a few things:
No trace of the colony remains. You are assuming that this also means "no trace of the physical mass of the entire planet which contained that colony ". This assumption of yours is fantasy; nothing more.
Marcus: ...We tried to track them. But we lost them at around sector 70..
Delenn: Theres a shadow base not far from there.
Ivanova: Exactly! so as soon we got back i had C&C MONITOR that area for any transmissions, anything unusual. The shadow base was located on a planet called arkada7. Its not there anymore.
Lennier: The base?
lyta: No! The planet! They destroyed...They destroyed an entire planet!
here we clearly see that "its not there anymore" means that the whole planet itself is not there anymore.. not just the mass upon which the the base/colony resided.
Zha'ha'dum was their homeworld for millions of years. That's quite a bit of time to prepare it for their eventual departure. It does not imply the ability to do this to any other world.
but what if the shadows had adopted another planet as their main hq, or home, wouldnt they have it similarly prepared for their eventual departure?..
we also dont know how long it took the shadows to prepare the means to shatter z'ha'dum. they couldve had the tools ready on day one of moving in, meaning it wouldnt have necessarily taken them millions of yrs to prepare for shattering the planet, just because they had stayed there for that amount of time.
Zha'ha'dum was not a normal planet. It is obviously moon-sized or smaller with no molten mantle, given the enormous fissures which are gouged deep into the planet. Gravity would close such a large fissure in a normal planet-sized object.
though i agree with you regarding the plausibility of the large fissures, and the fact we saw never saw supporting structures/frameworks as such. though to conclude that the planet has no mantle?.. perhaps the fissure wasnt deep enough.. afterall we dont exactly know how large z'ha'dum was.. However book 3 of the technomage trilogy nevertheless states z'ha'dum to have gravity 1.3 times normal.. cant remember the exact page, as i currently dont have the book on hand... heres a quote presented in another forum a year ago.
"The planet seemed to exist in twilight. The gravity, 1.3 times standard, pulled at his feet."
You're resorting to the use of gaming sites as evidence, and you don't realize that you come off as desperate?
information from b5wars was granted canon status along with those from the novels and graphic novels approved by jms (all).. making it binding/accompanying canon to information directly from the series.. and at the very least holds official status.
He also said that we can destroy planets today, using nuclear weapons. He obviously means "destroy" only in the sense that Hiroshima was "destroyed", even though the ground under the city was completely untouched and there were large numbers of survivors.
true enough.. but the above quote regarding the status of arkada 7 definitely means that the whole planet was destroyed/shattered along with the base.