Planet Rotation Speeds

[Spoo]

Renegade 13 said:
From everything I've read over the past several years, the general consensus is that a roughly Mars-sized planetoid ran head-on into the proto-Earth, hitting with sufficient force to liquify, well, pretty much everything. The impact blasted up sufficient material into orbit that eventually coalesced into the Moon. This theory is supported by the fact that all the Moon material they've ever studied is the same as the material the Earth's crust is composed of, but nothing deeper than the crust, suggesting a massive impact origin.

Of course. What I meant is, we don't know things like the relative velocities or the angle of impact. Thus, we don't know what Earth's original rotation rate was.