There's more star-stuff out there but it's not dark matter

May 30, 2012
A radio image of a small nearby galaxy, the Large Magellanic Cloud, made with CSIRO radio telescopes. The bright areas are where the most atomic hydrogen gas is found. Credit: S. Kim et al. / CSIRO

(Phys.org) -- More atomic hydrogen gas — the ultimate fuel for stars — is lurking in today's Universe than we thought, CSIRO astronomer Dr. Robert Braun has found.

This is the first accurate measurement of this gas in close to our own.

Just after the Big Bang the Universe's matter was almost entirely hydrogen atoms. Over time this gas of atoms came together and generated galaxies, stars and planets — and the process is still going on. Astronomers want to understand where, when and how the atomic gas is transformed to better understand the Universe in which we live.

By taking a new look at some archival data, Dr. Braun, Chief Scientist at CSIRO Astronomy and Space Science in Sydney, Australia, has discovered that galaxies around us are hiding about a third more atomic than previously calculated.

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Dr Robert Braun discusses hidden atomic gas

The study also shows that the gas is distributed very differently from how it was in the past, with much less in the galaxies' outer suburbs than billions of years ago.

"This means that it's much harder for galaxies to pull the in and form new stars," Dr. Braun said. "It's why are forming 20 times more slowly now than in the past."

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Dr Robert Braun discusses how the gas in galaxies has changed over time.

The new finding doesn’t help solve the problem of "Dark Matter" — lots of mass, detectable by its gravity, that we haven't yet identified.

"Even though there’s more atomic hydrogen than we thought, it's not a big enough percentage to solve the problem. If what we are missing had the weight of a large kangaroo, what we have found would have the weight of a small echidna," Dr. Braun said.

Nevertheless, the work will continue to feed into our understanding of how galaxies evolve over time.

Dr. Braun based his work on observations made with radio telescopes: CSIRO's Parkes and Australia Telescope Compact Array telescopes in New South Wales (eastern Australia) and other radio telescopes in the USA and the Netherlands. His paper has been published in The Astrophysical Journal.

Explore further: Astronomers release most detailed catalogue ever made of the visible Milky Way

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IronhorseA
3.8 / 5 (5) May 30, 2012
" have the weight of a small echidna,"

So, did Dr. Braun use 'echidna' to make us use google today, or does he not realize a more common animal would have made a better comparison?
FroShow
5 / 5 (4) May 30, 2012
@IronhorseA:
I'm glad he did, I wouldn't have known about the echidna otherwise.
Notice that he's from Australia? where perhaps the echidna is a well known animal. Who knows, maybe the obscurity/rarity of the animal was meant to highlight his analogy.
PlayoffRace_com
1.7 / 5 (3) May 30, 2012
I often hear physicists talk about there being only left over matter because matter won out the battle between anti-matter and matter, leaving only a small amount of left over matter. This seems completely implausible. I think the more likely scenario is simpler and far more elegant; that not all the antimatter annihilated with matter, but rather equal amounts of each survived this annihilation phase (Perhaps it was these annihilations that drove the inflation of the universe to begin with). As much of the matter and anti-matter annihilated there was some that escaped this annihilation phase and clumped together with like matter and like antimatter. Eventually the annihilations calmed down and the universe stopped expanding at it's remarkable pace and there were now clumps of the universe filled with matter and clumps of the universe filled with antimatter. Whole galaxies eventually formed out of matter and so is the same of antimatter. So there you have it. This is our universe!
chromosome2
5 / 5 (6) May 30, 2012
It's a nice idea, PlayoffRace, but we've looked for photons from annihilation of matter and antimatter in the intergalactic medium and even the space between galaxy clusters, and we can say with pretty high certainty that that isn't the case. BUT--- if we were to discover, and we're doing experiments on this now, that antimatter and matter gravitationally repel eachother, then we would expect less annihilation in said spaces.. but I don't know if it'd be *enough* less to save the hypothesis from the cosmic observations we have carried out to this point.
dschlink
not rated yet May 30, 2012
@IronhorseA:
I'm glad he did, I wouldn't have known about the echidna otherwise.
Notice that he's from Australia? where perhaps the echidna is a well known animal. Who knows, maybe the obscurity/rarity of the animal was meant to highlight his analogy.


Quite right and being one of the very few egg-laying mammals, well know down-under.
IronhorseA
not rated yet May 30, 2012
@IronhorseA:
I'm glad he did, I wouldn't have known about the echidna otherwise.
Notice that he's from Australia? where perhaps the echidna is a well known animal. Who knows, maybe the obscurity/rarity of the animal was meant to highlight his analogy.


Quite right and being one of the very few egg-laying mammals, well know down-under.

