Since the time of Hubble, astronomers have been trying to measure as accurately as possible the rate of expansion, referred to as the “Hubble constant. ”
يحاول الفلكيون منذ ايام هابل ان يقيسوا بأدق ما يمكن سرعة التمدد ،‏ التي تدعى ثابت هابل Hubble constant‏ .‏