Virtual 'universe machine' sheds light on galaxy evolution

Virtual 'universe machine' sheds light on galaxy evolution
A UA-led team of scientists generated millions of different universes on a supercomputer, each of which obeyed different physical theories for how galaxies should form. Credit: NASA, ESA, and J. Lotz and the HFF Team/STScI

How do galaxies such as our Milky Way come into existence? How do they grow and change over time? The science behind galaxy formation has remained a puzzle for decades, but a University of Arizona-led team of scientists is one step closer to finding answers thanks to supercomputer simulations.

Observing real galaxies in space can only provide snapshots in time, so researchers who want to study how galaxies evolve over billions of years have to revert to . Traditionally, astronomers have used this approach to invent and test new theories of , one-by-one. Peter Behroozi, an assistant professor at the UA Steward Observatory, and his team overcame this hurdle by generating millions of different universes on a supercomputer, each of which obeyed different physical theories for how galaxies should form.

The findings, published in the Monthly Notices of the Royal Astronomical Society, challenge fundamental ideas about the role dark matter plays in galaxy formation, how galaxies evolve over time and how they give birth to .

"On the computer, we can create many different universes and compare them to the actual one, and that lets us infer which rules lead to the one we see," said Behroozi, the study's lead author.

The study is the first to create self-consistent universes that are such exact replicas of the real one: computer simulations that each represent a sizeable chunk of the actual cosmos, containing 12 million galaxies and spanning the time from 400 million years after the Big Bang to the present day.

Each "Ex-Machina" universe was put through a series of tests to evaluate how similar galaxies appeared in the generated universe compared to the true universe. The universes most similar to our own all had similar underlying physical rules, demonstrating a powerful new approach for studying galaxy formation.

The results from the "UniverseMachine," as the authors call their approach, have helped resolve the long-standing paradox of why galaxies cease to form new stars even when they retain plenty of hydrogen gas, the raw material from which stars are forged.

Commonly held ideas about how galaxies form stars involve a complex interplay between cold gas collapsing under the effect of gravity into dense pockets giving rise to stars, while other processes counteract star formation.

For example, it is thought that most galaxies harbor supermassive black holes in their centers. Matter falling into these black holes radiates tremendous energies, acting as cosmic blowtorches that prevent gas from cooling down enough to collapse into stellar nurseries. Similarly, stars ending their lives in supernova explosions contribute to this process. Dark matter, too, plays a big role, as it provides for most of the gravitational force acting on the visible matter in a galaxy, pulling in cold gas from the galaxy's surroundings and heating it up in the process.

"As we go back earlier and earlier in the universe, we would expect the dark matter to be denser, and therefore the gas to be getting hotter and hotter. This is bad for star formation, so we had thought that many galaxies in the early universe should have stopped forming stars a long time ago," Behroozi said. "But we found the opposite: galaxies of a given size were more likely to form stars at a higher rate, contrary to the expectation."

In order to match observations of actual galaxies, Behroozi explained, his team had to create virtual universes in which the opposite was the case—universes in which galaxies kept churning out stars for much longer.

If, on the other hand, the researchers created universes based on current theories of galaxy formation—universes in which the galaxies stopped forming stars early on—those galaxies appeared much redder than the galaxies we see in the sky.

Galaxies appear red for two reasons. The first is apparent in nature and has to do with a galaxy's age—if it formed earlier in the history of the universe, it will be moving away faster, shifting the light into the red spectrum. Astronomers call this effect redshift. The other reason is intrinsic: - if a galaxy has stopped forming stars, it will contain fewer blue stars, which typically die out sooner, and be left with older, redder stars.

"But we don't see that," Behroozi said. "If galaxies behaved as we thought and stopped forming stars earlier, our actual universe would be colored all wrong. In other words, we are forced to conclude that galaxies formed stars more efficiently in the early times than we thought. And what this tells us is that the energy created by and exploding stars is less efficient at stifling star formation than our theories predicted."

