Looking for warm dark matter

Looking for warm dark matter
Two simulations of galaxy formation at the epoch when the universe was only about one billion years old. The top ("CDM") shows clumps and filaments of young galaxies using a conventional treatment of non-interacting dark matter, while the bottom ("sDAO") shows the slightly different - but measurable - differences that occur if dark matter instead could interact with some particles. Astronomers show that future precise measurements of large-scale galaxy structures could help constrain the nature of the mysterious dark matter in the universe. Credit: Bose et al. 2019

In the last century, astronomers studying the motions of galaxies and the character of the cosmic microwave background radiation came to realize that most of the matter in the universe was not visible. About 84% of the matter in the cosmos is dark, emitting neither light nor any other known kind of radiation. Hence it is called dark matter. One of its other primary qualities is that it only interacts with other matter via gravity: it carries no electromagnetic charge, for example. Dark matter is also "dark" because it is mysterious: it is not composed of atoms or their usual constituents like electrons and protons. Particle physicists have imagined new kinds of matter, consistent with the known laws of the universe, but so far none has been detected or its existence confirmed. The Large Hadron Collider's discovery of the Higgs boson in 2012 prompted a burst of optimism that dark matter particles would soon be discovered, but so far none has been seen and previously promising classes of particles now seem to be long-shots.

Astronomers realize that dark matter is the dominant component of matter in the universe. Whatever its nature, it profoundly influenced the evolution of galactic structures and the distribution of the cosmic microwave background radiation (CMBR). The remarkable agreement between the values of key cosmic parameters (like the rate of expansion) derived from observations of two completely different kinds of large-scale cosmic structures, galaxies and the CMBR. lend credence to inflationary big bang models that include the role dark matter.

Current models of dark matter presume it is "cold," that is, that it does not interact with any other kinds of matter or radiation—or even with itself—beyond the influences of gravity. This version of cosmology is therefore called the cold dark matter scenario. But cosmologists wonder whether more precise observations might be able to exclude even small levels of interactions. CfA astronomer Sownak Bose led a team of colleagues in a study of one very popular (if speculative) "dark matter" particle, one that has some ability to interact with very light particles that move close to the speed of light. This version forms one of several possible warm dark matter (perhaps more accurately called interacting dark matter) scenarios. In particular, the hypothetical are allowed to interact with neutrinos (neutrinos are expected to be extremely abundant in the hot early universe).

The scientists used state-of-the-art cosmological simulations of galaxy formation to a model with this kind of warm dark matter. They find that for many observations the effects are too small to be noticeable. However, the signature of this warm dark is present in some distinct ways, and in particular in the way distant galaxies are distributed in space, something that can be tested by mapping galaxies by looking at their hydrogen gas. The authors conclude that future, highly sensitive observations should be able to make these tests. Detailed new maps of the distribution of hydrogen gas absorption could be used to support—or exclude—this warm possibility (see the figure), and shed light on this mysterious cosmic component.


Explore further

Tracer galaxies probe the cosmic background

More information: Sownak Bose et al. ETHOS – an Effective Theory of Structure Formation: detecting dark matter interactions through the Lyman-α forest, Monthly Notices of the Royal Astronomical Society (2019). DOI: 10.1093/mnras/stz1276
Citation: Looking for warm dark matter (2019, August 5) retrieved 23 August 2019 from https://phys.org/news/2019-08-dark.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.
362 shares

Feedback to editors

User comments

Aug 05, 2019
Dark matter is a supersolid that fills 'empty' space, strongly interacts with ordinary matter and is displaced by ordinary matter. What is referred to geometrically as curved spacetime physically exists in nature as the state of displacement of the supersolid dark matter. The state of displacement of the supersolid dark matter is gravity.

The supersolid dark matter displaced by a galaxy pushes back, causing the stars in the outer arms of the galaxy to orbit the galactic center at the rate in which they do.

Displaced supersolid dark matter is curved spacetime.

In the Bullet Cluster collision the dark matter has not separated from the ordinary matter. The collision is analogous to two boats that collide, the boats slow down and their bow waves continue to propagate. The water has not separated from the boats, the bow waves have. In the Bullet Cluster collision the galaxy's associated dark matter displacement waves have separated from the colliding galaxies, causing the light to lense

Aug 05, 2019
Dark matter


Dogs flew spaceships. Aztecs invented the vacation. Men and women are the same sex. Your brain is not the boss. Yes! That's right, everything you know, is wrong.

Aug 05, 2019
In the late 1800's we were pretty sure that the entire universe was permeated with a medium called luminiferous ether. That was the only way how we could explain how light behaved as a wave, and could travel through vacuum. The requirements for ether to exist beggared belief, but the mathematical and theoretical grounds for it to exist were irrefutable. I mean, we could see light from stars, therefore ether had to exist.

When the explanation to an observation involves hypotheses built on hypotheses, maybe the explanation is wrong.

But hey, we can see that galaxies exist, so dark matter has to exist. Right? And since the universe still expands in spite of the dark matter, dark energy has to exist. Right? Or, maybe the fundamental assumption we make about gravitational fields are wrong.

Aug 05, 2019
There's no question we dont fully understand gravity. Considering we dont have a unified theory that combines gravity with quantum mechanics and that our current best understanding of gravity has known places where it can't be applied.
The argument is if the observed effect of dark matter and dark energy can be reconciled within that lack of understanding of how gravity works without conflicting with everything that currently works out mathematically. Dark Matter and energy are pretty big flaws if they are one and it seems far fetched that it wouldn't conflict with how we know gravity works at smaller scales. And there is no rule saying both things are linked. Our understanding of gravity can be flawed and dark matter can be real. However, it seems mighty odd for the lhc to not have produced it if it's the most abundant thing in the universe by far and could only get that way if it's easy to make and stable.

Aug 05, 2019
Recently two papers have been published. The first one deals with the measurement of the speed of rotation of galaxies and, in our view, closes the issue of the existence of dark matter. The second one argues that the expansion of the universe is not accelerating. However, this fact does not answer the question as to what in general is the cause of the universe's expansion and does not address the widespread opinion that 70% of the universe consists of dark energy.
https://www.acade...k_Energy

Aug 05, 2019
Science, a contradictory discipline

Now Darkmatter is Warm
Despite
84% of the matter in the cosmos is dark, emitting neither light nor any other known kind of radiation
Where this signature of warmth
is not in heat
But
In the distribution of Galaxies
Which
Strangely, consist solely of matter that is warm, so not darkmatter, but matter
Which might seem a contradiction in terms, but this is science, a contradictory discipline

Aug 05, 2019
But hey, we can see that galaxies exist, so dark matter has to exist. Right? And since the universe still expands in spite of the dark matter, dark energy has to exist. Right? Or, maybe the fundamental assumption we make about gravitational fields are wrong.
......not only this, but also consider that galaxies have a rotation rate which must also be evidence for existence of something unexplained, like why does the Earth rotate around the Sun? Gotta be DM because nothing else can sufficiently explain why everything in the Universe rotates around other things in the local neighborhoods of galactic clusters. :-)

Aug 05, 2019
oh benni only you are dumb enough to confuse the Earth's rotation with it's orbit around the Sun
next you will complain that DM is making the water in your toilet bowl go around when your caretaker flushes for you

i hope you are still working on correcting Newton's math
cause you can't just leave it for a frenchie (not a belgie!) to do all your math problems for you, ehm?

Aug 05, 2019
And the article says: "Dark matter is also "dark" because it is mysterious: it is not composed of atoms or their usual constituents like electrons and protons. Particle physicists have imagined new kinds of matter, consistent with the known laws of the universe, but so far none has been detected or its existence confirmed. The Large Hadron Collider's discovery of the Higgs boson in 2012 prompted a burst of optimism that dark matter particles would soon be discovered, but so far none has been seen and previously promising classes of particles now seem to be long-shots."

