An item on Quartz reports that two
separate groups of scientists have decided that there may be a “mirror
universe” in which time moves backwards. That time moves backwards shouldn’t
surprise readers of this blog. However, this doesn’t happen in some mirror
universe, but in our very own world. As I explained here, time in our universe takes a
step backwards for every step forwards, so we live in a superposition of
forward-time and backward-time universes. We only see the forward-time universe
because the expansion of the universe guarantees that one direction of time
always has more spacetime points and therefore more particles than
antiparticles. All the antiparticles were annihilated, leaving essentially no
trace of the backward-time universe. However, all of the backward-time
spacetime points are still around because points don’t annihilate. This is a
good thing because we couldn’t explain the stardard model without them. Follow
the link for more information.
