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Ripples in space-time could explain the mystery of why the universe exists

Inflation stretched the tiny universe into a macroscopic size and turned cosmic energy into matter. But it likely created an equal amount of matter and antimatter. It's not clear why but the authors probe one theory that a phase transition after inflation led to a tiny bit more matter than anti-matter and also created cosmic strings which would produce slight ripples in space-time known as gravitational waves.
Inflation stretched the tiny universe into a macroscopic size and turned cosmic energy into matter. But it likely created an equal amount of matter and antimatter. It's not clear why but the authors probe one theory that a phase transition after inflation led to a tiny bit more matter than anti-matter and also created cosmic strings which would produce slight ripples in space-time known as gravitational waves.
(Image: © R. Hurt/Caltech-JPL, NASA, and ESA Credit: Kavli IPMU - Kavli IPMU modified this figure based on the image credited by R.Hurt/Caltech-JPL, NASA, and ESA)

A new study may help answer one of the universe's biggest mysteries: Why is there more matter than antimatter? That answer, in turn, could explain why everything from atoms to black holes exists. 

Billions of years ago, soon after the Big Bang, cosmic inflation stretched the tiny seed of our universe and transformed energy into matter. Physicists think inflation initially created the same amount of matter and antimatter, which annihilate each other on contact. But then something happened that tipped the scales in favor of matter, allowing everything we can see and touch to come into existence — and a new study suggests that the explanation is hidden in very slight ripples in space-time.

"If you just start off with an equal component of matter and antimatter, you would just end up with having nothing," because antimatter and matter have equal but opposite charge, said lead study author Jeff Dror, a postdoctoral researcher at the University of California, Berkeley, and physics researcher at Lawrence Berkeley National Laboratory. "Everything would just annihilate."

Related: Twisted physics: 7 mind-blowing findings

Obviously, everything did not annihilate, but researchers are unsure why. The answer might involve very strange elementary particles known as neutrinos, which don't have electrical charge and can thus act as either matter or antimatter.

One idea is that about a million years after the Big Bang, the universe cooled and underwent a phase transition, an event similar to how boiling water turns liquid into gas. This phase change prompted decaying neutrinos to create more matter than antimatter by some "small, small amount," Dror said. But "there are no very simple ways — or almost any ways — to probe [this theory] and understand if it actually occurred in the early universe."

But Dror and his team, through theoretical models and calculations, figured out a way we might be able to see this phase transition. They proposed that the change would have created extremely long and extremely thin threads of energy called "cosmic strings" that still pervade the universe. 

Dror and his team realized that these cosmic strings would most likely create very slight ripples in space-time called gravitational waves. Detect these gravitational waves, and we can discover whether this theory is true.

The strongest gravitational waves in our universe occur when a supernova, or star explosion, happens; when two large stars orbit each other; or when two black holes merge, according to NASA. But the proposed gravitational waves caused by cosmic strings would be much tinier than the ones our instruments have detected before. 

However, when the team modeled this hypothetical phase transition under various temperature conditions that could have occurred during this phase transition, they made an encouraging discovery: In all cases, cosmic strings would create gravitational waves that would be detectable by future observatories, such as the European Space Agency's Laser Interferometer Space Antenna (LISA) and proposed Big Bang Observer and the Japan Aerospace Exploration Agency's Deci-hertz Interferometer Gravitational wave Observatory (DECIGO). 

"If these strings are produced at sufficiently high energy scales, they will indeed produce gravitational waves that can be detected by planned observatories," Tanmay Vachaspati, a theoretical physicist at Arizona State University who wasn't part of the study, told Live Science. 

The findings were published Jan. 28 in the journal Physical Review Letters.

Editor's note: This story was updated to correct the organizations in charge of LISA. It is run by the European Space Agency, not NASA, which is a collaborator on the project.

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Originally published on Live Science.

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  • rod
    Admin said:
    A new study may help answer one of the universe's biggest mysteries.

    Ripples in space-time could explain the mystery of why the universe exists : Read more

    Interesting, one million years after the BB, perhaps the matter vs. anti-matter conflict can be solved. This conflict in the model takes place, one second after the BB event so if solved, that seems to leave a radiation filled universe for quite sometime after the BB, and the CMBR evolved about 380,000 years after the BB. Testable predictions made here though.
    Reply
  • rod
    Something else strikes me about this new model to solve the matter vs. anti-matter conflict. In the BB model, the time period from Planck time after the BB until about 3 minutes after the BB, is the BBN or Big Bang nucleosynthesis phase and this impacts the production of H/He, and a little Li too, especially if matter emerges after 1 million years it seems in the model.
    Reply
  • rod
    After reviewing this interesting report, here are some other sites reporting this in cosmology too. https://physics.aps.org/synopsis-for/10.1103/PhysRevLett.124.041804, https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.041804
    A source sent me this info. "The neutrinos envisaged here are called "sterile neutrinos", they are supposed to have large masses (exceeding 10^9 GeV), and they have never been observed (unlike the ones we are familiar with in beta-decay and related processes): see the APS commentary here:" I also note comments like this "“If sterile neutrinos behave as theorized, then lepton number is not conserved, and sterile neutrinos created in the early Universe could have decayed more readily into particles than antiparticles. One consequence of this, White and colleagues show, is the formation of structures called cosmic strings immediately before the period of cosmological inflation.”

    Going back in time *before the period of cosmological inflation* to solve here in the BB evolutionary origin for the universe. Okay, the history of the universe from Planck time to 3 minutes after the BB is getting very interesting, and perhaps the cosmology department is now going back before the Planck time and BB event itself :)
    Reply
  • foxpup
    Why the universe exists.....hmmm..
    It seems to me that the need for souls to have a context to interact and develop relationships is the reason WHY the universe exists. Its sad when people can be so educated about natural science and mathematics but have such emaciated understanding of philosophy and metaphysics. I blame it on the established cultural norm of assuming that all that exists is the physical and that causation isn't always the rule followed, both of which are faith statements and probably false if science is worth anything, and it is.
    Reply