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The Time Travel Paradoxes of Back To the Future
brumgrunt sent in a fun little piece to get your brain going on a cloudy monday morning. Despite countless viewings of BTTF I still never thought of a few of these. "Throughout Back To The Future Part III, there has to be two Deloreans in 1885. Also, why don't George and Lorraine recognize their son? Why doesn't the time machine disappear in the alternative 1985? These and more Back To The Future paradoxes explored..."
Even if you're precise on the exact time of day and year you'll still be in space. the solar system moves too!
I picture a lone Delorean, forever floating through empty space at 88 miles per hour.
I don't understand why you post first about a frame of reference problem and then joke about 88 miles per hour ... in reference to what? In the movies the DeLorean is traveling at 88 miles per hour as would be seen by an observer standing on Earth's surface. But to someone standing perfectly still in reference to the absolute center of the solar system -- as you seem to imply time machines are initially calibrated to -- then the velocity of the DeLorean would change with the velocity of the Earth around the Sun. Why are you only referencing the solar system and not galaxy or nebula or universe? So ... yeah, 88 miles per hour for those of us still on Earth many miles away. But your own post suffers the same problem that the movie suffers which is a frame of reference to the velocity and position.
... Or maybe claim that you machine is anchored to Earth's gravity well to simplify things a bit more?
...
Basically for new writers who write a science fiction time travel story you gotta make sure you mention briefly that you solved the orbit/rotation/surface problem and have calibrated your time machine to account for the ever changing topography of the Earth as well as its orbit and rotation
They were fun movies and nothing more. It might be fun to dissect them but if this is news, stand back in awe for my dissection of about a hundred other movies
My work here is dung.
The article states: "Even appreciating that they didn't know 'Calvin Klein' for long, his impact upon them was such that they'd still have an idea what he looks like, many years later."
I think the author overestimates how much visual memory is likely to fade after 30 years. I just saw some high school classmates after 25 years and looked over some old HS photos. I could barely recall the linking between HS photos and names of the people I saw daily for over three years - including some I lusted after with all the strength of a stereotypical adolescent. Without photographic backup (did Marty get in any photos at the dance?) I doubt they could remember his look very well after only knowing him for a week or so. Combining this with later knowing Marty's face since birth and gradual growth, I do not find it at all implausible that they wouldn't recognize his as a teenager as looking like "Calvin".
Well, according to Einstein's description of gravity this may not be such an issue as you think. The Earth's movements are, after all, governed by gravity. Now gravity doesn't so much "curve" an object's course, as it bends spacetime around the object's path (which is a straight line).
And you're here on the Earth's surface, so you're moving along the same line. You hop in your car, start deviating from the straight-line path by 88mph, and then... what, exactly?
Your post (and many people's intuition) assumes that you suddenly change velocity in all dimensions, so that you move in time but stay at a fixed position in space. The problem is, the concept of a "fixed point in space" is a figment of human imagination; there's no such thing. A fixed point in space implies a prefered frame of reference, and there simply is no such thing.
So what spacial trajectory does the time machine follow? Well, why would it not continue moving at 88mph deviation from the straight-line path through curved spacetime that it's already following - that being the same line being followed by the Earth?
Gravity would cause the time machine to "follow" the Earth as it moved through time. Not the Earth's gravity, as many other posters have suggested, but rather the Sun's gravity and the other various forces that move the Earth.
There are many, many, many problems with time-travel fiction, but the idea that you would be lost in space just isn't one of them.