According to Behroozi, creating mock universes of unprecedented complexity required an entirely new approach that was not limited by computing power and memory, and provided enough resolution to span the scales from the "small"—individual objects such as supernovae—to a sizeable chunk of the observable universe.

"Simulating a single galaxy requires 10 to the 48th computing operations," he explained. "All computers on Earth combined could not do this in a hundred years. So to just simulate a single galaxy, let alone 12 million, we had to do this differently."

In addition to utilizing computing resources at NASA Ames Research Center and the Leibniz-Rechenzentrum in Garching, Germany, the team used the "Ocelote" supercomputer at the UA High Performance Computing cluster. Two-thousand processors crunched the data simultaneously over three weeks. Over the course of the research project, Behroozi and his colleagues generated more than 8 million universes.

"We took the past 20 years of astronomical observations and compared them to the millions of mock universes we generated," Behroozi explained. "We pieced together thousands of pieces of information to see which ones matched. Did the we created look right? If not, we'd go back and make modifications, and check again."

To further understand how galaxies came to be, Behroozi and his colleagues plan to expand the UniverseMachine to include the morphology of individual and how their shapes evolve over time.


Explore further

Hubble observes tiny galaxy with big heart

More information: Peter Behroozi et al, UniverseMachine: The correlation between galaxy growth and dark matter halo assembly from z = 0−10, Monthly Notices of the Royal Astronomical Society (2019). DOI: 10.1093/mnras/stz1182
Citation: Virtual 'universe machine' sheds light on galaxy evolution (2019, August 10) retrieved 21 September 2019 from https://phys.org/news/2019-08-virtual-universe-machine-galaxy-evolution.html
This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
1616 shares

Feedback to editors

User comments

Aug 10, 2019
Why conclude that "the energy created by supermassive black holes and exploding stars is less efficient at stifling star formation.."? Wouldn't assuming that dark matter was less dense in the past have the same effect?

Aug 10, 2019
"Wouldn't assuming that dark matter was less dense in the past have the same effect?"

Ain't no dark matter cause ain't no space cause ain't not globe Earth.

Aug 10, 2019
@kschmadeka
Ain't no grammar

Aug 10, 2019
Everyone knows the Earth is that much more pointy, due to Dark Matter. The gravity expert who fell to his death probably lacked sufficient faith in Dark Matter and so it trolled him into forgetting how pointy the Earth is

Aug 10, 2019
Suppose you multiply light-like gravity effects by a cosine with a waveform embodying a static sinusoid and with a wavelength that could be equated to galactic scale. Use the simplest way to give all gravity a fundamental quantum wave-basis is what I mean. Giving it spin-2 symmetry could be a matter as simple as supposing counter-rotating vectors balance out due to a highly-random radiated virtual field-carrier handedness covering the complete set of planes including all lines passing through a source. It makes a concentric ripple for gas to be stored along with any other normal matter, one that can be said to show Dark Matter just because it's not found in GR.

Aug 10, 2019
"universes most similar to our own all had similar underlying physical rules, ... galaxies formed stars more efficiently in the early times than we thought."

This is interesting since it fits with the recent survey that found lots of early, mature galaxies [ https://www.space...ion.html ]. That paper noted that early star formation rates has been 100 times as high as what astronomers had believed and used in models. Taking the 10-100 times uncertainty out should make it as quantifiable as biology. (Cells are famously crazy bad at math: they divide in order to multiply! :-) )

- tbctd -

Aug 10, 2019
- ctd -

Here is the same problem a year ago, when else LCDM models had owned everything else the last years: "Perhaps the simulations' single biggest lesson so far is not that scientists need to revise their overarching theory of cosmology, but rather that problems lurk in their understanding of astrophysics at smaller scales. In particular, their theory of star formation comes up wanting, Springel says. To produce realistic galaxies, modelers must drastically reduce the rate at which clouds of gas form stars from what astrophysicists expect, he says. "Basically, the molecular clouds form stars 100 times slower than you'd think," he says.

