without the moon, earth would likely have become a tectonically dead world a few billion years ago.
Why? Something to do with tidal influence on the core?
I'd also like to know. I supposed there must have been a lot of heat from the initial impact, tides must also happen inside the Earth, but I wonder how different the Earth would have looked like techtonically without the Moon?
No plate tectonics? So perhaps resurfacing event(s) like on Venus?