Massive holes 'punched' through a trail of stars likely caused by dark matter

September 7, 2016 by Sarah Collins, University of Cambridge
Artist's impression of dark matter clumps around a Milky Way-like galaxy. These clumps are invisible and can only be detected through their gravitational effect on visible matter. The clumps, also known as subhaloes, come in a range of sizes with the smallest one set by the mass of the yet to be discovered dark matter particle. The more massive the dark matter particle, the slower the dark matter moves, and the easier it is for regions in the early universe to collapse and form small subhaloes. In this work, a tidal stream from a disrupting globular cluster is used to probe their presence. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge). Photo: Color image of M31 from Adam Evans. Dark matter clumps from Aquarius, Volker Springel (HITS)

The discovery of two massive holes punched through a stream of stars could help answer questions about the nature of dark matter, the mysterious substance holding galaxies together.

Researchers have detected two massive holes which have been 'punched' through a stream of stars just outside the Milky Way, and found that they were likely caused by clumps of , the invisible substance which holds galaxies together and makes up a quarter of all matter and energy in the universe.

The scientists, from the University of Cambridge, found the holes by studying the distribution of stars in the Milky Way. While the clumps of dark matter that likely made the holes are gigantic in comparison to our Solar System – with a mass between one million and 100 million times that of the Sun – they are actually the tiniest clumps of dark matter detected to date.

The results, which have been submitted to the Monthly Notices of the Royal Astronomical Society, could help researchers understand the properties of dark matter, by inferring what type of particle this mysterious substance could be made of. According to their calculations and simulations, dark matter is likely made up of particles more massive and more sluggish than previously thought, although such a particle has yet to be discovered.

"While we do not yet understand what dark matter is formed of, we know that it is everywhere," said Dr Denis Erkal from Cambridge's Institute of Astronomy, the paper's lead author. "It permeates the universe and acts as scaffolding around which astrophysical objects made of ordinary matter – such as galaxies – are assembled."

Current theory on how the universe was formed predicts that many of these dark matter building blocks have been left unused, and there are possibly tens of thousands of small clumps of dark matter swarming in and around the Milky Way. These small clumps, known as dark matter sub-haloes, are completely dark, and don't contain any stars, gas or dust.

Dark matter cannot be directly measured, and so its existence is usually inferred by the gravitational pull it exerts on other objects, such as by observing the movement of stars in a galaxy. But since sub-haloes don't contain any , researchers need to develop alternative techniques in order to observe them.

The technique the Cambridge researchers developed was to essentially look for giant holes punched through a stream of stars. These streams are the remnants of small satellites, either dwarf galaxies or globular clusters, which were once in orbit around our own galaxy, but the strong tidal forces of the Milky Way have torn them apart. The remnants of these former satellites are often stretched out into long and narrow tails of stars, known as stellar streams.

Comparison between the observed stream and two simulated streams. The blue points show the observed stream which has been colored blue to distinguish it from the other streams. In reality, the color of its stars look more like the previous figure. Note the underdense regions on the left and right. The green points show a simulated stream evolved in a smooth potential without dark matter clumps. In contrast to the observed stream, this stream appears smooth and does not have any gaps. The red points show a simulated stream which has been struck by two clumps of dark matter with masses of one million Suns (left) and fifty million Suns (right). These perturbations produce the same gaps as what is seen in the data. Although the dark matter clumps themsevlves are invisible, they create gaps in the stream which can be detected. If confirmed, these two dark subhaloes would represent the lowest mass clumps detected to date. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge)

"Stellar streams are actually simple and fragile structures," said co-author Dr Sergey Koposov. "The stars in a stellar stream closely follow one another since their orbits all started from the same place. But they don't actually feel each other's presence, and so the apparent coherence of the stream can be fractured if a massive body passes nearby. If a dark matter sub-halo passes through a stellar stream, the result will be a gap in the stream which is proportional to the mass of the body that created it."

The researchers used data from the stellar streams in the Palomar 5 globular cluster to look for evidence of a sub-halo fly-by. Using a new modelling technique, they were able to observe the stream with greater precision than ever before. What they found was a pair of wrinkled tidal tails, with two gaps of different widths.

By running thousands of computer simulations, the researchers determined that the gaps were consistent with a fly-by of a dark matter sub-halo. If confirmed, these would be the smallest dark matter clumps detected to date.

