Our universe may have a pair of twins running back in time-Information Technology
A novel theory suggests that there may be another “anti-universe”, running back in time before the Big Bang.
An anti-universe running back in time could explain dark matter and cosmic inflation.
The idea that the universe was initially small, hot and dense, and so uniform that time had symmetry, goes against the time of our universe.
If true, the new theory means that dark matter isn’t so mysterious; it’s just a new flavor of a spooky particle called a neutrino that can only exist in this universe. And this theory implies that there would be no need for a period of “inflation” that rapidly expanded the size of the nascent universe immediately after the Big Bang.
If true, future experiments in search of gravitational waves, or to reduce the mass of neutrinos, could answer once and for all whether this anticosmic mirror exists.
Physicists have identified a set of fundamental symmetries in nature. The three most important symmetry points are: charge (if you flip the charges of all the interacting particles to their opposite charges, you get the same interaction); parity (if you look at the mirror image of an interaction you will get the same result); and time (if you run an interaction back in time, it will be the same).
Physical interactions mostly obey these symmetries, which means that sometimes there are violations. But physicists have never observed a violation of the combination of all three symmetries at the same time. If you take every interaction observed in nature and flip the charges, get a mirror image and run it back in time, those interactions will behave exactly the same.
In a newly accepted paper published in the Annals of Physics, the scientists propose to extend this coherent symmetry. Normally this symmetry applies only to interactions – the forces and fields that make up the physics of the universe. But perhaps, if this is such an extremely important symmetry, it applies to the entire universe. In other words, this idea extends this symmetry from applying only to the “agents” of the universe (forces and fields) to the entire physical object of the universe.
Creating dark matter
We live in an expanding universe. This universe is filled with lots of particles that do a lot of interesting things, and the evolution of the universe moves forward over time. If we extend the concept of CPT symmetry to our entire universe, our view of the universe cannot be the whole picture.
Instead, there must be more. To maintain CPT symmetry in the entire universe, a mirror image universe is required for its own balance. This universe would have all the charges opposite to us, flipped in a mirror, and run backwards in time. Our universe is just one of a pair of twins. Taken together, the two universes obey CPT symmetry.
For a universe that respects the CPT naturally expands and fills itself with particles without a prolonged period of theoretical rapid expansion, but the theoretical picture of that event is extremely dim.
But an invisible particle pervading the universe and interacting only through gravity sounds a lot like dark matter.
The researchers found that the conditions imposed by obeying CPT symmetry would fill our universe with right-handed neutrinos, enough to account for dark matter.
We will never have access to our twin universe, the CPT mirror universe, because it existed “behind” the Big Bang, before the universe began. Researchers have found several observable consequences of this idea.
If physicists can accurately measure the mass of neutrinos, and one of them is indeed massless, that would greatly bolster the idea of a CPT symmetric universe.
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