Most likely, star formation flags because feedbacks from supernovae and supermassive black holes drive gas out of a galaxy." [ https://www.scien...s-cosmic ]

That tension between different observations (and so models) should now be resolvable, I hope.

Aug 10, 2019
Why conclude that "the energy created by supermassive black holes and exploding stars is less efficient at stifling star formation.."? Wouldn't assuming that dark matter was less dense in the past have the same effect?


? That cosmic filaments are slowly gravitationally congealing is a part of models, else they wouldn't form galaxy clusters at all. Remember that initial density and speed fluctuations in the inflation field/cosmic background radiation is 10^-5 of average field density, nothing like the density difference between a galaxy and the intergalactic medium.

But the reason they mention it is because it has been the trend in astronomy, as soon as jets and galactic outflow started to be understood. Well, not *completely* understood as was known and it now becomes blatantly visible, see my longish comment. TL;DR: The outflow/inflow models will now be modified, but the resulting uncertainty should start to be of order 1 (~ 100 %) hopefully. No worse than biology ...

Aug 10, 2019
[Off topic, but I should say the maximal uncertainty, since ordinarily we can get down to tens of percents which rivals liquid phase chemistry, or even better when we study evolutionary processes over long times. (The combinatorial trees will never be exactly known, but the relative degree of uncertainty is just therefore awesome: the LUCA is a fact known with a 10^-2000+ uncertainty!)]

Aug 10, 2019
@torbjorn_b_g_larsson
Aren't there LCDM models that overpredicts the number of halos at higher redshifts?

Aug 10, 2019
Since my publication the first of the year I have noticed several articles in science sites that agree.
Interested how my publication has stirred similar thought ? I will take this as good for science.

https://drive.goo...K6c2HB2R

Aug 10, 2019
The universe is complicated, really complicated! You just won't believe how vastly mindbogglingly complicated it is.

Aug 10, 2019
Errrr, this sounds wrong. If these simulations are correct and complete, why do they take so little computer time when all the rest take enormously more? IDGI. Lot of self-referencing in there, too. What's going on here? How come these folks get different results than all previous models? @torbjorn, got anything?

Aug 10, 2019
I always question outlier results, and these appear to be outlier results, with no explanation for why they're outliers, and apparently using some new algorithm that lets them be generated using far less computer power than previously. On top of that, there's a lot of self-referenced previous papers here. All three of those are warning signs, to my mind. Right now I'm not buying this paper.

Aug 10, 2019
Blackholes: matter and energy goes in - Nothing comes out

Galactic Galaxies: by Daniel Stolte, University of Arizona
Galaxies harbour supermassive black holes in their centres
Matter falling into these black holes
Radiates tremendous energies
Acting as cosmic blowtorches

Foreth
Back to basics
This Universe
Is this vacuum
As vacuum by its very definition
Is singular
There is only one Universe
As the Universe the trillions of galaxies we observe occupy

So, why is Daniel Stolte
Simulating infinite numbers of Universe
When there is only one universe
The UNIVERSE we exist in

Then the piece de la resistance
BLACKHOLES
A requisite of a blackhole
Everything goes in - Nothing comes out

Aug 10, 2019
Quiescent Galactic Blackholes

Foreth, on our door step
Nigh on 25,000Lys
There lies at our Milkyway's galactic centre
Sagittarius*A
A quiescent blackhole
A super massive blackhole
That
Unlike Daniel Stolte definition of nonexistent radiating blackholes
Sagittarius*A is closer to the true definition of a blackhole
Foreth
Sagittarius*A is quiet
Invisible in gamma-radiation
For we know this
For we are never ever going to get as close as 25,000Lys to another blackhole
For what we observe at 25,000Lys
Is a non radiating blackhole as theory predicts for true blackholes
For true blackholes are none radiating and quiet
Just as Sagittarius*A is
Our quiescent blackhole

Aug 10, 2019
LOL
If it didn't LOOK right, they would go back and make modifications, then check it again. If it STILL didn't LOOK right, they would again go back and make more modifications, etc.

