where G is the gravitational constant and H = H 0 is the present value of the Hubble constant. The value for H 0, as given by the European Space Agency's Planck Telescope, is H 0 = 67.15 kilometres per second per megaparsec. This gives a critical density of 0.85 × 10 kg/m, or about 5 hydrogen atoms per cubic metre. This density includes four significant types of energy/mass: ordinary matter (4.8%), neutrinos (0.1%), cold dark matter (26.8%), and dark energy (68.3%).