According to this site, they are: a) between 1-3 kilometers across; b) far too big to make any sense.
I can't imagine the amount of power it would require to keep something that big hovering off the ground. There were definitely shades of Independence Day in the arrival of the ships, though. I doubt the writers were at all concerned with scientific feasibility! It just looks cool! And I admit, it was cool. If only the rest of the show were so interesting...
Independence Day ripped off V, not the other way around. http://www.thescifiworld.net/interviews/kenneth_johnson_01.htm
Of course that's true, since V predated ID4 by 13 years. Then again, the moment I first saw the original V back in 1983, I could tell right off that it was imitating Arthur C. Clarke's 1953 novel Childhood's End: I'm a lifelong fan of Kenneth Johnson's work, but one thing he's not is original.
How can something be self derivative? Were the Centurions in nuBSG derivative, or what about that black car with the swooshy red light in that (mercifully) short lived Knight Rider revival? To be fair though, as Christopher points out there are other examples in sci-fi that pre-date ID4 and/or the original V. Even District 9 has used the very same imagery. To me though, a fleet of giant ships suddenly appearing over Earth and broadcasting a message for all mankind will forever be the Vogon constructor fleet. As for who ripped off who, I rather suspect Devlin and Emmerich are more familar with the original V than they are with anything written by Clark. It is after all, not uncommon for something to rip of homage something without realising that it was itself already a rip-off/homage. A similar example would be the way 'Invasion of the Bodysnaters' has been endlessly copied while the source material itself appears ot have been heavily influenced by (the much better) 'The Puppet Masters'. As for the ships, they already established that they're powered by magical marbles. Seriously though, it's no more or less implausible than the anti-gravity and inertial cancelling tech seen in shows like Star Trek, Stargate, Farscape or even BSG with it's magical FTL teleportation drive.
But in the passage you quote there, even Clarke admits the idea is not terribly original. "Countless times this day had been described in fiction". If Johnson is unoriginal than so is Clarke.
^No, you're misreading it. Clarke was referring to "this day" as in the day humanity made first contact with aliens. That doesn't mean that those "countless" prior stories about first contact had described those aliens as hovering over Earth's cities in gigantic ships. Since Clarke says it's been described "countless times," he's obviously talking about the general concept of First Contact, not the specifics of how it happens or what comes next.
Assuming they've got anti-gravity, probably a lot les than accelerating the ship to near-light velocities for inter-stellar flight. Any sensible engineer would design the ship so that holding station above any vaguely 1G-ish planet would be stand-by power, with more available for boosting for flight.
^No, any sensible engineer would design the ship to orbit the planet and send down reasonable-sized landing craft. Contrary to what Star Trek and other shows tend to claim, orbit requires no power at all.
Speaking technically, they are big ASS. The engineers weren't in charge of the design of those suckers. Think about it from a PR perspective. Anna does.
I'm not sure how reliable it is, but this site says the original motherships were 3.2 kilometers or more in circumference, which means a bit over 1 km in diameter (circumference = pi x diameter). I'm not sure that sounds quite right. But going from memory and impressions, I'd say the old and new ships are roughly the same size.
The original V claimed they were 3 miles across. I'm not sure it's quoted in the dialog, but I distinctly remember it in the summary/previews of the first or second mini-series. Most likely The Final Battle. I can still hear that narrator's voice stressing "three miles across."
Looking back I'm not sure all of the Visitor ships in the original were the same size anyway. When Pamela's ship arrived in TFB, wasn't it larger than Diana's?
That sounds about right. One kilometer did strike me as too small. For what it's worth, Midtown Manhattan is about two miles wide east to west. The new motherships are clearly far smaller: http://gallery.v-fans.net/displayimage.php?album=29&pos=225 It looks like the mothership there stretches roughly from Second Avenue to Madison Avenue, or a little less, which would make it only around 2/3 of a kilometer across, or 2/5 of a mile. So a lot smaller than the originals.
There was no real indication of that. It simply came down and rested slightly off in the distance beyond the L.A. Mothership. It did get a much more unique arrival showing it menacingly passing over in space and descending into the atmosphere before it came to float nearby Diana's ship. Oh, they are definitely smaller and they also hover at a much lower altitude.
^But they are better-looking. For the most part, this remake has been a disaster, but I do give them credit for two things: Morena Baccarin and the design of the motherships. (Well, exteriors only. Given that the mothership interiors are entirely virtual sets, you'd think they could've made them a little less sparse, grey, and boring. Maybe that would make up for how bad the compositing is.) The original motherships always looked too much like squished hamburgers to me.
I'm pretty sure the dull sparseness is quite intentional and I happen to think the eerie feeling of unreality the compositing imbues actually works in the show's favour. As if the ship itself is wearing a "false skin" disguise just as much as the Visitors are and that there's something very sinister beneath the austere surface...just like Anna. Perhaps I'm being somewhat overly positive, but I honestly had no real expectation that the show would even be watch-able. The original never really engaged me and I fully expected the remake to be even less interesting but I have to admit, it's slowly starting to grow on me.