metrology 0.1.0

The physical constants the quantum-gravimeter crates share: CODATA 2018 fundamental constants, standard gravity, and the astronomical units of mass, distance and time.
Documentation

metrology

The physical constants the quantum-gravimeter crates share, defined once: the exact SI defining constants, the CODATA 2018 values of G, α, μ₀, ε₀ and the particle masses, standard gravity, and the astronomical units of mass, distance and time.

Install

cargo add metrology

Example

use metrology::{C, G, HBAR, SOLAR_MASS};

// The Schwarzschild radius of the Sun, 2GM/c²: about 2.95 km.
let r = 2.0 * G * SOLAR_MASS / (C * C);
assert!((r / 2953.3 - 1.0).abs() < 1e-3);

// The Planck length, √(ħG/c³).
assert!(((HBAR * G / C.powi(3)).sqrt() / metrology::PLANCK_LENGTH - 1.0).abs() < 1e-5);

What is inside

Group Constants Source
SI defining constants (exact) C, H, HBAR, E_CHARGE, K_B, N_A, R_GAS SI Brochure 2019
Measured G, ALPHA, MU_0, EPS_0, M_E, M_P, AMU, M_H, PLANCK_LENGTH CODATA 2018
Energy EV, KEV
Earth and astronomy G0, GM_EARTH, GM_SUN, SOLAR_MASS, PARSEC, MPC, YEAR IERS Conventions 2010; IAU 2015 B3

How it is checked

A test checks that the derived constants agree with each other: ħ = h/2π, R = N_A k_B, μ₀ε₀c² = 1, α = e²/4πε₀ħc, the Planck length, and the solar mass.

One of six crates in quantum-gravimeter: metrology (constants) · geopotential (the gravity field) · gravimetry (missions and GRACE) · gravitational (waves) · gravitics (frontier gravity) · plasmoid (fusion plasma).