Big Bang Created a Mirror Universe Where Time Runs Backwards, Scientists Say

Scientists say Big Bang may have created mirror universe where time travels backwards

Scientists say the Big Bang may have created a mirror universe much like our own where time travels backwards.

Two leading theories explain the direction of time by the way of the relatively uniform conditions of the Big Bang. reports:  At the very start, what is now the universe was homogeneously hot, so much so that matter didn’t really exist. It was all just a superheated soup. But as the universe expanded and cooled, stars, galaxies, planets, and other celestial bodies formed, birthing the universe’s irregular structure and raising its entropy.

One theory, proposed in 2004 by Sean Carroll, now a professor at Caltech, and Jennifer Chen, then his graduate student, says that time moves forward because of the contrast in entropy between then and now, with an emphasis on the fact that the future universe will so much more disordered than the past. That movement toward high entropy gives time its direction.

The new theory says a low entropy early universe is inevitable because of gravity, and ultimately that’s what gives time its arrow. To test the idea, the theory’s proponents assembled a simple model with nothing more than 1,000 particles and the physics of Newtonian gravity. Here’s Lee Billings, reporting for Scientific American:


But here’s the twist: The expansion after the simulated Big Bang didn’t just happen in one direction, but two. The simple Big Bang they modeled produced two universes, one a mirror of the other. In one universe, time appears to run forwards. In the other, time runs backwards, at least from our perspective.

Here’s Billings again, interviewing lead author Julian Barbour from the University of Oxford:


From that perspective, maybe George Lucas’s Star Wars didn’t take place a long time ago in a galaxy far, far away, but in the far future—our deepest past—of our mirror universe.