Anyone who has played the game, "JENGA" might notice the similarities to computing of millions of possible Universes.

"Traditionally, astronomers have used this approach to invent and test new theories of galaxy formation, one-by-one. Peter Behroozi, an assistant professor at the UA Steward Observatory, and his team overcame this hurdle by generating millions of different universes on a supercomputer, each of which obeyed different physical theories for how galaxies should form."

Not saying that their method is unsound, but the ONLY reality is the reality of the ONE REAL UNIVERSE and the machinations that give it the ability to create galaxies and Stars.
The inclusion of Dark Matter as some kind of proof that a certain mechanism would not occur if DM did not exist is prolonging a faerie tale


Aug 10, 2019
The inclusion of Dark Matter as some kind of proof that a certain mechanism would not occur if DM did not exist is prolonging a faerie tale
......it fixes just about every fantasy of the failures for which Pop-Cosmology is unable to give us scientific answers.

For example, they have an immutable fantasy that every cm³ of the Universe contains 0.3 DM particles supposedly at an 5:1 ratio of DM to Ordinary Matter within that cm³, yet they can't isolate such a vast quantity of what should be the most common & easily accessible mass in the Universe.

Aug 10, 2019
The terrible result of all this Dark Matter hullabaloo without providing completely UNASSAILABLE EVIDENCE for the existence of Dark Matter, is that past, present and future science majors will be under the impression that the evidence FOR DM has already been found, and can never again be refuted and falsified. THIS IS BAD SCIENCE. It has already been shown that Dark Matter is too intangible to prove its existence, but for its claimants, it JUST HAS TO BE THERE. WHY? Because certain physicists and astrophysicists declare it to BE.
They STILL HAVEN'T provided the Absolutes that "can be taken to the bank", so to speak. But they continue to confuse future scientists by making big claims for it.

Aug 10, 2019
The terrible result of all this Dark Matter hullabaloo without providing completely UNASSAILABLE EVIDENCE for the existence of Dark Matter, is that past, present and future science majors will be under the impression that the evidence FOR DM has already been found, and can never again be refuted and falsified. THIS IS BAD SCIENCE. It has already been shown that Dark Matter is too intangible to prove its existence, but for its claimants, it JUST HAS TO BE THERE. WHY? Because certain physicists and astrophysicists declare it to BE.
They STILL HAVEN'T provided the Absolutes that "can be taken to the bank", so to speak. But they continue to confuse future scientists by making big claims for it.


You don't understand the first thing about science, you moron. Neither does the cretin Benni. You are just mentally deranged posers on a comments section.

Aug 10, 2019
https://www.space...led.html

Dark Matter map. Extra-curricular gravity. Notice how uniformly wavy it is. The spatial spectrum appears highly organized around a single peak.

Aug 10, 2019
The best evidence for there being something there is:
1. Galaxy rotation curves
2. Galaxy dynamics within galaxy clusters (this is how it was originally discovered)
3. Gravitational lensing in places there is no visible matter
4. Baryon acoustic oscillations, shown both in:
4a. Planck and WMAP measurements of the CMB, and
4b. Large area galaxy distribution, which agrees with the CMB results
5. Stellar velocity dispersions (a separate matter from galaxy rotation curves, though it is related)

This is hard evidence for matter we cannot see. The proof it's matter relies upon the essential difference between matter and energy or fields; matter reacts to an increase of space (if the amount of matter is unchanged) by an inverse square law; radiation or energy or fields react by an inverse cube law. The phenomena attributed to DM react by inverse square.

Nowhere to run, nowhere to hide. There's something there and it acts like matter, but we can't see it. What do you want to call it?

Aug 10, 2019
I will propose another difficulty in the big bang idea. None of these models can explain how galaxies set themselves in orbital motion. Nor can they explain rotating suns. Nor can explain rotating and orbital motion of planets. The physics doesn't seem to be there. To quote Sir Isaac Newton: "Gravity explains the motions of the planets, but it cannot explain who set the planets in motion."

