Why are names of the days of the week IDENTICAL in the Indian (which includes not just Aryan languages, but also Tamil e.g.) and ancient Greek culture (which I believe influences the rest of Europe)? Is it a remnant of the common PIE history or is it a later cultural transmission?

by BrashtacharKeKhiladi

Just adding more to it, the Indian names come from their system of astrology, Navagraha and the order it seems is identical to the Hellenistic one...

https://en.wikipedia.org/wiki/Navagraha

But the question is, does it mean that the Navagraha system itself is Aryan in origin? But if so, why is the system of worship better developed in the south of India (which suggests it came from the South)? If not, was it developed later in the South?

MooseFlyer

To be clear, you're asking about the fact that the planetary association of the days are the same right? Because the actual names aren't.