"Because they have something in common," she said.
(I always overlook the obvious.)
So, what, fundamentally, do the starship Enterprise and the Guggenheim museum have in common?
They both are not square.
They're not round in every way or in all the same ways, but they're not fundamentally square.
Almost every humanmade thing around me is square, from this laptop I am typing on, to the table it sits on and the room and house we are in.
Why?
Things don't have to be square. (I'm not.)
Here are some more images of non-square structures and floaty things that remind me of the starship & the museum. (See also Bulletin Board #1, below)
.
.
LEFT:
The Pantheon, Rome, first built in 27 B.C. *
Like the starship and the museum, it has a sort of outrigger feature (its square porch).
RIGHT:
A Sinhalese outrigger, from Bjorn Landstrom's The Quest for India.
Found on Indigenous Boats blog, "small craft outside the Western tradition."
LEFT:
Pile of Melmac cups
From My Vintage Addiction
RIGHT:
From the BBC: Lost Palaces of Iraq.
"The Great Mosque at Samara is the most memorable architectural image in Iraq.
The minaret was built in about 850 AD and is a 52m-tall spiral."
ABOVE: Mosque in Bougouni, Mali. From Architecture in Medieval Islamic Empires 
ABOVE: Radio station headquarters in Krakow, Poland. From the cool blog One Good Thing, which has many examples of nonsquare structures. More images here.
ABOVE: Starship C-57D, from Forbidden Planet (1956). **
ABOVE: Altocumulus lenticularis clouds, from Lee. "Lenticular" clouds are lens-shaped. Also called wave clouds or flying saucer clouds, because they are sometimes confused for UFOs. The Alaska Science Forum notes that when wave clouds form in layers (like above), they are called pile d'assiettes, French for "pile of plates".
Weather balloon. Half the images I found of weather balloons were on UFO sites... This one's from eHow "What Does a Weather Balloon Do?" Turns out they measure the weather in the atmosphere. 
LEFT:
Pneumatic bubbles installation, Los Angeles, 2007.
They inflate and deflate when people touch them. More photos at Fox Lin (design team).
RIGHT:
Handsculpted porcelain jellyfish.
(These are several feet in height, and made entirely of porcelain--including their... whatever you call their dangly bits.)
From Coe & Waito (links to their blog), found on Trendhunter
Captain Nemo and the crew of the Nautilus observing jellyfish, from the 1870 French edition of Jules Vernes' 20,000 Leagues Under the Sea (image from Ocean Explorer).
A diving submarine from Nautilus Submarines & Diving Systems(For Kellie.)
____________________
* Re The Pantheon
Hadrian, who built the Pantheon that survives:
"My intentions had been that this sanctuary of All Gods should reproduce the likeness of the terrestrial globe and of the stellar sphere...** RE: Forbidden Planet Spaceship
The cupola...revealed the sky through a great hole at the center, showing alternately dark and blue.
This temple, both open and mysteriously enclosed, was conceived as a solar quadrant. The hours would make their round on that coffered ceiling so carefully polished by Greek artisans; the disk of daylight would rest suspended there like a shield of gold; rain would form its clear pool on the pavement below, prayers would rise like smoke toward that void where we place the gods."
Bit of trivia: Joss Whedon codenamed the search-and-rescue ship on the planet Miranda C57D, after the Forbidden Planet spaceship, in his Firefly film Serenity. Miranda is Prospero's daughter in Shakespeare's Tempest, upon which The Forbidden Planet is based.
