Re: We know all that!
There are limits though, and basing a storyline on things which are simply impossible no matter how you look at it ! Like the moon getting 6 times heavier without changing size - apart from where did all the extra mass come from to be that heavy it would need to be made from something as dense as solid plutonium. And why would something 'born' in space have wings and be seen flapping them to fly off - wings in space are totally useless.
The writing on Doctor Who seems to be increasingly based on 'we can do this, and it would look cool' without any application of critically thinking 'yes but WHY would that happen' :(