A supposedly mythical world (pronounced "all-DAY-uh") that is deep red-orange with a thick cloud cover when its planet-wide EM screen is not in effect. Built millenia ago to avoid marauders, the screen's cloak deteriorated the ozone layer long ago and rendered its citizens sterile with radiation poisoning. Its ocean life had already been killed off a generation prior to the planet's discovery by the crew of the U.S.S. Enterprise in 2364.