Slashdot Mirror
Half the Universe's Missing Matter Has Just Been Finally Found (newscientist.com)
An anonymous reader shares a report: The missing links between galaxies have finally been found. This is the first detection of the roughly half of the normal matter in our universe -- protons, neutrons and electrons -- unaccounted for by previous observations of stars, galaxies and other bright objects in space. You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull. But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far. Two separate teams found the missing matter -- made of particles called baryons rather than dark matter -- linking galaxies together through filaments of hot, diffuse gas. "The missing baryon problem is solved," says Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, leader of one of the groups. The other team was led by Anna de Graaff at the University of Edinburgh, UK. Because the gas is so tenuous and not quite hot enough for X-ray telescopes to pick up, nobody had been able to see it before.
"Just been finally found"?
How about "Just been found" or "Finally been found"?
I've been saying for years that "dark matter" and "dark energy" aren't really things. They're placeholders for some type of matter or interaction we'll discover later.
That we're finally able to detect these baryon filaments is a solid step in the right direction to finally solving the "dark" mystery.
Not quite. TFA and TFS say that Dark Matter exists *and* they just found the missing "regular" matter. (highlighting mine):
You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull.
But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far.
It must have been something you assimilated. . . .
Completely agree with you - Occam's Razor Wins Again...
Or maybe "Swings Again", depending on how you take your puns...
They found some of the missing baryon matter. This is the normal matter that is around us every day. Dark matter is stuff that has momentum and exerts a gravitational field but doesn't interact electromagnetically, so we can't see it. We believe most of the matter in the universe is dark matter but we also believe there is a lot more of the normal baryon matter out there but we just don't know where or what it is. These studies have shown that there are filaments of hot gas stretching between galaxies. The density of this gas is extremely low but the volume it occupies is huge so it contributes to a large amount of the baryon matter in the universe.
Well let's hope they find it all at once. Because if they keep only finding half of what's missing we could be here forever.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
This has nothing whatsoever to do with dark matter or dark energy, and does nothing whatsoever to disprove the existence of either of those things. We knew this stuff existence, our models said it was in the intragalactic expanse, it's just it's hard to directly see because it's extragalactic: it's not inside stars, so it mostly doesn't emit light, and when it does it's not very bright.
In fact, I'd even go so far as to say that this is just more (indirect) evidence for the existence of dark matter: it helps confirm our models/simulations of galaxy formation, and those models don't work without dark matter, and considerable amounts of it (far more of it than the "missing" baryonic matter they found, in fact).
"None can love freedom heartily, but good men; the rest love not freedom, but license." --John Milton
now we know
Shit? There's a bomb?
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Dark matter was a thing till scifi canned it!
This is the first detection of the roughly half of the normal matter in our universe -- protons, neutrons and electrons -- unaccounted for by previous observations of stars, galaxies and other bright objects in space. You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull. But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far.
This paper is talking about the missing non-dark matter that the current models said should be there. I had nothing to do with dark matter, and the matter they found has no impact on the expected amount of dark matter in the universe.
I browse on +1 so AC's need not respond, I won't see it.
Baryon filaments have nothing whatsoever to do with dark matter or dark energy. Finding them is progress in validating current models since it finds matter that our current models say should be out there. It also strengthens the cause of "dark" matter/energy, since if our current models predict something (the presence of ordinary matter not currently detectable) that's verified by discoveries, it strengthens those models.
This still doesn't mean there has to be actual dark matter of course. Physicists once believed there had to be an "Ether" in which light waves could propogate, because it was the only reality they could model. When Michaelson and Morley showed that the speed of light was independent of direction of travel, physicists scrambled to attribute various properties to Ether to account for their findings. Einstein ended up modelling a reality where the speed of light was a universal constant, and his model was eventually proven to be more accurate than the etheric model.
It's very likely we'll never "see" dark matter. Likely we'll find a better model of the universe, something that makes gravity weaker at intergalactic distances, and dark matter will go the way of Ether. I'm less well versed in dark energy, but I bet it'll turn out to be something that vanishes too once we have a better universal model.
Something to do with socks and dryers, no doubt.
Sheesh, evil *and* a jerk. -- Jade
Slashdot of all places should get the summary right. It sounds uneducated when they treat baryons as a distinct type of particle rather than a category that includes many familiar ones.
Does that matter exist between stars and not only between galaxies? Can it be used as fuel for spaceships? Inquiring minds want to know.
And I stand by my statement about three peer-reviewed papers.
-- Tigger warning: This post may contain tiggers! --
It only makes sense for something as large as a galaxy in motion to shed a bit during travel. They produce enough of their own light.
