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Galaxies Twice As Bright As Previously Thought

Soulskill posted more than 5 years ago | from the intergalactic-dust-buster dept.

Space 139

Astronomers led by Simon Driver of Scotland's University of St. Andrews have discovered that interstellar dust shades us from as much as 50% of the light emitted by stars and galaxies. The scientists compared the number of galaxies we could see "edge-on" against the number which were "facing us," reasoning that dust would obscure more of the former, since we already receive less light from them. SPACE.com notes, "In fact, the researchers counted about 70 percent fewer edge-on galaxies than face-on galaxies." A NYTimes report provides some additional details: "Interstellar dust absorbs the visible light emitted by stars and then re-radiates it as infrared, or heat, radiation. But when astronomers measured this heat glow from distant galaxies, the dust appeared to be putting out more energy than the stars. 'You can't get more energy out than you put in, so we knew something was very wrong,' said Dr. Driver. The results also mean that there is about 20 percent more mass in stars than previously thought."

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139 comments

what what? (-1, Troll)

Anonymous Coward | more than 5 years ago | (#23453336)

in the butt

Re:what what? (0, Troll)

Mental Maelstrom (1268890) | more than 5 years ago | (#23455984)

True. This is quite a scandal! I mean - "how could science be wrong!?!?". LOL.

I wonder how soon will they discover carbon dating is twice as erronous as previously though...

So there's more dust than previously thought... (4, Interesting)

msauve (701917) | more than 5 years ago | (#23453338)

is there any reason this can't be the unaccounted "dark matter" astronomers are always talking about?

Re:So there's more dust than previously thought... (4, Informative)

BadAnalogyGuy (945258) | more than 5 years ago | (#23453382)

Dark matter is non-interacting. It only exerts a gravitational force. It would not obscure the light of galaxies (except to bend the light through gravitious pull).

Re:So there's more dust than previously thought... (3, Insightful)

Vectronic (1221470) | more than 5 years ago | (#23453412)

"except to bend the light through gravitious pull"

hence, "obscure" ... :P

Re:So there's more dust than previously thought... (4, Informative)

FooAtWFU (699187) | more than 5 years ago | (#23454178)

Have you measured the effect of gravity on light recently? You ever notice how your flashlight beam actually falls towards the ground when you aim it straight out? No? That's because it's trivially small.

To obscure light, matter would need to absorb it. Assuming that it cannot, the closest to "obscuring" that gravitational interactions could do is to bend it a little so it's facing a different direction. Lensing, and all that fun. I suppose in the worst case, a patch of dark matter could act to randomly diffuse the light going through it, but since it IS matter and it is gravitationally bound, it tends to form clusters like other matter, and you're not going to see diffusion over the million-light-year gaps between the galaxies being observed.

Re:So there's more dust than previously thought... (1)

Vectronic (1221470) | more than 5 years ago | (#23454784)

Yes, as far as I am aware, "obscure" means to make less than whole, make unclear, or even make rare, etc.

So diffusion, by means of gravitational pull is a form (or an act?) of obscuring the object by diffusing the light emitting/reflecting from the object.

It does not matter how fractionally small this diffusion is, the point is... it is diffusing the light.

And I really dont understand how you made the greater distance seem less important, like the flashlight gets effected more in its span of 10 feet than trillions of miles or whatever in a light year...

If the ray of light is bent/redirected, even if its basically infinitely small, means it could be thousands of miles of course by the time it gets here... its not like light travels in famillies, and there are parent photons making the child photons come back on course...

Re:So there's more dust than previously thought... (3, Informative)

no1home (1271260) | more than 5 years ago | (#23455224)

It's not so much obscuring as mildly redirecting. It's called gravitational lensing. (http://en.wikipedia.org/wiki/Gravitational_lensing) This is what causes effects like the halo around a distant back lit object or the optical illusion of two copies of the same object (star, galaxy).

Re:So there's more dust than previously thought... (1)

Vectronic (1221470) | more than 5 years ago | (#23455572)

Yeah im aware of that, but I would consider that, on some level, obscuring the light...

From the wiki you suggested: http://en.wikipedia.org/wiki/Image:BlackHole_Lensing_2.gif [wikipedia.org]

Granted, the effect is magnified by billions of times with a blackhole, the source is still being obscured slightly as it passes various objects, even if those objects only effect the light via gravitation and not direct refraction, nothing we see is exactly what it (theoretically) looks like given that there isnt a pure vacuumous void absent of everything including the light itself...lol

Its all distorted to some degree, which, I would also consider obscured.

Re:So there's more dust than previously thought... (3, Informative)

The_Wilschon (782534) | more than 5 years ago | (#23455868)

Fine, but that's pretty clearly not what TFA meant by "obscured". So context-ignoring semantic wrangling aside, gravitational lensing is not particularly relevant here.

Re:So there's more dust than previously thought... (4, Interesting)

msauve (701917) | more than 5 years ago | (#23453660)

According to the Wikipedia article, dark matter "does not emit or reflect enough electromagnetic radiation to be observed directly." Why does that exclude this dust, which at the time that statement was made was unobserved, and therefore fit into the definition?

Furthermore, the definition says nothing about "non interacting," and it seems to me that the real definition is more like "matter we know must exist because of its gravitational effects, but for which we can't account." (i.e. either we can't see it, or we're not looking correctly because we dont' know what we're looking for) Just as with the dust at hand, how do we know it is "non interacting," or that it "doesn't emit or reflect" radiation, if we don't know what it is?

If this newly found dust blocks light, what does it do with the visible light it absorbs? Seems to me, it must re-radiate it (at a lower frequency, like a black object in the sun?) So, if it re-radiates the energy it absorbs, then why hasn't that been noticed before? Is all this re-radiated energy just part of the cosmic microwave background radiation?

Re:So there's more dust than previously thought... (5, Informative)

zippthorne (748122) | more than 5 years ago | (#23453842)

He wasn't suggesting that the DUST is the dark matter. He was suggesting that the stars' unaccounted-for mass is, at least part of, the "dark" matter: the matter that we cannot observe except by it's gravitational effects.

The article suggests two things by stating that the dust is obscuring galaxies more than previously thought:

1) there is more mass in the galaxies than previously thought (to be generating the light we don't see)

2) there is more mass in the dust than previously thought.

"dark" matter is in it's essence, unaccounted for matter. In a sense, Neptune was a "dark" planet until it was observed. Astronomers have suggested that the reason we haven't observed the "missing mass" is that it is not observable. The article does, in fact, suggest that at least part of the missing mass may be unobservable for mundane reasons rather than new physics.

Re:So there's more dust than previously thought... (3, Informative)

cnettel (836611) | more than 5 years ago | (#23454022)

Just to make things clear, even a doubling of the amount of mass in stars would only reduce the amount of dark matter by a few percent (and then we have the dark energy...).

