critical density kritieke dichtheid ρ_c The density needed for a closed universe. density dichtheid 密度 gram per cubic centimetre gram per kubieke centimeter gram per cubic metre gram per kubieke meter kilogram per cubic decimetre kilogram per kubieke decimeter kilogram per cubic metre kilogram per kubieke meter microgram per cubic centimetre microgram per kubieke centimeter milligram per cubic metre milligram per kubieke meter