ROFLMAO
This is disgraceful behaviour: Particle Physicists have "imagined". This says it all. These scientists - ALL OF THEM - should give back their Ph.D's to their respective Universities, and beg forgiveness for using their 'imaginings' to decide what their idea of what are the components of this 'mysterious'Dark Matter'. Has the "Scientific Method" now become the imaginings of a group of Faerie Fluff Aficionados

Aug 05, 2019
In the late 1800's we were pretty sure that the entire universe was permeated with a medium called luminiferous ether. That was the only way how we could explain how light behaved as a wave, and could travel through vacuum.
And in 1905, Einstein penetrated the last argument against photons in his paper on photoelectricity, which won a Nobel Prize in Physics and was the beginning of the end for aether. SRT, also published that year, knocked the last pins from underneath it.

When the explanation to an observation involves hypotheses built on hypotheses, maybe the explanation is wrong.
I don't see hypothesis built on hypothesis, Both SRT and GRT have been extensively verified in many different ways.

maybe the fundamental assumption we make about gravitational fields are wrong.
GRT is not an assumption. It's a theory, and has withstood every test anyone could come up with for a hundred years. You'll need much better evidence.

Aug 05, 2019
There's no question we dont fully understand gravity. Considering we dont have a unified theory that combines gravity with quantum mechanics and that our current best understanding of gravity has known places where it can't be applied.
I know of only one: inside a black hole. Do you have another? Lack of photons didn't cause Maxwell to turn out wrong. We still use it today.

The argument is if the observed effect of dark matter and dark energy can be reconciled within that lack of understanding of how gravity works without conflicting with everything that currently works out mathematically.
Not just mathematically. It's a matter of both experiment and observation. GRT makes specific and detailed predictions, and every test for a hundred years verifies it.
[contd]

Aug 05, 2019
ROFLMAO
This is disgraceful behaviour: Particle Physicists have "imagined". This says it all.
Can't make an omelet without cracking a few eggs... can ya? No. You can't. There's more brain power in one physicist's pinky than all your runny whites and yolk combined ...

Aug 05, 2019
Dark Matter and energy are pretty big flaws if they are one and it seems far fetched that it wouldn't conflict with how we know gravity works at smaller scales
Actually, neither is far fetched in those terms. The amount of DM needed on a universe-wide scale is so small that it wouldn't have detectable effects inside our Solar System. It takes a whole galaxy to see it. I'll address the idea that they are the same in just a moment.

And there is no rule saying both things are linked.
They're not.

Our understanding of gravity can be flawed and dark matter can be real. However, it seems mighty odd for the lhc to not have produced it if it's the most abundant thing in the universe by far and could only get that way if it's easy to make and stable.
Not at all. Photons were extremely difficult to detect, and gravitons so difficult that we haven't yet. This is one of the main reasons we need a quantum theory of gravitation, besides black holes.


Aug 05, 2019
There's no question we dont fully understand gravity. Considering we dont have a unified theory that combines gravity with quantum mechanics and that our current best understanding of gravity has known places where it can't be applied.


I know of only one: inside a black hole
After they merge, what's inside can still be heard during the ringdown -- if there's any strange or new physics therein, we'll hear it...

Sounds of Spacetime: The basics of binary coalescence

Aug 05, 2019
Photons were extremely difficult to detect, and gravitons so difficult that we haven't yet.
Ne dis jamais jamais, but apparently a detector sensitive enough for a graviton would have to be so massive that it would collapse into a black hole. See Is Gravity Quantum?

Aug 06, 2019
No, I'd never say never, but considering a large contingent are looking for quantum gravity and we haven't even found gravitons yet, it looks about as difficult as someone coming up with relativity without Newton's Laws.

Aug 06, 2019
Folks are too impatient. This is gonna take a long time. We'll be incredibly lucky if we know about quantum gravity this century.

Aug 06, 2019
I don't see hypothesis built on hypothesis, Both SRT and GRT have been extensively verified in many different ways.


I agree that SRT and GRT have been extensively verified. And yet, we have to resort to the modern day luminiferous ether to explain the formation of galaxies and the expansion of the universe.

I am not contending that SRT and GRT are wrong. Newtonian mechanics also performs admirably at certain scales. But when we apply those theories and they require bending over backwards to explain certain things, maybe it's time to see if our math and assumptions are wrong.

Dark matter is a hypothesis, and dark energy is a hypothesis built on a hypothesis. Neither have been observed yet (yes, I know... yet). The problem with the dark matter/energy explanation is that, just like ether, we can eliminate things, but can't formulate a falsifiable experiment. That makes me uncomfortable.

Hanging on to the dark matter explanation only gives credibility to loonies like SEU.

Aug 06, 2019
The first one deals with the measurement of the speed of rotation of galaxies and, in our view, closes the issue of the existence of dark matter.


What it closes the case on, is that the currently estimated mass of the galaxies cannot hold them together. That could result from a number of things - we haven't accounted for all the matter in interstellar space; there are way more intermediate mass black holes than we have estimated; there are way more cold brown dwarves than we have estimated; or, gravity works differently at galactic scales. Instead of jumping in to the "new ether" hypothesis, we should look for more conventional explanations.

Aug 06, 2019
Dark matter is a hypothesis, and dark energy is a hypothesis built on a hypothesis.
I diasgree. One is a theory of particles (at least as it stands now considering the GW170817 and simultaneous GRB170817A). The other is a part of GRT, and is a completely different phenomenon with different characteristics, different effects, and from a different cause.

Justify your statement, please.

Aug 06, 2019
Look at the Bullet Cluster. There is a place in between the two colliding clusters where there's no visible mass, but it makes a stronger gravitational lensing effect than either of the clusters that are receding from the point of impact.

That's no field effect, otherwise it would originate from the mass we can see and would be strongest there. Yet it's not. There is something there that interacts gravitationally, yet we cannot see it. What would you call it?

Aug 06, 2019
Meanwhile, despite a small discrepancy between Hubble SNeIa measurements and Planck CMB measurements, it is certain the universe is expanding implying exactly the opposite effect from DM. It does not attract, it repels.

What would you call that?

Aug 06, 2019
Faerie dust here, faerie dust there, alas, there is nary a single mote of faerie dust anywhere.

"It is an embarrassment that the dominant forms of matter in the universe remain hypothetical!" Jim Peebles

Maybe the reason the space physicists can't figure it out is because their brain power is all wrapped up within their pinkies. Makes sense given the guesswork they are promoting.

Aug 06, 2019
This kind of less constrained search is nice, now that detectors rule out the simplest forms of interacting dark matter. But so far the gravitational interacting only cold dark matter model fits best.

When the explanation to an observation involves hypotheses built on hypotheses, maybe the explanation is wrong.


Who else said it does? Dark matter falls directly out of relativistic models, and we have observed it in many different ways where the constraints (your "hypotehses") are tested with the observation range.

I don't think it is fair to say that aether was "the only way", since Maxwell derived his EM theory based on a mechanical analog. "Preferred way" perhaps, and it fell before quantum theory was discovered for much the same reason, we discovered that universal laws are relativistic.

- tbctd -

Aug 06, 2019
- ctd -

Please explain what "the fundamental assumption" about gravity is in quantitative (equation) form so we can see that it is not just opinion. General relativity has passed all tests so I suspect there remain no "assumptions" (untested constraint) at all.

The problem with the dark matter/energy explanation is that, just like ether, we can eliminate things, but can't formulate a falsifiable experiment. That makes me uncomfortable. ,,, What it closes the case on, is that the currently estimated mass of the galaxies cannot hold them together.