Which one of us is going to tell Blue Penguin production company (makers of the "Dark Matter" teevee series) that their show's been found?
I was just about to report it lost and file insurance claims...
sed -e 's/Chuck Norris/Rajnikant/g' joke > fact
The fact that these "filaments" are strung from one galaxy to another suggests they are clinging to or following some kind of structure, no?
When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
Completely agree with you - Occam's Razor Wins Again...
That's a butchering of Occam's Razor. The law is about preferring the most parsimonious hypothesis, i.e. the one that makes the fewest assumptions.
Dark matter being composed of a diffuse gas of standard baryonic matter could be the simplest hypothesis, but it makes many assumptions by implicitly refuting consolidating evidence against it. Wikipedia lists a few of them: https://en.wikipedia.org/wiki/...
You should really read the article. This isn't two independent groups scanning and suddenly discovering new pieces of the universe. It's basically a common data aggregating process applied to massive amounts of data to brighten faint emissions. Considering every star gazer with $5000 worth of equipment and a Mac does this every week, how many papers does that need to prove itself?
Of course the next step is to test it across more spots in the universe to hopefully find anomolies.
No.
So by half the matter in the universe, we are taking 2.0-2.3% tops.
Let me know when they are finally able to detect the infinite amount of matter the universe actually has, as well as its infinite everything else.
There's actually an infinite amount of everything and we're getting close to detecting it and having perfect memories of everything that has ever happened.
It was behind the couch along with all the missing cat toys, single socks and car keys. ;)
Anons need not reply. Questions end with a question mark.
And I stand by my statement about three peer-reviewed papers.
Well if you read to the bottom of TFA, there are links to two papers. So just need one more to shut you up then?
I browse on +1 so AC's need not respond, I won't see it.
This comment shows what happens when imdb commenters are metastasised into other parts of the Internet by the closure of the imdb comment section.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
Of course the other other missing half is the antimatter.
> we can observe it's gravitational interactions
Perhaps it's made of superfluous apostrophes?
I think that this is the first time the phrase "Has Just Been Finally Found" has been used, ever: https://www.google.com/search?...
The century has just began, at the current rate, I'm pretty sure that the century will have much greater claims.
Custom electronics and digital signage for your business: www.evcircuits.com
Apologies, but almost all of this is wrong.
Models based on observations indicated that 4% of the universe's mas/energy composition had to be normal, baryonic matter. Half of that 4% was missing until today. Dark matter, based on observations, needs to be approximately 23% of the mass of the universe. Otherwise galaxies would not have formed and would spin apart. Further, most of the mass of dark matter is associated with galaxies, and this matter was found between them. Details "matter" (unless of course they "energy").
as "University" vs "Universe." Good for them. Lol.
They just need to check the cushions of the OTHER couch.
Why start now?
I've been saying for years that "dark matter" and "dark energy" aren't really things. They're placeholders for some type of matter or interaction we'll discover later.
No they're real things, I kept them in the trunk of my car. Unfortunately I got really drunk a while back and haven't been able to remember where I parked. I'm guessing my car, and the missing dark matter/energy, are sitting in a police impound yard.
I've been saying for years that "dark matter" and "dark energy" aren't really things.
Which would make you right, and in accordance with every scientist that's looking at this, anywhere. And when we find those types of matter, or interaction, or weird gravitational effect, or whatever, we'll likely still call it "dark matter". Does that mean it becomes a thing then, but wasn't before?
Anyway, this isn't dark matter, or energy, it's the missing baryonic matter. Baryonic just basically means "regular stuff". Dark matter means "something else, not regular stuff".
A little knowledge still appears to be a dangerous thing.
Something to do with socks
Nope. Socks are the larval stage of wire clothes hangars.
Have gnu, will travel.
Would just cool down by emitting IR. Hot gas needs something to keep it hot, like a nearby star.
The article does not make sense.
you just wasted my reading skills
His ignorance covered the whole earth like a blanket, and there was hardly a hole in it anywhere. - Mark Twain
Dark matter is literally a placeholder for matter we expect to be there but can't detect.
If we've found X more matter, that means there's X less dark matter out there.
If I understand the summary correctly, they're not saying there's no dark matter. What they're saying is that even accounting for dark matter, there should be twice as much non dark matter out there than had previously been observed. And this is what they've claiming to have found.
You are not alone. This is not normal. None of this is normal.
Idiot. A = D (old matter) + E (Found matter). E B. so it/s (D+E) + B = all matter. You're the fifth idiot who said that. Learn to read previous comments.
Hillary lost. Get over it.
Not until he gets his first edition, hardbound copy of "What Happened" signed and put in a display case.
