Heart of the TARDIS

The console opens, revealing the Heart.

The Heart of the TARDIS was the ship's soul. The connection to the Eye of Harmony is unclear. It is located beneath the central console, as configured by the Ninth Doctor. On one occasion it opened as if by itself because Blon Slitheen had programmed a Tribophysical waveform macro-kinetic extrapolator to tap into the greatest power source available, in this case the TARDIS. (DW: Boom Town) On another occasion it was forcibly opened by Rose Tyler, Jackie Tyler, and Mickey Smith, using an attached chain and the pull of a large truck. (DW: The Parting of the Ways)

The Heart appears to be bright energy which has varied in colour from milky-white to orange.

It is possible that the latter colour was due to the presence of vortex energy.

The Heart is telepathic; it can grant people's inner wishes for them, but it is unknown how far its power extends or how it works. The heart may also be responsible for the translation effect of the TARDIS. The Heart is also said to contain the last traces of Huon particles (DW: The Runaway Bride).

When Blon Slitheen looked into the Heart she regressed back to a Raxacoricofallapatorian egg, fulfilling her wish for a clean slate. (DW: Boom Town)

When Rose Tyler looked into the Heart it fulfilled her wish to save the Doctor and infused her with the Bad Wolf entity, so she could telepathically operate the TARDIS, sending it to Satellite Five and use god-like powers. In the process she was also infused with vortex energy. To save her life, the Ninth Doctor took the energy upon himself at the cost of his own life, regenerating into the Tenth Doctor. (DW: The Parting of the Ways)

Following the TARDIS reconstruction following a crash landing, the Heart of the TARDIS is now located in a small sphere beneath the TARDIS console, and partially submerged in a blue oily liquid.