. "They have fundamental importance to the theories, but their values are not predicted by the theories and have to be measured experimentally."
Mohr and his colleagues were part of the international effort to create a new definition for the kilogram -- one that is derived from fundamental constants rather than a block of platinum alloy that's been sitting in France since 1889. The goal was to create a standard for measuring mass that can withstand the test of time and not gain or lose weight through contaminations and degradations like a physical block of material would. The change took effect this Monday, May 20, on World Metrology Day.
It might seem like shifting fundamental constants would negate the whole premise of the redefinition.
But decades of experimental data have shown than any potential changes to the constants would be incredibly tiny -- less than one part in a hundred thousand trillion.
"That's pretty stable," said Mohr. "The variations -- even if they're there -- would be so small that we won't even have to think about them in most experiments."
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