I HAVE been pretty obsessed with space-time this year. Thankfully, I am a theoretical physicist and, in principle, this is my day job. But the more time I have spent returning to my roots with it, the stranger the whole thing has started to seem to me. As I wrote in an earlier column, it is actually pretty hard to explain this strange merger of what are ostensibly familiar, but actually incredibly distinct, concepts.
In your everyday life, you generally experience space and time as separate phenomena. Then along comes the physicist with some thought experiments about clocks, trains and…