Sorry, I was being facetious. However, that being said, had he been speaking to a general audience without an immediate internet connection he would have gotten blank stares followed by him say something along the lines of 'about the size of a largish guinea pig' ;P
chardo137
5 / 5 (4) May 30, 2012
In the early days of radio astronomy the 21cm wavelength radio waves from neutral atomic hydrogen was one of the most heavily studied areas of the radio spectrum, and was used as a tracer to map the Milky Way (our galaxy). Dr. Braun is the first person that I have heard of to explore this very important region of the spectrum using modern equipment. The equipment used by radio astronomers has improved to the point where interferometry has become a regular daily tool. I also appreciate anyone who uses the echidna as a scientific analogy. Great stuff!
tadchem
not rated yet May 30, 2012
Solve the Schroedinger wave equation with a principle quantum number N equal to the *reciprocal* of an integer (N = 1/k; l, m = 0) and you have a state of a single hydrogen atom that cannot participate in radiative transitions - i.e. it is "dark."
It is dynamically stable (the N = 1/k leads to a *periodic* state) and accessible only through high temperature inelastic collisions between hydrogen atoms. It still weighs the same as a hydrogen atom, but it cannot be 'seen'. The only detectable transition would be the spin-inversion wavelength, which would be strongly shifted to higher energy from the 21 cm line since the 'collapsed' periodic orbit involves a stronger spin-spin interaction between the electron and the proton.
Terriva
May 30, 2012
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Terriva
1 / 5 (6) May 30, 2012
So we can have whole denser areas of vacuum, which do exhibit gravitational lensing and gravity field, but they don't contain any detectable particles. Nevertheless, the other massive particles (the antimatter particles, like the positron and neutron rich atom nuclei) are attracted to these areas, because of their positive gravitational charge and they increase their density even more. So that the real dark matter clouds are formed with complex dynamics mixture of CMBR noise (cold DM) or neutrinos (warm DM) and antimatter/matter particles (hot DM), the relative composition of which changes from place to place. When the relative concentration of particles is high, then the dark matter tends to behave like clouds of interstellar gas. The freshly established shadows of dark matter formed during solar eclipses and planetary conjunctions contain only CMBR or neutrinos instead. This complex character makes trouble for schematic formal theories, which usually do account only to subset of DM.
Terriva
May 30, 2012
This comment has been removed by a moderator.
Terriva
1 / 5 (5) May 30, 2012
Note that whole gravastar is already a black hole in relativistic sense, because of Schwarzchild criterion for critical mass. But this black hole is very sparse and its event horizon is very slightly pronounced (fuzzball). It enables to radiate high amount of energy into outside like so-called white hole or "naked singularity". When the rotating gravastar condenses, the event horizon is gradually formed around equatorial area, and the flat object changes gradually into pancake. The flux of matter emanated with white hole becomes constrained to the polar jets and the matter emanated with them is condensing at the equatorial plane. The classical galaxy is formed gradually.

The central gravastar condenses gradually, until it evaporates most of excessive matter and its event horizon will expand over whole its surface, so it will change into "cold" black hole, described with classical relativity. The evaporation of matter from it still continues, but in form of lightweight neutrinos only.
Terriva
1 / 5 (4) May 30, 2012
I presume, the Milky Way is in this stage of evolution right now and it still radiates neutrino jets. When the central black hole will nearly evaporate, then the polar jets and neutrino flux become negligible and the galaxy will get the spherical shape again due the tidal forces between stars. Therefore the young galaxies (up to 0.5 Gyrs) are spherical, mild age galaxies (0.5 - 1,5 Gyrs) are flat with jets, older galaxies (2 - 10 Gyrs) are flat without jets and the very old galaxies (10 Gyrs) are getting elliptical again. So you can estimate the age of galaxy simply by looking at it shape. The size of galaxy matters here too, because the larger the galaxy is, the faster it develops. IMO most of old galaxies are swallowed with young ones gradually, or they may serve as a seeds during formation of new generation of galaxies. For example the famous Sombrero galaxy appears like the galaxy with two-generations of galaxies at the same place.
Vendicar_Decarian
5 / 5 (4) May 30, 2012
Where does the energy needed to manifest these gravitational "waves" come from?

"In dense aether model the gravity is result of shielding of graviton/gravitational waves with massive bodies, which do manifest with CMBR noise" - Foofie
Anda
not rated yet May 31, 2012
No one likes u, "Foofie" :) ;)
4570
not rated yet Jun 03, 2012
I would have thought that readership of a site like this one would be better educated - I'm quite surprised so many had to look up 'echidna'. And no, I've never been to Australia....
Lurker2358
not rated yet Jun 03, 2012
I would have thought that readership of a site like this one would be better educated - I'm quite surprised so many had to look up 'echidna'. And no, I've never been to Australia....


Quick, name a million different insect species...

What?! can't do it?

You should be better educated!!

Nah...

There's too many critters on the planet to remember...
Tuxford
1 / 5 (1) Jun 21, 2012
Where is the explanation for conclusion reached? How did they conclude the distribution of suburbial gas is different today than yesterday? I suspect it rests on the assumption of the Big Bang Fantasy cosmogenic model as reality, as always. Gas distribution in the far universe is likely far more difficult to detect, yielding inaccurate conclusions, easily concluded with a heavy bias toward relativist's fantasy.

What is needed is a rethink of basic assumptions regarding cosmogenic models when interpreting data, rather than always trying to fit the data to the accepted fantasy. But then, that would lead to ridicule! Watch out for 'group think' traps. It is a natural consequence of widespread egomania in our society. Most are more concerned with supporting their ego than finding the truth.