Giant 'bubbletrons' shaped the forces of the universe moments after the Big Bang, new study suggests

A transparent blue bubble in space with a bright star shining in the center
Hubble spies a giant gas bubble in space. (Image credit: NASA Goddard)

The extremely early universe featured the most cataclysmic, transformative and energetic events that ever occurred. Driving these energies was the expansion of the cosmos and the resulting fragmentation of the fundamental forces of nature. 

And in that fragmentation, massive bubbles may have emerged and collided with each other, powering up energies that would put to shame even our most advanced human-made particle accelerators, new research published June 27 on the preprint database arXiv suggests. 

Those awesome energies could have flooded the universe with dark matter particles, microscopic black holes, and much more, the researchers wrote. And the name of those ultra-energetic, early universe structures? Meet the "bubbletrons."

Related: James Webb Space Telescope reveals how galaxies made the early universe transparent

Bubbles of chaos

The four fundamental forces of nature — electromagnetism, strong nuclear, weak nuclear and gravity — are not always so different. At high energies, these forces begin to merge. We can already detect this in our most powerful particle colliders, where electromagnetism and the weak nuclear force merge into a united "electroweak" force. While not proven, physicists strongly suspect that at even higher energies the other forces also merge into a single, unified force.

But the only time the universe had the energies needed to do this was less than a second after the Big Bang. As the cosmos cooled and expanded from that early state, the forces split off from each other in titanic moments of phase transition. This splitting might have been smooth and serene, like the transition of ice melting into water, or incredibly violent, like the transition of water boiling into vapor.

If the transitions were violent, then the universe could have been briefly filled with gigantic bubbles, the new research suggests. Outside these bubbles, the unified forces remained. But inside the bubbles, the cosmos would have been completely different, with the forces split off from each other. Eventually these bubbles would have expanded and collided, completely converting the universe into the new reality.

But these bubbles wouldn't just have come and gone without leaving a trace, fizzing like an opened soda can. The bubbles would have carried truly enormous amounts of energy — orders of magnitude more energy than any human-made or natural process in the present-day cosmos.

The expanding edges of the bubbles could accelerate any nearby particles to incredibly high speeds. Those particles would then slam into others, just like they do in laboratory particle accelerator experiments, creating a shower of released energy and new particles. Additionally, the bubbles would have eventually merged, becoming another source of particle creation. 

The researchers discovered that these bubbletrons could have reached the energies necessary to trigger the formation of hypothetical dark matter particles. These particles would have enough mass and abundance to explain the observed amount of dark matter in the universe, according to the team's calculations. They could also have been factories of much more exotic objects, like microscopic black holes that immediately evaporated, adding their energy to the mix.

Most importantly, the researchers discovered that the expansion and collision of the bubbletrons would have created a cacophony of gravitational waves. Those gravitational waves would ring the whole universe like a gigantic bell and persist in the cosmos today, billions of years later.

Recent research points to a universe awash in a background hum of gravitational waves. While most of the waves are likely due to colliding supermassive black holes, some of them might be relics from processes in the extremely early universe, like the rise and fall of bubbletrons. The researchers pointed out that future analysis with pulsar timing arrays, as well as upcoming gravitational waves detectors like LISA and the Einstein Telescope, might be able to find direct evidence for the significant — but fleeting — existence of the bubbletrons.

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Paul Sutter Contributor

Paul M. Sutter is an astrophysicist at SUNY Stony Brook and the Flatiron Institute in New York City. Paul received his PhD in Physics from the University of Illinois at Urbana-Champaign in 2011, and spent three years at the Paris Institute of Astrophysics, followed by a research fellowship in Trieste, Italy, His research focuses on many diverse topics, from the emptiest regions of the universe to the earliest moments of the Big Bang to the hunt for the first stars. As an "Agent to the Stars," Paul has passionately engaged the public in science outreach for several years. He is the host of the popular "Ask a Spaceman!" podcast, author of "Your Place in the Universe" and "How to Die in Space" and he frequently appears on TV — including on The Weather Channel, for which he serves as Official Space Specialist.

