1. Well, from what I know and from how I understand things, all planes have the same laws of physics. All are formed of condensed mana, as I understand it, and that's how a powerstone creates a pocket dimension/plane within itself when charged. The laws of physics of a plane can probably differ a little if a particular color of mana is dominant there; i.e. in Serra's Realm Xantcha was dying because being phyrexian, her essence is black mana, while Serra forged her realm entirely of white mana which would extinguish any sources of its opposite, black. Also, because it was made of white mana, it had a decidedly white-mana look to it; an afternoonish golden-hued sky, clouds, small patches of floating meadows, pearly white towers, etc. On the other hand, Phyrexia is filled with black mana and even weakened Urza when he entered it for a brief time. A world made up of blue mana would probably be made up of either endless blue skys and clouds, endless oceans, or a combination, and gravity would probably mean nothing there, even time might be slowed or quickened there, a little. I can't remember Pyrulia or whatever, I read Thran months and months ago when it came out. :)

2. No, referring to my first answer, a powerstone plane is not made up of the contents which charged it; it reduces the stuff to the raw mana that it was composed of when it sucks it up; the mana that Radiant was made of would be scattered across the plane like only so much dust.

3. I'm guessing so, yes. Powerstones might exist in the pocket dimension, just as any other mineral or gemstone may, but powerstones don't exactly come charged right out of the mine. It took the Thran a powerful mana rig to suck magma from Dominaria's core and condensed it into raw mana while shoving it into the powerstone to charge it. I'm just not sure if the powerstone plane would become unstable after having its own molten core sucked from it, since powerstones are charged from an outside, artificial source and may only have a limited mana supply; powerstones DO become depleted eventually, it just takes a few millenia. :) Draining their own internal mana supply to charge other powerstones would likely deplete the mana stores that charged them faster than they can regenerate their mana supply, at any rate, since it takes tremendous amounts of magma I believe. *shrugs* Not to mention that it could be dangerous to create planes within planes within planes; what if someone found the original powerstone and obliterated it? Or what if they hooked it up to an artifact to power it; the people inside would likely find their little world begin to turn unstable and suffer from natural disasters at an ever-increasing rate, especially if they were still draining its mana supply to charge more powerstones.

4. Yes, people could probably do that. Once again though, there's that danger factor. Then there's also the problem of actually entering and exiting the powerstone planes. The Thran didn't have the chance to figure that out before Yawmoth's betrayal. It would probably be incrediably difficult even for a planeswalker, as the powerstone planes would exist outside of the normal multi-verse and would have extra difficulties to overcome when trying to enter or leave. It probably wouldn't be worth the mana the planeswalker had to expend to go back and forth like that.

5. Yes, probably, if their mana supply IS limited and not self-replenishing, then they probably collapse when out of mana.

6. Yes, if a 'mother plane' collapses, then all of the powerstones on that plane will be obliterated as well, thus bringing a sudden apocalypse to all inhabiting those powerstone planes and destroying all of the powerstones in THAT plane as well, bringing an apocalypse to the inhabitants of its own powerstone planes, etc.

7. I'm not sure on that one. Phyresis and Pthesis may be latin, but I wouldn't know. I only know english and a little bit of spanish.

8. Probably, if they take the time and care to do so and put the right proportions of mana in it.

9. I wouldn't know. Supposedly Yawgmoth thought that the brain or one of the glands within the brain of a planeswalker held the power to become a planeswalker. But I'm pretty sure that it just comes from a special trait in the person's soul. Yawgmoth may have slain Dyfed and as her soul departed, he drew the mana from her corpse into himself using the devices of Phyrexia... I'm not sure though.

~ /\/\ist Phantom ~