Back to the Future: Does physics of Marty's time travel add up?

Today is 21 October 2015 – the date Marty McFly and Doc Brown travel to in Back to the Future Part II. Can we reconcile the films with reality?

Forward to the Future: Visions of 2045

TIL that Carl Sagan considered Back to the Future 2 the greatest time travel movie ever made, due to the movie's accuracy in handling the multiple timelines. : r/todayilearned

10 of the best time travel movies ever made according to a director at the Centre for Time

The Physics of Back to the Future, by Ethan Siegel, Starts With A Bang!

Back To The Future's Time Travel Explained: How It Works & Is It Accurate?

Best Time Travel Movies: 'Groundhog Day' 'Hot Tub Time Machine,' More – IndieWire

Time Travel - Is It Possible? Quantum Physics Time Travel Rules

The 25 Greatest Time-Travel Movies Ever Made

Back to the Future (creative franchise): What are some of your favourite BTTF time related oddities/changes that occur through the film? - Quora

Philosophies, Free Full-Text

The Making of 'Back to the Future' (TV Short 1985) - IMDb

Back to the Future Part III (Film) - TV Tropes

How Do You Get 1.21 GigaWatts For Your Time Machine?

Is time travel possible?