In de Sitter space, the Gibbons-Hawking temperature is proportional to this quantity. The square of this quantity divided by its past value may be expressed as a sum of four powers with coefficients denoted by capital omegas. The critical density varies with the square of this quantity, which is added to this quantity’s time derivative in one form of the Friedmann (-5[1])acceleration equation. A namesake “tension” is due to the disagreement (15[2])over whether this quantity, which is defined as the ratio of the (*) scale factor and its derivative, is closer to 68 or (10[1])74 kilometers per second (10[1])per megaparsec. (-5[1])The reciprocal of this quantity gives an estimate for the age of the universe under linear expansion. For 10 points, what deceptively-named constant characterizing the “flow” of the universe is named for the same astronomer as the precursor of the James Webb Space (10[1])Telescope? ■END■ (10[1])