You read like a reasonable person, but also as someone that has no idea about cosmology outside of the erroneous troll version ("DM/DE is not useful, not testable, blah, blah, blah"). Who said that these are not tested (has passed many tests!) or that DM predicts just the mass of galaxies (predicts structure from cosmic filaments to dwarf galaxies, cluster collisions, BAO, flat space, 80 % of matter energy, ...)? Be fair, study it.

Aug 06, 2019
- ctd -

Hanging on to the dark matter explanation only gives credibility to loonies like SEU.


That is unfortunate, but cannot be allowed to hinder the fact finding of science - we don't live in medieval times any longer. It is better to let people educate themselves. Please come back if you cannot find a suitable Wikipedia (say) article or review on cosmology. I also suggest Susskind's free Stanford University video lectures on cosmology, if you can digest the smidgen of graduate physics in there - he is a research edge scientist still, and an awesome lecturer!

Meanwhile, don't be afraid to comment. Just don't try to make claims that is your personal opinion as if they are supported by facts. Try to find references (maybe you opinions *are* supported!).

Aug 06, 2019
"There is something there that interacts gravitationally, yet we cannot see it. What would you call it?"

Barycenter?

Aug 06, 2019
Please see Possible Dark Matter Mass Candidates in Spinning Sphere Theory. In this theory there are fractals that are incredibly stable states of 2, 6, and 42 particles that could be candidates for dark matter.

Aug 06, 2019
we dont have a unified theory that combines gravity with quantum mechanics

our current best understanding of gravity has known places where it can't be applied

Both of those claims are irrelevant to large scale cosmology, which is large scale classic, hence the standard cosmology is precisely "standard".

But they are also wrong. It is a common claim the we have no quantum field theory for gravity, the problem is that we have one that goes up to Planck scales [ http://www.schola...d_theory ]. Similarly it is fairly easy to see that today the remaining unknown physics is inside black holes - I omit references, because it is a new and long chain of them - and it is doable to make that physics consistent with known physics. (There is a different problem with that though, as someone noted on a similar thread, that consistency is bad since it is not testable outside of black holes.)

Aug 06, 2019
"There is something there that interacts gravitationally, yet we cannot see it. What would you call it?"

Barycenter?


? A barycenter is just the coordinate origin of a system of gravitating masses [ https://en.wikipe...rycenter ]. By definition it is not interacting and the masses are; it is just a convenient reference frame.

Spinning Sphere Theory


? There is no such theory (which is presumably why you don't give a reference link).

Aug 06, 2019
Maybe the reason the space physicists can't figure it out is because their brain power is all wrapped up within their pinkies. Makes sense given the guesswork they are promoting.


Lol. This comes from a clown who believes Earth used to orbit Saturn, and Venus came flying out of Jupiter! Among other bizarre, impossible nonsense.

Aug 06, 2019
http://www.schola...d_theory

These clowns apparently want to suggest Einsteinian gravitational waves represent all quantum aspects of low-energy gravity. If Einstein was stupid enough to sell that idea himself I somehow managed to miss his paper on that.

Aug 06, 2019
I mean there is low energy Einsteinian gravity having nothing to do with Einstein's gravitational waves, otherwise Einstein would have claimed that GR is totally a quantum gravity wave theory. Peer review on quantum gravity is a joke.

Aug 06, 2019
Hey @torbjorn, that article on Scholarpedia is pretty interesting, but the code in it won't render in Chrome. Is it TeX, or LaTeX, or MathJax, or what?

On edit, never mind, I had to whitelist cloudflare.com.

Aug 06, 2019
By the way, effective field theory is a worthless cookbook recipe good only for pretending a non-renormalizable thing can be re-normalized.

Aug 06, 2019
This kind of less constrained search is nice, now that detectors rule out the simplest forms of interacting dark matter. But so far the gravitational interacting only cold dark matter model fits best.
.torbjorn_b_g_larsson........moron, how can it "fit best" when none has ever been found?

Why is it everytime the Susskinds of Cosmology dream up & build the next most sensitive DM detection device it crashes in utter failure?

Hey, torbjorn_b_g_larsson, if you think you're so damn smart about this stuff, why don't you & Susskind just get together & separate some of that 5:1 ratio of DM to Ordinary Matter from some of the dirt we walk on?

Clown Pop-Cosmologists like you torbjorn_b_g_larsson are the epitome of why REAL SCIENCE in Cosmology studies suffers so badly. You believe silly stuff like DM mass that exists at a 5:1 ratio over ordinary mass is so miniscule that it's almost impossible to isolate, when in fact at 5:1 odds it should be overwhelmingly easy. Next excuse?


Aug 06, 2019
Just don't try to make claims that is your personal opinion as if they are supported by facts.


Thanks for the pointer to the lecture series. It's extremely interesting.

However, I didn't mean to come across as stating opinions as facts. I am stating my opinions as my own opinions. I am in a field of science that has nothing to do with theoretical physics - although you might argue that "everything" has to do with theoretical physics :p

My opinion/concern is that dark matter was hypothesized as an explanation for the fact that galaxies simply don't fly apart. Currently, the major observation pointing to dark matter is the fact that galaxies don't fly apart. It seems to me like circular logic.

Yes, I am aware of the gravitational lensing effect observed in the bullet cluster - but if we weren't in a hurry to look at it through the "lens" of dark matter (pun intended), could there be other hypotheses that explain the observation?

Aug 06, 2019
.torbjorn_b_g_larsson........moron, how can it "fit best" when none has ever been found?

Why is it everytime the Susskinds of Cosmology dream up & build the next most sensitive DM detection device it crashes in utter failure?

Hey, torbjorn_b_g_larsson, if you think you're so damn smart about this stuff, why don't you & Susskind just get together & separate some of that 5:1 ratio of DM to Ordinary Matter from some of the dirt we walk on?

Clown Pop-Cosmologists like you torbjorn_b_g_larsson are the epitome of why REAL SCIENCE in Cosmology studies suffers so badly. You believe silly stuff like DM mass that exists at a 5:1 ratio over ordinary mass is so miniscule that it's almost impossible to isolate, when in fact at 5:1 odds it should be overwhelmingly easy. Next excuse?



Get back to cleaning the toilets, janitor boy. Figured out how 14C decays, yet? Lol.

Aug 06, 2019
@Benni

, why don't you & Susskind just get together & separate some of that 5:1 ratio of DM to Ordinary Matter from some of the dirt we walk on?

Hey Benni how about you providing some proof of your jackass janitor theories? :)

Aug 06, 2019
Yes, I am aware of the gravitational lensing effect observed in the bullet cluster - but if we weren't in a hurry to look at it through the "lens" of dark matter (pun intended), could there be other hypotheses that explain the observation?
.......sure, just take up a study of "Deflection of Light by a Gravitational Field" in General Relativity.

The .torbjorn_b_g_larssons write up their Comments as if gravitational lensing does not exist EXCEPT in the presence of a Cosmic Fairy Dust they label Dark Matter.

Einstein predicted within 0.02% of error exactly how much a light ray would be deflected as it passes the peripheral disc of the Sun. Einstein didn't do this by factoring a 5:1 ratio of some kind of hidden gravity source that he couldn't calculate, he used ONLY the OBSERVABLE MASS of the Sun.

Aug 06, 2019
Einstein didn't do this by factoring a 5:1 ratio of some kind of hidden gravity source that he couldn't calculate, he used ONLY the OBSERVABLE MASS of the Sun.


Oh, crap! I am not "in your camp" Benni. I am simply voicing doubt, but I see now that in polarized discussions (like everywhere nowadays), there's no middle ground.

No, Einstein didn't need to take in to account DM in his calculations, because it wouldn't have mattered (no pun intended there). The effects of dark matter, if it exists, would only manifest at galactic scales. The volume of the Sun is way too small to see the effects of dark matter as hypothesized.

