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 causal future of the world line is also in its causal past, a situation which is akin to time travel. Such a solution was first proposed by Kurt Gödel, a solution known as the Gödel metric, but his (and others') solution requires the universe to have physical characteristics that it does not appear to have, such as rotation and lack of Hubble expansion. Whether general relativity forbids closed time-like curves for all realistic conditions is still being researched. Wormholes are a hypothetical warped spacetime which are permitted by the Einstein field equations of general relativity. A proposed time-travel machine using