Computer Model Points To the Missing Matter

eldavojohn writes "There exists a little-known problem of missing regular matter that has perhaps been overshadowed by the mysteries of dark matter and dark energy. Computer models show that there should be about 40% more regular matter than we see... so where is it? From the article: 'The study indicated a significant portion of the gas is in the filaments — which connect galaxy clusters — hidden from direct observation in enormous gas clouds in intergalactic space known as the Warm-Hot Intergalactic Medium, or WHIM, said CU-Boulder Professor Jack Burns... The team performed one of the largest cosmological supercomputer simulations ever, cramming 2.5 percent of the visible universe inside a computer to model a region more than 1.5 billion light-years across.' This hypothesis will be investigated and hopefully proved/disproved when telescopes are completed in Chile and the Antarctic. The paper will be up for review in this week's edition of the the Astrophysical Journal."

Bad name.

[morgan_greywolf (835522)]

Warm-Hot Intergalactic Matter? WHIM? The WHIM Hypothesis? I mean, it just SOUNDS like he made it up on whim!

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[eclectro (227083)]

I mean, it just SOUNDS like he made it up on whim!

Agreed. If he would have giving it any thought he would have named the large expanse of hot gas the O'Reilly Cloud.

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[Yez70 (924200)]

...you mean Belt(s).

Re:Bad name.

[networkBoy (774728)]

It's all moot anyway:

cramming 2.5 percent of the visible universe inside a computer

In other news the computer coalesced into a black hole and devoured the solar system, Al Gore included. It then spit out his belt. News at 11.
-nB

Obvious

[0racle (667029)]

Isn't the answer obvious? [wikipedia.org]

Not Dark Matter

[iamlucky13 (795185)]

Since I'm sure the question will be asked, no this missing mass is not dark matter, as both the summary and the article are clear to emphasize. I wanted to repeat that. The primary evidence for dark matter is the galactic rotation curves. The article is talking about gaseous normal matter that we believe exists, but hasn't spotted yet. This missing gaseous matter is nowhere near sufficient in mass to explain the gravitational effect of dark matter and is being looked for on a scale larger than galaxies. The missing mass is an estimate 2% of the mass of the universe, whereas dark matter is an estimate 25%.

Also, I though it interesting that the is a very interesting rendition of the nearby universe. It's not related to the article, but it does show the filamentary structure the article talks about. [nasa.gov]

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[explosivejared (1186049)]

Right on, the matter the article discusses matter that should be there as pointed out in the Dirac equation. The universe should, based on theory, be made up of a certain percentage of baryons (three quark particles).

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[fnordboy (206021)]

That's not correct. The article discusses matter that should be there as pointed out by the http://en.wikipedia.org/wiki/Friedmann_equations/ [wikipedia.org]Friedmann equations and similar equations that describe the http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation [wikipedia.org] cosmic microwave background. The Dirac equation doesn't say anything about the composition of the universe.

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[Chosen Reject (842143)]

no this missing mass is not dark matter

You can say that again. It's mostly a transparent green haze from what I can see of it. The guy sitting in the next cubicle just found a good amount of that Warm-Hot gas and has released it into the workplace.

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[scapermoya (769847)]

very true. this dark matter does not need to be special in any way, it can be dust. but it has to be right around galaxies for the rotation curves to work out. there simply aren't enough stars to account for the way our (and every other) spiral galaxy behaves relatively far from its center. dark energy on the other hand is a different (and unrelated) story.

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[fnordboy (206021)]

Actually, if it was dust, we'd be able to see it with radio telescopes, since it emit very low frequency radiation. The dark matter can't emit any radiation whatsoever.

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[scapermoya (769847)]

i think with the current evidence, it is safe to say that most dark matter is strictly non-baryonic (the mass we are used to). there is no doubt, however, that dust and other baryonic matter in all kinds of forms (clouds of gas, dwarf stars, planets, you name it) contribute to dark matter. what we must quibble about now is the amounts, the proportions.

by the way, dust doesn't just spontaneously emit radio waves. if that were true, all the dust on our planet would likely make radio stations impossible. the

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[fnordboy (206021)]

Ok, fair point - there are a lot of little, dense things like brown dwarfs and planets that we can't currently observe. However, these can only be a tiny component of the "dark" stuff that we don't see. If brown dwarfs or planets comprised a significant chunk of the dark matter, it would be detected by gravitational microlensing events, and those observations suggest that dense baryonic objects (such as stars, brown dwarves, etc.) aren't a big (which is to say, dynamically important) component of the gala

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[iamlucky13 (795185)]

Sorry if I'm misreading your post, but what I was saying in my original post is that the matter the article is dealing with is a completely separate issue in astronomy from dark matter. You seem to be interpreting it as saying dark matter is probably actually normal matter. I won't get into that debate here but just want to clarify that this is not what either the paper or I was suggesting.