I will refrain from commenting further on these boards.

RNP
Aug 06, 2019
@Benni

Einstein predicted within 0.02% of error exactly how much a light ray would be deflected as it passes the peripheral disc of the Sun. Einstein didn't do this by factoring a 5:1 ratio of some kind of hidden gravity source that he couldn't calculate, he used ONLY the OBSERVABLE MASS of the Sun.


We have been through this before but you still fail to understand the basic facts, so I will have to again remind you that the measured density of DM means that the DM encompassed by the WHOLE solar system has a mass equivalent to about two large asteroids. Such a tiny effect is, currently, undetectable, particularly in a volume as small as the sun.

The huge mass of DM compared to normal matter arises because the density of DM is almost the same between stellar systems as it is within them, and the space between then is WAY bigger.

The upshot of all this is that one should NOT expect DM within systems as small as solar systems to have significant dynamical effects.

Aug 06, 2019
Clown Pop-Cosmologists like you torbjorn_b_g_larsson are the epitome of why REAL SCIENCE in Cosmology studies suffers so badly. You believe silly stuff like DM mass that exists at a 5:1 ratio over ordinary mass is so miniscule that it's almost impossible to isolate, when in fact at 5:1 odds it should be overwhelmingly easy. Next excuse?


Neutrinos didn't exist until they were directly detected either, right? And why was it so hard to detect them when 100 billion solar neutrinos pass through your thumbnail every second?

Aug 06, 2019
mr b, you do NOT want to ask where he keeps those thumbs to hide them from the pernicious onslaught of neutrinos whizzing on through

yup, in his very own blackhole!

i warned you not to ask...

Aug 06, 2019
the measured density of DM means that the DM encompassed by the WHOLE solar system has a mass equivalent to about two large asteroids. Such a tiny effect is, currently, undetectable, particularly in a volume as small as the sun.
...ohhhhh, but mister freelance journalist, I get the density argument, the problem with it is that you won't tell us what the IGM density per cm³ is, but that it exists in a ratio of 5:1 to ordinary matter.

OK genius journalist, supposing I'm positioned right on a DM Particle located halfway between our Sun & the next star, what is the distance to the next DM Particle? A meter? A kilometer? More? You'd better be careful with your answer because there are reasonable estimates of the quantity of gaseous & nano-meter sized particles of the ISM & IGM & all have an inherent gravity field just like your asteroid comparison. And if in your comparison you do not come up with 5 times more material than the ISM or IGM, your asteroid comparison is meaningless.

Aug 06, 2019
Look at the Bullet Cluster. There is a place in between the two colliding clusters where there's no visible mass, but it makes a stronger gravitational lensing effect than either of the clusters that are receding from the point of impact.

That's no field effect, otherwise it would originate from the mass we can see and would be strongest there. Yet it's not. There is something there that interacts gravitationally, yet we cannot see it. What would you call it?
says Schneib

More than likely, it is Mirror Matter. All the signs point to it.

Aug 06, 2019
- ctd -

Hanging on to the dark matter explanation only gives credibility to loonies like SEU.
says Runesmith

That is unfortunate, but cannot be allowed to hinder the fact finding of science - we don't live in medieval times any longer. It is better to let people educate themselves. Please come back if you cannot find a suitable Wikipedia (say) article or review on cosmology. I also suggest Susskind's free Stanford University video lectures on cosmology, if you can digest the smidgen of graduate physics in there - he is a research edge scientist still, and an awesome lecturer!

Meanwhile, don't be afraid to comment. Just don't try to make claims that is your personal opinion as if they are supported by facts. Try to find references (maybe you opinions *are* supported!).
says Torbjorn (with his blinders on)

Apparently, Runesmith dislikes the 'Dark Matter' hypothesis, and for some reason, think that SEU is all for it, which is so untrue. Then Torbjorn pipes up....

Aug 06, 2019
-contd-
Then Torbjorn the Swede pipes up, without fully reading what Runesmith has said, and proceeds to interpret Runesmith's hostility towards SEU as being caused by SEU's belief in Dark Matter, which is false also.
After which Torbjorn the Swede brushes Runesmith off as being without knowledge of science and gives him 'what for'.
hahahahahaaaah Another one bites the dust.

Aug 06, 2019
Clown Pop-Cosmologists like you torbjorn_b_g_larsson are the epitome of why REAL SCIENCE in Cosmology studies suffers so badly. You believe silly stuff like DM mass that exists at a 5:1 ratio over ordinary mass is so miniscule that it's almost impossible to isolate, when in fact at 5:1 odds it should be overwhelmingly easy. Next excuse?


Neutrinos didn't exist until they were directly detected either, right? And why was it so hard to detect them when 100 billion solar neutrinos pass through your thumbnail every second?
says Bojingles

Why not put it this way, jingles, "Neutrinos were only suspected but still not proven to exist, until they were directly detected with far advanced instruments."
Now doesn't that sound better, jingles?
Really? That many neutrinos pass through a thumbnail? Per second? When were they counted last?

Aug 06, 2019
.torbjorn_b_g_larsson........moron, how can it "fit best" when none has ever been found?

Why is it everytime the Susskinds of Cosmology dream up & build the next most sensitive DM detection device it crashes in utter failure?

Hey, torbjorn_b_g_larsson, if you think you're so damn smart about this stuff, why don't you & Susskind just get together & separate some of that 5:1 ratio of DM to Ordinary Matter from some of the dirt we walk on?

Clown Pop-Cosmologists like you torbjorn_b_g_larsson are the epitome of why REAL SCIENCE in Cosmology studies suffers so badly. You believe silly stuff like DM mass that exists at a 5:1 ratio over ordinary mass is so miniscule that it's almost impossible to isolate, when in fact at 5:1 odds it should be overwhelmingly easy. Next excuse?



Get back to cleaning the toilets, janitor boy. Figured out how 14C decays, yet? Lol.
says the Anthropology major

There is no such thing as Dark Matter, jonesy. Get used to it, Mopman

Aug 07, 2019
Really? That many neutrinos pass through a thumbnail? Per second? When were they counted last?
.........as is characteristic of Pop-Cosmology acolytes, he started running his mouth before checking the known data base of facts...........it's about 300/cm³, he forgot to read schneibo's favorite textbook at Wiki.

RNP
Aug 07, 2019
@Benni

... I'm positioned right on a DM Particle located halfway between our Sun & the next star, what is the distance to the next DM Particle?..... You'd better be careful with your answer because there are reasonable estimates of the quantity of gaseous & nano-meter sized particles of the ISM & IGM & all have an inherent gravity field just like your asteroid comparison. And if in your comparison you do not come up with 5 times more material than the ISM or IGM, your asteroid comparison is meaningless.

The ISM in the solar neighbourhood is approximately 0.01 hydrogen atoms per cubic cm ( https://courses.l...the-sun/ )
So the DM density is 30 times that of the ISM in the solar neighbourhood.

Also, you should remember the DM extends way beyond the baryonic matter.

RNP
Aug 07, 2019
@Benni
Somehow I lost a sentence in the previous post.

The density of DM in the solar neighbourhood is equivalent to approximately 0.3 hydrogen atoms per cubic cm ( http://cdms.berke...n36.html )

Aug 07, 2019


There is no such thing as Dark Matter, jonesy. Get used to it, Mopman


Really? According to whom? A scientifically illiterate retard who thinks he is an alien lizard? I think we can safely ignore such morons.

Aug 07, 2019
Why not put it this way, jingles, "Neutrinos were only suspected but still not proven to exist, until they were directly detected with far advanced instruments."


The verbiage was chosen intentionally to illustrate a point, I'm not surprised that went over your head.

.........as is characteristic of Pop-Cosmology acolytes, he started running his mouth before checking the known data base of facts...........it's about 300/cm³, he forgot to read schneibo's favorite textbook at Wiki.


