▁qu as ar ▁yet ▁observed . ▁The ▁qu as ar ▁em itted ▁the ▁light ▁observed ▁on ▁Earth ▁today ▁less ▁than ▁ 6 9 0 ▁million ▁years ▁after ▁the ▁Big ▁Bang , ▁about ▁ 1 3 . 1 ▁billion ▁years ▁ago . ▁ ▁The ▁qu as ar ' s ▁lum inos ity ▁is ▁estimated ▁at ▁ ▁solar ▁lum inos ities . ▁This ▁energy ▁output ▁is ▁generated ▁by ▁a ▁super mass ive ▁black ▁hole ▁estimated ▁at ▁ ▁solar ▁masses . ▁According ▁to ▁lead ▁astronom er ▁B añ ados , ▁" This ▁particular ▁qu as ar ▁is ▁so ▁bright ▁that ▁it ▁will ▁become ▁a ▁gold ▁mine ▁for ▁follow - up ▁studies ▁and ▁will ▁be ▁a ▁cru cial ▁labor atory ▁to ▁study ▁the ▁early ▁universe ." ▁ ▁Sign ific ance ▁The ▁light ▁from ▁U L AS ▁J 1 3 4 2 + 0 9 2 8 ▁was ▁em itted ▁before ▁the ▁end ▁of ▁the ▁theoret ically - pred icted ▁transition ▁of ▁the ▁inter gal actic ▁medium ▁from ▁an ▁elect r ically ▁neutral ▁to ▁an ▁ion ized ▁state ▁( the ▁epo ch ▁of ▁re ion ization ). ▁Qu as ars ▁may ▁have ▁been ▁an ▁important ▁energy ▁source ▁in ▁this ▁process , ▁which ▁marked ▁the ▁end ▁of ▁the ▁cos mic ▁Dark ▁A ges , ▁so ▁obser ving ▁a ▁qu as ar ▁from ▁before ▁the ▁transition ▁is ▁of ▁major ▁interest ▁to ▁theoret icians . ▁Because ▁of ▁their ▁high ▁ult rav io let ▁lum inos ity , ▁qu as ars ▁also ▁are ▁some ▁of ▁the ▁best ▁sources ▁for ▁studying ▁the ▁re