Re:So there's more dust than previously thought... (5, Interesting)

EtaCarinae (1149927) | more than 5 years ago | (#23454216)

Perhaps this will have implications for some of the standard candles [wikipedia.org]? If objects suddenly aren't that far off, they will shrink in size and kinetic energy estimates will drop making the case for dark matter weaker.

Because... (4, Interesting)

Jane Q. Public (1010737) | more than 5 years ago | (#23454860)

So-called "dark matter" (which so far is only a hypothesis, not even a real theory), DOES NOT INTERACT with our "normal" universe, except through gravity. Therefore, it does not absorb light. It could bend light (gravitational lensing) but not absorb it.

Personally, I find the idea of "dark matter", as currently envisioned, to be little more than superstitious hand-waving. I think the concept is unlikely in the extreme to be shown valid, and instead that other sources will be found for the observed effects (like, as the other responder pointed out, more mass than previously thought in existing stars).

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 5 years ago | (#23453740)

Score -3, Does Not Know What The Hell He Is Talking About

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 5 years ago | (#23453770)

Dark matter is non-interacting. It only exerts a gravitational force. It would not obscure the light of galaxies (except to bend the light through gravitious pull).
As it has been defined, yes.

However, the requirement for dark matter as a theoretical entity comes from observations that the mass required to explain motion on the galactic scale is far greater than the observable mass.

If we now observe that we had previously missed 16.7%* of the total mass present, the amount of inferred dark matter must decrease accordingly.

Obviously, this doesn't explain away the whole discrepancy. But it does make it somewhat smaller.

*20/120 x 100

Re:So there's more dust than previously thought... (1, Informative)

Anonymous Coward | more than 5 years ago | (#23453826)

'Exotic' dark matter, which interacts only gravitationally, is a purely theoretical phenomenon. It was invented to try to account for the discrepancy between mass observed through gravitational effects, compared to optical methods.

With optical methods we now observe more mass through optical methods, and that discrepancy is smaller. The need for the theoretical, exotic 'dark matter', which has never been observed, has been decreased, if this study's results turn out to be accurate.

Re:So there's more dust than previously thought... (5, Interesting)

Planesdragon (210349) | more than 5 years ago | (#23454328)

Dark matter is non-interacting. It only exerts a gravitational force.
No, not at all.

Dark Matter is a theoretical answer to "the universe has more matter than it looks like." If the universe, in fact, actually has more matter, then there's less, possibly zero, need for the hand-waving "Dark matter" theory.

Unless an astrophycisst (sic - lazy) has actual numbers as to what % of the total matter is "dark", we won't know what effect, if any, this discovery has on the dark-matter theory.

Re:So there's more dust than previously thought... (5, Informative)

shma (863063) | more than 5 years ago | (#23455324)

There seem to be a lot of questions about dark matter, so I'll do my best to answer them.

1)Dark matter is indeed postulated to account for the discrepancy between gravitational measurements of the mass distribution of galaxies vs evidence from other sources.

2)We know that dark matter can't be accounted for by large mass objects (like planets, asteroids, dust, etc) because CMB measurements tell us that the total amount of baryonic matter ('normal' matter made up of protons and neutrons) is a small fraction of the total matter in the universe (around 15%). So it must be made of heavy non-baryonic particles. This, by the way, is the reason why the discovery mentioned in TFA has little impact on dark matter. There is already an upper limit on the amount of baryonic mass in the universe, irrespective of what we see with telescopes.

3) We know that these particles can't interact electromagnetically or with the strong force, otherwise they would end up in atoms (either as part of the nucleus or orbiting the nucleus). In this case, these atoms would be much heavier than normal atoms and we would see evidence of them in the spectral lines of stars.

4)That leaves us with particles which interact only through the weak force, like neutrinos. We have also found that dark matter plays an important role in the formation of structure in the universe, and in order for structure to form in the way it has, the dark matter must be moving at non-relativistic speeds at that time. This rules out the neutrino, which would be moving at speeds very close to the speed of light at that time.

Wrong... (3, Insightful)

msauve (701917) | more than 4 years ago | (#23456130)

...We know that dark matter can't be accounted for by large mass objects (like planets, asteroids, dust, etc) because CMB measurements tell us that the total amount of baryonic matter ('normal' matter made up of protons and neutrons) is a small fraction of the total matter
What you mean to say is that the theory of life, the universe and everything which you subscribe to breaks if there is no exotic dark matter. There is no proven "upper limit on the amount of baryonic mass in the universe," there are only theories and hypothesis which make that claim as part of their model. I won't try and prove a negative by saying that theory is necessarily wrong, but the onus is on you to prove that portion of it correct by finding some of this imaginary non-baryonic mass. Myself, I'll claim that the Flying Spaghetti Monster [venganza.org] plays with the gravitational "constant" to fool with us. Prove me wrong.

Your circular logic fails to prove that dark matter exists.

Re: Dark Semantics (5, Interesting)

hxnwix (652290) | more than 5 years ago | (#23457052)

the onus is on you to prove that portion of it correct by finding some of this imaginary non-baryonic mass...Your circular logic fails to prove that dark matter exists.
I assume you're going for +5 funny, but here is your dark matter [wikipedia.org]. From wikipedia: Composite image of the Bullet cluster shows distribution of ordinary matter, inferred from X-ray emissions, in red and total mass, inferred from gravitational lensing, in blue.

The various discrepancies referred to by the GP are interesting because they represent quantifiable gaps in cosmological theory. The discrepancy between observation and Newtonian prediction of the period of Mercury's orbit could be explained by unsatisfactory inventions such as the interstellar ether; similarly, dark matter began as a stopgap invention.

However, as the GP mentioned, surprising evidence is cropping up that the universe contains vast quantities of weakly-interacting matter. That doesn't mean we should throw our hands up as you do and claim it's the flying spaghetti monster. We ought to continue observing, theorizing, predicting, checking and refining our understanding of the universe. Perhaps non-intuitive sorts of matter do exist! Or, the investigation of it might lead to theories superseding the current ones as relativity replaced Newtonian physics.

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 5 years ago | (#23455998)

if plasma pervades the universe and acts as a conductor then all galaxies would be on the same circuit, hence, the amount of energy observed coming from one galaxy is actually an amalgam of its' own energy and that of its' neighbors.
dark matter is not needed the electric universe model.

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 5 years ago | (#23455978)

No, msauve apparently meant the minimum of 20% additional mass of stars and its gravitational effects. How much mass was accounted to be in the form of dark matter again?

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 4 years ago | (#23456090)

I should have scrolled down a bit before writing...

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 4 years ago | (#23456792)

(except to bend the light through gravitious pull).
so it is interacting then...you can't have it both ways and "dark matter" is a load of flat-earth, global warming type hocus pocus.

Re:So there's more dust than previously thought... (2, Funny)

Anonymous Coward | more than 5 years ago | (#23453404)

Hopefully there will be too much matter now and we can all build careers around theories of dark anti-matter.

