Do you know how a TARDIS works? Do you want to? Then read this.
We all know about the four dimensions - length, width, height, and time. What most people don’t know about is the other thirteen. Yes, you heard me right. String theory is one of the more popular ideas in theoretical physics right now, but the hitch is that it doesn’t work mathematically unless you posit that there are seventeen dimensions.
Now, we’re not really sure what these dimensions do, but we do have these pictures of Calabi Yau manifolds that portray what seventeen dimensions should look like mathematically.
If you walk down the street in a straight line, you’re not walking down it in a straight line - the line is curved along the surface of the Earth at an imperceptible level due to subjectivity. Imagine if what we perceive as four dimensional is really seventeen dimensional. Everything is curved, twisted at sharp angles, interconnected - like a big ball of wibbly wobbly timey wimey stuff. That line that you see as straight could actually be parabolic or hyperbolic and you just can’t tell. And as such, the shortest distance between the two points is not the straight line you imagine you’re walking, but to translate yourself through one of the thirteen other dimensions.
This is how a TARDIS theoretically works - not only in travel, but in containing within itself a much larger inside. A strand of DNA is approximately 3 meters long and can be contained within a human cell, whose size varies but usually has a volume of approximately 2000 um, or 0.002 meters. While not exactly how this works, it’s a good analog for imagining how it does - the twists and turns of seventeen dimensional spacetime allow for a large four dimensional object to fit inside a much smaller one.
This is why it is called a Time and Relative Dimensions in Space.
Strange, how a show about time travel that’s fifty years old accidentally predicted modern physics… Must be a coincidence.