Nope, this "found" matter was already accounted for in the known matter area. The amount of dark matter / dark energy hasn't changed.
How diffuse would that defuse gas be?
If I had a DeLorean... I would probably only drive it from time to time.
You (and the submitter or editor) seem to think that baryonic matter is something exotic. It is not. Baryons are the family of particles that comprise exactly three quarks, and include the protons and neutrons that make up all known (and unknown) elements. You're almost entirely made of baryonic matter.
The real article says it's baryonic matter precisely to convey that it's mundane matter, and not mesons like pions or any of the really strange stuff like pentaquarks.
Shit? There's a bomb?
Yes, there will be a rapid diffusion of gas, if you don't defuse it first.
If I had a DeLorean... I would probably only drive it from time to time.
Nope, this "found" matter was already accounted for in the known matter area. The amount of dark matter / dark energy hasn't changed.
I understand that claim, but TFS sure as shit didn't make that clear.
Regardless, the entire premise of "dark matter" is that our observations of matter are incomplete.
It's fundamentally a "knowns, known unknowns, unknown unknowns" shell game.
You're claiming that this was part of the "known unknowns" because we "know" the sum of the "knowns" and "known unknowns". This may be what TFA is saying, but the very fact that we have an "unknown unknowns" category means we really don't "know" shit. That category was literally made up to make the math work given our assumptions.
Or both
Why not? You must know why not.
Zeno's paradox.
It's also not half the missing matter. Dark Matter is matter just not made of atomic constituents (protons, neturons and electrons) generally called baryonic matter. Only 4% of the universe is made of baryonic matter which, if the summary is correct and the half of this which was missing has been found this means that only 2% of the missing mass-energy of the universe has been discovered. There is a remaining 25% of the mass-energy of the universe in Dark Matter (which is still matter, just not baryonic) and ~71% which is Dark Energy which is the vacuum energy.
So, I suppose if you just refer to matter alone then ~ 7% of the missing matter of the universe has been found but that is still nowhere near 50%, to claim that much you have to specify "50% of baryonic matter" or find Dark Matter (but in that case it would probably be a lot more than 50% found).
The universe has an infinite amount of everything.
This is the first detection of the roughly half of the normal matter in our universe -- protons, neutrons and electrons
Well technically since ~4% of the universe is made of protons, neutrons and electrons (baryonic matter) and ~25% is made of Dark Matter arguably "normal matter" is, in fact, Dark Matter since it is about 6 times more abundant by mass. Plus the headline is wrong since Dark Matter is matter too so really only ~7% of the missing matter has been found which is a lot less than 50%.
Baryonic means Proton and Neutron sized stuff. Dark matter means not yet found stuff.
There will be, but it will be on repeat.
You should check out the history of the discovery of the neutrino, a particle invented to make the maths work given our assumptions. Also very similar to dark matter as it barely interacts with normal matter.
Interestingly when Fermi refined the theory giving a neutrino, Nature refused to publish it as too far out there.
https://en.wikipedia.org/wiki/...
The positron also was theorized first on the basis that Dirac's new theory allowed it. Though at first it wasn't considered as a new particle. https://en.wikipedia.org/wiki/...
https://en.wikipedia.org/wiki/Inverted_totalitarianism
All matter was dark matter at some point in time. There is an infinite amount of everything.
Apologies, but almost all of this is wrong.
Models based on observations indicated that 4% of the universe's mas/energy composition had to be normal, baryonic matter. Half of that 4% was missing until today. Dark matter, based on observations, needs to be approximately 23% of the mass of the universe. Otherwise galaxies would not have formed and would spin apart. Further, most of the mass of dark matter is associated with galaxies, and this matter was found between them. Details "matter" (unless of course they "energy").
Perhaps I'm mistaken, but according to current theories (e.g., the standard 6-parameter lambda-CDM model)...
~4% baryonic matter
~23% dark matter (needed to explain formation of galaxies and larger scale structures)
~73% dark energy (needed to explain observed expansion rate of the universe)
This current discovery only addresses part of the postulated, but previously unobserved 4% baryonic matter.
FWIW, Dark matter is a bit a kludge in that a single type of dark matter in the model (cold dark matter) doesn't seem to explain things either (this is called the small scale problem). So there are proposals for "warm/cold" dark matter. And nobody really has a clue about dark energy... So yes, details "matter".
No, Baryonic means pastry, and dark matter is what happens if you leave it in the oven for too long.
My understanding is that the story is about finally "seeing" half of the hidden baryonic mass that was inferred to exist from other data. That suggests that there is still a more baryonic mass that we only infer exists; it remains hidden.
