▁objects ▁in ▁a ▁fixed ▁" space " ▁moving ▁apart ▁into ▁" empt iness ", ▁as ▁space ▁itself ▁growing ▁between ▁objects ▁without ▁any ▁acceleration ▁of ▁the ▁objects ▁themselves . ▁The ▁space ▁between ▁objects ▁shr inks ▁or ▁grows ▁as ▁the ▁various ▁ge odes ics ▁conver ge ▁or ▁diver ge . ▁ ▁Because ▁this ▁expansion ▁is ▁caused ▁by ▁relative ▁changes ▁in ▁the ▁distance - def ining ▁metric , ▁this ▁expansion ▁( and ▁the ▁result ant ▁movement ▁apart ▁of ▁objects ) ▁is ▁not ▁restricted ▁by ▁the ▁speed ▁of ▁light ▁upper ▁bound ▁of ▁special ▁relativ ity . ▁Two ▁reference ▁frames ▁that ▁are ▁glob ally ▁separated ▁can ▁be ▁moving ▁apart ▁faster ▁than ▁light ▁without ▁viol ating ▁special ▁relativ ity , ▁although ▁whenever ▁two ▁reference ▁frames ▁diver ge ▁from ▁each ▁other ▁faster ▁than ▁the ▁speed ▁of ▁light , ▁there ▁will ▁be ▁observable ▁effects ▁associated ▁with ▁such ▁situations ▁including ▁the ▁existence ▁of ▁various ▁cosm ological ▁hor iz ons . ▁ ▁Theory ▁and ▁observations ▁suggest ▁that ▁very ▁early ▁in ▁the ▁history ▁of ▁the ▁universe , ▁there ▁was ▁an ▁infl ation ary ▁phase ▁where ▁the ▁metric ▁changed ▁very ▁rapidly , ▁and ▁that ▁the ▁remaining ▁time - dep end ence ▁of ▁this ▁metric ▁is ▁what ▁we ▁observe ▁as ▁the ▁so - called ▁Hub ble ▁expansion , ▁the ▁moving ▁apart ▁of ▁all ▁grav itation ally ▁un bound ▁objects ▁in ▁the ▁universe . ▁The ▁expand ing ▁universe ▁is ▁therefore ▁a ▁fundamental ▁feature ▁of ▁the ▁universe ▁we ▁inhab it ▁– ▁a ▁universe ▁fund ament ally ▁different ▁from ▁the ▁static ▁universe ▁Albert ▁Ein stein ▁first ▁considered ▁when ▁he