“Traversable Achronal Retrograde Domains in Spacetime” is the name of a scientific paper written by physicists Dr. Ben Tippett and Dr. Dave Tsang. Yes, not only do they study black holes and Einstein’s theory of general relativity, but they deliberately named theorized spacetime bubbles TARDIS. We want to be their best friends.
Basically, the proposed real life TARDIS is a bubble of spacetime capable of moving backward and forward along a loop of time. If several of these loops could be spliced together, it would allow the TARDIS to travel between any point in space and time.
Of course, though the theory is sound, building such a thing would step outside of the bounds of normal matter. Presumably, that’s why the Gallifreyans had to grow them.