Meteor...could it be...

[Griss]

Not too sure about that.
Dalamud originally was just a tiny dot right next to the moon, so actually it's not that big.
Considering Hydaelyn has an atmosphere pretty similar to the one our RL earth has, that thing would probably get reduced to way less mass on it's way through the outer layers of the atmosphere and also would probably split up, leading to many meteors of different sizes raining down on Eorzea.
Looking at all the holes and stuff seen in some 2.0 pictures, I don't think the moon raining down on us would have to lead to mass extinction

Oh, and just because it was build by people does not make it less of a mini moon.
My house is not a machine either just because it was built by man.

Assuming that melphina is of the same size and distance from hydalin as the earths moon. How big would this "Tiny speck" have to be to be visible to the naked eye?

You do get the its not a moon reference right?
Go back and watch star wars.
Write back to me when the empire destroys alderaan by slamming the death star into it.

[Atoli]

Assuming that melphina is of the same size and distance from hydalin as the earths moon. How big would this "Tiny speck" have to be to be visible to the naked eye?

Some satellites with the size of a bus are visible to the naked eye.
Granted, they are not as far away as the moon, but whatver Dalamud is, it wouldn't have to be too big to be visible from Eorzea.
So still probably not big enough to lead to mass extinction

You do get the its not a moon reference right?
Go back and watch star wars.
Write back to me when the empire destroys alderaan by slamming the death star into it.

I'm not into nerdy guys stuff like Star Wars
Isn't the death star that black orb Darth Vader rides on while screaming NOOOOOOOOO?