OPTION 2: Spin the Universe

In 1949, Kurt Gödel, Einstein’s friend and Princeton colleague, figured out a solution that made it possible for the Universe to contain ready-made time machines. All it requires is that the Universe is rotating. This Gödel Universe contains closed loops that literally act like time machines. Travel around one and you would arrive at yesterday. Go around again and you’d get to the day before that.

The path of light rays in a Gödel Universe is bent into a banana shape by cosmic rotation. This means that it’s always possible to beat a light beam – that is, to travel faster than light – by travelling in a straight line from one tip of the banana to the other.

Scientists, including Einstein, were spared sleepless nights because nature doesn’t appear to have created a rotating Gödel Universe. Instead, as American astronomer Edwin Hubble discovered in the 1920s, we live in expanding Universe whose galaxies are flying apart like pieces of cosmic shrapnel in the aftermath of a titanic explosion: the Big Bang.

A spinning Universe would create readymade time machines. Sadly, our Universe doesn’t spin.