▁hel ium , ▁the ▁main ▁ing red ients ▁created ▁in ▁the ▁Big ▁Bang . ▁The ▁galax y ' s ▁prim ord ial ▁make up ▁suggests ▁that ▁its ▁rate ▁of ▁star ▁formation ▁has ▁been ▁much ▁lower ▁than ▁that ▁of ▁other ▁galaxies ▁of ▁similar ▁age . ▁The ▁galax y ▁has ▁been ▁studied ▁with ▁most ▁of ▁NASA ' s ▁teles cop es , ▁including ▁the ▁Sp itzer ▁Space ▁T eles cope , ▁the ▁Ch andra ▁X - ray ▁Observ atory , ▁and ▁the ▁Far ▁Ult rav io let ▁Spect ro scop ic ▁Explorer ▁( F USE ). ▁However , ▁it ▁remains ▁a ▁mystery ▁why ▁I ▁Z wick y ▁ 1 8 ▁formed ▁so ▁few ▁stars ▁in ▁the ▁past , ▁and ▁why ▁it ▁is ▁forming ▁so ▁many ▁new ▁stars ▁right ▁now . ▁ ▁In ▁ 2 0 1 5 ▁a ▁study ▁found ▁a ▁very ▁large ▁region ▁of ▁ion ised ▁hel ium ▁in ▁this ▁small ▁galax y , ▁which ▁tends ▁to ▁be ▁more ▁frequent ▁in ▁very ▁distant ▁galaxies ▁with ▁low ▁presence ▁of ▁met als . ▁The ▁ion ization ▁of ▁hel ium ▁implies ▁the ▁presence ▁of ▁objects ▁em itting ▁a ▁radiation ▁inten se ▁enough ▁to ▁knock ▁electrons ▁off ▁the ▁hel ium ▁atoms . ▁Scient ists ▁therefore ▁conclude ▁that ▁I ▁Z wick y ▁ 1 8 ▁must ▁contain ▁Population ▁III ▁stars , ▁which ▁are ▁almost ▁absent ▁in ▁all ▁other ▁galaxies ▁in ▁the ▁local ▁universe . ▁ ▁Dist ance ▁Astronom ers ▁at ▁the ▁Space ▁T eles cope ▁Science ▁Institute ▁in ▁Baltimore , ▁Maryland ▁and ▁the ▁European ▁Space ▁Agency ▁disc ern ed