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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 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.

  • Tounces
    Thought it was well-established that cosmic inflation came before the hot big bang.
    Reply
  • Ma`at
    It is a ribbon - comprised of many of these 'strings' - that holds up the earth into its position. These strings are being cut one by one. What will happen when they are all cut I wonder?
    Reply
  • mintaslanxor
    Tounces said:
    Thought it was well-established that cosmic inflation came before the hot big bang.
    You thought wrong.
    Reply
  • mintaslanxor
    Ma`at said:
    It is a ribbon - comprised of many of these 'strings' - that holds up the earth into its position. These strings are being cut one by one. What will happen when they are all cut I wonder?
    Ma`at said:
    It is a ribbon - comprised of many of these 'strings' - that holds up the earth into its position. These strings are being cut one by one. What will happen when they are all cut I wonder?
    Seems to me these strings you're talking of are not supporting your brain any longer.
    Reply
  • Docjaarn
    mintaslanxor said:
    You thought wrong.
    No he didn't. It's a matter of perspective and therefore opinion. Personally inflation first, if it even happened, makes far more sense. This article by Ethan Siegel gives a nice explanation: https://www.google.com/amp/s/www.forbes.com/sites/startswithabang/2019/10/22/what-came-first-inflation-or-the-big-bang/amp/
    Reply
  • TorbjornLarsson
    admin said:
    A new study may help answer one of the universe's biggest mysteries.

    This is an unlikely toy theory, though since it is testable they should go for the test.

    Why it is unlikely is triple fold. 1. It relies on a supersymmetry, string based hypothesis, which is problematic since neither LHC nor ACME see a natural particle energy range supersymmetry just above the standard model energy range. "The existence of right-handed neutrinos is further natural when the standard model gauge groups are unified into an SO(10) grand unified theory. Here and below, whenever we refer to the seesaw mechanism, it is meant to be a type-I seesaw together with thermal leptogenesis." . 2. One of the advantaged of staying away from GUT theory is that it removes its unobserved generic proton decay. 3. One of the advantages of inflation is that it dilutes unobserved spatial topological defects such as cosmological strings.
    Reply
  • TorbjornLarsson
    Docjaarn said:
    No he didn't. It's a matter of perspective and therefore opinion.

    Yes, in a manner of speaking, since it depends on your definition of "big bang" https://profmattstrassler.com/2014/03/26/which-parts-of-the-big-bang-theory-are-reliable/ ]. That illustration is old, and inappropriate to the article science (see * below).

    However, the new generation of cosmologists, who are raised with inflation being well tested (dark energy observed 1998, cosmic background spectra 2003), seem to converge on big bang as the expansion with a low Hubble expansion rate comparable with the current rate Sutter@Space.com]. They can then say that the release of the inflation field potential energy drives the big bang expansion, 'puts the bang in the big bang' xJCX2NlhdTcView: https://www.youtube.com/watch?v=xJCX2NlhdTc].

    For a different perspective of just a Hot Big Bang era, but still giving the correct physics (wait for the retake on inflation at the end!), an inspiring "I described it 'rong before, but now I know better" popularization: "The Big Bang is probably not what you think it is". P1Q8tS-9hYoView: https://www.youtube.com/watch?v=P1Q8tS-9hYo
    It has been 7 years since the Planck observatory nailed the standard LCDM cosmology (2013), and almost 2 years since its last data release nailed the form of inflation (2018; tested in two independent ways, it is eternal "slow roll" inflation with natural exit). The current Hubble rate tension can possibly (though unlikely, since it's hard) modify LCDM, but inflation depends mostly on flat space (and cosmic background spectra statistics) which is readily seen in the cosmic background spectra and won't go away. So it is high time that all popularization gets this correct!

    *) And on that topic of "Who's on first", I'm all for phase transitions as the high energy inflation field gave way for low energy fields such as our standard particles and dark matter fields (which is consistent with inflation physics), and possibly high energy non-linear couplings if that is what it takes to give the observed fast "natural exit" out of inflation (again consistent with observed physics). Just not such high energy that they reintroduce topological defects such as cosmic strings (that are not seen).
    Reply
  • ianlib
    Docjaarn said:
    No he didn't. It's a matter of perspective and therefore opinion. Personally inflation first, if it even happened, makes far more sense. This article by Ethan Siegel gives a nice explanation: https://www.google.com/amp/s/www.forbes.com/sites/startswithabang/2019/10/22/what-came-first-inflation-or-the-big-bang/amp/
    Science writer and scientist John Gribbin also theorizes inflation before the Big Bang. https://www.amazon.ca/Before-Big-Bang-Kindle-Single-ebook/dp/B00T6L43NY
    Reply
  • TorbjornLarsson
    ianlib said:
    Science writer and scientist John Gribbin also theorizes inflation before the Big Bang. https://www.amazon.ca/Before-Big-Bang-Kindle-Single-ebook/dp/B00T6L43NY

    Quite. But it is a bit dated and from what I can glean even Gibbins seems to stay in the tradition of putting a time limit on inflation. The inflation theory is a bit odd as well. looks like some mishmash of early Guth and Linde theories, and gives bubble universes. Planck 2018 constrains inflation physics from observation and gives an indefinite ("eternal") inflation process with natural pocket universes instead. (Bubble universe comes from a different kind of physics.) I'm not saying that it's time to popularize the latest, most likely inflation observations (though maybe it is), just that authors should start reject the junk - such as, arguably*, claims of a definite time of inflation or of an underlying positive spatial curvature et cetera. The second video I linked to (links show up in the forum version of comments) is in that "good" tradition. Of course, the most important junk to reject is the claim that big bang started in a specific, small volume or defining it as the first process since the latter definition is both problematic and seems discarded by most young generation cosmologists.

    *) I had to wade through a whole lot of claims of proof that inflation has to be finite and none - so far - has stood up as without problems. Of course, IMO.
    Reply
  • nakamura
    The proposed theory explains HOW matter was not annihilated due to an amazing condition 1 million years after the big bang. It does not explain "WHY the universe exists".

    Furthermore, the title incorrectly implies that the theory answers, "Why is there something rather than nothing?" This question was stated by Leibniz - a great theologian and mathematician, an inventor of calculus - 300 years ago. He was not aware of contemporary physics, but he thoroughly understood philosophical implications. From this question he developed the contingency argument for God's existence.

    Trent Horn has a good explanation of Leibniz argument in the online article: "Why is there something instead of Nothing?"
    Reply