In the article, the short review of the opinions on the six days (Gen 1) is presented. Despite the domination of the literal understanding through the ages, today’s Biblical commentaries and even Catechism suggest rather symbolical understanding, perhaps because of the natural sciences findings. The article emphasizes that after the coordinate system is changed, the literal understanding becomes valid. Moreover, cosmological constants enable to calculate the time period from one system to other. The quantum physics sheds the interesting light on the early story of the Universe, too.