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Metrology

All articles tagged with #metrology

Envelope Trick Highlights Subtle Biases in Measuring Gravity’s Constant
science9 days ago

Envelope Trick Highlights Subtle Biases in Measuring Gravity’s Constant

An NIST redo of the 2007 BIPM measurement of the gravitational constant G, using a blinded-envelope approach to avoid bias, yields a result close to the French value but with a 0.0235% discrepancy after adjustments; Schlamminger also identifies a newly observed spurious torque driven by temperature gradients and residual gas in the vacuum, suggesting unaccounted biases in the uncertainty budget and underscoring the ongoing challenge of precisely measuring G and the importance of reproducibility.

via The Debrief|
#gravitational-constant#gravity#metrology
Gravity’s oldest constant remains unsolved after 340 years
science13 days ago

Gravity’s oldest constant remains unsolved after 340 years

Space.com reports that the gravitational constant Big G—the oldest fundamental constant in physics—remains the least precisely known after 340 years. A decade-long effort led by NIST’s Stephan Schlamminger used a refined torsion‑balance experiment with an envelope bias to avoid “intellectual phase locking,” producing a Big G value slightly lower than CODATA’s standard. The result, among 17 measurements, suggests a possible revision to Earth's mass if correct, but the persistent discrepancies between experiments mean the fundamental mystery of gravity’s strength is not solved.

via Space|
#big-g#codata#gravity
Gravity Makes Time Local: Atomic Clocks Detect Millimeter-Scale Time Differences
science20 days ago

Gravity Makes Time Local: Atomic Clocks Detect Millimeter-Scale Time Differences

The most precise optical atomic clocks can now detect gravitational time dilation over a mere millimeter in a lab: clocks at the bottom run slightly slower than those at the top, enabling direct tests of general relativity at human scales. With precision around one part in 10^21—roughly one second in 30 billion years—this landmark achievement opens practical avenues for gravimetry, geophysics, and possibly redefining the second, signaling that time is locally shaped by gravity rather than universally uniform.

via Space Daily|
#atomic-clocks#general-relativity#gravitational-time-dilation
Big G defies precision again as latest measurement clashes with CODATA
science1 month ago

Big G defies precision again as latest measurement clashes with CODATA

After a decade-long effort at the National Institute of Standards and Technology to measure Newton’s gravitational constant Big G, Schlamminger and colleagues report a value of 6.67387e-11 m^3 kg^-1 s^-2 that is about 0.0235% lower than the replicated result and inconsistent with the CODATA standard, highlighting the long-standing scatter in Big G measurements. The team blind-tested the experiment to avoid bias and published their findings in Metrologia, underscoring that precision metrology often raises questions and may point to small systematic biases rather than new physics.

via CNN|
#bigg#codata#fundamental-constants
NIST's decade-long hunt keeps Big G from settling on a single precise value
science1 month ago

NIST's decade-long hunt keeps Big G from settling on a single precise value

NIST researchers spent a decade replicating a Cavendish-style experiment to measure Big G, testing copper and sapphire masses with an electrostatic twist, and report G = 6.67387×10^-11 m^3/kg/s^2—about 0.0235% lower than the BIPM value. The result adds another data point but does not resolve the long-standing discrepancy, highlighting gravity’s weakness and Earth’s background noise as ongoing challenges — while advancing precision instrumentation and metrology.

via Ars Technica|
#big-g#gravitational-constant#metrology
Big G Remains Elusive as a Decade of Gravity Tests Clash with CODATA
physics1 month ago

Big G Remains Elusive as a Decade of Gravity Tests Clash with CODATA

After a decade of cross‑Atlantic replication led by NIST, the new measurement of the gravitational constant G disagrees with both the 2013 BIPM result and CODATA’s current value, highlighting that Big G is still the least precisely known fundamental constant and that the true value remains unresolved despite improved methods (including a blinded measurement to reduce bias).

via Nature|
#bigg#bipm#gravitationalconstant
Photons Hit Quantized Hall Drift, Echoing Quantum Hall Effect
science3 months ago

Photons Hit Quantized Hall Drift, Echoing Quantum Hall Effect

Researchers demonstrated a quantized transverse drift of light that mirrors the electronic quantum Hall effect, using a frequency-encoded photonic Chern insulator. The photon steps depend only on fundamental constants, potentially establishing an optical standard for ultra-precise measurements and strengthening quantum photonic technologies; the result, published in Physical Review X, could impact metrology and sensor development.

via ScienceDaily|
#light#metrology#photonics