"If dark matter can exist in clumps smaller than the smallest dwarf galaxy, then it also tells us something about the nature of the particles which dark matter is made of – namely that it must be made of very massive particles," said co-author Dr Vasily Belokurov. "This would be a breakthrough in our understanding of dark matter."

Comparison between the observed stream and two simulated streams. This is the same as the previous figure but with no labels. Credit: V. Belokurov, D. Erkal, S.E. Koposov (IoA, Cambridge)

The reason that researchers can make this connection is that the mass of the smallest clump of dark matter is closely linked to the mass of the yet unknown particle that dark matter is composed of. More precisely, the smaller the clumps of dark matter, the higher the mass of the particle.

Since we do not yet know what dark matter is made of, the simplest way to characterise the particles is to assign them a particular energy or mass. If the particles are very light, then they can move and disperse into very large clumps. But if the particles are very massive, then they can't move very fast, causing them to condense – in the first instance – into very small clumps.

"Mass is related to how fast these particles can move, and how fast they can move tells you about their size," said Belokurov. "So that's why it's so interesting to detect very small clumps of dark matter, because it tells you that the itself must be very massive."

"If our technique works as predicted, in the near future we will be able to use it to discover even smaller clumps of dark matter," said Erkal. "It's like putting dark matter goggles on and seeing thousands of dark each more massive than a million suns whizzing around."

Explore further: 3 knowns and 3 unknowns about dark matter

More information: Denis Erkal et al. 'A sharper view of Pal 5's tails: Discovery of stream perturbations with a novel non-parametric technique.' arXiv:1609.01282 , arxiv.org/abs/1609.01282

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76 comments

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jeffensley
3.9 / 5 (8) Sep 07, 2016
Newbie question here... do we even know if DM exerts a force of attraction or repulsion?
RNP
3.7 / 5 (15) Sep 07, 2016
@jeffensley
The idea of DM is that it only interacts by gravity (and possibly the weak nuclear force). Therefore, generally speaking, the force it exerts on ordinary matter is attractive.

bobbysius
4.2 / 5 (10) Sep 07, 2016
Per current dark matter models, it exerts an attractive force. Dark matter has mass and thus interacts with ordinary matter via gravity (and only via gravity)
jeffensley
3.9 / 5 (7) Sep 07, 2016
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplainable behavior of visible bodies?
bschott
1.3 / 5 (16) Sep 07, 2016
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplainable behavior of visible bodies?

Only unexplainable if you limit your options for what the explanation can be. For instance, how can a DM "clump" punch through a stream of stars without any becoming gravitationally bound to the clump? In other words, if a DM clump is approaching a stellar stream, the gravity of the clump should cause the stream to bulge towards it during its approach and at least a few stars should be bound to it when it passes through.....perhaps instead of a pointless model some observations based on the physics of the interaction theorized should be carried out....like maybe at least one stellar body moving in a fashion to support this theory. Or maybe it would be easier to prove that DM also causes the periodic gaps in Saturns rings.....( not that the scale is close or anything).

Another joke article about a joke theory.
RNP
3.5 / 5 (13) Sep 07, 2016
@jeffensley
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplanable behavior of visible bodies?


Perhaps it is better stated as: To date, dark matter is the best explanation we have for numerous otherwise unexplained observations of visible bodies. That is to say that, although it is still possible that the observed effects may be due to a breakdown in our understanding of gravity (theories such as MOND and modified GR, such as TeVeS theories), evidence is growing that the effect is best described by a form matter that does not interact electromagnetically - i.e. DM.
RNP
3.4 / 5 (17) Sep 07, 2016
@bschott
Only unexplainable if you limit your options for what the explanation can be. For instance, how can a DM "clump" punch through a stream of stars without any becoming gravitationally bound to the clump?


The holes show that some stars HAVE been dragged away, but the number that would actually become gravitationally bound to the DM halo will be extremely small due to the large relative velocities involved. In either case the numbers are so small they would be all but impossible to identify in any realistic observations.

Or maybe it would be easier to prove that DM also causes the periodic gaps in Saturns rings.....


Another joke article about a joke theory.


These comments contribute nothing.
TheGhostofOtto1923
4.6 / 5 (10) Sep 07, 2016
jeffensley5 / 5 (1) 1 hour ago
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplainable behavior of visible bodies?
Physorg is probably the worst place for asking people to educate you about science. Conversely the internet is easy to search and it is relatively easy to tell what are dependable sources and what are not.
bschott
2.2 / 5 (17) Sep 07, 2016
The holes show that some stars HAVE been dragged away,

The holes are evidence that there are no stars there, that is all. Evidence the stars have been dragged away would be observing it happen. As I said, finding one of the missing ones and charting it's new axial velocity, then tracing that forward to find the next opportunity to observe an interaction. This would be indisputable evidence, not a bullshit model based around a theory with no observational support other than a gap in a stream.
but the number that would actually become gravitationally bound to the DM halo will be extremely small due to the large relative velocities involved. In either case the numbers are so small they would be all but impossible to identify in any realistic observations.

