The Many Directions of Time

Alex Mayer of Stanford has written a book entitled The Many Directions of Time, to be published this year, in which he will lay out a new theory of time. His personal web site contains presentations and papers that outline this theory, which he summarizes like this:

The lectures are based on a single underlying idea that drove the insights they contain: that time is not a single dimension of spacetime but rather a local geometric distinction in spacetime. While this may seem very esoteric, it is actually quite simple.

Not too long ago, people thought the Earth was flat, which meant they thought that gravity pointed in the same direction everywhere. Today, we think of that as a silly idea, but at the same time, most people today (including most scientists) still think of spacetime as if it were a big box with 3 space dimensions and 1 time dimension. So, like gravity for a flat Earth, the single time dimension for the 'big box universe' points in one direction, from the Big-Bang into the future. A lot of lip service is given to the idea of "curved spacetime", but the simplistic 3+1 'box' remains the dominant concept of what cosmic spacetime is like.

Imagine that 'the arrow of time' in the Universe, like gravity on Earth, is pretty much the same everywhere, yet also different everywhere relative to everywhere else. That means that the 'arrow of time' points in different directions in spacetime depending on where you are, so time has a geometry just like space has a geometry. The novel idea that there are an infinite number of time dimensions in the Universe revolutionizes gravitational theory and much of modern science with it. A number of outstanding scientific mysteries are definitively solved, including observations that lead to the concepts of 'dark energy' and 'dark matter'. You will know what these are after you read the lectures.