Source please. You also didn't address the underlying counter to your lame argument of "why can't I detect it if there's so much of it?"

Aug 07, 2019
>Rguy,

The density of DM in the solar neighbourhood is equivalent to approximately 0.3 hydrogen atoms per cubic cm


Recall my warning you ahead of time about what you'll find?

The interstellar medium averages roughly 1 atom of hydrogen or helium/cm³, with density as great as 1000 atoms/cm³ commonly found and sometimes as small as 0.1 atom/cm³ found but extremely rare.

Between us & the next closest star expect to find at a minimum of 1 atom/cm³ ordinary matter compared to your fabled 0.3 equivalent of Cosmic Fairy Dust, but that's only the beginning because this does not include ions & subatomic particles or nano-meter sized particles known to exist at a density of a 1-2 dozen/km³.

Next I'm presuming you'll propose that the 0.3 DM equivalent at a 3:1 deficit on the AVERAGE, does not mean there is minimally 3 times more gravity within that cm³ from the presence of ordinary matter as compared to DM, right? Got your INFERRED GRAVITY math ready?

Aug 07, 2019
The ISM in the solar neighbourhood is approximately 0.01 hydrogen atoms per cubic cm ( https://courses.l...the-sun/ )

So the DM density is 30 times that of the ISM in the solar neighbourhood.
.....you cherry picked old numbers, 0.01 is a garbage number not even in the table at WkiPedia of all places, move your decimal point two places to the right: https://en.wikipe...r_medium


Aug 07, 2019
Why not put it this way, jingles, "Neutrinos were only suspected but still not proven to exist, until they were directly detected with far advanced instruments."


The verbiage was chosen intentionally to illustrate a point, I'm not surprised that went over your head.

.........as is characteristic of Pop-Cosmology acolytes, he started running his mouth before checking the known data base of facts...........it's about 300/cm³, he forgot to read schneibo's favorite textbook at Wiki.


Source please. You also didn't address the underlying counter to your lame argument of "why can't I detect it if there's so much of it?"
says Bojingles

YOUR choice of verbiage was much too simplistic. This is Physorg, not high school Science class.
You also failed to separate MY comment from Benni's, making it seem that I should answer for Benni.
I'm almost certain that you can do better, jingles.

Aug 07, 2019


There is no such thing as Dark Matter, jonesy. Get used to it, Mopman


Really? According to whom? A scientifically illiterate retard who thinks he is an alien lizard? I think we can safely ignore such morons.
says Castrovagina while hugging his mop

Calling me an 'alien lizard' won't get you into my good graces, Mop man.
Actually, s'truth, there is NO such thing, substance, creature, dust or gas, particle or wave, or galactic superhero called, or consisting of "Dark Matter".
Only in your most wildest imaginings, and in the imaginings of Astronomers, Astrophysicists, and your fellow Mop and bucket men is there such a damp squid as Dark Matter. Matter of ANY kind is readily seen/detected - no woowoo involved. No faerie furfels required, jonesy.
If you and Schneib and all others such as Torbjorn continue to believe in the imaginings of clueless scientists, then you are in danger of becoming a lunatic. You might as well go out at night and howl at the Moon.

Aug 08, 2019
YOUR choice of verbiage was much too simplistic. This is Physorg, not high school Science class.

What?

You also failed to separate MY comment from Benni's, making it seem that I should answer for Benni. I'm almost certain that you can do better, jingles.

They are separated. What you mean to say is that I didn't note which came from whom. This is not necessary though, as the individuals they were addressed to should know what they did or did not write. Although, given your lack of common sense, I suppose this was not wise on my part.


Aug 08, 2019

Calling me an 'alien lizard' won't get you into my good graces, Mop man.
Actually, s'truth, there is NO such thing, substance, creature, dust or gas, particle or wave, or galactic superhero called, or consisting of "Dark Matter".
Only in your most wildest imaginings, and in the imaginings of Astronomers, Astrophysicists, and your fellow Mop and bucket men is there such a damp squid as Dark Matter. Matter of ANY kind is readily seen/detected - no woowoo involved. No faerie furfels required, jonesy.
If you and Schneib and all others such as Torbjorn continue to believe in the imaginings of clueless scientists, then you are in danger of becoming a lunatic. You might as well go out at night and howl at the Moon.


Lol. Moron.

RNP
Aug 08, 2019
@Benni
One of the reasons that I find it pointless arguing you is the fact that
you obviously do not read the references given to you (I.e. You will never learn anything).

You asked a very specific question (.."I'm positioned right on a DM Particle located halfway between our Sun & the next star.."). If you had read the references you would know that the solar system is located in a low density ISM region called the "local bubble" which has a ISM density much lower than the average.

The average ISM density over the whole galaxy is indeed closer to 1 H atom per cubic cm,
and the DM density is only 1/3. However, as pointed out in my previous post,
DM occupies a much larger volume (~8 times more) than baryonic matter.
Also, DM continues BEYOND the galaxy into inter-galactic space where the IGM densiity
is only ~0.0001 H/cubic cm while the DM density remains close to 0.3.

Can you begin to see why you are wrong now?

Aug 08, 2019
However, as pointed out in my previous post,
DM occupies a much larger volume (~8 times more) than baryonic matter.
.....and I made the prediction you would try this when I wrote:
Next I'm presuming you'll propose that the 0.3 DM equivalent at a 3:1 deficit on the AVERAGE, does not mean there is minimally 3 times more gravity within that cm³ from the presence of ordinary matter as compared to DM, right?
.....you never fail to disappoint when you screw up so badly & need to go on a hunt in search of rhetoric to do a cya.

Also, DM continues BEYOND the galaxy into inter-galactic space where the IGM density
is only ~0.0001 H/cubic cm while the DM density remains close to 0.3.
...amazing stuff, this Cosmic Fairy Dust. You Pop-Cosmology acolytes have never isolated any of it to prove it even exists, but boy there isn't anything about it's properties that you don't already know everything including that it occupies 8 times more volume of space to get inferred gravity?

RNP
Aug 08, 2019
@Benni
OK. So, you again do not actually even try to understand or address the science or the data, and simply resort to ridiculously childish language .

Go on, try to prove something I have said wrong. We all know you can't, you moron.

Aug 08, 2019
...amazing stuff, this Cosmic Fairy Dust. You Pop-Cosmology acolytes have never isolated any of it to prove it even exists, but boy there isn't anything about it's properties that you don't already know everything including that it occupies 8 times more volume of space to get inferred gravity?


We are really not interested in the thoughts of a scientifically illiterate janitor.

Aug 08, 2019
@RNP.

Re your response to @Benni on IGM density, may I ask how up-to-date your figures were? I ask this because we've been finding humongous quantities of gas and dust which, until more recently, was never even suspected to be there in such abundances----even in early (alleged) BB epochs! Taking all that into account, plus the fact that such recent 'tip of the iceberg' discoveries point to even greater abundance of all sorts of faint/low-brightness material (eg, dusty plasmas, carbonaceous/iron etc molecules/pebbles, protoplanets, protostars and defunct stars, ie, black holes, neutron stars, dim white/blue dwarfs etc), then it behoves anyone trying to 'correct @Benni' to at least have the most up-to-date understandings of what ordinary matter is out there but not previously allowed for when calculating ordinary matter densities of IGM (and 'Voids') .

ps: have you updated your 'supernovae' data re increasing number of variables compromising 'standard candle' techniques? :)

Aug 08, 2019
@Benni
OK. So, you again do not actually even try to understand or address the science or the data, and simply resort to ridiculously childish language .

Go on, try to prove something I have said wrong. We all know you can't.
.....sure just look at updated 2019 IGM density estimates, everything you quote is from the 90's, you know, that's the last century. Data on this stuff is not static, the only thing that is static is your brain's ability to absorb new data.....like UnrealRC suggested that maybe you should try looking at new data?