Aug 11, 2019
The terrible result of all this Dark Matter hullabaloo without providing completely UNASSAILABLE EVIDENCE for the existence of Dark Matter, is that past, present and future science majors will be under the impression that the evidence FOR DM has already been found, and can never again be refuted and falsified. THIS IS BAD SCIENCE. It has already been shown that Dark Matter is too intangible to prove its existence, but for its claimants, it JUST HAS TO BE THERE. WHY? Because certain physicists and astrophysicists declare it to BE.
They STILL HAVEN'T provided the Absolutes that "can be taken to the bank", so to speak. But they continue to confuse future scientists by making big claims for it.


You don't understand the first thing about science, you moron. Neither does the cretin Benni. You are just mentally deranged posers on a comments section.
says CastroStupido

The evidence is in that it is YOU who is the mentally deranged poser.

Aug 11, 2019
-contd-
I am well aware of what Science and its methods and goals are supposed to BE, and how it has, instead, become more of a political playbook to predict those things that are impossible or highly improbable to achieve; while promising that it will happen sometime in the near future. But, as in the case of Dark Matter, that future never comes. And it won't, because it can't.
That alleged 80 - 85%(?) over and above normal and regular Matter is simply the Spaces and Voids in the Universe which have remained empty space since the time of the initial expansion. They exist to accommodate any future normal Matter/Energy IN THE EVENT THAT MORE IS CREATED. Such Spaces are like a cupboard, an empty closet, a garage without a car. It has a purpose for however long it must wait.
Dark Matter is not a tangible substance, just as 'time' is of no tangible substance that could be quantified and detected. Both are the hopes and dreams of those who wish them to be real.

Aug 11, 2019
I will propose another difficulty in the big bang idea. None of these models can explain how galaxies set themselves in orbital motion. Nor can they explain rotating suns. Nor can explain rotating and orbital motion of planets. The physics doesn't seem to be there. To quote Sir Isaac Newton: "Gravity explains the motions of the planets, but it cannot explain who set the planets in motion."
says Bart_A

It would be best to capitaiise the word, "who" for emphasis. "...but it cannot explain WHO set the planets in motion."
There, That's better.
I think that you know already WHO it is that is responsible for setting all the galaxies, Stars and planets in motion. This Universe is, after all, HIS UNIVERSE. Humans and other Life Forms are only temporary visitors. To believe otherwise is simply anthropocentric.
Take a marble and place it in the middle of a small dish with a flat bottom and sloped sides. Give the marble a good spin. There's no moral to this story. It's just fun.

Aug 11, 2019
The best evidence for there being something there is:
1. Galaxy rotation curves
2. Galaxy dynamics within galaxy clusters (this is how it was originally discovered)
3. Gravitational lensing in places there is no visible matter
4. Baryon acoustic oscillations, shown both in:
4a. Planck and WMAP measurements of the CMB, and
4b. Large area galaxy distribution, which agrees with the CMB results
5. Stellar velocity dispersions (a separate matter from galaxy rotation curves, though it is related)

This is hard evidence for matter we cannot see. The proof it's matter relies upon the essential difference between matter and energy or fields; matter reacts to an increase of space (if the amount of matter is unchanged) by an inverse square law; radiation or energy or fields react by an inverse cube law.

Nowhere to run, nowhere to hide. There's something there and it acts like matter, but we can't see it. What do you want to call it?


Cow PooPoo seems appropriate.

