# What's the status of time travel? **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2003, 1:23pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746 "2003-03-03T13:23:46Z")\ **Posts on this page:** 10\ **Page:** 10
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [September 7, 2018, 6:17pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/181 "2018-09-07T18:17:09Z")
> [@Alessan](#): > > What are the rules? Do you want to know the first rule, or the second rule? ---
**Author:** ![Slash1972](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/slash1972/32/6461_2.png) [@Slash1972](https://boards.straightdope.com/u/Slash1972)\ **Post date:** [September 7, 2018, 6:44pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/182 "2018-09-07T18:44:48Z")
> [@Lemur866](#): > > Do you want to know the first rule, or the second rule? SHHHHHHHH! You are not supposed to talk about it! ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 7, 2018, 7:19pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/183 "2018-09-07T19:19:14Z")
> [@Slash1972](#): > > SHHHHHHHH! You are not supposed to talk about it! FLT Club? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 7, 2018, 8:25pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/184 "2018-09-07T20:25:21Z")
“Faster Light Than”? And anything that can be used for FTL travel can be used for time travel, and vice-versa. ---
**Author:** ![Grey](https://avatars.discourse-cdn.com/v4/letter/g/b782af/32.png) [@Grey](https://boards.straightdope.com/u/Grey)\ **Post date:** [September 7, 2018, 8:35pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/185 "2018-09-07T20:35:13Z")
> [@Slash1972](#): > > Ah, I see. Thanks! > > Is GR the thing that is corrected for in GPS satellites and such? Both actually. SR due to their velocity relative to the observer and GR due to their position in the Earth’s gravity well compared to earth bound clocks. ---
**Author:** ![Just\_Asking\_Questions](https://avatars.discourse-cdn.com/v4/letter/j/ba9def/32.png) [@Just\_Asking\_Questions](https://boards.straightdope.com/u/Just_Asking_Questions)\ **Post date:** [September 7, 2018, 9:52pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/186 "2018-09-07T21:52:21Z")
> [@Chronos](#): > > “Faster Light Than”? I wanted the parallel so much I fudged a little.🆒 It’s a cross between FTL and “flight”. ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 7, 2018, 10:07pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/187 "2018-09-07T22:07:11Z")
> [@Alessan](#): > > What are the rules? The first rule of FTL Club is ‘don’t open a wormhole inside your own future light cone’. There may be others, but I’d have to ask my future self. ---
**Author:** ![Lemur866](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lemur866/32/434_2.png) [@Lemur866](https://boards.straightdope.com/u/Lemur866)\ **Post date:** [September 7, 2018, 10:22pm UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/188 "2018-09-07T22:22:03Z")
I can’t remember who wrote this six word short story, but I’ve always like it: “a Time Machine! Help I’ve invented” ---
**Author:** ![mandala](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mandala/32/95_2.png) [@mandala](https://boards.straightdope.com/u/mandala)\ **Post date:** [September 8, 2018, 12:38am UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/189 "2018-09-08T00:38:56Z")
> [@Chronos](#): > > “Faster Light Than”? > > And anything that can be used for FTL travel can be used for time travel, and vice-versa. Does this apply to the Alcubierre Drive, which attains effective FTL but does not exceed c in local reference frames? In fact, the ship with a AD is effectively stationary in local reference frames. How would time dilation occur? ---
**Author:** ![eburacum45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eburacum45/32/8690_2.png) [@eburacum45](https://boards.straightdope.com/u/eburacum45)\ **Post date:** [September 8, 2018, 10:09am UTC](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746/190 "2018-09-08T10:09:45Z")
The Alcubierre drive can be used for time travel because it can move between different frames of reference faster than light. Because of the Lorenz transformation, locations with very different velocities have very different planes of simultaneity. See the Andromeda Paradox for an extreme example of this; a person standing on the sidewalk has a different plane of simultaneity to someone in a motor car. > **[Rietdijk–Putnam argument | Andromeda paradox](https://en.wikipedia.org/wiki/Rietdijk%E2%80%93Putnam_argument#Andromeda_paradox)** > > Roger Penrose advanced a form of this argument that has been called the Andromeda paradox in which he points out that two people walking past each other in the street could have very different present moments. If one of the people were walking towards the Andromeda Galaxy, then events in this galaxy might be hours or even days advanced of the events on Andromeda for the person walking in the other direction.\[contradictory\] If this occurs, it would have dramatic effects on our understanding of The fact that a ship travelling in an Alcubierre warp bubble has no internal time dilation has no effect on this. You can still use an FTL ship using Alcubierre drive to travel between the past and present of moving frames of reference. [Previous page](https://boards.straightdope.com/t/whats-the-status-of-time-travel/158746.md?page=9)