Do you need me to link how many rogue stars we have observed WITHOUT knowing where to look? This would be a cakewalk in comparison.
These comments contribute nothing.

Fitting of the article.
bschott
2 / 5 (12) Sep 07, 2016
jeffensley5 / 5 (1) 1 hour ago
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplainable behavior of visible bodies?
Physorg is probably the worst place for asking people to educate you about science. Conversely the internet is easy to search and it is relatively easy to tell what are dependable sources and what are not.

Not the first time I have agreed with something you said...although I doubt it is for the reasons you said it. Thanks for the chuckle.
RNP
3.6 / 5 (14) Sep 07, 2016
@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?
Phys1
3.5 / 5 (11) Sep 07, 2016
For instance, how can a DM "clump" punch through a stream of stars without any becoming gravitationally bound to the clump?

That is a good question. You should have stopped there instead of supplying your usual flawed answers and stupid sarcasm.
The answer is that only by a, very unlikely, collision with a third body could a star become bound to a DM clump.
Phys1
3.7 / 5 (12) Sep 07, 2016

The holes are evidence that there are no stars there, that is all.

You omit the fact that the stars SHOULD have been there.
Evidence the stars have been dragged away would be observing it happen.

That's stupid. Are you stupid? Honest answer please. How were (are?) your grades for science related subjects?
Phys1
3.8 / 5 (10) Sep 07, 2016

Only unexplainable if you limit your options for what the explanation can be.

Exactly. So stop that.
jeffensley
2.6 / 5 (5) Sep 07, 2016
I see I'm getting DM and DE confused. The little research I did today made me realize my own thoughts on what makes the most sense go along with the Lemaitre theory of an expanding universe... space being created everywhere at all times. But then I read a post about the "quantization" of the observed redshift of galaxies which to a novice's mind, opens a whole new realm of possibilities.
HannesAlfven
1.7 / 5 (12) Sep 07, 2016
The article states: "But they don't actually feel each other's presence, and so the apparent coherence of the stream can be fractured if a massive body passes nearby. If a dark matter sub-halo passes through a stellar stream, the result will be a gap in the stream which is proportional to the mass of the body that created it."

Since we are apparently speculating, how about the gaps are simply stars dimming and brightening as a wave of charged particles flow along the plasma filament created by the stellar highway?

Or, what if the filament has passed through a region of differing magnetic field or charge density?

Do the theorists have any reason to believe that ONLY dark matter can cause such an observation?
Phys1
3.5 / 5 (11) Sep 07, 2016
@HA
It is so easy to find alternative explanations.
Good work, HA.
O wait, you're wrong.
RNP
3 / 5 (12) Sep 07, 2016
@jeffensley
The "quantization" of the galaxy redshifts is a myth left over from early observations that covered an extremely small region of the sky and only included very nearby galaxies (only ~100 galaxies in total). They therefore had little statistical significance. No such quantization is present in the HUGE surveys that we have available to us today (e.g. the GAMA survey which includes 300,000 galaxies: http://icc.dur.ac...cs/O11).
Benni
1.9 / 5 (14) Sep 07, 2016
@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?


Yeah, dust lanes hiding background stars.

Depending on which angle at which the dust lane is being observed, it can appear as a "hole" if it is being observed END ON, or it can can appear as a DARK STREAK for many light years distance if being observed at a transverse angle to a so-called "hole".
RNP
3.2 / 5 (15) Sep 07, 2016
@HannesAlfven
....Since we are apparently speculating, how about the gaps are simply stars dimming and brightening as a wave of charged particles flow along the plasma filament created by the stellar highway?

Or, what if the filament has passed through a region of differing magnetic field or charge density?

Do the theorists have any reason to believe that ONLY dark matter can cause such an observation?


No they do not. Indeed they acknowledge so in the title of the article which says that DM is the "likely" cause of the holes. However, the EU nonsense you mention is a non-starter for an alternative, as it would have observational consequences that are easily refutable.
RNP
3.3 / 5 (16) Sep 07, 2016
@Benni

@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?