Re:So there's more dust than previously thought... (1)

Darfeld (1147131) | more than 5 years ago | (#23454054)

This would be great! With that I bet we can achieve antigravity and light-speed travel...

Re:So there's more dust than previously thought... (3, Interesting)

FooAtWFU (699187) | more than 5 years ago | (#23454198)

There's already way too much matter. They took a look at the physics, and they expected that there should be an equal amount of matter and anti-matter out there from when the Universe got created, but as far as they can tell, there isn't. So some process at the beginning of the Universe made slightly more Matter than Antimatter, and this asymmetry is already one of the greatest unsolved problems of physics.

Re:So there's more dust than previously thought... (0)

Anonymous Coward | more than 4 years ago | (#23456836)

It's thought that a fluctuation in quantum mechanics caused what we consider the "Big Bang" and subsequently, the creation of the universe.

Re:So there's more dust than previously thought... (4, Interesting)

ObjetDart (700355) | more than 5 years ago | (#23453420)

IANAA, but IIRC, the answer is no. It's been calculated that dark matter, whatever it is, must be nonbaryonic [wikipedia.org], so it can't be explained by extra interstellar dust, larger stars, etc.

Re:So there's more dust than previously thought... (1, Informative)

Anonymous Coward | more than 5 years ago | (#23453466)

Not exactly. Try the wikipedia article on dark matter [wikipedia.org] first.

The composition of dark matter is unknown but may include ordinary and heavy neutrinos, recently postulated elementary particles such as WIMPs and axions, astronomical bodies such as dwarf stars and planets (collectively called MACHOs), primordial black holes and clouds of nonluminous gas. Also, matter that might exist in another universe but might affect ours via gravity would be consistent with some theories of brane cosmology. Current evidence favors models in which the primary component of dark matter is new elementary particles, collectively called nonbaryonic dark matter.
This article suggests a new model where much more of it might be dust and stars.

Re:So there's more dust than previously thought... (2, Insightful)

BadAnalogyGuy (945258) | more than 5 years ago | (#23453498)

From Wikipedia: The dark matter component has vastly more mass than the "visible" component of the universe

From the summary: there is about 20 percent more mass in stars than previously thought

Even if we assume that "vastly more mass" means 51% of all mass in the universe, we still have the problem of a lot of missing mass even with the increased estimations of stellar mass and interstellar dust.

This study may increase our precision in our calculations of universe mass, but it is by no means eliminating dark matter as a theory.

You are ignoring... (2, Interesting)

msauve (701917) | more than 5 years ago | (#23453996)

The "20% more mass in stars" may just be the tip of the iceburg. The article doesn't mention the amount of mass in the dust itself.

Since there is no evidence for exotic black matter (other than observed gravitational effects), doesn't Occam force us to assume that the gravitational effects which we do observe are likely due to what we know about?

Why would it be incorrect to say this newly discovered dust has mass x (equal to the necessary dark matter mass), which scientists can determine from it's gravitational effects?

Re:You are ignoring... (1, Funny)

Anonymous Coward | more than 5 years ago | (#23454096)

Mmmmh... iceburger...

Re:You are ignoring... (2, Insightful)

Ravon Rodriguez (1074038) | more than 5 years ago | (#23454140)

Occam's tells us that we should select the theory that introduces the fewest assumptions. In this case, we can assume that the extra mass is accounted for by dark matter, or that the galaxies are emitting more light than we can see. Occam's doesn't appear to apply.

LOL. (2, Insightful)

msauve (701917) | more than 5 years ago | (#23454278)

You ignored the HUGE ASSUMPTION, unsupported by any facts (except gravitational effects), that any exotic black matter exists, in any quantity. THE ONLY REASON it is theorized is because nothing else had been identified which could cause those gravitational effects. Now there is evidence of previously unknown mass.

You obviously don't know how to apply Occam if you prefer an unproven hypothetical to something which is observably evident.

Re:LOL. (2, Insightful)

Ravon Rodriguez (1074038) | more than 5 years ago | (#23454596)

It is NOT observably evident. What is observably evident is a mass increase of 20 percent. That in no way accounts for all of the unobserved matter. And I'm not applying Occam's, I'm saying Occam's doesn't apply here. Both situations are hypothetical. Get a clue.

Re:You are ignoring... (1)

shawb (16347) | more than 5 years ago | (#23454340)

There is theoretical evidence for the existance of exotic black matter: deuterium. According to our current models of nucleosynthesis in the big bang, if all of matter which gravitational observations predict is baryonic (I.E. neutrons, protons + electrons) then the high density during initial conditions would have fused the vast majority (if not all) of the deuterium into helium.

It is also possible that our calculations are off with some portion of the equations: a fundamental misunderstanding or oversimplification of gravity or nucleosynthesis on certain spacial scales could throw the equations WAY off.

Tail wagging the dog... (4, Insightful)

msauve (701917) | more than 5 years ago | (#23454468)

Science is about explaining observations (evidence) with testable theory, not claiming a theory to be evidence.

The emperor has no clothes.

Then PLEASE... (1)

Jane Q. Public (1010737) | more than 5 years ago | (#23454916)

tell people to stop calling it the Dark Matter "theory"!!! It is only a hypothesis, not a theory, as I have pointed out on /. many times.

I have seen so many instances of people wrongly assuming that Dark Matter and String "Theory" are accepted fact, when neither of them are even good theories yet. It is distressing. Has science education failed that miserably in recent years?

Re:So there's more dust than previously thought... (5, Interesting)

jabuzz (182671) | more than 5 years ago | (#23454726)

The point is that the new model shows that what was previously thought to be sown up, the shortfall between the observed matter, and the amount required to account for the observed behavior is not quite as sown up as we thought.

So while this discovery does not mean that we have now observed all the mass necessary, it does mean that it would be prudent to look again very hard at how we have derived the mass of the universe in case we have left out mass along the line.

There are also other challenges on dark matter. The reason the whole concept exists is that there does not appear to be enough visible matter to explain the rotation of galaxies. However even this has recently being challenged, with the argument that using Newtonian dynamics to model galactic rotation is flawed, and if you do the same modeling using General Relativity (much much harder to do) the missing mass appears to vanish. I am the first to admit that there are issues with the paper that proposes this. However it is an important new avenue of research.

There is also the possibility that we might have gravity wrong, at very low accelerations which would also make dark matter go away.

My personal feeling is that dark matter is about as likely as the ether, and in reality we have not counted the mass accurately and are miss-applying theories.

Then again I think Copenhagen interpretation is hokum as well.

Baryonic dark matter... (1)

msauve (701917) | more than 5 years ago | (#23453714)

according to the Wikipedia article you cited, is calculated from observations of the cosmic microwave background radiation.

But, this newly found dust, which blocks light, must do something with that energy - either gain mass or re-radiate it, right? Could not that re-radiation be a part of the CMB, which would in turn have an affect on the calculated amount of baryonic dark matter. If it's not part of the CMB, where is this lost energy accounted for?