Dark matter was detected gravitationally and generally believed to be non-baryonic. The matter in question has not b

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[ajs (35943)]

What I find interesting is that both dark matter and this missing matter exist only as the result of comparing our mathematical extrapolations with observation. When we finally learn the truth (will we?) of what makes up our universe, I have to wonder if it will have any resemblance to our guesses over the last 50 years or so... Personally, I doubt it.

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[Eternauta3k (680157)]

He made a semi-decent point, which is countered by saying we'll ever know what the universe is really like.

Check behind the couch.

[Anonymous Coward]

That's where my missing matter always turns up.

Does WHIM == ISM?

[explosivejared (1186049)]

Not a Physicist

Is the WHIM the same as the interstellar medium? [wikipedia.org] From what I've read they sound a very similar.Does this mean that the missing baryonic matter has been staring us right in the face the whole time in the expanses between stars?

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[Tejin (818001)]

This is more an intergalactic medium [wikipedia.org], thought to be even more tenuous than interstellar medium, which is in turn more tenuous than interplanetary space.

What I think they're talking about (RTFA? Me? no time for that!) is the slightly-less-vaccuumy-than-total-vaccuum filaments that link galactic clusters. There could be a lot of matter hidden there where we can't see well because it's far from light sources like stars, and is thus cold and dark just like empty space.

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[fnordboy (206021)]

You are mostly correct - what we're talking about are the filaments that link galaxy groups and clusters. However, this gas isn't actually all that cold - its temperature is generally between 100,000 and 1,000,000 Kelvin, making it emit in the ultraviolet. That particular waveband is very hard to observe, and the filaments are also quite diffuse - so it hasn't been seen because it emits in an inconvenient energy band (that can only be seen by orbital telescopes), and is also very, very dim.

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[AikonMGB (1013995)]

I am also not a physicist (Aerospace Engineer), but here's my understanding for what its worth: "Interstellar Medium" comprises the gases etc. that exist between stars within a galaxy, while WHIM stands for "Warm-Hot Intergalactic Medium", meaning the gases etc. that exist between galaxies.

Hope that helps,

Aikon-

Oh! Oh!

[Dr. Eggman (932300)]

What is "what lies outside of the visible universe, lies the unseen," Alex. Or maybe the vast interstellar distances is enough for the missing matter to be spread so thinly across it as to be practically undetectable. Quick! Somebody with math skills, how big is the known universe, how many atoms of missing matter would 40% be, and then from that how many atoms per cubic something-or-other is that?

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[zappepcs (820751)]

err... the answer is .... 42!

Packing Penuts

[jameskojiro (705701)]

The missing matter is in those Packing peanuts that the scientist's equipment was shipped with.

I think I know where it will be found

[hyades1 (1149581)]

"...hidden from direct observation in enormous gas clouds in intergalactic space..." >p>

If all that missing matter is contained in gas clouds, I think I know where to find it. There's an election coming up, right?

Follow the trail...

[Anonymous Coward]

...of left socks and you'll find all the missing matter in the universe.

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[PPH (736903)]

Left socks?! Now you tell us!

We got the sign wrong again. Fix the model and get ready for another run.

missing matter != dark matter?

[Hatta (162192)]

I was under the impression that dark matter was, by definition, matter we can not detect. So I don't understand how there can be "regular" matter that's hidden. If you can't see it, how do you know it's there? Well you can detect its gravity, but that's how we detect dark matter. So how do you distinguish this stuff from the dark matter? What's the difference?

Re:missing matter != dark matter?

[belthize (990217)]

    Dark Matter is matter that's not made up of normal baryonic material. As a matter of fact you can detect it but not enough to matter.

    Over and above the missing 'dark matter' there's the matter of the missing regular matter.

