DeLorean time machine DeLorean time machine The DeLorean time machine is a fictional automobile-based time travel device featured in the "Back to the Future" franchise. In the feature film series, Dr. Emmett Brown builds a time machine based on a DeLorean DMC-12 car, to gain insights into history and the future. Instead, he ends up using it to travel over 30 years of Hill Valley history (from 1985 to 2015) with Marty McFly to change the past for the better and to undo the negative effects of time travel. One of the cars used in filming is on display at Universal Studios Hollywood
Time travel of violating causality. The absence of time travelers from the future is a variation of the Fermi paradox. As the absence of extraterrestrial visitors does not prove they do not exist, so the absence of time travelers fails to prove time travel is physically impossible; it might be that time travel is physically possible but is never developed or is cautiously used. Carl Sagan once suggested the possibility that time travelers could be here but are disguising their existence or are not recognized as time travelers. Some versions of general relativity suggest that time travel might only be possible in