In "Back to the Future" movie the characters try to power the time machine installed into a car by diverting a lighting.
They know that a lightning should strike the clock installed on a specific building at a specific moment of time. For the time travel to happen they need a huge jolt of energy and the car moving at 88 miles per hour. So they attach a thick wire (looks like a thick steel cable) to the clock and position that wire above the road at the height slightly greater than the height of the car, install a conductive rod onto the car and somehow connect that rod to the time machine.
They drive the car to the wire so that the lightning strikes exactly at the same moment when the rod on the car touches the wire and so the lightning energy goes into the rod and into the time machine in the car.
I always wondered whether this is practically possible (time travel aside of course).
I expect the following two problems:
- for the whole thing to function the rod has to touch the wire at exactly the right moment and the electric discharge happens at about the speed of light which is damn fast TM, so precise enough timing can't be achieved without a computer but in the movie the car is being driven by one of the characters
- when the lightning strikes the clock and runs down the wire it will likely ionize the surrounding air and discharge into the ground underneath the wire before reaching the road
The first problem can be solved by using a computer to drive the car. The second problem can perhaps be solved by insulating the wire everywhere except above the road. Neither seems to have been done in the movie.
Are there any other problems in that electrical setup? Can it technically work?
Best Answer
Yes it surely is. People divert lightning all the time using fine wires dragged up into the sky, as user30997 suggested.
The Doc already knew approximately when the tower was going to be hit, so all he had to do was to give the lightning a nice length of wire to follow.
The mistake they made though was trying to get the car to touch the wire at the exact moment the lightning struck. As you pointed out, they'd have to get the timing superhumanly accurate.
What they should have done was have a spool of fine wire in the car, paying it out as they drove away from the clock tower. That way they'd only have to make sure that the car was travelling at 88mph when the lightning struck. This would still have required timing accurate to a few seconds, and I don't know if the clock had a second hand.
Personally, I think he should have just carved out a nice little niche for himself as the inventor of Rock and Roll.