The Movie: Back To The Future (1985)
The Time Travel Scenario: Marty McFly (Michael J Fox) is transported back to 1955 in a Delorean that his friend Emmett “Doc” Brown (Christopher Lloyd) has converted into a chronology-spanning machine.
Back in the past, Marty decides to see what his parents were like as teens – and in the process, disrupts his family’s timeline, represented by a photograph of him and his siblings.
If Marty can’t get his folks together, he’ll vanish from existence! Look out – he’s already fading…
The Problem: It’s based on some very old, very dodgy ways of thinking about time travel physics.
We’ll let science mag Discover take this one: "When Marty McFly changes the past, the future 'instantaneously' changes.
"What the hell is that supposed to mean? Time measures the temporal interval between different events in space-time, and can be quantified by clocks.
"There is no set of clocks outside the universe, with respect to which you can go muck around in the past and have effects propagate into the future 'at the same time.'
"Likewise, your brain is not going to change to remember things differently, nor will any other record-keeping device such as diaries or photographs or embarrassing sex tapes. Sorry about that."
Albert Einstein Says: “If the facts don't fit the theory, change the facts.”
In Other Words: if your film is good enough, people won’t mind if you cheat a little.
Next: Timecop
Comments
Desperation
Jul 10th 2009, 10:21
" (we’d like to credit them with the iPod and blame them for Johnny 5), " I'm sorry, you appear to have got these the wrong way round.
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sowasred2012
Jul 10th 2009, 13:58
I always refer back to the parallel outcome idea in time travel movies these days - it's the only way to stay sane. Kudos to Terminator Salvation for running with the idea that they could be in an alternate timeline now, but I have a big problem with some of it's internal logic - (SPOILERS, kinda) as the movie opens Connor is freaking out cos he's discovered Skynet has started R&D on the T-800 model, yet Marcus, a guy who signed his body over to Cyberdyne upon his execution FIFTEEN YEARS ago, displays way more advanced tech then we've seen in previous terminators. Why put R&D into a model that can be beat by a unit you created 15 years ago? I was almost expecting this to be addressed, or at least hinted at, in the movie with some sort of time travel explanation - but I saw nada. Unless you count the stunt casting of Helena Bonham Carter, and the extra notice she makes you pay to that opening scene might suggest that story will be told in a sequel, but I'm not confident that's the case.
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chriskilmartin
Jul 10th 2009, 14:03
agreed
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WayneCha
Aug 17th 2011, 8:04
I'm not sure what you were getting at with "Back to the Future," but my problem with the film is that Marty and his siblings start to fade out in the photo towards the end when it would make more sense if the photo itself started to vanish instead. Why would anyone take a pic of nothing, right? Still, it's a ridiculously entertaining flick regardless.
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