Re:Baryonic dark matter... (2, Interesting)

cnettel (836611) | more than 5 years ago | (#23454056)

The CMB has overall a black-body (heat) signature. It's shifted, however, most reasonably explained with the expansion of the universe and the associated Doppler effects. An object at the current "background temperature" would NOT emit radiation with the background signature. Nothing with a well-defined temperature would emit anything like it today, unless it's exotic in some way... That makes the assumption of non-interaction just as plausible (from a layman perspective).

Re:Baryonic dark matter... (2, Informative)

Anonymous Coward | more than 5 years ago | (#23454530)

Wow, your post is complete disinformation. I've never seen that on slashdot. Normally only a part of it is wrong.

The CMB *has* the blackbody signature of an object at 2.725 kelvin. It is even the most precise blackbody ever found. The "shift" you're talking about is more accurately a multiplicative factor of about 1000. Multiplicative factors map a theoretical blackbody signature to another one with no distinction possible.

Re:So there's more dust than previously thought... (2, Informative)

IdahoEv (195056) | more than 5 years ago | (#23453840)

What this will do is reduce the amount of dark matter that is necessary to explain the observed gravitational effects.

Dark matter is theorized to exist because galaxies behave gravitationally as if they have more mass than we can account for based on the light we see; dark matter makes up the difference. Since this result demonstrates that there is more light-emitting matter than we previously believed, it explains a slightly larger proportion of the observed gravity. Hence, a slightly smaller amount of dark matter exists than previously believed.

It's not remotely enough of an increase to explain away all of the missing mass. IIRC there is a lot more dark matter than luminous matter, so an increase of 20% in the amount of luminous matter will only make a small difference.

Re:So there's more dust than previously thought... (1)

Gerzel (240421) | more than 5 years ago | (#23453854)

Exactly!

Those calculations prove that just as calculations previously proved that there must be a luminiferous either to transmit light!

Re:So there's more dust than previously thought... (1)

bemo56 (1251034) | more than 5 years ago | (#23453906)

It might not be an answer to the unaccounted for "dark matter", but every now and then a astrologist comes forward and says there should be more mass in the universe but is not large enough to be explained by "dark matter". This "dust" could possibly be an answer to some of those theories.

I'll enjoy watching this pan out

Re:So there's more dust than previously thought... (1)

DarkOx (621550) | more than 4 years ago | (#23456722)

every now and then a astrologist comes forward
I think you possibly ment astronomer or astrophysicist, my astrologist is the guy the tells me I am going to bicker with all my friends who insists that my interpersonal relationships are almost soley governed by my sign.

Doesn't this screw up lot of other things, too... (1)

msauve (701917) | more than 5 years ago | (#23454034)

Aren't all astronomical distance measurements [gsu.edu], which are fundamentally based on brightness (except for parallax), now subject to revision?

Re:Doesn't this screw up lot of other things, too. (2, Interesting)

Tacvek (948259) | more than 5 years ago | (#23454812)

That seems reasonable. It may be that some of the things requiring unusual theories like quantum gravity or gobs of non-baryonic matter, may in fact just be due to inaccurate distance measurements. My understanding is that much of those theories are due to unusual observed movements, that don't seem to correspond to gravity on regular matter. But if are distance calculations are wrong, then perhaps that was all there was too it. The fact that this 20% is only a minuscule fraction of the amount of alleged dark matter existing is immaterial if the calculations for the total amount of mass that should exist are based on significantly flawed numbers. This I would not be shocked to see a major drop in the amount of non-luminous (dark) matter needed if the numbers are re-run.

Furthermore... (3, Interesting)

msauve (701917) | more than 5 years ago | (#23455102)

since the article was concluded more light dimming for "edge on" galaxies, then there should be a futher test: current distance measuring objects and metrics (Cepheid Variables, etc.) should show that "edge" galaxies are further away than "face" galaxies, on average. (this wouldn't affect galaxies measured by red shift, which would equally off).

Surely, there's a database somewhere with distances and galaxy types which could be easily looked at to see if that's true.

It would also be interesting to know how much this affects the Hubbel constant.

Finally, the conclusions seem to only recognize the effect within other galaxies, but there would be no reason to think similar dimming doesn't occur from interstellar dust within the Milky Way. If so, then extragalactic objects should be dimmer (and more distant based on flawed calculations) on average when they lie in certain directions. (e.g. most dimming when looking through the galactic center near Sagittarius).

Re:Furthermore... (1)

X10 (186866) | more than 4 years ago | (#23456788)

Surely, there's a database somewhere with distances and galaxy types which could be easily looked at to see if that's true.
I think the uncertainty in distances of galaxies is greater than the difference in distance for facing and edge-on galaxies.

Re:Doesn't this screw up lot of other things, too. (0)

Anonymous Coward | more than 5 years ago | (#23455260)

Not quite. It has implications for standard candles, but astronomers are working on standard rulers.

There are few distance measurements based (or hinged) *purely* on amplitude (e.g. the mass-brightness relation), and those are studied regularly because they are unsafe for any number of reasons, not least of which is lensing and absorption by cold gas clouds (this is the Cepheid variable extinction problem).

The worry that these relations can be unreliable led to the Tully-Fisher relation, which attempted to correlate mass-brightness with redshift introduced in rotating galaxies. This was very clever and useful, since it was readily demonstrated that galactic rotation speeds are directly related to galactic mass (which is measurable in a variety of ways), and also, relevantly, led to the discovery that galaxies were often much less luminous than expected from the mass-luminosity relationship.

Thus, "dark" (literally non-luminous) matter accounted for a substantial amount of mass -- enough to speed up galaxy rotation and inter-galaxy orbital motions (and deepen lensing, and influence the thermalization of inter-galactic matter with respect to the CMBR, and otherwise show up in tests for mass).

The bright side (no pun intended) is that at large ranges (extragalactic distances), luminosity was not really an especially interesting tool for distance measurement as much as a check on relationships among more useful tools (expansion and dynamical parallax and angular relationships generally, cosmic redshift, eclipsing studies, and so forth). Generally, SNIa light curves are useful.

These problems led to the discovery of the Diamater-sigma relation for elliptical galaxies, which, as observational tools improve, is liable to become the most useful tool in extra-galactic distance measurements, as it avoids some problems in Tully-Fisher, which has some important assumptions about galactic rotation (and is not useful for nonrotating galaxies).

Finally, amplitude attenuation by normal matter has workarounds, since you can track absorption-reemission spectral lines, and since normal matter clouds are often transparent in a variety of frequencies (typically IR and radio) which still permit useful magnitude-distance calculations.

