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The Search for Dark Matter and Dark Energy

ScuttleMonkey posted more than 7 years ago | from the someone-needs-to-turn-on-a-light dept.

Space 212

mlimber writes "The New York Times Magazine has a lengthy article on dark matter and dark energy, discussing the past, present, and future. 'Astronomers now realize that dark matter probably involves matter that is nonbaryonic ["meaning that it doesn't consist of the protons and neutrons of 'normal' matter"]. And whatever it is that dark energy involves, we know it's not 'normal,' either. In that case, maybe this next round of evidence will have to be not only beyond anything we know but also beyond anything we know how to know.'"

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I'm all for it (1)

GregPK (991973) | more than 7 years ago | (#18323921)

So long as they don't create a black hole somewhere. :)

Re:I'm all for it (1)

GregPK (991973) | more than 7 years ago | (#18323953)

I've always been kinda curious as to what this dark matter is. Maybe the Nuetrino research will shed some light on this issue.

Re:I'm all for it (1)

scoot80 (1017822) | more than 7 years ago | (#18324013)

Its easy - its this matter thats dark. Kinda like chocolate, only not as sweet. Use extra sugar!

Re:I'm all for it (1, Funny)

Anonymous Coward | more than 7 years ago | (#18324743)

If they want to find dark energy, then all they have to do is visit Redmond Washington. Steve Ballmer's soul is pure darkness and evil.

Re:I'm all for it (2, Informative)

Compholio (770966) | more than 7 years ago | (#18324711)

So long as they don't create a black hole somewhere. :)
It wouldn't matter, tiny black holes go away on their own. The derivation is not listed here (it's just stated) but I can assure you that it's loads of fun to calculate.

http://en.wikipedia.org/wiki/Black_hole#Black_hole s_and_Earth [wikipedia.org]

Do we need to know? (1)

mrbluze (1034940) | more than 7 years ago | (#18324957)

To (inaccurately) quote some lines from "Yes, Minister":

Jim: Why do you need to know?

Secretary: I need to know to know whether I need to know.

Jim: Well, okay, what do you need to know?

Secratary: I need to know E V E R Y T H I N G!

Jim: Oh..

Probably OT, but my thoughts on this (-1, Troll)

Anonymous Coward | more than 7 years ago | (#18323931)

I had some dark matter near the opening of my anus, but CmdrTaco used a couple dozen energetic thrusts to pound it back in

Knowing Know (5, Funny)

Reason58 (775044) | more than 7 years ago | (#18323957)

In that case, maybe this next round of evidence will have to be not only beyond anything we know but also beyond anything we know how to know.
I knew he was going to say that.

Re:Knowing Know (4, Funny)

Tackhead (54550) | more than 7 years ago | (#18324161)

> > In that case, maybe this next round of evidence will have to be not only beyond anything we know but also beyond anything we know how to know.
>
> I knew he was going to say that.

As long as we're quoting Rumsfeld, "You do high-energy physics with the particle accelerators you have. It's not the particle accelerator you might want or wish to be able to build at a later time."

Re:Knowing Know (1)

e9th (652576) | more than 7 years ago | (#18324277)

You're not a theologian, are you?

Funny you should say that... (1, Interesting)

Anonymous Coward | more than 7 years ago | (#18324487)

Because "knowing how to know" is what the word Scientology means.
And on that note, no, I'm not a Cult of Scientology member :)

Re:Knowing Know (0)

Anonymous Coward | more than 7 years ago | (#18325195)

"There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. There are things we don't know we don't know."
-Rummy

Can dark matter just be.. (4, Interesting)

Wah (30840) | more than 7 years ago | (#18324001)

...big black holes that have already eaten everything around them? (i.e the "edges" of the universe)

..."in-transit" energy from 100,000,000,000 stars?

...large amounts of completely non-reflective dust and asteroids?

...a side effect of over-estimating the size of the universe? (i.e. stars like our 5 billions light years away don't exist anymore)

/real questions
//just curious..