Aug 11, 2019
How do Galaxies come into Existence

Galaxy Evolution - by Daniel Stolte
Each Ex-Machina universe
Put through a series of tests
How similar galaxies appeared
In the generated universe
Compared to the true universe

Foreth it appears, Daniel Stolte
Hatheth ignored the greatest conundrum since sliced Galaxies
Galactic galaxy rotation
Without solving this basic, but absolute conundrum
Galaxies theoretically, according to all rules of gravitational orbital's
Galaxies defy all traditional laws of orbital motion
Orbiting in 250million years
Irrespective of radii
Irrespective of mass
Irrespective of starry numbers
All galaxies rotate equally
In 250million years
Foreth
Astronomers have observed this astronomical fact, as fact
Despite
This addition or subtraction of darkmatter
Despite additional of darkenergy
Even modifying Isaacs's gravity
All these and more fail in their explanation of galaxy orbitals

Daniel Stolte, has also failed to solve this basic requisite - Galactic galaxy rotation

Aug 11, 2019
The Bullet Cluster shows x-rays do not image as compact gravity sources (only DM fanatics have a deep conceptual problem with that), regardless of their supposed cluster-dominating mass the x-rays lack gravitational coherence, all the DM effect is clearly centered over the two galaxy clumps. It is the smoking gun for Dark Matter fanatic insanity. The CMB is another inkblot for DM fanaticism.

Aug 11, 2019
The BAO, luminous mass organized in spatial spectral peaks, i.e. more cosmological-scale wavy field effects you might as well also insist cannot possibly resemble extracurricular gravity.

Aug 11, 2019
Not that it's proof-positive Dark Matter is all about money and not about physics (snicker), the supreme head extremist fanatic advocate for Dark Matter publishes regularly in Forbes and has the whole laundry-list of Dark Matter insanity, which he calls a "suite."

Aug 11, 2019
The GIGO produced by these computer games is nothing more than an utter waste of resources. If the plasma ignoramuses and Darkists refrained from their nonsense it would certainly cut down on AGWism.

Aug 11, 2019
This is the Bullet Cluster "problem" that Dark Matter fanatics solved: There are lots of x-rays positioned in-between two clusters but no obvious extra gravity effect to be blamed on Dark Matter supposedly there along with it. In some images the x-rays show much brighter and splotchier than in later versions of the BC image. DM is the dumb aura, extracurricular gravity, tracking with the two separating clusters, if not for magical inexplicable-Dark-Matter-absence-revealing powers of the multiple variably-bright x-ray versions of the picture.

Aug 11, 2019
When you do an image search on dark matter the reason you get near the top a blue ring looking like a fuzzy target without a center-dot is because Dark Matter follows regular matter around like a dumb aura. The blue ring is just the innermost ripple of quantum gravity's static fundamental galactic-scale waveform.

Aug 11, 2019
gosh, it's a wonderment at how stupid the looneyticks are
farta, sillyegghead, hennibenni, annoyimgmousie, cantthink
not a shred of common sense among them
expressing their envy as posers, sore losers, bungling incompetents

that more intelligent & far better qualified experts in the sciences are actually paid for their hard work.
what a concept!

while the loons listed have to beg & tantrum like five-year olds to get anyone to notice their childish scrawlings

psst... can i tell you a secret?
that whole rotation thingamabob?
watch an ice skater
same mechanism as rotation of a star or planet or orbital motions
shhh, it's a secret
if you tell anybody?
the Uranus Conspiracy will hunt you down
& belabor you with the comicbooks that are your only evident reading material

for the amusemento grande!
you woomongers are supporting my Theory of Stupid Design by drunken, hooligan deities

resulting in the stochastic reality we are trapped in...

thanks goofs!
whata bunch of punk suckers...

Aug 11, 2019
@torbjorn_b_g_larsson
Aren't there LCDM models that overpredicts the number of halos at higher redshifts?


I linked to an article that seems to observe they do match, if the radio galaxies can be found by other groups are are accepted. As for the rest, see the link to the Science article that describes the current status of cosmological modeling (as well as the Ex-Machina finds).

There is a new corner case of a discovery of small, diffuse galaxies with nearly no stars which is less understood. But observations are few and difficult and I would not worry about it - there is no better physics found and Ex-Machina seem to agree.