Yeah, dust lanes hiding background stars.


The problem with that as an explanation is that stars are visible behind the stream in these regions (http://arxiv.org/...v1.pdf).

bschott
1.8 / 5 (16) Sep 07, 2016
You omit the fact that the stars SHOULD have been there.

You claim they should be without knowing why, how do you know they SHOULD be? The origin of the streamer is a theory in itself so there is no evidence to support they should be unless you can find the missing ones you useless tool.
The answer is that only by a, very unlikely, collision with a third body could a star become bound to a DM clump.

It's hilarious and a bit scary how much invalidated physics is locked in this statement, mom needs to cook the chicken longer basement boy.
That's stupid. Are you stupid?

Wow...
But since sub-haloes don't contain any ordinary matter, researchers need to develop alternative techniques in order to observe them.

Now that was stupid.

Sorry you cannot fathom why claiming stars are missing due to a punch through by a DM clump requires locating the "missing" stars. Also sorry you tried to pretend to be a physicist and it isn't working out....
bschott
1.8 / 5 (15) Sep 07, 2016
@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?

I don't need to provide an alternate explanation when this one has so much wrong with it that Phys1 may as well have come with it. I could propose one after examining all the requisite observational data, thus applying reality instead of models which satisfy the one single criteria of explaining a hole where it is assumed there wasn't one when in fact we do not know if it hasn't always been there or where the missing stars went...
abecedarian
3.4 / 5 (5) Sep 07, 2016
If these 'holes' punched through these structures, wouldn't one expect to see some sort of formation resembling 'wake' or 'bow shock' comprised of the displaced stars?

Or, as these are nearby, could those dark streaks result from physical encounters with the Milky Way, as in these structures actually crossed through part of it and the stars that were in the structure were captured by the galaxy? If the structure is orbiting the galaxy, and rotating, say, like a propeller, the thin streak could be the result of a perpendicular traversal through the galaxy and the wider streak from a more oblique angle.

Think:
Thin dark area: galaxy= ----- ; structure crosses in this orientation |
... or ...
Wide dark area: galaxy= ----- ; structure crosses in this orientation \ or /

Dark areas are where stars once were but became captive to the galaxy.

I know in 99.999% wrong, but am only hypothesizing.
IMP-9
4.7 / 5 (12) Sep 07, 2016
Yeah, dust lanes hiding background stars.


Extinction maps were examined as they mention in the paper. It's not dust.
Phys1
3.2 / 5 (9) Sep 07, 2016
The answer is that only by a, very unlikely, collision with a third body could a star become bound to a DM clump.

It's hilarious and a bit scary how much invalidated physics is locked in this statement, .

Don't blame your weak nerves on "invalidated physics".
Get a real diagnose.
this one has so much wrong with it

It is unclear exactly what you mean.
There may be a lot wrong with you instead.
TheGhostofOtto1923
5 / 5 (4) Sep 07, 2016
jeffensley5 / 5 (1) 1 hour ago
Thank you for the replies. And based on my limited understanding, we also only "see" it by the unexplainable behavior of visible bodies?
Physorg is probably the worst place for asking people to educate you about science. Conversely the internet is easy to search and it is relatively easy to tell what are dependable sources and what are not.

Not the first time I have agreed with something you said...although I doubt it is for the reasons you said it. Thanks for the chuckle.
Sorry b but I was going to include this little musing of yours
For instance, how can a DM "clump" punch through a stream of stars without any becoming gravitationally bound to the clump?
-as exhibit #1.

Just to be clear.
Benni
1 / 5 (12) Sep 07, 2016
@Benni

@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?


Yeah, dust lanes hiding background stars.


The problem with that as an explanation is that stars are visible behind the stream in these regions (http://arxiv.org/...v1.pdf).


Hey, dust lanes are not walls....!!!! There are varying degrees of opaqueness unique to any density of material in any Dust Lane of any galaxy we observe. Your problem is that anything that appears odd looking to you must have an explanation that starts with DM as the first choice of most likely explanations, and the stuff has never been PROVEN to exist.


mbee1
1.7 / 5 (10) Sep 07, 2016
Look all they have is a suspected distribution of stars around a void, That void may or may not exist depending on how you interpret the data in the study. If it exists the most likely explanation is not dark matter it is a black hole wandering around. Dark matter is a math construct which is popular right now like skittles is with kids. Since nobody has actually proved dark matter exists it is all BS dressed up in fancy math and speculation which gives them the next grant, the sports car and the fancy expensive wife.
Colbourne
1 / 5 (2) Sep 08, 2016
I would expect dark matter to have a repulsive effect on normal matter. Has this been shown here ?
Phys1
3.7 / 5 (9) Sep 08, 2016
@Benni
I T I S N O T D U S T.
Phys1
4 / 5 (8) Sep 08, 2016
Look all they have is a suspected distribution of stars around a void,

An observation. All they have is some evidence.
That void may or may not exist depending on how you interpret the data in the study.