Re:So there's more dust than previously thought... (1)

Jump (135604) | more than 5 years ago | (#23454500)

is there any reason this can't be the unaccounted "dark matter" astronomers are always talking about?
Yes and no. Yes, because now that this is 'known' we have to remove some mass from the 'dark matter' budget and add it to dust and stars. However, 'normal' matter is only 4% and 92% of that is gas, not stars or dust. So increasing the contribution of 'stars' or 'dust' will not change the amount of missing (dark) matter significantly. So, no, in the the sense that it won't explain any significant part of the 'dark matter'.

Re:So there's more dust than previously thought... (1)

The_Wilschon (782534) | more than 5 years ago | (#23455852)

Yes. The dark matter is not only deduced but unseen matter, the deduction that leads us to conclude that it exists also leads us to expect it to have a significantly different distribution in galaxies than the luminous matter does. Simply increasing the mass of all or most stars by 20% cannot account for the observed effects which have been attributed to dark matter.

Re:So there's more dust than previously thought... (2, Informative)

scratchpaper (1175477) | more than 5 years ago | (#23456938)

Hi everyone, I teach astronomy, and I see this all the time: the term "dark matter" is almost always misconstrued to be some strange, exotic form of matter. In reality, its just an umbrella term meaning ANY kind of matter that, for one reason or another, is obscured from our observations. So yes, IS dust clouds could be a significant contributor to the "missing matter" that we think is out there. Really, anything we can't directly observe. Think about it: no detector is 100% efficient, and no observation equipment can scan ALL the frequencies of the EM spectrum. We can cover good portions of it, but not all...so there's some vital information missing. Also, cool objects emit vastly less broadband radiation, so objects like old dead dwarfs (red, white and black), "failed" stars like brown dwarfs, exoplanetary systems just to name a few do not contribute much to the "light" we receive from the rest of the universe. And light is really ALL we have to go on in observational astronomy. And let's not get started on neutrino mass... :)

Oh NOOOES! (1, Funny)

hyperz69 (1226464) | more than 5 years ago | (#23453358)

Interstellar dust shades us from as much as 50% of the light emitted by stars and galaxies. It's universal darkening. Time to call Al Gore and head out into space. Those space aliens may not care what all the ion fuel is doing to the space environment, but Al will teach them!

so you just bought a new nigger (-1, Troll)

Anonymous Coward | more than 5 years ago | (#23453440)

Congratulations on your purchase of a brand new nigger! If handled properly, your apeman will give years of valuable, if reluctant, service.

INSTALLING YOUR NIGGER.
You should install your nigger differently according to whether you have purchased the field or house model. Field niggers work best in a serial configuration, i.e. chained together. Chain your nigger to another nigger immediately after unpacking it, and don't even think about taking that chain off, ever. Many niggers start singing as soon as you put a chain on them. This habit can usually be thrashed out of them if nipped in the bud. House niggers work best as standalone units, but should be hobbled or hamstrung to prevent attempts at escape. At this stage, your nigger can also be given a name. Most owners use the same names over and over, since niggers become confused by too much data. Rufus, Rastus, Remus, Toby, Carslisle, Carlton, Hey-You!-Yes-you!, Yeller, Blackstar, and Sambo are all effective names for your new buck nigger. If your nigger is a ho, it should be called Latrelle, L'Tanya, or Jemima. Some owners call their nigger hoes Latrine for a joke. Pearl, Blossom, and Ivory are also righteous names for nigger hoes. These names go straight over your nigger's head, by the way.

CONFIGURING YOUR NIGGER
Owing to a design error, your nigger comes equipped with a tongue and vocal chords. Most niggers can master only a few basic human phrases with this apparatus - "muh dick" being the most popular. However, others make barking, yelping, yapping noises and appear to be in some pain, so you should probably call a vet and have him remove your nigger's tongue. Once de-tongued your nigger will be a lot happier - at least, you won't hear it complaining anywhere near as much. Niggers have nothing interesting to say, anyway. Many owners also castrate their niggers for health reasons (yours, mine, and that of women, not the nigger's). This is strongly recommended, and frankly, it's a mystery why this is not done on the boat

HOUSING YOUR NIGGER.
Your nigger can be accommodated in cages with stout iron bars. Make sure, however, that the bars are wide enough to push pieces of nigger food through. The rule of thumb is, four niggers per square yard of cage. So a fifteen foot by thirty foot nigger cage can accommodate two hundred niggers. You can site a nigger cage anywhere, even on soft ground. Don't worry about your nigger fashioning makeshift shovels out of odd pieces of wood and digging an escape tunnel under the bars of the cage. Niggers never invented the shovel before and they're not about to now. In any case, your nigger is certainly too lazy to attempt escape. As long as the free food holds out, your nigger is living better than it did in Africa, so it will stay put. Buck niggers and hoe niggers can be safely accommodated in the same cage, as bucks never attempt sex with black hoes.

FEEDING YOUR NIGGER.
Your Nigger likes fried chicken, corn bread, and watermelon. You should therefore give it none of these things because its lazy ass almost certainly doesn't deserve it. Instead, feed it on porridge with salt, and creek water. Your nigger will supplement its diet with whatever it finds in the fields, other niggers, etc. Experienced nigger owners sometimes push watermelon slices through the bars of the nigger cage at the end of the day as a treat, but only if all niggers have worked well and nothing has been stolen that day. Mike of the Old Ranch Plantation reports that this last one is a killer, since all niggers steal something almost every single day of their lives. He reports he doesn't have to spend much on free watermelon for his niggers as a result. You should never allow your nigger meal breaks while at work, since if it stops work for more than ten minutes it will need to be retrained. You would be surprised how long it takes to teach a nigger to pick cotton. You really would. Coffee beans? Don't ask. You have no idea.

MAKING YOUR NIGGER WORK.
Niggers are very, very averse to work of any kind. The nigger's most prominent anatomical feature, after all, its oversized buttocks, which have evolved to make it more comfortable for your nigger to sit around all day doing nothing for its entire life. Niggers are often good runners, too, to enable them to sprint quickly in the opposite direction if they see work heading their way. The solution to this is to *dupe* your nigger into working. After installation, encourage it towards the cotton field with blows of a wooden club, fence post, baseball bat, etc., and then tell it that all that cotton belongs to a white man, who won't be back until tomorrow. Your nigger will then frantically compete with the other field niggers to steal as much of that cotton as it can before the white man returns. At the end of the day, return your nigger to its cage and laugh at its stupidity, then repeat the same trick every day indefinitely. Your nigger comes equipped with the standard nigger IQ of 75 and a memory to match, so it will forget this trick overnight. Niggers can start work at around 5am. You should then return to bed and come back at around 10am. Your niggers can then work through until around 10pm or whenever the light fades.

ENTERTAINING YOUR NIGGER.
Your nigger enjoys play, like most animals, so you should play with it regularly. A happy smiling nigger works best. Games niggers enjoy include: 1) A good thrashing: every few days, take your nigger's pants down, hang it up by its heels, and have some of your other niggers thrash it with a club or whip. Your nigger will signal its intense enjoyment by shrieking and sobbing. 2) Lynch the nigger: niggers are cheap and there are millions more where yours came from. So every now and then, push the boat out a bit and lynch a nigger.

