If planets, moons and asteroids are formed by clumps of
> irregular debris accreting and clumping together by the force
> of gravity, then of course there’ll be hollows in between the
> The key word being "if" here... That theory is an old one and
> it has been around for a long, long time before any exoplanets
> were discovered and studied. And based on what we've learned in
> the last couple of decades seems to indicate that many
> extra-solar planetary systems could not have formed by the
> accretion of gases/elements, as previously believed (before we
> had any real data on the subject, I might add)... Which means,
> at this particular juncture, the bottom line is: We honestly
> don't know.
What's the theory for the formation of exo-planets? Can you provide a link?