November 13, 2019

A New Take on Time Travel

“Most lovers of science fiction are quick to tell you that there’s a “time-honored” (pun intended) way to build a time machine – somehow get a wormhole and use it as a bridge to travel through time. (It’s even worked in movies such as Thor and Interstellar.)

According to general relativity – this might actually work. However, when it comes to our understanding of the Universe, general relativity may not be the final word. While general relativity does a great job at predicting how macroscopic objects like stars and planets move and interact, it is not a fundamental explanation of the Universe. It doesn’t take into account the very small, weird world of quantum mechanics. According to general relativity, large objects, such as planets, stars or galaxies, interact in a continuous manner. Gravity itself is a continuous force. In quantum mechanics, however, space, matter, energy, interactions… everything… are quantized. That means that there is a grainy-ness in space – that if you zoom up far enough – you should see the “pixels” of space.

To try to understand how general relativity can be united with quantum mechanics, physicists have been attempting to develop a theory of quantum gravity. A successful theory would explain both the very large – planets and clusters of galaxies – and the very small – atoms and quarks. There are several models of quantum gravity that unite the very large with the very small. And a recent paper looks into if time travel is possible in these models of quantum gravity.”

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