Re:Can dark matter just be.. (5, Informative)

Gil-galad55 (707960) | more than 7 years ago | (#18324099)

Large black holes are located at the center of galaxies, and their mass can be determined by examining rotation curves, etc. They are not dark matter candidates. Primordial black holes are not massive enough. There is some possibility that dark matter could be non-luminous dust, but there are some limits placed on observations of the comsic microwave background, which would have had to travel over 13 billion light years through such dust without being significantly attenuated.


The 'size' of the universe is an ill-defined question. We can only observe what's in our past light cone, and it is *that* universe which suffers from a budget shortfall of matter/energy.

Re:Can dark matter just be.. (4, Informative)

radtea (464814) | more than 7 years ago | (#18324639)

There is some possibility that dark matter could be non-luminous dust, but there are some limits placed on observations of the comsic microwave background, which would have had to travel over 13 billion light years through such dust without being significantly attenuated.

Galactic dark matter, which is required to explain the rotation curves of spiral galaxies, can be completely explained by baryonic dark matter, which would be at least partially dust.

Extra-galactic dark matter cannot be primarily baryonic. The baryon density of the universe is known from big bang nucleo-synthesis and the primordial H/He ratio, and is too small to account for extra-galactic dark matter. Therefore extra-galactic dark matter has no relation at all to galactic dark matter, as it cannot be made of the same stuff as galactic dark matter.

So there are at least two completely different, totally unrelated dark matter problems. One can and probably is solved by baryons. The other requires exotic particles or possibly exotic physics.

Re:Can dark matter just be.. (3, Interesting)

rasputin465 (1032646) | more than 7 years ago | (#18324815)

So there are at least two completely different, totally unrelated dark matter problems.

You're right that the universal baryon density doesn't specifically constrain galactic dark matter. But Occam's Razor suggests there is only one dark matter problem. Besides, you would have to explain why galaxies would have one type of dark matter while galaxy clusters have a completely different kind (and we know intra-cluster dark matter is non baryonic). It's much easier to explain the dark matter evidence at all scales by postulating just one culprit.

Re:Can dark matter just be.. (1)

rucs_hack (784150) | more than 7 years ago | (#18324699)

Hawking speculates that micro black holes are throughout the universe. That makes for a lot of places where dark matter could hide.

I can't find a paper in which he says this, so no citation.

Dark Matter Exists (5, Informative)

baboonlogic (989195) | more than 7 years ago | (#18324897)

Here [cosmicvariance.com] is an excellent article by Sean Carroll [preposterousuniverse.com] of the California institute of Technology that explains why all the suggestions of the parent post may not be correct.

Basically, what it says is that if two large clusters of galaxies went right through each other, and dark matter was really like the normal matter in the way the parent post suggests, we would get a different result from what would happen if dark matter was for real. Astronomers have discovered one such system and this provides conclusive evidence for the existence of dark matter.

Re:Can dark matter just be.. (1)

kocsonya (141716) | more than 7 years ago | (#18325403)

> ...large amounts of completely non-reflective dust and asteroids?

The idea of completely non-reflective matter has already been examined with regards to the Olbers-paradox. The basic rebuttal is that if a material is completely non-reflective (i.e. a perfect black-body) then it is constantly absorbing the radiation around it (i.e. energy) and thus it heats up. Then it should start to radiate (black-body radiation) until it reaches a thermal equilibrium when it radiates exactly as much energy as it receives, transforming the unknown spectra of inbound radiation to the black-body radiation spectra of outbound energy.

It can not be dark for long and no matter how massive it is, the many billion years should have been enough for it to go above the about 3K ambient temperature of the background radiation's, so we should be able to see it.

Any known material does that (due to the conservation of energy), except for black holes. Actually, even black holes have a Hawking radiation, but that is an interesting thing because the bigger the black hole the less it radiates, so if you have an enormously huge one it radiates very little.

To get something really dark you need an object that can absorb energy without radiating any. If you can change enery into matter (say create a hydrogen atom out of a handful of photons) and disperse the hydrogen quietly, that might work but as far as I know (I am no physicist at all) we don't know how to turn energy to matter yet (apart from the black hole, which turns incidental radiation to rest mass).

