In article , (G=EMC^2 Glazier) wrote:
Tom All this begs the question. IHow can rocks in our solar system be
all that different from each other? It makes sense that the Moon can
have no sedimentary rock. The Moon rocks were studied and found to be
3.5 billion years old,and Earth's rocks much younger. Maybe your right
Tom we are getting our information from different books Go figure
Bert

I'm getting my info from actual research papers, I think you're getting
yours from old books or are misunderstanding what you are reading. The
oldest moon rocks, btw, are between 4.4 and 4.5 billion years, not 3.5
billion, but are still younger than the earth.

We're obviously not talking about sedimentary rocks, but lunar rocks
returned to earth are remarkably similar to earth rocks apart from the
abundance of water and volatile elements. Those facts alone don't rule out
capture theory but *do* support the impact theory and rule out other,
earlier, moon formation theories. The fact that capture of a large object
such as the moon by a planet the size of the earth is hugely improbable,
and that all the recent studies support its formation via impact, make
impact a much more likely scenario than capture.

Pointing out that other planets have captured moons is completely
irrelevent, as the earth-moon system is pretty unique and capturing small
asteroid-sized bodies by a planet is *much* easier than the earth
capturing a moon-sized object.

The literature is out there if you want to look.