Aug 11, 2019
Since my publication the first of the year I have noticed several articles in science sites that agree.
Interested how my publication has stirred similar thought ? I will take this as good for science.

https://drive.goo...K6c2HB2R


? You haven't published anything, if it just is on google drive, and so it is not science. (More seriously in such a case, do you think anyone has read it? What fantasy world do you live in?)

Aug 11, 2019
Errrr, this sounds wrong. If these simulations are correct and complete, why do they take so little computer time when all the rest take enormously more?... How come these folks get different results than all previous models? @torbjorn, got anything?


That is the point, they don't get different results (except stuff like star formation rates). From the paper: "The adopted cosmology (flat CDM; h = 0.678, Omega_m = 0.307, σ_8 = 0.823, n_s = 0.96) is compatible with Planck15 results (Planck Collaboration et al. 2016)."

I haven't time to check right now, but IIRC 10+ million galaxies as they have is necessary to get significant results in cosmological simulations. As for doing an ensemble calculation, IIRC there have been some with 1000's of universes with different parameters before.

Aug 11, 2019
There's something there and it acts like matter, but we can't see it. What do you want to call it?


And note that they test the current cosmology very well, they find that the best match is to have something like it but further away it is worse match.

The star formation rate problem that they see was known, see my 2nd link to the Science review, which is why it is nice that observation (of the radio galaxies) and simulation seems to be able to agree. We'll see if the new observations and new simulations are accepted, and if they fit in every detail, but it naively looks that way - they fit.

Aug 11, 2019
I was thinking more about the galaxy formation rates and star formation rates than cosmology parameters; and this methodology claims to use less computer time. I still don't get what's going on here.

On edit, we cross-posted. OK, I'll look a bit more carefully, but don't be surprised if I have more questions.

Aug 11, 2019
I was thinking more about the galaxy formation rates and star formation rates than cosmology parameters; and this methodology claims to use less computer time. I still don't get what's going on here.
Were you thinking of D3M ?

Aug 11, 2019
@Proto, I'm getting the impression this has nothing to do with D3M; as far as I could see it isn't mentioned.

Aug 11, 2019
@torbjorn_b_g_larsson
Aren't there LCDM models that overpredicts the number of halos at higher redshifts?


I linked to an article that seems to observe they do match, if the radio galaxies can be found by other groups are are accepted. As for the rest, see the link to the Science article that describes the current status of cosmological modeling (as well as the Ex-Machina finds).

There is a new corner case of a discovery of small, diffuse galaxies with nearly no stars which is less understood. But observations are few and difficult and I would not worry about it - there is no better physics found and Ex-Machina seem to agree.
says Torbjorn the Swede

The article specifically says, EX-MACHINA UNIVERSES in the Multiverse sense. But for some strange reason. Torbjorn is referring to ex-machina GALAXIES. Someone should tell Torbjorn that his reference to Ex-Machina wrt galaxies in THIS Universe makes no sense to those who use their thinking processes.

Aug 11, 2019
gosh, it's a wonderment at how stupid the looneyticks are
DaSchneib, rrwillj, CastroGiobango, theghostofotto1923
not a shred of common sense among them
expressing their envy as posers, sore losers, bungling incompetents

that more intelligent & far better qualified experts in the sciences are actually paid for their hard work.
what a concept!

while the loons listed have to beg & tantrum like five-year olds to get anyone to notice their childish scrawlings

psst... can i tell you a secret?
that whole rotation thingamabob?
watch an ice skater
same mechanism as rotation of a star or planet or orbital motions
shhh, it's a secret
if you tell anybody?
the Uranus Conspiracy will hunt you down
& belabor you with the comicbooks that are your only evident reading material

you woomongers are supporting my Theory of Stupid Design by drunken, hooligan deities

resulting in the stochastic reality we are trapped in...

whata bunch of punk suckers...


