The design intent is that QUIDs must withstand the rigors of space travel - no sharp edges and no chemicals that could hurt space tourists.

"None of the existing payment systems we use on earth - like cash, credit or debit cards - could be used in space," said Professor George Fraser from the University of Leicester. "Anything with sharp edges, like coins, would be a risk to astronauts while the chips and magnetic strips used in our cards on Earth would be damaged beyond repair by cosmic radiation."

The QUID is made from a space-qualified polymer - PTFE (polytetrafluoroethylene). This material is widely used by space agencies because of its durability and versatility. Earthlings know it better as "teflon," and are well-aware of its resistance to high temperatures and corrosive materials. (Merchants will like the ease with which QUIDs slide out of consumer's pockets.)

The rounded edges of the QUID make it safer, and also encompass the eight planets orbiting a sun which are part of the design. Each of the orbiting planets contain a serial number; taken together, these numbers will give each QUID disc a unique code to prevent counterfeits.

What's a QUID worth? The current exchange rate for the new currency is £6.25 to the QUID (or US$12.50 or about 8.68 Euros).

(Quasi Universal Intergalactic Denomination detail)

Hopefully, as we travel further from Earth and spread throughout the galaxy, people will not confuse the QUID with the "quid" - a slang term for the British pound sterling, possibly deriving from the location of the Royal mint at Quidhampton, Wiltshire, England.

Science fiction fans are probably more used to terms like the ubiquitous "credit." Here's a sample of more interesting future currency names:

"Authority pays the same for ice now as thirty years ago. And that's not okay. Worse yet, Authority scrip doesn't buy what it used to. I remember when Hong Kong Luna dollars swapped even for Authority dollars. Now it takes three Authority dollars to match one HKL dollar..."
(From Robert Heinlein's 1966 novel The Moon is a Harsh Mistress)

Philip K. Dick fans enjoy swapping the genetically unique truffle skins from his 1964 novel The Three Stigmata of Palmer Eldritch:

...Mr. Icholtz brought out his wallet and began counting out skins. "Very little publicity will be attached to this at first. But eventually--" He offered Hnatt the stack of brown, wrinkled, truffle-skins which served as tender in the Sol system...
(Read more about the truffle skins)

Readers are encouraged to contribute more science-fictional currency names.