Like (-1, Offtopic)

Anonymous Coward | more than 7 years ago | (#18324003)

Like, whatever

How about ... (5, Insightful)

Anonymous Coward | more than 7 years ago | (#18324005)

Very large bodies don't behave according to Newton. Very small bodies behave according to the rules of quantum physics, so it's clear that one law doesn't regulate every case. Dark matter/energy are just a fudge factor because we can't explain what happens without them, but that doesn't prove that they exist. All that is proven is that we don't understand what is happening.

Not really... (4, Insightful)

Gil-galad55 (707960) | more than 7 years ago | (#18324159)

On the contrary, very large bodies are extremely well-approximated by Newton, as it is the slow-velocity, weak field limit of General Relativity. There is already good photographic evidence for dark matter in the form of colliding galaxies (do your Google work), and current observational evidence points pretty strongly towards dark energy in the form of a cosmological constant. While it's true we don't know what that means, it's not just a fudge factor.

Re:Not really... (4, Insightful)

vmcto (833771) | more than 7 years ago | (#18325409)


You better tell John Moffat that very large bodies are extremely well-approximated by Newton so he can stop wasting his time on Tensor-Vector-Scalar [wikipedia.org] gravity.

Dark matter seems like far from settled science to me. But it always does amaze me how dark matter proponents tend to treat it's existence just like the followers of intelligent design treat God.

Re:How about ... (2, Interesting)

Biogenesis (670772) | more than 7 years ago | (#18324419)

I thought this too for a long time, but it seems that the only evidence for dark matter isn't just galactic rotation curves. I'm having trouble finding it through Google, but while I was studying astrophysics last year we were shown an image of a gravitationally lensed quasar, but without any visible foreground stars. The lensing may have been caused by a clump of baryonic matter that just happened to be cold and not emitting much light, but it may also be dark matter. So unfortunately it's not quite as simple as, say, using general relativity to calculate a galactic rotation curve.

Personally I'm still hopeful that Newtonian gravity doesn't work at large distances, someone discovering some new gravitational physics (like, working out a quantum model for gravity is a good start) would be more exciting to me personally than just knowing that there's something that's mostly undetectable floating around in the universe.

Oh, and very large bodies also obey the laws of quantum physics, just taking them into account is a waste of time as the effects are insignificant. AFAIK there isn't a situation where QM doesn't apply correctly. In the same way as you can take special relativity into account when you're driving in your car, the maths works and it's correct but the effect is so small it is truly insignificant.

Math should be carefully applied (0)

Anonymous Coward | more than 7 years ago | (#18324749)

Math is our attempt to describe nature. Too many engineering students (and sadly even graduates) are only too happy to plug a bunch of variables into an equation and think they've covered the situation. Basically, interpolation is usually safe and extrapolation is pretty dodgy. At the frontiers of scientific knowledge, applying math is almost always extrapolating.

The situation with dark matter reminds me of where physics was at the end of the ninteenth century. If you'd asked scientists in 1880 what the frontiers of physics were, they would have told you that things were pretty much wrapped up except for one or two niggling problems. On the other hand, dark matter seems positively reasonable if you compare it with string theory. ;-)

BTW. Try calculating the deBrogle wavelength of a galaxy. Hmm. What else do we know that is that small?

Re:How about ... (1)

suv4x4 (956391) | more than 7 years ago | (#18324599)

Very large bodies don't behave according to Newton. Very small bodies behave according to the rules of quantum physics, so it's clear that one law doesn't regulate every case.

Don't forget that this "law" is simply an equation based on observable evidence. If it doesn't govern very large bodies, it simply means the equation is incomplete and missing one or more variables that start to matter at large scale.

Re:How about ... (0)

Anonymous Coward | more than 7 years ago | (#18324637)

Dark matter/energy are just a fudge factor because we can't explain what happens without them,

and as such are concepts that astrophysicists borrowed from accounting...