Aug 08, 2019
Re your response to @Benni on IGM density, may I ask how up-to-date your figures were? I ask this because we've been finding humongous quantities of gas and dust which, until more recently, was never even suspected to be there in such abundances


Wrong. As explained numerous times. This is baryonic matter that was expected to exist but hadn't been previously detected. Next.

Aug 08, 2019
As for the density of the IGM, it is < 1 atom per cubic metre. Which equates to < 0.000001 atoms per cc.

Aug 08, 2019
@ Really-Skippy. How you are Cher? I'm good, if I was doing any better I would have to feel guilty, thanks for asking.

I ask this because we've been finding humongous quantities of gas and dust
Since I have not seen any papers with your name on it, I guess by "we" you mean the Earthmen Club, eh? Do you keep it in a spare closet until you can bring it out at the same time you bring out the book about your toes and everything?

Oh yeah, I almost forget. Are the rest of the "we" okay with you trying to get some share of the credit? Do the rest of the "we" even know who the Really-Skippy is?

RNP
Aug 09, 2019
@Benni
..... everything you quote is from the 90's,


Trivially false. Both of the references I gave you are from around 2008 (which you would have known had you bothered to look at them), If you are trying to claim that the density estimates have changed since then, then provide a reference. I bet you can't!

Aug 09, 2019
Lets take a galaxy cluster for example. The centre of gravity of the cluster to an object located outside the cluster (at a greater radius) is a point inside the cluster defined by the gravity of the masses physical layout within the cluster/system. The centre of gravity (COG) is a point where all the individual galaxies gravity overlaps at equal densities/strengths. If you are located in that COG point you wouldn't be attracted to any of the galaxies/mass within the cluster/system, it's the COG point where gravity is balanced within the cluster/system. It would also be the point where the mass density is at its greatest to the cluster/system. If there is DM would its density be greatest at the COG point?

RNP
Aug 09, 2019
@beeds
Yes, indeed, you are right, the DM density is at its highest in the centre of a gravitationlly bound system such as a galaxy cluster (or within an individual galaxy) but the physics is not yet complete. This is because we do not know if DM profiles are "cuspy", i.e. rising to very large values in the centre, or "cored" where they rise quickly in the outskirts but rise more slowly in the central regions.

There is a nice YouTube video discussing DM profiles in galaxies, the observations, their
current limitations, and the problems resolving this issue here; https://www.youtu...3tBSlFxU

Aug 09, 2019
@Benni
..... everything you quote is from the 90's,


Trivially false. Both of the references I gave you are from around 2008 (which you would have known had you bothered to look at them), If you are trying to claim that the density estimates have changed since then, then provide a reference.
.....you & Cvag like that word "trivially". I wonder why?

But anyway, the answer is YES, that "density estimates" have changed. They have had plentiful publicity in Astro-Physics journals, you just don't like reading about those changes because they give you major headspin.

All recent IGM density estimates (<10 yrs) have changed dramatically as well as ISM, this due to better instrumentation employed on board space probes that actually MEASURE the quantity of HITS our interplanetary probes encounter between planetary orbits even beyond Pluto, they're called HIT COUNTERS & their use for recording particle hits has changed the entire ISM & IGM estimates.

RNP
Aug 09, 2019
@Benni
All recent IGM density estimates (<10 yrs) have changed dramatically as well as ISM,


Pure BS, and you and everybody else following this thread knows it!

Give a reference you liar/idiot.

RNP
Aug 09, 2019
@Benni
.you & Cvag like that word "trivially". I wonder why?


Do you not understand the word trivial? It means that something is valueless. In this case we use it because your comments are valueless - they show an ignorance of science and ignore the simplest and most basic facts. But that's your style isn't it? TRIVIAL!!

Aug 09, 2019
If you are located in that COG point you wouldn't be attracted to any of the galaxies/mass within the cluster/system, it's the COG point where gravity is balanced within the cluster/system. It would also be the point where the mass density is at its greatest to the cluster/system. If there is DM would its density be greatest at the COG point?
.......you start out stating that at the COG barycenter there is no gravitational attraction to "any of the mass", then contradict yourself that DM density would be greatest at exactly that same point.

Apparently you've come up with another trick of magic this DM Cosmic Fairy Dust is able to perform at a COG, you've now discovered NEUTRAL GRAVITY by DM in an area of your proposed highest density of DM, yeah, just more major headspin concocted within the culture of Pop-Cosmology psycho-babble.

RNP
Aug 09, 2019
@Bwnni
.you start out stating that at the COG barycenter there is no gravitational attraction to "any of the mass", then contradict yourself that DM density would be greatest at exactly that same point.


LOL.

You really don't have ANY understanding of physics , do you? You would not have made such an inane and inaccurate comment if you did.

Aug 09, 2019
All recent IGM density estimates (<10 yrs) have changed dramatically as well as ISM,


Pure BS, and you and everybody else following this thread knows it!

Give a reference you liar/idiot.
.....I'm not here to be your cyber babysitter, besides I've already given you the Wiki link above & you simply don't like it because it detracts from your argument that your fictional 0.3 density of DM/cm³ exists. In reality you have no evidence of such a particle has ever been discovered with the density within any such space anywhere in the entirety of the Universe, so now you binge out on yet another name calling rant......typical of the Pop-Cosmology culture living here.

Aug 09, 2019
".......you start out stating that at the COG barycenter there is no gravitational attraction to "any of the mass""

within the system at that COG point, but from outside that's the point you get attracted/directed to the system.

" then contradict yourself that DM density would be greatest at exactly that same point. "

all mass/gravitational densities would be greatest at the COG relative to the system, but balanced.

RNP
Aug 09, 2019
@Benni
.....I'm not here to be your cyber babysitter, besides I've already given you the Wiki link above & you simply don't like it because it detracts from your argument that your fictional 0.3 density of DM/cm³


More lies. There is nothing in the Wkipedia link that disproves what I am saying, and your inability to provide actual evidence for your claims further demonstrates your inherent dishonesty.

For now, I am done with you, as, for those following this thread, you have again been clearly exposed you as a liar and an idiot.

Aug 09, 2019
.....I'm not here to be your cyber babysitter, besides I've already given you the Wiki link above & you simply don't like it because it detracts from your argument that your fictional 0.3 density of DM/cm³ actually exists


More lies. There is nothing in the Wkipedia link that disproves what I am saying, and your inability to provide actual evidence for your claims further demonstrates your inherent dishonesty.

For now, I am done with you, as, for those following this thread, you have again been clearly exposed you as a liar and an idiot.
......once again, willfully ignoring the most recent ISM & IGM data that exists even in WkiPedia links.

Hey, psycho-babbler, this is the 21st Century & we have better data collecting instrumentation that torpedoes all those headspin arguments that Pop-Cosmology culture concocts here in this chatroom.

RNP
Aug 09, 2019
@Beeni
Just a side issue.. You clearly do not know what the word psychobabble means'. It is defined as; "...a form of speech or writing that uses psychological jargon, buzzwords, and esoteric language to create an impression of truth or plausibility. "

None of the arguments you have been presented with have anything to do with psychology, so what, in your usual inept manner, are you actually trying to say?

Aug 09, 2019
@Beeni
Just a side issue.. You clearly do not know what the word psychobabble means'. It is defined as; "...a form of speech or writing that uses psychological jargon, buzzwords, and esoteric language to create an impression of truth or plausibility. "

None of the arguments you have been presented with have anything to do with psychology, so what, in your usual inept manner, are you actually trying to say?


Like Benni would provide a rational argument LMAO, or even better, a reference to an actual paper...
Have to say I always enjoy seeing Benni put in his place with surgical precision :D
Thanks for the giggles @RNP !

