4. Holqa gurraacha isa guddaa:- Holqi gurraachi kun immoo kan isaan uumaman yeroo uumama gaalaaksiiwwanii yoo ta’u hangi isaanii hanga (mass) aduu dachaa miliyoona tokko hanga biliyonootaa ta’u danda’a. Fakkeenyaaf holqa gurraacha gaalaksii keenya (milk way) keessatti argamu kan saajitaaras A (sagittarius A) kan jedhamu hanga aduu miliiyoona afur ta’e qaba.