But that this has nothing to do with the dark matter and dark energy that is also inferred by current best theories.
Someone has made a comment suggesting that much of the dark energy is the "vacuum energy", which I take as a reference to the energy that is demonstrated in the Casimir effect. I find that interesting and I might consider subscribing to your magazine.
Good one, and progenitor is the next dodgy flange pastry. Not "The" progenitor. B randing is everything to the Daleks.
The ignorance of the average slashdot poster. I thought everyone knew that paperclips are embryo wire clothes hangers.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
The article doesn't say that some of the dark matter has been accounted for by this gas, but rather, some missing "regular" matter.
The supposed amount of dark matter in the universe doesn't change a bit based on this discovery.
You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull. But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far.
So yes, the article (and also the summary quoted) made it very clear that this discovery had nothing to do with Dark Matter and doesn't change any calculations regarding Dark Matter.
You have probably heard about the hunt for dark matter, a mysterious substance thought to permeate the universe, the effects of which we can see through its gravitational pull. But our models of the universe also say there should be about twice as much ordinary matter out there, compared with what we have observed so far.
So this discovery does not change anything we postulate about Dark Matter.
Dark matter is as dark matter does
What the two teams detected now was matter which differs in at least two aspects from Dark Matter:
Well let's hope they find it all at once. Because if they keep only finding half of what's missing we could be here forever.
Wow, that was brilliant. I love your brain, whoever it is.
"The agriculture ministry is not in charge of Gundam" - Japanese ministry official.
And the other half... is AOL discs... am I right?
Well, since leptons do not interact with gluons, they are not affected by the quantum chromodynamics sector which defines the interactions between quarks and gluons... Hahhh!.. just kidding.
As stated in other posts, the answer to the question "..we've now observed it and no longer require that "fix" in our valid maths. Right?" is "no". As the article states,
"This is the first detection of the roughly half of the NORMAL matter in our universe – protons, neutrons and electrons – unaccounted for by previous observations.."
I can only presume that joh did not explain his answer because it is obvious.
My understanding is that the story is about finally "seeing" half of the hidden baryonic mass that was inferred to exist from other data. That suggests that there is still a more baryonic mass that we only infer exists; it remains hidden.
Nah, you are part of the other half - and so am I. The other half (not the subject of this story) is simply known as "the observable universe".
You can be forgiven for making this mistake because the title is phrased incorrectly; the second sentence of the summary just finally does a better job at explaining what's up.
Personally, I feel writing "Half the universe’s missing matter..." instead of "The missing half of the universe’s matter..." is a far worse grammatical transgression than the "just been finally found". One the author should receive a stern dressing-down over. :-P
Sorry for the low-effort shitpost... I couldn't resist.
Your argument is persuasive. It is certainly possible that my failure to detect a second probable grammatical error of the same form as the first one had led me to a wrong conclusion.
Unfortunately the likelihood that there is a systemic failure to use proper grammar in the story destroys its credibility rather than clarifying anything.
This story is worthless. But the comments do suggest that filaments of baryonic matter exist between galaxies and have significant total mass. So there is redeeming value in slashdot publishing this very badly written story, even if the story itself is trash.
The title says "matter" and whatever Dark Matter is it is most definitely matter so either the reference to "matter" is wrong or the 50% number is wrong because what is described is not the discovery of 50% of the missing matter in the universe, only 50% of the missing baryonic matter.
So what you are saying is that you didn't even bother to read the summary, much less the article or the actual papers linked in the article, and you are arguing the validity of all that based on the headline?
I browse on +1 so AC's need not respond, I won't see it.
I'm betting some cat knocked it there.
-- Wiccan Army, 13th Airborne Division "We will not fly silently into the night"
... in the last place they left it!
Tracy Johnson
Old fashioned text games hosted below:
http://empire.openmpe.com/
BT
They found dark matter that was half the missing matter that isn't dark matter but was too dark which is why it was missing and that matters but we still haven't found dark matter.
The simplest answer would be "Because God wills it" - whatever the question is.
Saloon bar scientist fails it.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
No, what I am saying is that a title saying "Half the Universe's Missing Matter Has Just Been Finally Found" is wrong. Half the Universe's missing BARYONIC matter has been found, which is ~7% of the Universe's matter or ~2% of the Universe's mass-energy. There is no reading of that title which is correct regardless of what the summary, the article or anything else says.
The matter referred to in the summary is ordinary matter, like you find in the atmosphere or the lint trap. There's nothing special about it, except that we hadn't noticed it.