I bet that chair is getting unimaginably uncomfortable, ey @Benni boy ?
Or have you started floating using alien powers like StupidEgg ???

Hahahaha


Aug 09, 2019
Hey, psycho-babbler RNP, this is the 21st Century & we have better data collecting instrumentation that torpedoes all those headspin arguments that Pop-Cosmology culture concocts here in this chatroom.

@Beeni
Just a side issue.. You clearly do not know what the word psychobabble means'. It is defined as; "...a form of speech or writing that uses psychological jargon, buzzwords, and esoteric language to create an impression of truth or plausibility. "

None of the arguments you have been presented with have anything to do with psychology, so what, in your usual inept manner, are you actually trying to say?
...it is your argument that Dark Matter exists at a SPECIFIC density of 0.3 particles/cm³, yet no one has ever found any to substantiate the basis for such a claim, that is classic Pop-Cosmology psycho-babble.

Aug 09, 2019
@RNP
@Castro
@Benni.

From @RNP to @Benni:
Both of the references I gave you are from around 2008
@RNP, you should catch up to what has happened in the intervening ten years of observations with vastly better scopes/instruments/reviews before you continue on that tack with @Benni.

Consider:

- newly observed deep space material mass is way more than the needed 'missing mass' quantity; and there is even more to be found with newer scopes etc being planned/commissioned as we speak. The term 'tip of the iceberg' is apt for what we have observed over the last ten years.

- nature of 'dark' (previously too-faint-to-see) matter is now more likely to be ORDINARY (ie, NOT alleged 'non-EM-interacting') stuff which I already mentioned is now understood to occupy deep space adding up to quantities explaining much of the gravitational dynamics observed.

- in BB timeline, any non-EM-interacting DM would ALL have gone DIRECTLY into BHs EARLY ON; think about it!

Take care. :)

RNP
Aug 10, 2019
@RealityCheck
- newly observed deep space material mass is way more than the needed 'missing mass' quantity; and there is even more to be found with newer scopes etc being planned/commissioned as we speak.


You are lying again. Either provide a reference that you think proves your point or go away and take your stupid misinterpretations of real science with you.

Aug 10, 2019
@RNP.
- newly observed deep space material mass is way more than the needed 'missing mass' quantity; and there is even more to be found with newer scopes etc being planned/commissioned as we speak.
You are lying again. Either provide a reference that you think proves your point or go away and take your stupid misinterpretations of real science with you.
Tch, tch, mate, where have you been? its all in physorg articles over the last ten years and more, including up to days ago! Read up! :)

ps: Oh, and you studiously avoid answering my question/observation re non-EM-interacting dark matter NOT being retarded/ejected etc by the usual EM dynamics around BHs; and so would have all gone directly into BHs early in BB scenario timeline. You cant have it both ways: either there was no BB or there was no 'non-EM-interacting' dark matter. Choose one-----OR explain WHY 'non-EM-interacting' could have survived early densest stage of BB when 'direct accretion' into BHs was possible. :)

Aug 10, 2019
pps @RNP.

Here's a couple most recent for you to catch up to, mate:

1) https://phys.org/...ark.html
Another reason these galaxies appear so weak is because larger galaxies, even in the present day, tend to be shrouded in dust, which obscures them more than their smaller galactic siblings.

2) https://phys.org/...axy.html
"Most matter in the universe is diffuse, hot, and outside of galaxies," says Ravi. "This state of matter, although not 'dark,' is difficult to observe directly. However, its effects are clearly imprinted on every FRB, including the one we detected at such a great distance."
Please catch up/connect all the dots. :)

Aug 11, 2019
I got one more question regarding the COG point.
If there is rouge mass in the system that's not gravitationally bound to any of the galaxies/masses of the cluster. Does the rouge mass get moved/attracted to the COG point and start to form a new galaxy/object at the COG point, if there is enough rouge mass to seed it while the system evolves?

Aug 11, 2019
@beeds, an interesting thought experiment.

Such an object would have to be, and remain in, the exact barycenter; what you call the "COG point." Not only that, but its own barycenter (or COG) would have to be at that point. The slightest deviation would result in it experiencing an unbalanced gravity from the rest of the cluster, and in it moving away from that point. Since a cluster is dynamic, with all its galaxies moving around, it must be obvious that that point would move; and there is no force keeping the mass centered.

It would be impossible for any mass to exist at that point but not be gravitationally bound; it's incorrect to state that any mass could be there and not be gravitationally bound to all of the other mass in the cluster. There is no shield for gravity; it goes right through mass. If there's a mass there, it will feel gravity.
[contd]

Aug 11, 2019
[contd]
There is no gravity to put such a mass at that point; in fact, the net gravity there is zero, leaving the mass free to move; and once it does it is inevitably attracted by the side it moves toward, more and more the farther it gets from the barycenter.

Your very good question has allowed a point that the trolls don't get (or will not admit to it) and I can see why you asked it. I don't intend to insult or demean you for asking; so please don't take it that way. I hope you learned something from the answers.

Aug 11, 2019
I just thought of a good analogy. Imagine a pencil balanced on its point. The slightest movement of the eraser end of the pencil will inevitably result in it falling over. The slightest breath of air, the slightest touch, and it falls. This is the situation for a mass whose barycenter is at the barycenter of a galaxy, a galaxy cluster, or any other collection of other masses that has a barycenter.

Again, @beeds, thanks for a great question.

Aug 11, 2019
pps @RNP.

Here's a couple most recent for you to catch up to, mate:

1) https://phys.org/...ark.html
"Most matter in the universe is diffuse, hot, and outside of galaxies," says Ravi. "This state of matter, although not 'dark,' is difficult to observe directly. However, its effects are clearly imprinted on every FRB, including the one we detected at such a great distance."
Please catch up/connect all the dots. :)


None of this will matter to the Pop-Cosmology acolytes living here, their immutable fantasies are sacred & should never be trod upon. Once THEIR 0.3 DM/cm³ data points have been set it must forever remain unchanged or their fictional ratio of 5:1 takes a massive hit.

I wonder about the size of the tin-foil hat RNP wears to Trekkie Conventions. Does it have a point on it as well?


Aug 11, 2019
This Ever Increasing Matter Occupying this Vacuum - by RealityCheck

For to this Inter Galactic Medium density
We've been finding
Humongous quantities of gas and dust which
Until more recently
Was never even suspected to be there in such abundances
Even in early BB epochs
Taking all that into account
Plus the fact that such recent
Tip of the iceberg
Discoveries point to even greater abundance
Of all sorts of faint
Low-brightness material
Dusty plasmas
Carbonaceous
Iron molecules
Pebbles
Protoplanets
Protostars and defunct stars
Blackholes
Neutron stars
Dim white
Blue dwarfs
Then it behoves anyone
To at least have the most up-to-date understandings
Of what ordinary matter is out there
But not previously allowed for
When calculating ordinary matter densities of IGM and Voids

RealityCheck
Upon completion of your TOE
What is youreth solution to including?
This ever increasing mass occupying this vacuum
Once your Theory of Everything hits HEFFERS in Trinity Street

RNP
Aug 11, 2019
@RealityCheck

Here's a couple most recent for you to catch up to, mate:

Idiot!. The fact that you think the references you provided contribute in any way to your argument shows precisely how ignorant you are. Neither of the papers have (or claim to have) any impact on the DM content of the universe. For pity's sake man, learn some astronomy!!!!

Aug 11, 2019
@RealityCheck

Here's a couple most recent for you to catch up to, mate:

Idiot!. The fact that you think the references you provided contribute in any way to your argument shows precisely how ignorant you are. Neither of the papers have (or claim to have) any impact on the DM content of the universe. For pity's sake man, learn some astronomy!!!!


