Asteroid An asteroid was a chunk of rock in space , large compared to many things such as flora and fauna but small compared to planet s and star s . They were similar to , but not to be confused with , comet s , planetoid s and dwarf planet s , and were usually located in asteroid belt s . ( TV : " The Invisible Enemy " ) Once an asteroid entered the Earth ' s atmosphere , it became a meteor . ( TV : " Detained " ) Asteroid impacts . Sufficiently large asteroids could create massive amounts of damage when they hit a planet , causing mass extinction s and societal collapse . Wherever they landed , all the surroundings would be incinerated within seconds . The impact would kick up a cloud of dust which could cover the planet and cause an " Impact Winter " for months or years . Burning debris and acid would happen . Following the " Impact Winter " was the " Ultraviolet Spring " , which would cause mutation s and cancer . ( AUDIO : " Blood of the Daleks " ) The extinction of the dinosaur s was believed to be caused by an asteroid impact , ( TV : " Time and the Rani " , " Fragments " ) but it was actually caused by a spacecraft . ( TV : " Earthshock " ) Red Rocket Rising was hit by an asteroid after the manipulations by the Dalek s . ( AUDIO : " Blood of the Daleks " ) As recounted by K9 Mark 2 , the civilisation on the planet Ceres was wiped out by an asteroid , the approach of which they were oblivious to notice due to the symbiotic , two - class Master / Scribe system , which was created with the substance cerulium . ( TV : " Sirens of Ceres " ) Liveable asteroids . While many asteroids were barren and lifeless , some supported life , either naturally or due to design . The Sycorax were native to asteroids and fashioned starship s out of other , smaller asteroids . ( TV : " The Christmas Invasion " ) A wide variety of buildings and structures were built into asteroids , including the Bi - Al Foundation , ( TV : " The Invisible Enemy " ) Braxiatel Collection , ( PROSE : " Tears of the Oracle " ) the Delirium Archive , ( TV : " The Time of Angels " ) Demon ' s Run , ( TV : " A Good Man Goes to War " ) Lavonia , ( AUDIO : " Fear of the Daleks " ) the Shadow Proclamation headquarters ( TV : " The Stolen Earth " ) and the Stormlight House . ( COMIC : " Mortal Beloved " ) Other asteroids were centres of trade , such as one on which the rare metal Bazoolium was sold . ( TV : " Army of Ghosts " ) They generally needed special features to bring the gravity to acceptable levels . ( PROSE : " Tears of the Oracle " ) Usage of asteroids . The Ice Warrior s dropped an asteroid on Paris in 2086 ; this was the beginning of the Thousand Day War . ( PROSE : " GodEngine " , PROSE : " Beige Planet Mars " ) The Dalek s disguised their saucers as asteroids to fool their opponents upon their approach . ( COMIC : " The Only Good Dalek " ) The Rani intended to use an asteroid made of strange matter to create a Time Manipulator . ( TV : " Time and the Rani " ) A prisoner was trapped in prisons that looked like asteroids . ( TV : " Detained " ) Other references . During the Eternal s ' race for Enlightenment , some of their ships went through an asteroid storm . ( TV : " Enlightenment " ) Upon taking Rose Tyler to see the Earth ' s destruction in the year five billion , the Ninth Doctor mentioned asteroids as one of the things human ity thought would cause their extinction . ( TV : " The End of the World " ) While on their honeymoon , Amy Pond and Rory Williams visited a planet and an asteroid who were also on their honeymoon . ( TV : " Death of the Doctor " , TV : " The Night After Hallowe ' en " ) On " By the Light of the Asteroid " the characters lived on an asteroid . ( TV : " Voyage of the Damned " ) Chasm Forge was built above an asteroid , which it also mined resources from . ( TV : " Oxygen " )