Yup. I agree

Aug 12, 2019
I was thinking more about the galaxy formation rates and star formation rates than cosmology parameters; and this methodology claims to use less computer time. I still don't get what's going on here.
Were you thinking of https://medium.co...88564f8c ?
says Protoplasmix

D3M is too smart, too fast, and too far advanced. It beats all the others, which is excellent for computational Physics and Astrophysics, but too dangerous for use in robotics.

Aug 12, 2019
Russians noticed Dark Matter researchers were not winning any prizes for finding nothing, just grant money, so they came up with a special Dark Matter prize, it has been tentatively named the Holy Big Fat Blue Zero award.

Aug 12, 2019
Russians noticed Dark Matter researchers were not winning any prizes for finding nothing, just grant money, so they came up with a special Dark Matter prize, it has been tentatively named the Holy Big Fat Blue Zero award.
says 154

LOL I wanted to award you a plus 1 ( +1 ) for your observation, but you had already been smacked with a minus 2 by those who can't bear the thought that Dark Matter is being proved the all-time FAERIE DUST WOO OF THE CENTURY.

Aug 12, 2019
Presented here are the ideas about the origin and evolution of galaxies based on the new paradigm about the real physical and elastonic spaces. The classical Big Bang model, where our world is suddenly born out of nothing, replaced by a model in which there is evolutionary change of the space leading to the emergence of metric and energy. Gradually formed elastonic space which then goes into a flat Euclidean space with the presence of particles and physical fields.
https://www.acade...ome_From

Aug 13, 2019
I was thinking more about the galaxy formation rates and star formation rates than cosmology parameters; and this methodology claims to use less computer time. I still don't get what's going on here.

On edit, we cross-posted. OK, I'll look a bit more carefully, but don't be surprised if I have more questions.


Of course. I have questions of my own too, haven't read the paper yet, just saw that it came down on the current large tension re self consistency in these semi-analytic models (but still agree with - or at least is based on - Planck cosmology).

Here is more (?) on how the simulation was done:

""Peter Behroozi, an assistant professor at the UA Steward Observatory, said simulating a single galaxy requires 10 to the 48th computing operations. "All computers on Earth combined could not do this in a hundred years. So to just simulate a single galaxy, let alone 12 million, we had to do this differently," he said.

- tbctd -

Aug 13, 2019
- ctd -

As such, each simulated universe was coded to obey different physical theories on how galaxies should form. Over a three-week period, the "Ocelote" supercomputer at the UA High Performance Computing cluster crunched numbers, processing data on more than eight million simulated universes and 12 million galaxies spanning from about 400 million years after the Big Bang to present day."

[ https://www.techs...ion.html ]

Aug 13, 2019
Schneibo sez:
This is hard evidence for matter we cannot see. The proof it's matter relies upon the essential difference between matter and energy or fields; matter reacts to an increase of space (if the amount of matter is unchanged) by an inverse square law; radiation or energy or fields react by an inverse cube law. The phenomena attributed to DM react by inverse square.

Nowhere to run, nowhere to hide. There's something there and it acts like matter, but we can't see it. What do you want to call it?


Your selective application of the Inverse Square Law is never applied to the Black Hole Singularity where pseudo-science predicts INFIINTE GRAVITY can exist on a FINITE MASS.

You imagine you're such a genius in digressing about inferred gravity & it's effects, then how about you producing from Einstein's SR or GR the source INFINITE GRAVITY for BHs, that gravity is not mass dependent? You can't, but it's your favorite selective funny farm pseudo-science.


Aug 13, 2019
^^^^^ Lol. Says a scientifically illiterate clown who doesn't know what a half-life is, and thinks 14C is subject to gamma decay!

Aug 23, 2019
It would be best to capitaiise the word, "who" for emphasis. "...but it cannot explain WHO set the planets in motion."


No it wouldn't you fool. You don't need to add artificial emphasis, the readers are perfectly capable of understanding the meaning of the quote. It makes you look in-eloquent and uneducated when you type like that.

Aug 25, 2019
Still just a blink away from monkeys looking at the lights in the sky. Perspective is relative.

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