We keep explaining it to the idiot, he keeps failing to understand it!

RNP
Aug 11, 2019
@RealityCheck
As you have again proven yourself ineducable, I am putting you back on ignore.

Aug 11, 2019
@RNP
@Castrogiovanni.
Idiot!. The fact that you think the references you provided contribute in any way to your argument shows precisely how ignorant you are. Neither of the papers have (or claim to have) any impact on the DM content of the universe. For pity's sake man, learn some astronomy!!!!
What are you on, mate? How can any sane objective observer pretend that finding enormous quantities of previously-too-faint-to-see ORDINARY matter not be relevant in falsifying the claim for 'non-EM-interacting DM'? Just because those observers/reports don't state it explicitly for you, it behoves you to objectively connect-the-dots for yourselves. Is your personal animus and biases so impenetrable that you wilfully grasp at flimsy evasions and insults in order to deny the bleeding obvious happening right under your noses re this and other points made for the benefit of YOUR educational update?

Now, please address my point re 'non-EM-interacting' DM going into BHs in early BB era. :)

Aug 11, 2019
@RNP.
As you have again proven yourself ineducable, I am putting you back on ignore.
Don't run away like that, mate; be brave and actually address the science/logic point already made in the ps to my post of yesterday; to wit:
ps: Oh, and you studiously avoid answering my question/observation re non-EM-interacting dark matter NOT being retarded/ejected etc by the usual EM dynamics around BHs; and so would have all gone directly into BHs early in BB scenario timeline. You cant have it both ways: either there was no BB or there was no 'non-EM-interacting' dark matter. Choose one-----OR explain WHY 'non-EM-interacting' could have survived early densest stage of BB when 'direct accretion' into BHs was possible. :)
Why so shy? I have put that to you and your fellow travellers here at physorg for some time now, and none of you have actually dared to address that. Please do so now; without the usual personal animus, biases and insults. Thanks. :)

Aug 11, 2019
@RNP
@Castrogiovanni.

While you are at it, here's another reference re enormous quantities of previously-too-faint-to-see ORDINARY matter recently found that were previously 'unexpected':

http://www.astron...ty-space
A team of astronomers....has found short strings of faint galaxies in what were previously thought to be extremely empty parts of space. ... "We weren't sure what we'd find when we looked at voids in detail, but it was amazing to find so many of these tendrils lurking in regions that have previously been classified as empty,"...

"This means that voids might be much smaller than we previously thought and that galaxies that were previously thought to be in a void might just be part of a tendril," said Alpaslan.

The GAMA team plan to catalog more tendrils for further study as their detailed map of the universe expands.
See? Tip of the iceberg. Wake up and catch up, guys. :)

Aug 12, 2019
@RealityCheck
I, too, thought that those voids were empty of galaxies and Stars where the void itself was a shrunken space that would expand further upon newly formed Stars being born within the void.
Thanks for the link, btw.
Those 'tendrils' reminded me of something that I hadn't thought of for a long time.

It seems to me that RNP and company are sticking to the existing consensus like glue.

Aug 12, 2019

Calling me an 'alien lizard' won't get you into my good graces, Mop man.
Actually, s'truth, there is NO such thing, substance, creature, dust or gas, particle or wave, or galactic superhero called, or consisting of "Dark Matter".
Only in your most wildest imaginings, and in the imaginings of Astronomers, Astrophysicists, and your fellow Mop and bucket men is there such a damp squid as Dark Matter. Matter of ANY kind is readily seen/detected - no woowoo involved. No faerie furfels required, jonesy.
If you and Schneib and all others such as Torbjorn continue to believe in the imaginings of clueless scientists, then you are in danger of becoming a lunatic. You might as well go out at night and howl at the Moon.


Lol. Moron.
says CastroGio

Which is Castro's way of saying, "I dunno. I'll get back to you on that later - like in a hundred years."

Aug 12, 2019
Darkmatter - You might as well go out at night and howl at the Moon

There is no such thing as Dark Matter
Calling me
An alien lizard
Won't get you into my good graces
Mop man
Actually
S'truth
There is NO such thing
Substance
Creature
Dust or gas, particle or wave
Or galactic superhero
Called
Or consisting of Dark Matter
Only in your most wildest imaginings
And in the imaginings of Astronomers
Astrophysicists
And your fellow Mop and bucket men
Is there such a damp squid
As Dark Matter
Matter of ANY kind is readily seen
Detected
No woowoo involved
No faerie furfels required
Jonesy.
If you and Schneib
And all others
Such as Torbjorn
Continue to believe in the imaginings of clueless scientists
Then you are in danger of becoming a lunatic
You might as well go out at night and howl at the Moon

Darkmatter by SEU

Aug 12, 2019
Darkmatter - You might as well go out at night and howl at the Moon

Away from our Moonchines darkside
Where strangely in these lunar Moonchine moonbeams
Not one single shredded string of darkmatters been observed
Foreth even as these wolverines
A howling on these Moonchine moonbeams
These darkestmatterist wolverines
Have nay coaxed one single shred of darkestmatter
Emerge on these moonbeams
As these ghostly shafts beam their path to this earthly matter
From galactic galaxy rotations
To galactic galaxies moving through this vacuum
These strings of darkestmatter
Not one tattered darkest strings been seen
Not one proof of galaxies moving through this vacuum
Been shown to be attributed to this darkly darkestmatter
Even though it's proposed 85% of matter in this vacuum is matter darkly
For when it was proposed we scoop handfuls of this darkestmatter atmosphere
Foreth darkestmatter nay exists on this earth

These darkest wolverines went out into the night a howling at this Moon

Aug 12, 2019


Which is Castro's way of saying, "I dunno. I'll get back to you on that later - like in a hundred years."


Nope. It is merely a statement of fact. As you have amply demonstrated.

Aug 12, 2019
This Ever Increasing Matter Occupying this Vacuum - by RealityCheck

RealityCheck
Upon completion of your TOE
What is youreth solution to including?
This ever increasing mass occupying this vacuum
Once your Theory of Everything hits HEFFERS in Trinity Street

Foreth RealityCheck, it would be interesting to know how you are going to keep your admiring public up to date informed
Foreth, your regular flybys on your magic carpet with your words of wisdom
Are somewhat flagging of late
As your magic carpet is no longer flapping in the wind

Come this All Hallows' Eve these witches will be broomsticking Trinity Street as you circle on your magic carpet

Aug 12, 2019
Our Version of the Theory of Every Thing

RealityCheck
You're not the only one to experience this eternal problem
As Dr Peerally also has this problem
For in these embers of physicsworld
Unusually for Dr Peerally
He regularly returned
Updating his TOE
On his own version of the Theory of Every Thing
So do not feel alone RealityCheck
Even the greatest scientists are alone in their world
For Dr Peerally had completed his TOE
He was coming back to physicsworld commentary
For we were leaving these embers of a world
Known only to the likes of Dr Peerally and Sir Roger Penrose
As you now know RealityCheck, sadly fore ever gone
Except in these memories in these phys.org quantum fluctuations

Aug 12, 2019


Which is Castro's way of saying, "I dunno. I'll get back to you on that later - like in a hundred years."


Nope. It is merely a statement of fact. As you have amply demonstrated.
says Castrogogo

What fact are you referring to, Mop man? There is nothing factual about "Dark Matter". Nothing of the kind exists in THIS Universe. You are beginning to sound like the former Vice President Biden who is now a candidate for the office of POTUS, who has said that, "We choose truth over facts". ROFLMAO

Hmmm Is it possible that YOUR versions of facts are coming from the wild imaginings of insane scientists? There are SOME scientists who had become troubled by their hypothesis that DM just has to be REAL and the future of their mental health depends on whether or not their hypothesis is vindicated. Hmmmm

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