Lynchings are best done with a rope over the branch of a tree, and niggers just love to be lynched. It makes them feel special. Make your other niggers watch. They'll be so grateful, they'll work harder for a day or two (and then you can lynch another one). 3) Nigger dragging: Tie your nigger by one wrist to the tow bar on the back of suitable vehicle, then drive away at approximately 50mph. Your nigger's shrieks of enjoyment will be heard for miles. It will shriek until it falls apart. To prolong the fun for the nigger, do *NOT* drag him by his feet, as his head comes off too soon. This is painless for the nigger, but spoils the fun. Always wear a seatbelt and never exceed the speed limit. 4) Playing on the PNL: a variation on (2), except you can lynch your nigger out in the fields, thus saving work time. Niggers enjoy this game best if the PNL is operated by a man in a tall white hood. 5) Hunt the nigger: a variation of Hunt the Slipper, but played outdoors, with Dobermans. WARNING: do not let your Dobermans bite a nigger, as they are highly toxic.

DISPOSAL OF DEAD NIGGERS.
Niggers die on average at around 40, which some might say is 40 years too late, but there you go. Most people prefer their niggers dead, in fact. When yours dies, report the license number of the car that did the drive-by shooting of your nigger. The police will collect the nigger and dispose of it for you.

COMMON PROBLEMS WITH NIGGERS - MY NIGGER IS VERY AGGRESIVE
Have it put down, for god's sake. Who needs an uppity nigger? What are we, short of niggers or something?

MY NIGGER KEEPS RAPING WHITE WOMEN
They all do this. Shorten your nigger's chain so it can't reach any white women, and arm heavily any white women who might go near it.

WILL MY NIGGER ATTACK ME?
Not unless it outnumbers you 20 to 1, and even then, it's not likely. If niggers successfully overthrew their owners, they'd have to sort out their own food. This is probably why nigger uprisings were nonexistent (until some fool gave them rights).

MY NIGGER bitches ABOUT ITS "RIGHTS" AND "RACISM".
Yeah, well, it would. Tell it to shut the fuck up.

MY NIGGER'S HIDE IS A FUNNY COLOR. - WHAT IS THE CORRECT SHADE FOR A NIGGER?
A nigger's skin is actually more or less transparent. That brown color you can see is the shit your nigger is full of. This is why some models of nigger are sold as "The Shitskin".

MY NIGGER ACTS LIKE A NIGGER, BUT IS WHITE.
What you have there is a "wigger". Rough crowd. WOW!

IS THAT LIKE AN ALBINO? ARE THEY RARE?
They're as common as dog shit and about as valuable. In fact, one of them was President between 1992 and 2000. Put your wigger in a cage with a few hundred genuine niggers and you'll soon find it stops acting like a nigger. However, leave it in the cage and let the niggers dispose of it. The best thing for any wigger is a dose of TNB.

MY NIGGER SMELLS REALLY BAD
And you were expecting what?

SHOULD I STORE MY DEAD NIGGER?
When you came in here, did you see a sign that said "Dead nigger storage"? .That's because there ain't no goddamn sign.

big shake-up (4, Interesting)

Bombula (670389) | more than 5 years ago | (#23453560)

Although the article does a good job of being nonchalant and avoiding hyperbole, it seems that there are going to be some major implications from this 'correction'. Some are alluded to in the article - that stars are brighter than expected and that some of the 'missing mass' in the universe has apparently been found. But doesn't that open up a big can of worms? Aren't recent dark matter and dark energy theories calibrated to older and - apparently - now inaccurate data about how matter/mass there is in the universe?

Anyone case to elaborate on what kind of shake-up this is going to have for astronomy and cosmology?

it's actually even worse than it is: they assumed (0)

Anonymous Coward | more than 5 years ago | (#23453746)

that the number of galaxies axis-on to us was EQUAL to the number of galaxies edge-on.

Perhaps foolish, since a galaxy can be face-on towards us in only a small-variation of orientations, but can be edge-on towards us in 360-degrees times whatever fudge-factor for "nearly-edge-on" is acceptable to gain the effect.

Therefore, there aren't *equal* numbers of face-on & edge-on galaxies, there should have been MORE edge-on galaxies, and therefore the effect is probably significantly greater than even this bombshell declares.

Mind You, IANAA, nor a mathematician, so ymmvs, eh?

Also, *this* assumes that half-way-between was simply not counted, and was a significant portion of 'em:
if they divided all the galaxies into Either facing, Or edge-on, then who knows at what angle the cut-off was.

Essentially, though, it's the equal-distribution between sets that bugs me, since it's a staggering assumption...

incorrect logic (0)

Anonymous Coward | more than 5 years ago | (#23454408)

They assumed that the number of galaxies axis-on to us was EQUAL to the number of galaxies edge-on.
Yes, and this is correct. We should expect that these two types of orientation would be observed equally; that is to say, the distribution of all possible orientations is is uniform. Another way of saying that is that there is no privileged position (no "special" galaxy) in the universe to which everything appears one way while appearing another way to observers anywhere else.

...a galaxy can be face-on towards us in only a small-variation of orientations, but can be edge-on towards us in 360-degrees times whatever fudge-factor for "nearly-edge-on" is acceptable to gain the effect.
Galaxies, like any other orientable object, have a single axis of orientation. However we define it, all other axes are simple transformations of this it, so we just pick a convenient one such as "right handed" axis of rotation. Our line of sight provides an orientation to which we can compare the axes of galaxies, and the result is an angle, which is always a two-dimensional thing, no matter the number of dimensions in question.

The problem with your reasoning is to think of face-on-edness as "only a small-variation of orientations" while you're willing to accept a large variation (in your words "360-degrees times whatever fudge-factor for "nearly-edge-on" is acceptable") for edge-on-edness. The angle is always just some number of degrees (radians). Just pick a threshold for "close enough": say, everything within 15 degrees of 0 (face on) and 90 (edge-on). If you want to consider *all* spiral galaxies (or individual stars, or whatever), just figure out if the angle is closer to 0 or 90. If every orientation of galaxies is equally represented in the universe, then the number in each category (edge- and axis-on) will be the same, no matter what angle you deem "good enough".

Therefore, there aren't *equal* numbers of face-on & edge-on galaxies, there should have been MORE edge-on galaxies... ...Mind You, IANAA, nor a mathematician...
If you still don't follow the math (which is just logic, so give it another go!), maybe you can see the error from a related but qualitatively different argument:

You claim that from our vantage point in the universe, here on earth in the Milky Way in The Place The Milky Way Inhabits, there are more galaxies pointing away from us (edge-on) than toward us. If your mathematical reasoning were correct, the same would be true of every other place in the universe. So you're claiming that more galaxies point away from any point in the universe than point toward it. Those galaxies have to point somewhere though! So this should provide intuition that your idea of "pointing toward" is narrow compared to your idea of "pointing away". The only alternative to that is that you really think that this point in the universe is different from all the other points (i.e. we have the privileged position in the universe). Essentially, though, it's the equal-distribution between sets that bugs me, since it's a staggering assumption... You seem to be denying the Copernican Principle here, so perhaps my second line of reasoning is lost on you, and you will have to rely on the first.

