Captain Robert April said:
Obviously, it's being made of something totally kewl, dude! since that appears to have been the primary consideration, how kewl it looks.
This is what happens when you start playing games with these kinds of longstanding assumptions, like the bulk of work on the Enterprise's construction being done in orbit. Ya tend to ignore the reasons why that assumption was made in the first place, like maybe it makes a helluva lot more sense to build a ship of that size in orbit. Never mind that nothing in canon spells out the process explicitly, the logical problems alone should be enough to chuck this notion of building it on the ground out the nearest airlock.
Maybe there's some minor plot point that necessitated building it on the ground, like Starfleet executives (I'm mean, Admirals) sitting nearby in their lounge chairs and admiring the ship while sipping Banana Daiquiris or soemthing.
Seriously, though, I hope the images of this ship are not going to be the final product in the movie. From what little I'm seeing here, it seems to be taking on certain of the visual traits that made the TMP refit Enterprise so disappointing. That hull lettering looks so goofy, it's laughable. It's so 1979. Toss out the disco ball and slap on the block lettering! And what's up with that hideous busy assembly around the lower saucer dome? That always struck me to be one of the mistakes
of the refit. Bring back the glowing dome, without the assembly!