If the sum of sigma-sub-m and sigma-sub-lambda equals one, then this quantity is inversely proportional to the expression “three times the square root of sigma-sub-lambda.” That expression containing this quantity can be derived by solving an equation involving the fraction “a dot over a,” where a is the scale factor. (-5[1])According to Dirac’s (-5[1])large numbers hypothesis, this quantity is inversely proportional to the gravitational constant. Einstein added the (*) cosmological constant to one of his field equations due to an existing belief that this quantity is infinite. This quantity is 9.3 (-5[1])billion if its namesake entity is “critical” but is around 1.5 times bigger if the namesake entity is “open.” For (10[1])10 points, name this (10[1])quantity, which according to the Planck satellite, is about 13.8 billion years. (10[1])■END■ (10[1])