In Stephen Hawking's A Brief History of Time the concept of imaginary time is brought into discussion. We all know of the 3 dimensions of space: length, width, and height and of course we have this forever ticking clock we call time. We can attribute real number values to these dimensions. For example, we are living so many degrees in the southern hemisphere, at -33° 52' 4.26" S latitude and 151° 12' 26.35" E longitude, 10 meters above sea level on 12/1/2808 at the stroke of midnight. There is no complex number needed to describe that spacetime location.
No big deal, right? Well, we face an interested position when we consider the possibility of complex numbers. For those of you who had a terrible math teacher in high school, or just never learned this concept, complex numbers are an extension of the real numbers to include imaginary components like the square root of negative 1. Mathematically, these are just as real as any other numbers but you probably won't be paying your electric bill with imaginary money. Long story short, what if time existed in some way in those imaginary components? Instead of "imaginary," what if they were just lateral numbers which represents alternate histories (and futures) of universes defined by the Schrodinger equation? That is, many alternate world's exist (either in a real sense or not) and their existence can be thought of by existing (in a mathematical sense) by the complex numbers. The wavefunction of a particle is explained using complex numbers, and even electricity is helped explained using complex numbers. Perhaps it is not too far of a leap to assume a more complete understanding of time can be achieved through a better understanding of complex numbers.
"What the hell?" You may ask in a generally interested but confused tone. Yes, it seems that imaginary time is just as real as complex numbers are real. They may not be useful in many everyday activities, such as buying coffee and checking your GPS to see how much longer your commute will be, but maybe there is a different dimension to time that we have yet to accept. To is, it seems to exist as a point that we experience as the present or at most can fathom as a line with the negatives (past) and positives (future) but what if it were more of a plane? One which alternate times are just as real?
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