Shocks in the early universe could be detectable today

October 27, 2016 by Lisa Zyga, Phys.org feature

Simulation showing cosmological initial conditions (left) evolving into shocks (right). Credit: Pen and Turok. ©2016 American Physical Society
(Phys.org)—Physicists have discovered a surprising consequence of a widely supported model of the early universe: according to the model, tiny cosmological perturbations produced shocks in the radiation fluid just a fraction of a second after the big bang. These shocks would have collided with each other to generate gravitational waves that are large enough to be detected by today's gravitational wave detectors.

The physicists, Ue-Li Pen at the Canadian Institute for Theoretical Astrophysics in Toronto, and Neil Turok at the Perimeter Institute for Theoretical Physics in Waterloo, have published a paper on the in the early universe and their aftermath in a recent issue of Physical Review Letters.

As the scientists explain, the most widely supported model of the early universe is one with a radiation-dominated background that is almost perfectly homogeneous, except for some tiny waves, or perturbations, in the radiation.

In the new study, Pen and Turok have theoretically shown that some of these early, tiny perturbations, which are small-amplitude waves, would have spiked to form large-amplitude waves, or shocks. These shocks would have formed only at very high temperatures, like those that occur immediately after the big bang.

The physicists also showed that, when two or more shocks collide with each other, they generate .

The results suggest that both colliding shocks and merging —like those detected earlier this year by the Laser Interferometer Gravitational-Wave Observatory (LIGO) experiment—contribute to the . Some researchers have previously speculated that the mergining black holes may have formed from the same perturbations that created the shocks and, further, that black holes of this size may make up the dark matter in our galaxy.

However, it would be possible to distinguish between merging black holes and colliding shocks because the gravitational waves emitted by shocks would be detected at far lower frequencies today since the wavelength would have been stretched by the expansion of the universe. Today the gravitational waves from shocks would have frequencies of 3 nHz, as opposed to the 100 Hz regime in which the LIGO experiment currently operates.

Based on their analysis, the scientists think that both current and future planned gravitational wave detectors will be able to detect the frequencies of gravitational waves emitted by shocks. These frequencies correspond to emission times of around 10-4 to 10-30 seconds after the .

Another interesting consequence of shocks in the early universe is that their interactions would have caused the surrounding radiation fluid to rotate, generating vorticity. This means that shocks in the early universe would have generated entropy in an otherwise perfect radiation fluid, in which normally the entropy cannot increase.

The possibility that shocks in the early universe could have generated gravitational waves, vorticity, and entropy could help scientists solve some of the more perplexing puzzles of the , such as why the universe has more matter than antimatter (the baryogenesis problem), as well as the origins of the magnetic fields that are observed in many astrophysical objects.

Explore further: Did the LIGO gravitational waves originate from primordial black holes?

More information: Ue-Li Pen and Neil Turok. "Shocks in the Early Universe." Physical Review Letters. DOI: 10.1103/PhysRevLett.117.131301
Also at arXiv:1510.02985 [astro-ph.CO]

Related Stories

Ripples in space key to understanding cosmic rays

October 17, 2016

In a new study researchers at the Swedish Institute of Space Physics have used measurements from NASA's MMS (Magnetospheric MultiScale) satellites to reveal that there are ripples, or surface waves, moving along the surface ...

What happens when black holes collide?

October 5, 2016

The sign of a truly great scientific theory is by the outcomes it predicts when you run experiments or perform observations. And one of the greatest theories ever proposed was the concept of Relativity, described by Albert ...

First gravitational waves form after 10 million years

September 5, 2016

If two galaxies collide, the merging of their central black holes triggers gravitational waves, which ripple throughout space. An international research team involving the University of Zurich has now calculated that this ...

Team predicts a universe crowded with black holes

June 22, 2016

A new study published in Nature presents one of the most complete models of matter in the universe and predicts hundreds of massive black hole mergers each year observable with the second generation of gravitational wave ...

Recommended for you

Understanding the building blocks for an electronic brain

October 22, 2018

Computer bits are binary, with a value of zero or one. By contrast, neurons in the brain can have many internal states, depending on the input that they receive. This allows the brain to process information in a more energy-efficient ...

Researchers study interactions in molecules using AI

October 19, 2018

Researchers from the University of Luxembourg, Technische Universität Berlin, and the Fritz Haber Institute of the Max Planck Society have combined machine learning and quantum mechanics to predict the dynamics and atomic ...

31 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1.4 / 5 (11) Oct 27, 2016
Stupendous! More LIGO GIGO...
barakn
4.6 / 5 (10) Oct 27, 2016
3 NANOhertz? Frequency of one cycle per 3800 years? It looks like you would have to detect 24 hours a day for a year to get even 1/3800th of a full phase of such waves. How would that be possible?

