aeon, eternity, every second, time, diuturnity, duration, length, infinitillion, cycle, annum, more...

instant, moment, second, minute, hour

eldest, second, new, phanerozoic, only, third, youngest, archean, present, oldest, natural

cosmic age,   1 billion years,   a billion years,   a million years,   one billion years,   10000 years,   one million years,   vast amount of time,   billions of years,   stage of evolution