Re:How about ... (1)

mrbluze (1034940) | more than 7 years ago | (#18325175)

Very large bodies tend to be slow, lumbering and unattractive and tend not to listen, especially not to Newton - so according to him they don't behave. Except of course when a large body is depicted in a Rubens. On the other hand, very small bodies were 'in' a while back, but I think the fashion industry got in trouble for promoting anorexia, and they didn't behave either, so we really just want healthy bodies.

As for dark bodies, well, they have a reputation of being fast and agile, except for large dark bodies, which are often seen on hip-hop videos in excessively large pants and reverse-worn caps. I once saw a very large dark body at the centre of The Galaxy Cafe, Bar and Bistro, eating a pile of burgers and drinking beer.

Now, all this talk about dark bodies is dark matter, which a lot of people think they know a lot about, but probably don't. Or they would like to, but they can't, because, well, how would you know, huh?

Anyone else care to shine some light on the subject?

Telescopes invented 400 years ago? (0, Troll)

FooBarWidget (556006) | more than 7 years ago | (#18324035)

From TFA: "Since the invention of the telescope four centuries ago"
I didn't know telecopes were that old. Is this a typo, and didn't they mean decades instead? If not, what did ancient telescopes do?

Re:Telescopes invented 400 years ago? (3, Insightful)

Reason58 (775044) | more than 7 years ago | (#18324117)

I didn't know telecopes were that old. Is this a typo, and didn't they mean decades instead? If not, what did ancient telescopes do?
Hans Lipperhey [ezinearticles.com] invented the telescope in the late 1500s.

Re:Telescopes invented 400 years ago? (0)

Anonymous Coward | more than 7 years ago | (#18324119)

Wiki it... anyway, Galileo claimed to have invented the telescope (which he didn't, howewer he did made it good enough for astronomy use) and he operated in the early 1600s.

Re:Telescopes invented 400 years ago? (4, Informative)

pla (258480) | more than 7 years ago | (#18324145)

"Since the invention of the telescope four centuries ago"
I didn't know telecopes were that old. Is this a typo, and didn't they mean decades instead? If not, what did ancient telescopes do?


FooBarWidget, meet Galileo: Widely credited as the inventor of the modern telescope, in 1609.

Though, as with all major developments in human history, some accounts have him as merely improving on preexisting tech, whether copying the work of Lippershey from 40 years before, or even the possibly MUCH older designs of the ancient Persians.

So no, not a typo.

Re:Telescopes invented 400 years ago? (1)

maughanahan (1053586) | more than 7 years ago | (#18324165)

Galileo was the first astronomer to use a telescope, back in the 16 hundreds (but he didn't invent it) http://en.wikipedia.org/wiki/Galileo [wikipedia.org]

Re:Telescopes invented 400 years ago? (1)

SirBruce (679714) | more than 7 years ago | (#18324167)

Ancient telescopes were essentially spyglasses or binoculars, allowing one to see a great distance. And it's true that there is some evidence that arabs used such devices to study the stars even earlier. But it's generally regarded that the first telescopes in the modern sense appeared around 1600, and you've probably heard of Galileo, who made his own telescope in 1609 and then founded the modern science of astronomy via his observations.

Re:Telescopes invented 400 years ago? (1)

spun (1352) | more than 7 years ago | (#18324175)

No, not a typo. You do remember a fellow named Galileo, right? Now, what was he famous for, I can't quite remember...

Why not look at the wiki page about the history of telescope? [wikipedia.org]

Re:Telescopes invented 400 years ago? (0)

Anonymous Coward | more than 7 years ago | (#18324319)

>Now, what was he famous for, I can't quite remember...

He made a tower of pizzas. But it leaned too much....

Re:Telescopes invented 400 years ago? (1)

joto (134244) | more than 7 years ago | (#18324377)

No, it's not a typo. Although I would probably say even older. The old telescopes did much the same as new telescopes. They would allow a viewer to put his eye close to the ocular, and through it spot distant objects enlarged through the combination of lenses and/or mirrors.

Re:Telescopes invented 400 years ago? (2, Funny)

Tsiangkun (746511) | more than 7 years ago | (#18324523)

I believe the children are the future.
I bet this one could have a nice career in the ministry of truth.

