TT is distinct from the time scale often used as a basis for civil purposes, Coordinated Universal Time (UTC). TT is indirectly the basis of UTC, via International Atomic Time (TAI). Because of the historical difference between TAI and ET when TT was introduced, TT is 32.184 s ahead of TAI.
tt is distinct from the time scale often used as a basis for civil purposes coordinated universal time (utc) tt is indirectly the basis of utc via international atomic time (tai) because of the historical difference between tai and et when tt was introduced tt is 32184 s ahead of tai