Yeah right, perhaps the stars are locally black?
If it exists the most likely explanation is not dark matter it is a black hole

Why ? Also, this is not excluded by the paper.
Dark matter is a math construct

So you belong to the mathless, factless sockpuppet army.
Phys1
4 / 5 (8) Sep 08, 2016
@bschott
Do you have an alternative explanation for these holes, or are you just going to denigrate the one given?

I don't need to provide an alternate explanation when this one has so much wrong with it that Phys1 may as well have come with it. I could propose one after examining all the requisite observational data, thus applying reality instead of models which satisfy the one single criteria of explaining a hole where it is assumed there wasn't one when in fact we do not know if it hasn't always been there or where the missing stars went...

The missing stars are still there ....
The simulation results resemble the observation ...
They conserve the number of stars ...
antialias_physorg
4.2 / 5 (10) Sep 08, 2016
I would expect dark matter to have a repulsive effect on normal matter. Has this been shown here ?

No, because if you do the math on that one the the distribution of DM would look totally improbable.

And please get this through your heads: That the name is 'dark matter' doesn't say anything about what it is (not even whether it's matter at all). So don't derive any properties from the name (other than that it has a gravitational effect like matter does and that we can't, currently, see it). It is just a label.

Deriving anything other than that from the name is like saying a funeral must be fun because 'fun' are the first three letters in 'funeral'.
bschott
1.8 / 5 (10) Sep 08, 2016
The missing stars are still there ....

LMAO...of course they are! Why would a clump of matter a few thousand LY in diameter with gravity of 50 million suns attract anything....
The simulation results resemble the observation ...

News flash basement boy, when programming a simulation, you can tailor the results any way you want
They conserve the number of stars ...

a clump of gravity equivalent to 50 million solar masses passed through a stellar streamer and left all the stars there eh? Are you capable of thinking at all?
bschott
1.4 / 5 (9) Sep 08, 2016
And please get this through your heads: That the name is 'dark matter' doesn't say anything about what it is (not even whether it's matter at all). So don't derive any properties from the name (other than that it has a gravitational effect like matter does and that we can't, currently, see it). It is just a label.

From the article:
dark matter, the mysterious substance holding galaxies together.

or
by inferring what type of particle this mysterious substance could be made of. According to their calculations and simulations, dark matter is likely made up of particles

hmmm....
then it also tells us something about the nature of the particles which dark matter is made of – namely that it must be made of very massive particles,


If your comment is directed at the scientists who wrote the paper, well done. If it is directed at the people commenting....WTF are we supposed to assume when every article states this crap?
antialias_physorg
4.4 / 5 (7) Sep 08, 2016
Some of the theories propose a form of matter. This is plausible because we know of only one substance that creates gravitational effects of the magnitude observed.
These theories are the easiest to evaluate, hence this is where the current focus of detector- and telescope-driven experiments is on.

But if you go to the list of DM theories then there are also several that posit non-matter sources. But as for now these are more at the exotic end of the spectrum.
Benni
1.7 / 5 (6) Sep 08, 2016
They conserve the number of stars ...


Uh oh, now we have "Conservation of Stars" as a new buzzword in followup to the most recent buzz of Shavo's "Conservation of Gravity" that he made up.

If your comment is directed at the scientists who wrote the paper, well done. If it is directed at the people commenting....WTF are we supposed to assume when every article states this crap?
.......On the money bshott, this is what we get when these Dark/Black Cosmology neophytes get on their math model bandwagons & imagine themselves as the new Pop-Sci culture elite. Why can't they figure out what Stephan Hawking had already figured out in his news conference release in April in which he debunked the whole concept of the existence of BHs that Schwarzschild came up with early in the last century. Then zany Zwicky adds more insult to the progress of real science with his imaginary Cosmic Fairy Dust.

Get up to speed DM/BH Enthusiasts, this is the 21st Century, not 20th.

bschott
2.1 / 5 (7) Sep 08, 2016
Fair enough AA. This site has an affinity for publishing articles written around papers assuming a particle.
This is plausible because we know of only one substance that creates gravitational effects of the magnitude observed.

