An italic capital G, the constant in Newton's law of gravitation.
Also known as: Big G, Newton's constant
G is the least precisely known of the major physical constants, and the only one in this batch that is still measured rather than fixed. Independent experiments disagree beyond their stated uncertainties, and the discrepancy is unresolved.
Denotes the constant of proportionality in Newton's law of universal gravitation, and appears in the Einstein field equations.
Contexts: Mathematics, Laboratory
Is the least precisely known of the major physical constants. Independent measurements disagree by more than their stated uncertainties, and no accepted explanation for the discrepancy exists.
The disagreement is between experimental groups about a measured value, not about what the symbol denotes or what the law says. CODATA publishes a recommended value with an uncertainty that reflects the spread.
Contexts: Mathematics, Laboratory
Is distinguished in speech as 'big G' from lower-case g, the local acceleration due to gravity, which is a different quantity with a different dimension.
Contexts: Mathematics, Laboratory
A capital Latin letter G set in italic type, an open circle with a horizontal bar turning inward at its right side.
Fundamental constants, though this one alone is still measured rather than fixed.