Re:Telescopes invented 400 years ago? (0)

Anonymous Coward | more than 7 years ago | (#18324691)

Wow....

Re:Telescopes invented 400 years ago? (0)

Anonymous Coward | more than 7 years ago | (#18324895)

>I didn't know telecopes were that old. Is this a typo, and
>didn't they mean decades instead?

Good grief. Do you really think we put a man on the moon only two years after the invention of the telescope?

What a maroon.

Re:Telescopes invented 400 years ago? (1)

glitch23 (557124) | more than 7 years ago | (#18325357)

I didn't know telecopes were that old. Is this a typo, and didn't they mean decades instead? If not, what did ancient telescopes do?

I hope you are kidding but if not, what do you think Galileo [wikipedia.org] used to observe the rings of Saturn?

Nothing to see here... (4, Funny)

L. VeGas (580015) | more than 7 years ago | (#18324047)

Please move along.

Re:Nothing to see here... (2)

SpaceLifeForm (228190) | more than 7 years ago | (#18324309)

Clueless, humourless, moderator strikes again.

Re:Nothing to see here... (0)

Anonymous Coward | more than 7 years ago | (#18324685)

Telling the same joke over and over isn't even slightly funny.

Re:Nothing to see here... (0)

Anonymous Coward | more than 7 years ago | (#18324803)

You must be new here.

Dammit (1)

bernywork (57298) | more than 7 years ago | (#18324053)

And I just got my head around Quantum Physics... Now they are throwing this at me.

I think this might be one of those things I chose not to learn and just leave to someone else.

Shining some light onto the matter (0)

Anonymous Coward | more than 7 years ago | (#18324089)

It's about time someone put some energy into looking at this!

"Dark energy" (2, Interesting)

omnilynx (961400) | more than 7 years ago | (#18324155)

At this point, dark energy is really nothing more than a fudge factor. It's certainly nothing like the normal concept of energy. We don't even know if it's a cosmological constant or if it varies over time and space, let alone whether it's a property of spacetime or some form of particle. So far, I'm still unconvinced that it actually exists: it seems more likely to me that the current theories are simply slightly off in their formulas, and can be resolved without recourse to another of Occam's entities.

Re:"Dark energy" (1)

Gil-galad55 (707960) | more than 7 years ago | (#18324191)

There is NO question that that expansion of the universe is accelerating. According to General Relativity, the ONLY way this can be happening is if the universe is dominated by a species with a negative pressure. If you're not happy with the name dark energy, call it 'quintessence', although this term has come to be applied to non-cosmological-constant dark energy, i.e., that provided by scalar fields in false vacuums, etc.

Re:"Dark energy" (1)

aristotle-dude (626586) | more than 7 years ago | (#18324345)

Sorry, but I think you completely ignored what the GP said and basically spouted a nonsensical stream of verbal diarrhoea which vaguely sounds like you know what the hell you are talking about when you actually don't. The GP was questioning the use of dark energy and dark matter as a kludge to make General Relativity work.

In my mind, we should not be looking for convenient stop gap solutions pulled out of thin air for this discrepancy between what is observed and General relativity but rather looking for a new model of the universe that fits in with what is observed.

Re:"Dark energy" (0)

Anonymous Coward | more than 7 years ago | (#18324433)

I'm not going to waste my time arguing on /., but FYI I work for a cosmologist. So in your mind you can think whatever the hell you want; I'll go publish a few papers.

Re:"Dark energy" (0)

Anonymous Coward | more than 7 years ago | (#18324777)

That's nothing. I'm your boss. I've published a few encyclopedias. Your papers are shit. You're fired.

Re:"Dark energy" (1)

alienmole (15522) | more than 7 years ago | (#18324875)

Er, if you "work for" a cosmologist, isn't he the one who'll be publishing papers?

Re:"Dark energy" (1)

aristotle-dude (626586) | more than 7 years ago | (#18324975)

I'm not going to waste my time arguing on /., but FYI I work for a cosmologist. So in your mind you can think whatever the hell you want; I'll go publish a few papers.
That's the fun thing about the internet. You can claim to be anything you want without having to prove yourself. This is especially true when you post as an anonymous coward.