    It's the missing regular matter that matters in this case.

Belthize

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[Hatta (162192)]

Ok, how do you know it's not made up of baryonic material if you can't see it? How do we know that this missing matter is made up of baryonic material if we can't see it?

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[Bryan K. Feir (11060)]

There's this story [slashdot.org] from a while back, which pointed to at least one case where the non-baryonic dark matter reacted differently from the baryonic matter. There was a galactic collision, and the non-baryonic matter sort of coasted on while much of the baryonic gas slammed together in the middle. Since non-baryonic dark matter reacts only to gravity, there are ways to distinguish between the two...

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[Intron (870560)]

I explained to my bank that my computer model showed 40% more money in my account than they listed. For some reason they refused to listen to me.

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[pln2bz (449850)]

Because equations that you believe to be good models of the universe tell you that more matter ought to be around somewhere.

As this quote relates specifically to dark matter, I would go one step further ...

Because equations that you believe to be good models of the universe tell you that more matter ought to be around somewhere, based upon an observation that large-scale structures do not behave as we expected them to, and under the assumption that charged particles in space (plasmas) tend to behave as flui

IBM = Incredibly Big Machine

[butterwise (862336)]

cramming 2.5 percent of the visible universe inside a computer

That is one big-ass computer.

Mentally shift the hyphen...

[RockRampantly (976282)]

I'll leave it up to others to imagine what a big ass-computer does.

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[jbeaupre (752124)]

As big as it was, it still kept saying the answer was 1.05. Luckily the solution scales well.

Re:IBM = Incredibly Big Machine

[jddj (1085169)]

All you need is a suitable improbability generator - say, a nice hot cup of tea - and a piece of fairy cake...

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[Oktober Sunset (838224)]

Shhhh... Never tell the femputer she has a big ass, seriously, she could have you snoo-snooed to death at any time

Mental Image:

[erroneus (253617)]

For a moment there, I was imagining some sexy blond showing off a computer system somewhere and then pointing to her head or something.

Does seeing matter?

[thewils (463314)]

I hope the people who add up the matter also include all the energy too. IANAAP (Astro-Physicist) but doesn't the fact that we can see all the universe add up to a helluva lot of matter that has been converted to energy to enable us to see everything. If matter is energy and vice versa, wouldn't energy also have gravitational attraction?

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[fnordboy (206021)]

Radiant energy (which is to say photons) is actually a very tiny fraction of the total energy density of the universe - something less than 0.1%. We ignore it in our simulations, but it's safe to do so.

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[thewils (463314)]

We ignore it in our simulations

That's good, but whenever I do that it always bites me on the ass later.

Poll: Location of Missing Matter

[davidwr (791652)]

Poll: Where will scientists find the missing matter?

* It's not missing. Our measurements are wrong.
* It's not missing. Our theories are wrong.
* In filaments between the galaxies.
* In an as-yet-undiscovered construct.
* In CowboyNeal's sock drawer.

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[phozz bare (720522)]

In the foam pellets the scientific equipment was packed in, of course.

Computer model?

[phatvw (996438)]

I reckon this is a wee bit offtopic, but it struck me - are there any scientific models that are not "computer models"? It used to be the case that if it was a computer model, you'd think, "Ooooh they are using computers, they must be smart". But now?

This stuff is absolutely fascinating. Good stuff from Colorado as always.

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[CheshireCatCO (185193)]

Sure, there are a lot of analytic models out there even today. Also, you can construct a physical model to study many phenomena (e.g., river formation in a lab).

It was given the Halibutrin

[gambolt (1146363)]

to give to the Iraqis.

It's now in the Cayman Islands.

Does missing matter matter?

[phozz bare (720522)]

Is this missing matter stuff that matters or is the matter of the missing matter merely a nerdy matter?

Inquiring minds want to know!

The answer is obvious!

[greg_barton (5551)]

...there should be about 40% more regular matter than we see... so where is it?

Behind you...

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[BiggerIsBetter (682164)]

Only 2.5% of the visible universe? Seven of nine could do this in the turbolift on the way back to the astrometrics lab and still have time for solitaire. (I am a Star Trek Voyager fan. ....or more accurately, THE voyager fan.)

Yes but to be fair, this simulation was actually done, and well, Seven Of Nine is fictional. It's not really an apples to apples comparison.