Dark matter has gravitational effects, visible not only in galactic rotation but in gravitational lensing, and predicted by theories of the Universe being created. It doesn't interact significantly electromagnetically. We have detected it by noticing that there are gravitational fields where there is no ordinary matter, or at least not enough to create the field. We haven't detected it in any other way.
What counts as detecting things? We see effects from various forces. We can touch things because of electromagnetic fields holding finger atoms out of the space containing spoon atoms. Hearing is similar. We can taste and smell based on chemistry, which is a function of electromagnetism. Seeing is straight transmission of electromagnetic waves/particles from an object into our eyes. If something doesn't interact electromagnetically, we have to detect it in a slightly more indirect manner.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
It's matter spread out between galaxies very thinly. We initially found dark matter because of how galaxies rotate and by gravitational lensing, means that dark matter can accumulate in something analogous to clumps at astronomical scales. The newly discovered matter doesn't act like how we've observed dark matter to act.
Also, there's far too little of it. Currently, we expect the Universe to be about 4% ordinary matter and about 25% dark matter, the remainder not being matter. We found half of the expected ordinary matter, which is less than a tenth of the dark matter we'd expect. There's not enough ordinary matter out there to produce the sort of universe we observe.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Neutrinos are dark matter, in the sense that they don't interact electromagnetically. Neutrinos can't explain observed dark matter, so there has to be another form. If we have hot dark matter (neutrinos) and not-that-hot dark matter (the stuff that holds galaxies together and forms gravitational lenses), I see no reason why we couldn't have warm and cold. (There's also no reason I know of to think neutrinos are necessarily related to ordinary dark matter, since they're forms of matter that share a single property.)
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
The ways we've detected dark matter are from concentrations of the stuff, so what gravity does at intergalactic distances really doesn't have anything to do with it. What we know we've got is something that creates a gravitational field and doesn't interact with the electromagnetic force. People have tried making different gravitational theories to explain galactic rotation, but I haven't heard of alternative explanations for gravitational lensing.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
No, this discovery is evidence for our theories that the Universe is 4% baryonic matter, and these theories predict there's about six times that much dark matter. We knew about half of the predicted baryonic matter, and found the other half. The newly found baryonic matter doesn't do what we've observed dark matter to do in any case.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
GP AC never mentioned Hillary. You appear to be the one who doesn't believe the election results.
Trump won. Get over it. That means that Trump is responsible for all the idiotic crap coming out of the White House. Clinton is politically irrelevant now, and Trumpistas blaming anything on her is pathetic.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
Errr, no. The "observable universe" is a concept that has nothing the least to do with the nature of matter in the universe. The universe could consist entirely of pentaquarks, squarks, boring baryon matter, or nothing but photons and the meaning of the "observable universe" would change not one, jot, iota or plugged nickel.
The "observable universe" it that region of the universe from which light could have got to your location, had it started travelling in the right direction at the start of the universe. Since forces happen by particles which travel at light speed or less, the observable universe is that portion of the universe which could possibly have affected your location. There is a corollary to this - locations at opposite directions in the observable universe as seen from your location cannot have interacted with each other in the lifetime of the universe to this date. Which is what makes the uniformity of the CMB and distribution of both matter and unobserved gravitating material ("dark matter", whatever that is) at such large separations so interesting, and is the main motivator of the "inflation" models of the early history of the universe.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Oops, my bad for using the words in a general/literal sense while the term is indeed commonly used in a more specific sense in astrophysics. Though I find it somewhat ironic that you went through great pedantic lengths explaining said specific meaning ("the region from which light could have reached you within the lifetime of the universe" would have been more than sufficient, thank you very much) WITHOUT SUGGESTING A VIABLE ALTERNATIVE (that is layman-friendly). Any attempts at constructive criticism? "The visible universe" comes to mind, except that a big portion of the thing is known from observations at non-visible wavelengths. "The electromagnetically radiative universe" gets a bit complicated and still doesn't cut it, among others because some parts of it have only been observed by gravitational lensing or by absorption of light from objects behind it. "The part of the universe we knew for sure to be there, until now" is accurate, but gets a bit long, and there's the philosophical issue of applying "for sure" to empirical science. I'm throwing my hands in the air and going with "the entity formerly known a the universe". Feel free to make suggestions, which will be held against the same pedantic standards :-P
I know! I've repeatedly called New Scientist "the tabloid of pop sci", and this story once again confirms my low esteem of it (albeit for other reasons than the usual).
To add insult to injury, slashdot almost never sources a science story from a decent outlet (e.g. Scientific American).
Well, if you tried to say what you mean, without misusing the technical terminology, then I might have an idea of what you were trying to say. As it is, you have failed in your attempt to communicate whatever it was that you were trying to communicate.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"