Do you honestly believe that a travelling clump a gravity as massive as they claim is required, passing through a stellar streamer, would leave a gap as the only evidence it was there? According to their simulation, it would either be 1/4 the mass of Sag.A or possibly 25 times more massive....just drifts up to a stream of stars, parts the waters like Moses (which I guess we are now modelling gravitic repulsion????) and drifts on through only leaving a gap???
I would expect dark matter to have a repulsive effect on normal matter. Has this been shown here ?

A comment from someone who might now be confused about how gravity manifests because of claims made in articles like this...

Sad.
imfromcanada
2.3 / 5 (6) Sep 08, 2016
If your comment is directed at the scientists who wrote the paper, well done. If it is directed at the people commenting....WTF are we supposed to assume when every article states this crap?


You pretty much proved his point. In each quote you mention, they state "likely made up" or "mysterious substance" or "must be made up of". Each one implies they think it should be particles, apparently massive ones, but they aren't sure, hence why they are still trying to find out. You know, the math says this, but until we prove it, or disprove it, we'll keep looking.
bschott
1.9 / 5 (9) Sep 08, 2016
You pretty much proved his point.

LOL...as I said, that depends on who he is addressing.
In each quote you mention, they state "likely made up" or "mysterious substance" or "must be made up of". Each one implies they think it should be particles, apparently massive ones, but they aren't sure,

No, they aren't. But they are sure that it is a gravitational effect, claim it has been modeled as one, then show us a simulation that matches the observation...but looks nothing like what would be left if a ball of gravity as large as they claim had actually interacted with the matter in the streamer.
hence why they are still trying to find out. You know, the math says this, but until we prove it, or disprove it, we'll keep looking.

The math says what we make it say, reality operates a lot differently unless the math is describing an observed reality. The math around DM does not describe reality, but they are looking for it as though it does.

antialias_physorg
4.5 / 5 (8) Sep 08, 2016
parts the waters like Moses

No. It rips the stars along. They state this clearly in the article that the filament structure is not self stabilizing (it just happened to form that way) and that a passing disturbance can destroy that "filament look". It's liek when you put a dye in runnning water and then wade accross it. Do you 'part the dye stream'? No, You just rip out a chunk of the stream. There's no 'parting' action involved.
Benni
1.6 / 5 (7) Sep 08, 2016
parts the waters like Moses

No. It rips the stars along. They state this clearly in the article that the filament structure is not self stabilizing (it just happened to form that way) and that a passing disturbance can destroy that "filament look". It's liek when you put a dye in runnning water and then wade accross it. Do you 'part the dye stream'? No, You just rip out a chunk of the stream. There's no 'parting' action involved.
...........You were out there & watched all this happen, right? Hey, do you believe, unlike Hawking, that infinite wells of gravity can exist on the surface of a finite stellar body? If you do, then you claim to be smarter than Hawking & all you have is a Biology degree.
antialias_physorg
4.5 / 5 (8) Sep 08, 2016
..You were out there & watched all this happen, right?

No. I am reporting what I got from the article. At no point did I state that the article represents reality or not. Their simulation does show a remarkable similarity to what is observed so there's grounds for following this up (e.g. by taking those theories that suggest some charecteristic signature emission and then looking at these patches of sky)
Phys1
4.3 / 5 (6) Sep 08, 2016
@Benni
Be careful, remember that you are a moron
with not a clue about science but a lot of stupid opinions.
You forgot, of course.
bschott
2 / 5 (8) Sep 08, 2016
No. It rips the stars along.

Firstly, I posted above that should happen and a self proclaimed physicist who lives in his moms basement said;.
They conserve the number of stars ...

Secondly, there is no evidence of that in the frame that is the observation, thirdly, they make no mention of that happening so how you got that from the article isn't clear (to me). Fourthly, also as I posted above that many "rogue" stars should be really easy to find given that we know where they came from.
It's almost like they are playing a giant physics game of "Let's see what anomalous observations we can pin on DM".
Phys1
4.4 / 5 (7) Sep 08, 2016
@bschott
You said that such a blob would gravitationally bind stars.
That is incorrect. It would impart a change of speed by the mechanism of gravitational slingshot.
You wouldn't be able to understand that.
Phys1
4.3 / 5 (6) Sep 08, 2016
@bschott
You stated that such a blob would gravitationally bind stars, which is incorrect.
Of course, everything you said in the past few years is incorrect without exception.
It would impart a change of speed by the mechanism of gravitational slingshot.
You wouldn't be able to understand that.
Phys1
4.2 / 5 (5) Sep 08, 2016
parts the waters like Moses

No. It rips the stars along. They state this clearly in the article that the filament structure is not self stabilizing (it just happened to form that way) and that a passing disturbance can destroy that "filament look". It's liek when you put a dye in runnning water and then wade accross it. Do you 'part the dye stream'? No, You just rip out a chunk of the stream. There's no 'parting' action involved.