You screwed up your math somewhere. It's one cycle every 11 years, not 3800. I'm guessing you forgot to include the number of days in a year. Still, 11 years is a stupendously long time.
Benni
1.7 / 5 (6) Oct 27, 2016
perturbations produced shocks in the radiation fluid


They didn't tell us what "radiation fluid" is. Is it testable? Observable? Is it Electro-magnetic or particle?
optical
Oct 27, 2016
This comment has been removed by a moderator.
Whydening Gyre
3 / 5 (2) Oct 27, 2016
perturbations produced shocks in the radiation fluid


They didn't tell us what "radiation fluid" is. Is it testable? Observable? Is it Electro-magnetic or particle?

The proposed environmental soup surrounding whatever "banged".By calling it "radiation" they must assume it is EM in nature. At what frequency? THAT is the question....
Do we have the technology to "see" it? Prob'ly not - yet...
These colliding shocks indeed exist and they form dark filaments connecting galaxies. They just weren't formed during Big Bang.

So... can you elaborite (briefly), Optical/Zeph?

Seeker2
1 / 5 (1) Oct 28, 2016
It's one cycle every 11 years, not 3800. I'm guessing you forgot to include the number of days in a year. Still, 11 years is a stupendously long time.
Wiki says one cycle in about 32 years.
Seeker2
3 / 5 (2) Oct 28, 2016
perturbations produced shocks in the radiation fluid


They didn't tell us what "radiation fluid" is. Is it testable? Observable? Is it Electro-magnetic or particle?

Looks like maybe they meant field, not fluid.
Seeker2
3 / 5 (2) Oct 28, 2016
It seems the vorticity effect would better explain the formation of galaxies and black holes, not missing antimatter, if such really is missing. This should probably also explain the dark matter question.
Seeker2
1 / 5 (1) Oct 28, 2016
These colliding shocks indeed exist and they form dark filaments per http://d3i3l3krai...ter.jpg. They just weren't formed during Big Bang.
Not sure how dark these filaments really are. If they really are dark I suppose they would have to be detected with gravitational lensing?
Benni
1.7 / 5 (6) Oct 28, 2016
perturbations produced shocks in the radiation fluid


They didn't tell us what "radiation fluid" is. Is it testable? Observable? Is it Electro-magnetic or particle?

Looks like maybe they meant field, not fluid. ..........doesn't matter anyway, the whole thing is a sloppy piece of crap.........what with coming to a conclusion that there existed 3 nhz of gravitational waves 14 billion years ago? It's only the last couple of years they think they've discovered actual gravity waves & based on that presupposition this guy now imagines he knows everything there is to know about anything that's got to do with gravity?

Not sure how dark these filaments really are. If they really are dark I suppose they would have to be detected with gravitational lensing?
......nothing in the article about " dark filaments". If such "filaments" existed why would that have anything to do with "gravitational lensing"?

optical
Oct 28, 2016
This comment has been removed by a moderator.
optical
Oct 28, 2016
This comment has been removed by a moderator.
shavera
3.9 / 5 (7) Oct 28, 2016
"Radiation fluid" is essentially applying a fluid description to a system of photons. It is a phrase with a specific meaning in physics. You could also talk about a 'photon gas' or other description. It allows for bulk motion of the system of particles as well as thermal motion of any one particle within the system.
optical
Oct 28, 2016
This comment has been removed by a moderator.
Seeker2
1 / 5 (3) Oct 28, 2016
"Radiation fluid" is essentially applying a fluid description to a system of photons. It is a phrase with a specific meaning in physics. You could also talk about a 'photon gas' or other description. It allows for bulk motion of the system of particles as well as thermal motion of any one particle within the system.
Could be but it seems like any fluid would radiate heat.
Seeker2
1 / 5 (3) Oct 28, 2016
@Seeker2, Whydening Gyre Dark matter filaments were observed already per http://newatlas.c.../23281/.
So it looks like we're caught up in a web of this stuff. Thanks.
Benni
1.7 / 5 (6) Oct 28, 2016
"Radiation fluid" is essentially applying a fluid description to a system of photons. It is a phrase with a specific meaning in physics. You could also talk about a 'photon gas' or other description. It allows for bulk motion of the system of particles as well as thermal motion of any one particle within the system.