  • rod
    My thoughts. The 8-page PDF report is interesting reading. I note here from the report. “Along with the electroweak (EW) and QCD transitions, known to be crossovers in the Standard Model (SM) , one or more first order phase transitions may have taken place in the first second after inflation. They are indeed commonly predicted in several motivated extensions of the SM, such as extra-dimensional , confining , or supersymmetric models , and solutions to the strong CP , flavour , or neutrino mass problems . Independently of where they come from, such early universe phase transitions may have far reaching consequences through the possible cosmological relics they can leave behind, e.g. primordial black holes , topological defects , magnetic fields , dark matter (DM) , the baryon asymmetry , together with a background of gravitational waves (GW) , to cite just a few. As the universe expands, sitting in its lowest free energy vacuum, another vacuum may develop at a lower energy due to the fall in temperature, eventually triggering a PT. If a PT is first order then it proceeds via the nucleation of bubbles of broken phase into the early universe bath (see e.g. for reviews), analogously to the PT of water to vapor. Bubble walls that expand with ultrarelativistic velocities store a lot of energy, locally much higher than both the bath temperature and the scale of the PT.” My note, the timeline provided here is "in the first second after inflation", so a post-inflation universe evolution model presented. This period overlaps with the quark-gluon plasma phase of the BB model, overlaps the 4 stages for the cosmic fireball said to create the universe and CMBR we see today. The Big Bang model of the Universe.,, my note the 4 stage fireball evolution to explain the CMB is found in the URL too. "The First Few Minutes: It takes GUTs ... and Quantum Physics" "A Fireball in four parts." "Heavy particle era", "Light particle era", "Radiation era", "Matter era". My note, given the approach of the 8-page PDF report for bubbletrons in the early universe, I think some of these bubbles with different vacuum energies, continue to evolve into other universes. A particular bubble evolved into our universe so we are here today to read this report. The bubble walls expand much faster than c velocity too, “Bubble walls that expand with ultrarelativistic velocities”.

    ref - Bubbletrons,, 27-June-2023. "In cosmological first-order phase transitions (PT) with relativistic bubble walls, high-energy shells of particles generically form on the inner and outer sides of the walls. Shells from different bubbles can then collide with energies much larger than the PT or inflation scales, and with sizeable rates, realising a `bubbletron'..."

    Edit, my bad about ultrarelativistic velocities and c. Wikipedia defines,
    "Ultrarelativistic limit" In physics, a particle is called ultrarelativistic when its speed is very close to the speed of light c.",
  • Unclear Engineer
    I always get more questions than answers when I read this type of thing.

    For one, what was the speed of light in the early universe, anyway? These articles seem to read like the speed of light was still 3 x 10^10 cm/sec when the universe was less than an inch in diameter. But, it was also full of very dense "stuff" (to use a generic word that makes it hard for pedantic people to dispute as a diversion). We know that the speed of light is affected by the density of stuff we currently have in or universe. So, what was the speed of light in the various stages postulated for the "Big Bang"?
  • rod
    Unclear Engineer said:
    I always get more questions than answers when I read this type of thing.

    For one, what was the speed of light in the early universe, anyway? These articles seem to read like the speed of light was still 3 x 10^10 cm/sec when the universe was less than an inch in diameter. But, it was also full of very dense "stuff" (to use a generic word that makes it hard for pedantic people to dispute as a diversion). We know that the speed of light is affected by the density of stuff we currently have in or universe. So, what was the speed of light in the various stages postulated for the "Big Bang"?
    As far as I can gather info here, c is always c back to the Planck epoch of BB model.
    You can see this too in Allen's Astrophysical Quantities, Fourth Edition, 2000 on cosmology. Even the Planck density uses c for the density of 5.1575 x 10^93 g cm^-3, page 650. The 8-page report here references concerns the BB timeline from about 10^-32 s to 1 s after postulated BB event. The paper overlaps other BB epochs now to explain the origin of the CMBR that must take place before the CMBR appears.
  • rod
    If folks read the wiki timeline, z numbers like 3600 are reported and 1100 for the CMBR today. The 3-minute mark after BB event, BBN takes place creating the correct amount of H, He, and perhaps a bit of Li. The redshift using cosmology calculators about 3.7 x 10^8 for z,
    At present, JWST sees objects with z about 13 confirmed.
  • Atlan0001
    What qualifies as "giant"? A speck, or a boulder, of dust?

    What qualifies as "big bang"? A discreet, or an indiscreet, quantity?

    What qualifies as relative? or real?

    Creation (BBT): Being absolutely (entirely) without fault or flaw . . . or any matched other for comparison in space or time! That isn't science! If this multi-dimensional -- especially including '0-' and/or '1-' -- multiverse universe is the matched other, the comparative, to that absolutely 1-d / 2-d flat "Flatland" universe ("Creation (BBT)"), it is always that in zero time (t=0(1)). There never was, never will be, anything more nor less.
  • Classical Motion
    It use to be every year or so, but now it seems monthly we get a new chapter to this novel.

    THE never ending novel. And the new chapter promises to change our outlook of it........but the next coming chapter brings us right back here.

    This circle never ends. We can only add another spin.
  • rod
    As I understand it, science is supposed to evolve :) Reports like this in cosmology present the evolutionary nature of cosmology for the BB model as more math studies take place using inflation and post-inflation universe expansion it seems. does report periodically on this topic like the history of the universe.
    It seems now as the new physics continues to *expand*, areas of overlap appear in the BB model timeline for the early Universe. The report on the history of the universe states, "The Big Bang was not an explosion in space, as the theory's name might suggest. Instead, it was the appearance of space everywhere in the universe, researchers have said. According to the Big Bang theory, the universe was born as a very hot, very dense, single point in space."

    No matter what, when space appears *everywhere in the universe*, we do have an instantaneous-action-at-a-distance force operating *in the beginning*.