Machine translation has existed long before ai though ai is now one of the ways to do. It has also has never been and is still not as good as a good human translator but it has already gotten much better and is improving rapidly. (Source: family member works in translations.)
Yes Sunday comes from day of the sun which was a translation of dies solis in Latin, same for Monday. And naming days of the week after celestial objects (which usually were also gods) comes from babylon and rome.
Yup but the days of the week are mostly Norse gods, Tuesday = Tyr, Wednesday Woden/Odin, Thursday = Thor, Friday = Freya. Though Saturday, Sunday and Monday come from the Latin week which was named after gods/planets.
Well that wont be the case for long. World population is barely growing and that is just because of Africa. Outside of Africa and central Asia only a handful of countries are even at replacement rate.