You are right. Stars are ejected from the stream.
Benni
1.7 / 5 (6) Sep 08, 2016
Some of the theories propose a form of matter. This is plausible because we know of only one substance that creates gravitational effects of the magnitude observed


Prescient..........so, "we know". Oh, that's it, "we know" there exists "only one substance....." .

Hey, anti-physics, those of us living in reality look in a mirror everyday and do not believe 80% of our bodies are a missing "substance". Maybe it's just more wishful thinking on your part?
Phys1
4.3 / 5 (6) Sep 09, 2016
@Benni
"do not believe 80% of our bodies are a missing "substance""
80% of your brains is still missing but you would not notice.
Benni
1 / 5 (6) Sep 09, 2016
@Benni
"do not believe 80% of our bodies are a missing "substance""
80% of your brains is still missing but you would not notice.


Well, we know that you wished 80% of your 5'-6" 275 lb frame were missing, but you won't get out of that armchair in your mother's basement to do anything about it. I guess you're just so weighed down by all those laptops with which you sign into all your accounts at Physorg that you've become immobile. I'm just trying to imagine how deep the potato chip crumbs must be around your armchair.
someone11235813
2.3 / 5 (3) Sep 11, 2016
I don't want to be churlish but shouldn't the article say 'possibly caused by DM' rather than 'likely'? Because we really don't know anything about DM other than it's there and it curves spacetime like all other forms of energy.
tinitus
Sep 11, 2016
This comment has been removed by a moderator.
tinitus
Sep 11, 2016
This comment has been removed by a moderator.
tinitus
Sep 11, 2016
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Phys1
5 / 5 (7) Sep 11, 2016
@Tinitus
The bullshit asymmetry principle is in your favour.
"The amount of energy needed to refute bullshit is an order of magnitude bigger than to produce it."
https://en.wikipe...rinciple
tinitus
Sep 11, 2016
This comment has been removed by a moderator.
RNP
3.7 / 5 (6) Sep 11, 2016
@tinitus
I'm just connecting the remote dots, which the specialized experts tend to overlook often.


No you are not. You are connecting random dots to construct (a patently false) view of the world that exists ONLY in your own mind. Your constant disparagement of the "experts" is just another symptom of your delusions.
tinitus
Sep 11, 2016
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tinitus
Sep 11, 2016
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RNP
3.5 / 5 (8) Sep 11, 2016
@tinitus
You are truly amazing. You know nothing about the subject, but you persist in writing these huge, nonsensical posts. You would be far better served if you spent your time actually learning the subject in which you seem so interested.
tinitus
Sep 11, 2016
This comment has been removed by a moderator.
RNP
3.3 / 5 (7) Sep 11, 2016
@tinitus
The nonsense that you post tells me that you know nothing about the subject. You clearly understand next to nothing about the consensus science that you are always critisizing, and your ideas are almost all refutable by observations.

As to appealing to authority, it is in fact advisable when you know NOTHING about the subject.
tinitus
Sep 11, 2016
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RNP
3.3 / 5 (7) Sep 11, 2016
@tinitus
Yet more obfuscation. The deviations from the consensual science that you are "pointing to" almost all exist only in your mind and are caused by your lack of understanding. You can try and give me an example if you want.
tinitus
Sep 11, 2016
This comment has been removed by a moderator.
RNP
2.6 / 5 (5) Sep 11, 2016
@tinitus
Yet more obfuscation.
RealityCheck
1.8 / 5 (5) Sep 11, 2016
Hi RNP, Phys1, tinitus. :)

Still very busy so can't stay long; just reading though again but noticed this continuing exchange about the above article's "likely" DM clumps punching holes in star trail etc.

I just wanted to ask what exactly is your respective opinions on what the author of above article assumes/claims in the Title.

I would like to hear (clearly and unambiguously) from each of you, whether you support OR not support the article's assumption/claim re (1) DM clumps existing in the Milky Way Halo and (2) doing that to the Star Trail observed?

