Parallel universes in fictionA parallel universe, also known as a alternate universe, parallel world, or alternate reality, is a hypothetical self-contained plane of existence, co-existing with one's own. The sum of all potential parallel universes that constitute reality is often called a "multiverse". While the five terms are generally synonymous and can be used interchangeably in most cases, there is sometimes an additional connotation implied with the term "alternate universe/reality" that implies that the reality is a variant of our own, with some overlap with the similarly named alternate history.
TorchwoodTorchwood is a British science fiction television programme created by Russell T Davies. A spin-off of the 2005 revival of Doctor Who, it aired from 2006 to 2011. The show shifted its broadcast channel each series to reflect its growing audience, moving from BBC Three to BBC Two to BBC One, and acquiring American financing in its fourth series when it became a co-production of BBC One and Starz. Torchwood is aimed at adults and older teenagers, in contrast to Doctor Whos target audience of both adults and children.
Sonic screwdriverThe sonic screwdriver is a fictional multifunctional tool in the British science fiction television programme Doctor Who and its spin-offs, used by the Doctor. Like the TARDIS, it has become one of the icons of the programme, and spin-off media such as The Sarah Jane Adventures and Torchwood have replicated its functions in devices such as the sonic lipstick, sonic blaster, sonic probe, sonic modulator and sonic cane. The sonic screwdriver was introduced in 1968 in the story Fury from the Deep, and used twice more (The Dominators and The War Games) during the Second Doctor's tenure.
