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A wild Modern theory suggest there may be another " anti - universe , " run backward in clip prior to the Big Bang .
The idea assumes that the earlyuniversewas minuscule , hot and dull — and so unvarying that metre looks symmetric going backward and forward .
If the universe has a twin and on that twin time runs backward, then scientists could explain dark matter.
If true , the newtheorymeans thatdark matterisn’t so mysterious ; it ’s just a unexampled flavor of a phantasmal particle called aneutrinothat can only live in this kind of cosmos . And the hypothesis connote there would be no penury for a period of " inflation " that rapidly exposit the size of the young cosmos soon after the Big Bang .
If true , then future experimentation to trace for gravitational waves , or to pin down the raft of neutrinos , could serve once and for all whether this mirror anti - universe exists .
Preserving symmetry
physicist have identify a set of fundamental symmetries in nature . The three most important symmetries are : charge ( if you interchange the charges of all the speck involved in an interaction to their opposite thrill , you ’ll get the same interaction ) ; parity ( if you look at the mirror epitome of an fundamental interaction , you get the same result ) ; and time ( if you run an interaction backwards in sentence , it calculate the same ) .
Physical interaction obey most of these correspondence most of the clock time , which mean that there are sometimes violations . But physicist have never observed a trespass of a combination of all three symmetries at the same time . If you take every single interaction note in nature and flip the charges , take the mirror figure , and run it backward in metre , those interactions deport exactly the same .
This cardinal symmetry is given a name : CPT symmetry , for flush ( degree Celsius ) , conservation of parity ( P ) and sentence ( T ) .
Related : What is multiverse hypothesis ?
In anew paperrecently accepted for publishing in the journal Annals of Physics , scientists propose prolong this combined proportion . ordinarily this symmetry only applies to fundamental interaction — the force out and fields that make up the physic of the cosmea . But perhaps , if this is such an incredibly significant balance , it apply to the whole total cosmos itself . In other words , this idea stretch out this symmetricalness from applying to just the " actors " of the macrocosm ( forces and champaign ) to the " stage " itself , the intact forcible object of the creation .
Creating dark matter
We live in an flesh out existence . This creation is filled with scads of particles doing lots of interesting things , and the evolution of the universe run forth in meter . If we extend the concept of CPT balance to our entire cosmos , then our view of the universe ca n’t be the entire picture .
Instead , there must be more . To preserve the CPT symmetry throughout the cosmos , there must be a mirror - image cosmea that balances out our own . This cosmos would have all opposite kick than we have , be alternate in the mirror , and take to the woods backward in meter . Our universe is just one of a similitude . Taken together , the two cosmos obey CPT symmetry .
The study research worker next asked what the consequences of such a universe would be .
They found many grand things .
For one , a CPT - respecting cosmos naturally expands and fill itself with mote , without the need for a long - theorized flow of speedy expansion cognise as inflation . While there ’s a lot of evidence that an event like pretentiousness take place , the theoretic picture of that event is incredibly bleary . It ’s so fuzzy that there is plenty of way for marriage offer of practicable alternative .
Second , a CPT - respecting universe would impart some additional neutrino to the mix . There are three known neutrino flavors : the electron - neutrino , mu-meson - neutrino and tau - neutrino . funnily , all three of these neutrino tang are exit - handed ( denote to the direction of its spin relative to its motion ) . All other particles known to physics have both left- and correct - handed varieties , so physicists have long wondered if there are extra right - handed neutrinos .
A CPT - respecting universe would demand the existence of at least one right - handed neutrino species . This species would be largely unseeable to aperient experimentation , only ever charm the residue of the universe through gravity .
But an invisible particle that floods the universe and only interacts via solemnity sounds a lot like dark matter .
The investigator found that the atmospheric condition imposed by obeying CPT symmetry would make full our universe with right - handed neutrinos , enough to account for the blue issue .
Predictions in the mirror
We would never have access to our twin , the CPT - mirror universe of discourse , because it exists " behind " our Big Bang , before the rootage of our cosmos . But that does n’t mean we ca n’t test this idea .
The researchers find a few observational event of this idea . For one , they predict that the three have sex odd - handed neutrino species should all be Majorana particles , which means that they are their own antiparticle ( in contrast to normal particles like the electron , which have antimatter counterparts call the positrons ) . As of now , physicists are n’t sure if neutrinos have this property or not .
Additionally , they predict that one of the neutrino species should be massless . presently , physicists can only place upper limits on the neutrino masses . If physicists can ever once and for all measure the neutrino masses , and one of them is indeed massless , that would greatly pad the melodic theme of a CPT - symmetric world .
Lastly , in this poser the event of inflation never occurred . Instead , the universe take with particles naturally on its own . Physicists conceive that inflation shook space - time to such a tremendous academic degree that it flooded the creation with gravitative waving . Many experimentation are on the hunt for these primordial gravitational wave . But in a CPT - symmetrical universe , no such wave should survive . So if those searches for aboriginal gravitational waves turn up empty , that might be a cue that this CPT - mirror universe of discourse model is right .
Originally published on Live Science .