Electro-magnetic fields are described as a "fluid" is that it? Never heard of it. In the Thermodynamics courses I've had, only particles (matter) can be a fluid, you know, like water is a "fluid". It is certainly a phrase "with a specific meaning in physics" in the Thermodynamics courses I've had, maybe you could lead us to the edition of the Thermodynamics book you studied from?
shavera
3.7 / 5 (6) Oct 28, 2016
This book is LITERALLY titled "Thermodynamics for beginners" https://books.goo...;f=false

It was covered in my grad school quantum mechanics class, specifically, anyway. Since it's mostly about a bosonic gas, and how thermodynamics behaves in bosonic and fermionic gases. (edit for clarity: Many of my grad classes just used class notes, not a textbook, which is pretty common)
Benni
1.7 / 5 (6) Oct 28, 2016
This book is LITERALLY titled "Thermodynamics for beginners" https://books.goo...;f=false

It was covered in my grad school quantum mechanics class, specifically, anyway. Since it's mostly about a bosonic gas, and how thermodynamics behaves in bosonic and fermionic gases. (edit for clarity: Many of my grad classes just used class notes, not a textbook, which is pretty common)


So you say......so say what the page number is that uses the term "radiatiion fluid", or is this just another one of those INFERRED dynamics concocted by the mystics of modern day cosmology? All you're doing is citing the book, how about doing better & write up a quote from it......shouldn't be more than a couple sentences long.
Seeker2
1 / 5 (2) Oct 29, 2016
@Seeker2, Whydening Gyre Dark matter filaments were observed already per http://newatlas.c.../23281/.
In this image the filaments appear strangely like the neurons connecting cells in the brain. Maybe the Boltzmann brain?
optical
Oct 29, 2016
This comment has been removed by a moderator.
optical
Oct 29, 2016
This comment has been removed by a moderator.
optical
Oct 29, 2016
This comment has been removed by a moderator.
Anda
5 / 5 (5) Oct 30, 2016
Oh no "aether dude" is back, today nickname's Optical... surreal as always!

About the "Radiation fluid" discussion, why don't you just google it before writing nonsense?
It's a perfect fluid often used as cosmological model for radiation-dominated epochs (wiki)
Benni
1.8 / 5 (5) Oct 30, 2016
About the "Radiation fluid" discussion, why don't you just google it before writing nonsense?

It's a perfect fluid often used as cosmological model for radiation-dominated epochs
........finally an explanation for why this marvelous stuff is not found in any book on Thermodynamics,

.......... except of course for Shavero's:
"Thermodynamics for beginners" https://books.goo...;f=false , It was covered in my grad school quantum mechanics class
........great goin' Mr Asstrophysicist, you admit having never taking a Thermodynamics course until you got to Grad School, and it was a course for "beginners"......... took my first Thermodynamics course in 1st semester sophomore year as as undergrad working on my Bachelor's in Engineering, then took two more semesters after that as an undergrad........and you sound like you consider it a significant accomplishment having waited until Grad School just to get into an "introductory" course.

optical
Oct 30, 2016
This comment has been removed by a moderator.
Benni
1.8 / 5 (5) Oct 31, 2016
"Thermodynamics for beginners" https://books.goo...;f=false , It was covered in my grad school quantum mechanics class


........great goin' Mr Asstrophysicist, you admit having never taking a Thermodynamics course until you got to Grad School, and it was a course for "beginners"......... took my first Thermodynamics course in 1st semester sophomore year as as undergrad working on my Bachelor's in Engineering, then took two more semesters after that as an undergrad........and you sound like you consider it a significant accomplishment having waited until Grad School just to get into an "introductory" course.
.........comparing my level of Undergrad education to your Graduate level leaves me with a deep curiosity: What was your Undergrad major? Please don't tell me it's my first guess, it's Journalism right? You took a "beginners" course for Thermodynamics in Grad school because it took you that long to come up to speed just to learn basic high school Algebra.

Seeker2
1 / 5 (2) Nov 03, 2016
@Seeker2, Whydening Gyre Dark matter filaments were observed already by lensing per http://newatlas.c.../23281/.
So they call them dark matter because only matter is known to cause lensing. But I'd say this interpretation is too restrictive. Lensing is caused by a gradient in spacetime expansion whether or not it is due to the presence of matter. Matter is non-expandable and it displaces expanding spacetime so spacetime is expanding less in regions of matter, causing a gradient in the expansion that we call gravity. But there could be regions of lower spacetime expansion between galaxies because expansion between galaxies stretches out spacetime density between them causing a gradient similar to what we see in gravity due to matter. So the gradient may just be due to stretching, not matter. Or so it seems.
Seeker2
1 / 5 (2) Nov 03, 2016
cont
Or, you could say, the force of expansion between galaxies comes from all directions and the galaxies hang together and sum up all these forces, at least to some extent. This total force is greater than the force between any two specific galaxies, resulting in stretching between the galaxies. I know. It's a stretch but it seems plausible. :)
Seeker2
1 / 5 (1) Nov 04, 2016
cont
Another way of looking at it is the stretching is due to the gravitational pull between galaxies.
hawkingsbrother
Nov 05, 2016
This comment has been removed by a moderator.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.