Magnetron

Magnetrons were used to transport massive objects, such as planets. The technology was possessed by both Daleks and Time Lords alike. A Time Lord supercruiser was known to be equipped with one, and seemed to operate on a similar principle to the Black Hole Carrier. It used gravity magnets to transport objects of huge mass. The Time Lord variant was known to have transported the entire Sol System. (DW: The Mysterious Planet, The Ultimate Foe) Although the underlying technology of the Dalek equivalent was never explored, it was key to the movement of 27 planetary bodies both to and from the Medusa Cascade. The Daleks' version was evidently somewhat more advanced than the Time Lord version, which destroyed most of Earth's surface when it was used on the planet; by comparison, the Dalek version did no apparent damage at all to the planet. (DW: Journey's End)

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The Daleks' time vortex magnatron. (DW: Day of the Daleks)

While it can be assumed that the Time Lord magnetron probably could have been used to transport objects through time as well as space, only the Dalek technology was explicitly been shown to have a temporal aspect. A Magnetron can move the space that the matter is immersed in, thus moving the matter itself. Some of the planets so moved were pulled from completely different moments in time. Moreover, the Daleks once used magnetron technology to effect a 21st century invasion of Earth. This particular version of the Dalek magnetron was specifically called a time vortex magnetron. (DW: Day of the Daleks)

Behind the scenes

• Despite the somewhat "pulp science fiction" name, magnetrons are in fact real-life devices, from which their use in Doctor Who can be reasonably extrapolated. Somewhat ironically, they are actually key to the transmission of television signals, along with being the source of power in microwave ovens. They allow for the quick production of a great deal of energy.