When you're having fun, time flies. Waiting in a traffic jam, not so much. Your birthday was last month, and your mortgage payment is due in a few days. The fact that we perceive time is certainly no illusion. But is it really there, or is it something we invented?
Early on in human history, we decided to start measuring the days and weeks, and eventually hours, minutes and seconds. Time was useful in organizing society, planting crops and getting ready for dates. Things worked extremely well until scientists started muddling it all up.
In the 17th century, English scientist Isaac Newton was pretty sure time existed as a universal constant. But in 1908, Hermann Minkowski, expanding on one of Einstein's ideas on the relationship between space and time, suggested a space-time continuum. This theory held that space and time were inextricably mixed, with all events occurring along the same timeline. Einstein presented his theory of general relativity not long after this and proposed that time is but an illusion.
Around the same time (if you believe in time, that is), the field of quantum mechanics grew out of an effort to explain the relationship between matter and energy. This presented a little problem for scientists trying to create a single, unified theory to account for the universe and its component parts. Quantum mechanics requires the existence of time to work. General relativity does not.
String theory saves the day (sort of).
In the past thirty years or so, string theory has become all the rage in the world of theoretical physics. Also called the theory of everything, this concept attempts to reconcile general relativity with quantum physics. The funny thing about string theory is that it throws everything out the window by asserting that our universe (along with our reliable set of laws of space, time and physics) is just one of an infinite number of possibilities. Gives a whole new meaning to the phrase "local time."
In the late 1990s, physicist Julian Barbour suggested that time is actually just a useful construct to measure change. For example, if you walk across the room, the person who started walking is not the same person who reaches the other side. You've changed completely, and your memory of the trip is just the brain sorting cognitive snippets left over from another you.
Barbour joins other scientists who suggest that infinite numbers of universes exist simultaneously, based on infinite possible outcomes resulting from infinite changes. Ever wish you could go back in time and do something over? Not to worry. Somewhere there's a universe where you got it right.
String theory is maddeningly complex and notoriously difficult to test through any ordinary scientific method, which may be its ultimate undoing. In a field long founded on requirements of proof, any theory not eventually proven is fair game for critics. But to date no contender has risen to the challenge.
So is time an illusion? Einstein may be right, but that won't mean diddly when your boss
asks why you were late to work.
Last edited by British-Army ; edited 6 times in total
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