For Decades, Some of the Atomic Matter in the Universe Had Not Been Located. Recent Papers Reveal Where It Has Been Hiding (wired.com) 58
In a series of three recent papers, astronomers have identified the final chunks of all the ordinary matter in the universe. From a report: And despite the fact that it took so long to identify it all, researchers spotted it right where they had expected it to be all along: in extensive tendrils of hot gas that span the otherwise empty chasms between galaxies, more properly known as the warm-hot intergalactic medium, or WHIM. Early indications that there might be extensive spans of effectively invisible gas between galaxies came from computer simulations done in 1998. "We wanted to see what was happening to all the gas in the universe," said Jeremiah Ostriker, a cosmologist at Princeton University who constructed one of those simulations along with his colleague Renyue Cen. The two ran simulations of gas movements in the universe acted on by gravity, light, supernova explosions and all the forces that move matter in space. "We concluded that the gas will accumulate in filaments that should be detectable," he said.
Except they weren't -- not yet. "It was clear from the early days of cosmological simulations that many of the baryons would be in a hot, diffuse form -- not in galaxies," said Ian McCarthy, an astrophysicist at Liverpool John Moores University. Astronomers expected these hot baryons to conform to a cosmic superstructure, one made of invisible dark matter, that spanned the immense voids between galaxies. The gravitational force of the dark matter would pull gas toward it and heat the gas up to millions of degrees. Unfortunately, hot, diffuse gas is extremely difficult to find. To spot the hidden filaments, two independent teams of researchers searched for precise distortions in the CMB, the afterglow of the Big Bang. As that light from the early universe streams across the cosmos, it can be affected by the regions that it's passing through. In particular, the electrons in hot, ionized gas (such as the WHIM) should interact with photons from the CMB in a way that imparts some additional energy to those photons. The CMB's spectrum should get distorted. Unfortunately the best maps of the CMB (provided by the Planck satellite) showed no such distortions. Either the gas wasn't there, or the effect was too subtle to show up. But the two teams of researchers were determined to make them visible. From increasingly detailed computer simulations of the universe, they knew that gas should stretch between massive galaxies like cobwebs across a windowsill. Planck wasn't able to see the gas between any single pair of galaxies. So the researchers figured out a way to multiply the faint signal by a million.
Except they weren't -- not yet. "It was clear from the early days of cosmological simulations that many of the baryons would be in a hot, diffuse form -- not in galaxies," said Ian McCarthy, an astrophysicist at Liverpool John Moores University. Astronomers expected these hot baryons to conform to a cosmic superstructure, one made of invisible dark matter, that spanned the immense voids between galaxies. The gravitational force of the dark matter would pull gas toward it and heat the gas up to millions of degrees. Unfortunately, hot, diffuse gas is extremely difficult to find. To spot the hidden filaments, two independent teams of researchers searched for precise distortions in the CMB, the afterglow of the Big Bang. As that light from the early universe streams across the cosmos, it can be affected by the regions that it's passing through. In particular, the electrons in hot, ionized gas (such as the WHIM) should interact with photons from the CMB in a way that imparts some additional energy to those photons. The CMB's spectrum should get distorted. Unfortunately the best maps of the CMB (provided by the Planck satellite) showed no such distortions. Either the gas wasn't there, or the effect was too subtle to show up. But the two teams of researchers were determined to make them visible. From increasingly detailed computer simulations of the universe, they knew that gas should stretch between massive galaxies like cobwebs across a windowsill. Planck wasn't able to see the gas between any single pair of galaxies. So the researchers figured out a way to multiply the faint signal by a million.
The missing mass... (Score:2)
The missing mass...
Be honest...
It's all AOL CDROMs, isn't it?
Re:We see it edge on (Score:4, Informative)
The thing about atoms is they are small and black. Space is black so we have little hope if they are arranged end to end and
That's not really how atoms work.
They aren't "black", they simply need incoming energy in order to emit energy of their own.
Not all atoms are in a position to be getting enough energy to do this, and of the ones that are, they may not be emitting enough energy for us to detect.
Atoms also can reflect energy, which leads into the fact that space is full of the stuff, meaning it isn't "black" either. It is however VAST so reflection is also only useful to detect atoms in certain situations.
The real issue is the energy once it reaches earth tends to be rather tiny.
Our detection equipment just isn't sensitive enough, not to mention we have a huge filter between us and it in the form of the atmosphere, the magnetosphere, and even the solar wind.
There is certainly an upper limit to what can be detected, but we are no where even close to it yet, and our equipment is getting better all the time as well as our ability to locate that equipment outside of earths filters.
Behind the washer/dryer? (Score:2, Funny)
I bet all that missing matter is with all the un-matched socks behind the washing machine and/or the clothes dryer.
