> Aine wrote:
> > This is true. The evidence is that life on Earth began pretty
> > much as soon as it could--within a few hundred million years.
> I never said anything about the "origins" of life and make
> clear note of the existence of life prior to the Pre-Cambrian
> explosion. As I said, simple life as what is seen prior to the
> Pre-Cambrian explosion does not necessarily require the Moon,
> but it is generally agreed land based life forms as we know it
> could not have evolved without it.
But that doesn't mean that the Moon is only 600 million years old. You can't use that to disprove that it's almost as old as the Earth.
> > As far as the so-called Cambrian explosion goes, it was more
> > increase in size coupled with the evolution of hard shells
> > exoskeletons that made fossil preservation much more likely.
> > Soft bodies don't fossilize well.
> You are ignoring the known mass extinctions that directly
> preceded the Pre-Cambrian explosion, for one, but also, no one
> doubts that the Pre-Cambrian explosion occurred, the debate is
> over the existence, or lack there of, of sufficient
> intermediary forms directly preceding it.
Nope, not ignoring it at all. What I'm saying is that it wasn't really an "explosion"; those life forms clearly had to have an ancestor further back that for whatever reason we don't know about yet. And there are probably plenty of species we'll never, ever know about, either Cambrian or Precambrian, simply because we don't have the fossils.
> > Excellent question. Since we can't observe rocky planets the
> > size of Earth directly, we don't know YET whether or not
> > rocky exoplanets have moons. It's a good bet that some of
> > do, though.
> But we can observe what is found in our solar system and make
> comparative analysis regarding the likelihood of proportionate
> size relative to its host which there is little doubt the Moon
> is unusually large among other things.
But we don't know if that's typical. Just because Earth/Moon is the only one we have direct knowledge of doesn't mean other systems are the same.
It is comparable to
> Neptune having a moon the size of Earth. Unfortunately, it is
> likely not common rocky planets have moons
> making our our Moon even more serendipitous.
> > We assume an awful lot because Earth and our solar system is
> > really the only analogue we have. Our solar system may or may
> > not be typical. We just don't know yet.
> And do we not also "assume an awful lot" regarding other life
> in the Universe because humans are the only analogue we have?
Of course we do--and we could be wrong.
> > Absolutely agree. Given enough time, even the most seemingly
> > impossible things can and will happen.
> Like extraterrestrials terraforming Earth?
> > Yep, and no matter what people think, the Moon is not hollow.
> > It wouldn't be quite so easy to do. One false move and you'd
> > send the Moon crashing into the Earth.
> Nope. You are limiting your thinking to current technology. But
> regardless, I did not say the Moon was entirely hollow, didn't
> even mention "hollow", but there is very good evidence
> suggesting there are numerous hollow areas under the surface.
I think you just missed the point.