Its empirical value is about 70 kilometers per second per megaparsec.
The density parameter is inversely proportional to the square of this parameter, and its square is on the left of the first Friedmann equation. For the scale factor a, this value is a-dot over a, and the value of this quantity is about one over the (*) age of the universe. Its empirical value is about 70 kilometers per second per megaparsec. This constant appears in a law of the same name relating the recessional velocity, or redshift, of galaxies to their distance, and that law containing this constant supports the expansion of the universe. For 10 points, give this constant named after an American scientist who also names a NASA space telescope.
The density parameter is inversely proportional to the square of this parameter, and its square is on the left of the first Friedmann equation.
Hubble constant (accept Hubble’s Law, or basically anything mentioning Edwin Hubble)