Re: (Score:1)
They could have answered this question much much earlier by simply dialing 411 and asking Information where the missing matter is at, or asking at the information desk in any airport.
Re: (Score:1)
I bet it is hidden within the depths of Uranus.
Re: (Score:1)
Uranus is not pronounced that way [cambridge.org].
It's " Your an us."
Re: (Score:2)
The teacher asked her students to tell a story about their weekend.
Little Johnny said, "Well, I yelled at my dog to get off the tracks, but he just played there and the train ran right over his ass.
Quietly, the teacher asked, "Don't you mean "rectum?"
Johnny shouted , "Wrecked 'em, hell, it almost killed 'em!"
Lost stuff, found (Score:3)
Re: (Score:2, Insightful)
Re: (Score:3)
thats_the_joke.jpg
Missing Baryonic Matter? (Score:2)
So, when it is said "Missing" in this context they mean missing in the sense of predictions of the Standard Model with respect to the conditions of the early Universe when baryonic matter formed, correct? Or is there some other definition of "Missing" relevant here? Does this cull any avenues of exploration with respect to the Standard Model? What are the implications for things like Loop Quantum Gravity and/or String Theory?
Re:Missing Baryonic Matter? (Score:5, Interesting)
So, when it is said "Missing" in this context they mean missing in the sense of predictions of the Standard Model with respect to the conditions of the early Universe when baryonic matter formed, correct?
Your first claim is correct.
It was missing only in that the standard model predicted it would be right where it is but we didn't before have sensitive enough equipment to detect it and prove it.
This just adds one more thing to the pile showing the standard model wasn't incorrect.
I can't say for either of the hypotheses "string theory" or "quantum loop gravity" you asked about, but I would assume no.
So far as predictions on the total mass from baryonic matter they already agreed with the other theories.
It's the non-baryonic and other stuff they tend to differ on, or I guess in the case of "other stuff" they tend to try and explain where the standard model doesn't.
Re: (Score:1)
Q. What are Standard Model, Loop Quantum Gravity and String Theory?
A. The three stooges.
Re: (Score:2)
They located mass that was uncounted for.
String theory is actually "String hypothesis," because it can't predict a goddam thing and there are no experiments that can be used to test it.
Same thing for loop quantum gravity. It's just a loopy mod of string theory.
The mass is baryonic by definition and part of the standard model. It is also part of the quantum theory model for reasons of "mass."
Re: (Score:2)
No need.
I have a library of books on the matter.
Thanks.
At last (Score:2)
All the atomic matter has been found, now only the non-atomic matter needs to be found too.
FTA: how they got the million-fold amplification (Score:5, Informative)
"First, the scientists looked through catalogs of known galaxies to find appropriate galaxy pairs — galaxies that were sufficiently massive, and that were at the right distance apart, to produce a relatively thick cobweb of gas between them. Then the astrophysicists went back to the Planck data, identified where each pair of galaxies was located, and then essentially cut out that region of the sky using digital scissors. With over a million clippings in hand (in the case of the study led by Anna de Graaff, a Ph.D. student at the University of Edinburgh), they rotated each one and zoomed it in or out so that all the pairs of galaxies appeared to be in the same position. They then stacked a million galaxy pairs on top of one another. (A group led by Hideki Tanimura at the Institute of Space Astrophysics in Orsay, France, combined 260,000 pairs of galaxies.) At last, the individual threads — ghostly filaments of diffuse hot gas — suddenly became visible."
Re: (Score:3)
Re: (Score:2)
See articles at
Fwd: TL;DR version (Score:3)
It was behind the couch along with all the missing cat toys, single socks and car keys. ;) [slashdot.org]
And here I thought we had located it back in 2017. [slashdot.org]
Re: (Score:2)
It is the same team, led by Hideki Tanimura, and the same technique. Presumably it just took a year to publish the paper, and then Slashdot covered it again even though it's not new information.
Need to improve the title (Score:2)
Try something like, "You would not believe where it was hiding!". But even that is becoming stale.
Calling my congressman (Score:1)
Something must be done to keep this atomic matter away from my children!
Too bad ST:TNG is off the air (Score:2)
Data and Geordi would’ve solved this in under 60 minutes, and probably would’ve made it all glow in the visible spectrum so the crew could appreciate it through the view screen.
Electric Universe Plasma Filaments (Score:2)
How is this any different from the Plasma Filaments that the Electric Universe guys have discussed for decades?
They've even shown that they must connect star systems with their galaxy and connect across galaxies.
I know where some of the missing gas is.... (Score:1)
..must consume less beans.
It was found? (Score:2)
Did your mom finally make you clean up your room and it was under your bed? It usually was where my stuff went.