It's just as easy to say that we have a different kind of place in the universe as it is to say that the distribution of spiral galaxy orientations is NOT uniform. They are in fact exactly the same thing, because galaxies that point away from certain places in the universe have to point toward other places.

it's a staggering assumption...
It is true that we can only examine Nature and if we don't agree, we, and not Nature, are in the wrong. However, it is not at all an *assumption* as you so naively put it. Perhaps it is also an assumption that it is the sun that goes around the earth, to someone unfamiliar with the evidence that it the other way around. To someone unfamiliar with the reasons we have to believe so, perhaps it is an assumption that the stars in the night sky are mostly smaller than the sun with a few being much larger. What appears to you as a bald assumption is actually an inference, and at that is one based on scientific analysis and not some mere guess.

Be careful about reasoning as well as mathematics. I've seen the former lead to more pseudo-science than I have the latter. That's because the reason can save you from faulty mathematics, but proper mathematics cannot save you from faulty reasoning. And you need both to get correct results.

Re:incorrect logic (0)

Anonymous Coward | more than 4 years ago | (#23456742)

I guess geometrical intuition must be inversely proportional to the amount of prose, because you are offbase and writing a lot about it.

We live in 3 spatial dimensions, so there are more ways to be edge-on than face-on.

To discretize a bit, imagine a die: 1,6 are the galactic poles, and 2,3,4,5 are the rim. Throw a "galaxy" on the floor, you'll see that it lands edge-on 2/3 of the time.

To reason about the continuous case, choose a random unit vector u, and look at the distribution of abs(arccos(u.x)). You'll see that it isn't a uniformly distributed angle between 0 and 90 degrees.

Re:incorrect logic^2 (1)

msauve (701917) | more than 4 years ago | (#23456846)

if you want to consider *all* spiral galaxies (or individual stars, or whatever), just figure out if the angle is closer to 0 or 90. If every orientation of galaxies is equally represented in the universe, then the number in each category (edge- and axis-on) will be the same, no matter what angle you deem "good enough".
If I understand your argument, you are incorrect.

For sake of example and clear terminology, picture a disc galaxy as being a disc in the earth, the edge aligned with the equator, and observers are equally spaced throughout the sky. It is then "face-on" for observers near the celestial poles (+90 and -90 declination), and "edge-on" for observers near the galactic equator (0 declination). This is exactly analogous to a single observer watching multiple randomly oriented discs.

If we simply chose which an observer is closer to (pole or equator), we will divide observers into two sets, those within 45 degrees of the equator ("edge on"), and those within 45 degrees of the poles ("face on").

It should be very clear, just by looking at a globe, that the angular area of the former is much greater than that of the latter. In fact, without doing any spherical geometry, I can tell that it is more than twice as large.

Let's call the area within 45 degrees of one pole 1 unit, which gives us 2 units of "face on" observers. For "edge on" observers, we have 1 unit at 0 degrees longitude, and other, non-overlapping areas centered at 90, 180, and 270. That gives us twice as many "edge on" observers as "face on" observers, and there are still unaccounted areas within 45 degrees of the equator.

You claim that from our vantage point in the universe, here on earth in the Milky Way in The Place The Milky Way Inhabits, there are more galaxies pointing away from us (edge-on) than toward us.
The OP is correct, depending upon how "face/edge-edness" is defined. If one takes a simple but incorrect approach, as you have ("everything within 15 degrees of 0 (face on) and 90 (edge-on)", the conclusions can be subject to significant error. I believe that was his point.

Re:it's actually even worse than it is: they assum (1)

naasking (94116) | more than 5 years ago | (#23454910)

You can also rotate the face-on galaxies about their axes too, so the assumption seems sound to me.

Re:big shake-up (1, Interesting)

Anonymous Coward | more than 5 years ago | (#23453750)

Does this have any affect on the estimations of the universe's rate of expansion? I understand that's based on measuring the brighness of supernova.

Re:big shake-up (3, Informative)

khallow (566160) | more than 5 years ago | (#23455818)

I believe you've nailed the major implication of this research. Assuming it turns out to be true, it may provide an alternate explanation for why distant supernova (type 1A) appear more distant than expected from their red shift.

Re:big shake-up (1)

justthinkit (954982) | more than 5 years ago | (#23454538)

Anyone case to elaborate on what kind of shake-up this is going to have for astronomy and cosmology?

And just before we start shaking, can someone point me to the calculation for the exact ratio of "full face" to "oblique" galaxies we were expecting to see? Starting with a definition of how full is "full". 51%? 90%? 99%? 99.99% I think it is more likely a random differentiation, like say 98.7654321%, or "Gee, it looks pretty full on to me, Jim". All of which makes the findings more like "20% more mass, plus or minus 200 to 2000% (we're not really sure)".

We are going to need standard galaxy sizes, standard dust distribution, standard distance of comparison (the standard dust distributions alone will probably not be feasible to find) -- and then we will need 10 to 100 of these to do a statistically meaningful comparison.

Haven't we got better things to do than invent theories based on too many assumptions for too little data? Personally, I've got LeBron to watch in 47 minutes.

Re:big shake-up (0)

Anonymous Coward | more than 5 years ago | (#23455880)

The hubble constant was estimated using systems with predictable true output, and correlating their redshifts, right? Doesn't this mean the whole size/age of universe thing is now messed up?

I thought part of the reason we needed to invoke dark energy was the idea that the stars farther away look like they're accelerating. How does this new observation affect that?

In other news... (4, Funny)

AstronomicUID (929210) | more than 5 years ago | (#23453564)

Researchers found to be half as bright as previously thought.

Mod up, please. (1)

Jane Q. Public (1010737) | more than 5 years ago | (#23454950)

I found this to be quite humorous, not "troll" at all. Please, modders, do not assume "troll" just because you didn't get the joke.

Re:Mod up, please. (2, Funny)

memorycardfull (1187485) | more than 5 years ago | (#23455312)

My theory is that some observers did not get the joke because the dimming effects of interstellar dust partially obscured its hilarity. This effect could be increased if observers are viewing the joke edge-on. Some hilarious jokes may even be completely undetectable to some observers. If my theory is true, most comments on /. may actually be twice as funny as they seem.

...shooting in the dark, so to speak... (2, Insightful)

BemoanAndMoan (1008829) | more than 5 years ago | (#23453674)

Wow, a simple, seemingly obvious (as always, in hindsight) observation that throws a lot of carefully balanced highly theoretical equations out of whack.

