For 10 points, name this proportionality parameter between an object's distance and its redshift, named for an American astronomer.
In a matter-dominated universe, the square of this value is inversely proportional to the cosmological constant, and during cosmic inflation the scale factor was proportional to e to the power of this value multiplied by time. Taking the time derivative of this value and dividing by this value squared, adding one, and negating gives the deceleration parameter, while the square of this value appears one one side of the Friedman equation. Easily defined as the time derivative of the scale factor divided by the scale factor, one over this value is approximately equal to the age of the universe. For 10 points, name this proportionality parameter between an object's distance and its redshift, named for an American astronomer.
In a matter-dominated universe, the square of this value is inversely proportional to the cosmological constant, and during cosmic inflation the scale factor was proportional to e to the power of this value multiplied by time.
{Hubble's} constant