If I find the time, I will return today/tomorrow to see what the answers were from each of you. Cheers all. :)
Uncle Ira
5 / 5 (1) Sep 11, 2016
@ Really-Skippy. How you are Cher? I am good, thanks for asking.

I just wanted to ask


A lot people want a lot of things. How come you are always asking, but you can not answer?

You are ever going to tell me what the NON-Keplerian Orbits are when you are talking about stars and galaxies? If it was just some gobbledygook you make up to try to fool Da Schnieb-Skippy why you don't just go ahead and fess up?

Oh yeah, I almost forget. If it would not be too much trouble,,,, "(clearly and unambiguously)" while you are not answering. Or if you do answer too but I don't have much hopes of that ever happening.
RealityCheck
1.7 / 5 (6) Sep 11, 2016
Hi Uncle Ira. :)

I explained all that to Da Schneib. You either didn't listen or didn't understand. No more time now to waste on more futile explanations to bot voting idiots too dumb to get out from under the bot-voting program which is skewing the site metrics (which skewing makes Protoplasmix's attempts at some meaningful 'survey and classification' exercise of the postings, opinions and ratings here a lost cause more likely to produce GIGO; and likely add to already un-sound exercise 'results' about as useful' and 'trustworthy' as the initial BICEP2 'exercise' and 'results' where incomplete and skewed data INPUT guaranteed GIGO outputs, claims and conclusions which were worse than useless to any actual scientific assessment of the real situation).

Bad luck, Ira, you sowed the seeds of your own stupidity and malice against one who tried to educate you. I am sorry now that I have to leave you in your self-imposed ignorance and malignancy; and of course, your bot-voting. :)
Uncle Ira
3 / 5 (4) Sep 11, 2016
Hi Uncle Ira. :)
How you are again Cher? Yeah, I am still good me, thanks for asking again.

skewing the site metrics (which skewing makes Protoplasmix's attempts at some meaningful 'survey and classification' exercise of the postings, opinions and ratings here a lost cause more likely to produce GIGO;
Non, not really. A "1" is a "1" no matter how you get it. Even if my computer did not give him to you I would so it all balances out in the end.

skewed data INPUT guaranteed GIGO outputs, claims and conclusions which were worse than useless to any actual scientific assessment of the real situation).
Well that is okayeei too. You are not the actual scientist so you would not being getting any actual assessment anyhoo.

Bad luck, Ira, blah, blah, blah,
Is that your way of saying all you were doing was gobbledygooking?

The 1's are the public service I do for humans and scientists that want to use the karma point slider thingy to not see your stuffs.
TrollBane
3 / 5 (2) Sep 11, 2016
Nice grouping of your shots.
RNP
3 / 5 (6) Sep 12, 2016
@RealityCheck
I just wanted to ask what exactly is your respective opinions on what the author of above article assumes/claims in the Title. I would like to hear (clearly and unambiguously) from each of you, whether you support OR not support the article's assumption/claim ...


Sorry RC, I have only just noticed this post. My personal stance is that observations definitively show that there is some effect that needs to be explained. While there is as yet no TOTALLY convincing evidence that it is a form of matter (rather than a MOND or MOG type effect) I have recently had to (reluctantly) accept that the evidence favours the former. The jury is still out, however.

The paper itself represents an attempt to test the consistency of the DM clump model for the formation of the gaps. It does not try to represent the results as evidence for DM, although the use of the word likely in likely in the titles does reveal the authors belief in it. I take it as it is presented
RNP
2.6 / 5 (5) Sep 12, 2016
@RealityCheck
I just wanted to ask what exactly is your respective opinions on what the author of above article assumes/claims in the Title. I would like to hear (clearly and unambiguously) from each of you, whether you support OR not support the article's assumption/claim ...


Sorry RC, I have only just noticed this post. My personal stance is that observations definitively show that there is some effect that needs to be explained. While there is as yet no TOTALLY convincing evidence that it is a form of matter (rather than a MOND or MOG type effect) I have recently had to (reluctantly) accept that the evidence favours the former. The jury is still out, however.

The paper itself represents an attempt to test the consistency of the DM clump model for the formation of the gaps. It does not try to represent the results as evidence for DM, although the use of the word likely in the title does reveal the authors belief in it. I take it as it is presented
RNP
3 / 5 (2) Sep 12, 2016
@To whom it may concern
I do not give a jot for your sockpuppet attacks. I do not judge myself on the basis of the opinions of such cowardly people.

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