Of course, it could prove to be equally inaccurate by failing to take into account some other grand unknown that in turn will prove to be obvious, but I can't help but feel sorry thinking of all those academics sitting around a table of hardly-touched pints and muttering "well, fuck..." to no one in particular.

--

"You're only as smart as the guys you think are smarter than you."

Re:...shooting in the dark, so to speak... (2, Insightful)

Falladir (1026636) | more than 5 years ago | (#23454030)

I suspect that the theories you're speaking of aren't actually *that* carefully balanced. A factor of 2 might seem huge, but we currently think there's several times more dark matter than normal matter in the universe, so I don't think this will put *that* much of a dent in the status quo.

Re:...shooting in the dark, so to speak... (2, Informative)

Tacvek (948259) | more than 5 years ago | (#23454906)

The dark matter theory comes from the caculated amount of total matter that should exist. As it is, a significant change in the amount of luminous matter would not change the amount of dark matter needed to reach that total by very much. However, what exactly is that total amount of energy based on? Presumably the amount of matter needed to correct the orbits of large systems. However, this throws distance measurements into doubt. My understanding is that distance measurements are based in part on observed brightness. Distances to objects of known intensity are calculated from the apparent intensity of objects of known actual intensity. However the calculations are surely based on the inverse square law. However the amount of light lost to this dust means that the inverse squares law is not really accurate. That means that the distances to those reference objects have been overestimated. That in turn means the distances to the other objects are incorrect too. If our distance measurements are incorrect, it seems quite reasonable that out calculated orbits are incorrect too. The orbits may be many, many, many times closer to what they should be based on luminous matter alone. That means the total matter needed could drop an enormous amount. If the total amount of matter needed is then quite close to the amount of luminous matter needed, it may be that we do not need to invoke the existence of enormous amounts of exotic matter.

No shit sherlock! (0)

Anonymous Coward | more than 5 years ago | (#23453682)

I guess all this really proves is how little we know about space despite professing to have studied it extensively.

Galaxies Twice As Bright... (1)

FurtiveGlancer (1274746) | more than 5 years ago | (#23453780)

No thanks to us, apparently.

I love the line about "10,000 nearby galaxies." If they're so close, why don't we visit more often?

Re:Galaxies Twice As Bright... (1)

FooAtWFU (699187) | more than 5 years ago | (#23454222)

Because gas is nearing $4 a gallon!

Re:Galaxies Twice As Bright... (1)

Fumus (1258966) | more than 5 years ago | (#23454690)

1 US gallon = 3.78541178 liters
4.00 USD = 8.69120 PLN

1 LITER of gasoline costs over 4,5 PLN in Poland. That's $8 a gallon.
And you're whining about high gas prices?

Because it has always ended badly. (2, Funny)

Jane Q. Public (1010737) | more than 5 years ago | (#23455210)

Really! Last time, Leo I and Leo II got into it over seniority, and ruined the whole event. Cetus tried to get everyone to get back in their chairs and calm down, and Triangulum made a few good points, but ultimately that was the end of our little get-together.

The time before that, Barnard's brought too much wine, which resulted in that whole inappropriate Sextans thing, remember? Canis Major tried to stick his huge Phoenix into Virgo and little Ursa Minor, and Draco was caught Fornaxing with Carina.

And the time before that, Andromeda called little Sagittarius an ugly dwarf, which started a huge row, and Tucana ended up giving us all the Boötes.

So, this has not exactly turned out to be the best of neigborhoods. I mean, with friends like these, who needs NGCs? No wonder everybody has been putting up those dust fences.

why is this a news? (5, Interesting)

Anonymous Coward | more than 5 years ago | (#23453920)

I'm not discounting the importance of this work scientifically, but the implications of dust in making a galaxy appear dim has been known for a long time, and this work no way gives us definitive answers to the nagging dust extinction issues.

Therefore it is questionable whether this is a popular-science news worthy finding. As someone who has worked closely in the field, I feel the way the report has been written only serves to fool the public into thinking something is really different about the current state of astronomy.

But then the public doesn't really care, you know. I wonder why astronomy news are so abundant in public, when most of them really have little implications for society and worse yet, the popular science articles often miss the gists of whatever the science discoveries really mean.

PR in astronomy is excellent in that they do fairly well on improving their public image, but often horrendous in conveying the substance of what they really do.

Obligatory 7th Century Zen reference (1)

xactuary (746078) | more than 5 years ago | (#23454270)

Shen Hsiu's stanza read:

Our body is the Bodhi-tree,

And our mind a mirror bright.

Carefully we wipe them hour by hour,

And let no dust alight.

To which Hui Neng (our hero, poetry slam winner, and hence, Zen's sixth Patriarch) answered:

There is no Bodhi-tree,

Nor stand of a mirror bright.

Since all is void,

Where can the dust alight?

Actually, they don't want to admit it but... (1)

jpellino (202698) | more than 5 years ago | (#23454520)

.. it was the sunglasses those rock-star astronomers were wearing.

Not Intergalactic Dust... (4, Informative)

florescent_beige (608235) | more than 5 years ago | (#23455152)

From reading TFA, the dust they are talking about is *within* the galaxies. Because of it galaxies don't emit as brightly edge-wise.

But perpendicular to the plane there is little dust absorption. So the brightness of galaxies viewed this way shouldn't need much correction. Since most galaxies are viewed this way due to the bias caused by this effect, why would there need to be a major rethink of stellar brightness? I'm not getting it.

Maybe it's galactic density that needs correction.

What about the Supernovas then? (1)

tagew (912783) | more than 5 years ago | (#23455400)

So I'm probably totally wrong here, but since light output from supernovas in distant galaxies are used to measure the distance to these galaxies, wouldn't a discovery like this have severe implications on the topography of the universe - ie. the galaxies we know the distance to based on supernova measurements could be closer than they really are? Or? /Tage

Distance ... (1)

PinkyGigglebrain (730753) | more than 4 years ago | (#23456252)

If we use the brightness of Type Ia Supernovae to determine the distance to neighboring galaxies wouldn't this discovery, if validated, mean that everything is closer than we thought?

And how would this affect the calculations of how the galaxy's gravity affects everything else?

If everything is closer than thought that would mean that the gravitational influence of the object would be greater than currently calculated?

Why would facing galaxies be obscured more? (1)

X10 (186866) | more than 4 years ago | (#23456744)

I don't think that dust obscures galaxies facing us more than galaxies we see edge-on. Dust reduces the light we see by a percentage. Galaxies we see edge-on seem brighter in the middle, but the percentage remains the same.

Calculated Distances have to be fixed (1)

yoyoq (1056216) | more than 5 years ago | (#23457136)

most distance calculations are based on luminosity, so if thats off, all the distances would have to be recalculated. thats interesting because that distance is also used in dark matter calculations.
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