Travel and other considerations? (1)

RyanFenton (230700) | more than 7 years ago | (#18324157)

Some questions that spring to mind:

If the grand majority of the 'stuff' in existence around the universe is matter that would be somewhat alien to our range of experiences, could this have an effect on inter-galactic travel? Would what we think it is so far be matter we'd have to worry about hitting and being damaged by at very high speeds?

Is it dangerous? Would it be inert enough that it would be safe for life to come in physical contact with it?

Could it be chemically interesting? Would the interactions with our environemnts' regular organic/metallic molecules theoretically lead to some new reactions or properties difficult to achieve otherwise?

Could it be used in manufacturing or packaging or similar industrial uses if contained? Can it be cheaply collected, once space travel is already assumed as an option?

Ryan Fenton

Re:Travel and other considerations? (1)

Gil-galad55 (707960) | more than 7 years ago | (#18324227)

Dark matter is not chemically interesting since, by definition, it doesn't interact with normal matter. Hence, it's unlikely to be 'useful' in any current fashion!

As far as whether it's dangerous -- if dark energy is a cosmological constant, it's a property of spacetime, and you are in a sense exposed to it right now. As for dark matter, again, it's something that would pass right through you, much like neutrinos.

Re:Travel and other considerations? (2, Interesting)

monster811 (752356) | more than 7 years ago | (#18324813)

If it doesn't interact by the electromagnetic force, it cannot affect anything chemically. If it doesn't interact by the strong force, it cannot cause nuclear reactions. Even if it interacts by the weak force, the effect would be equivalent to the neutrinos already coursing through us. To my understanding, it's an explanation for effects specifically by gravity, which we already are experiencing.

Re:Travel and other considerations? (1)

rasputin465 (1032646) | more than 7 years ago | (#18325097)

If it doesn't interact by the strong force, it cannot cause nuclear reactions.

Well no, the weak force is also a nuclear interaction. The indirect evidence for dark matter so far invokes only its gravitational effects, but all but the most exotic theories for it's production (in order for it to have the properties we observe today) require that it is also weakly interacting.

Dazzling (4, Funny)

psaunders (1069392) | more than 7 years ago | (#18324163)

That same year, Michael Turner, the prominent University of Chicago theorist, delivered a paper in which he called this antigravitational force "dark energy." ... "It really is very different from dark matter," Turner said. "It's more energylike."

That's an educated opinion, if I've ever heard one.

Off topic (0, Offtopic)

mycroft822 (822167) | more than 7 years ago | (#18324211)

Ok so i know this is off topic, but why are wild hypotheses like this taken so seriously when things like ESP/human mind altering random probability kind of things laughed at so widely when they actually have many different studies confirming it happens?

Social politics (1)

HomelessInLaJolla (1026842) | more than 7 years ago | (#18324243)

There's no money in globally regulating ESP. There's massive amount of taxpayer money to be siphoned off when funding and regulating particle accelerators, nuclear reactors, and telescopic arrays.

The primary driving motive behind 99% of everything which happens in the world: create debt, maintain debt, keep people in debt, work those people until they die from debt.

Re:Off topic (2, Insightful)

Gil-galad55 (707960) | more than 7 years ago | (#18324271)

Because they're not really wild hypotheses at all. You can OBSERVE the rotation curves of galaxies and see they don't match up with the estimates of the matter content. SOMETHING is there, so your only real quibble might be with the cryptic name 'dark matter'. Likewise, SOMETHING is causing the universe to expand, as shown by observations of standard candles such as Type 1A supernovae.


These are things that can be and are published in scientific journals. Whereas the only real observable evidence for the phenomena you mentioned are documentaries :/

Re:Off topic (1)

rasputin465 (1032646) | more than 7 years ago | (#18325471)

Damn you! you seem to be the only other commenter who knows a thing or two about cosmology, and you got here before I did :-P

Re:Off topic (2, Insightful)

jpflip (670957) | more than 7 years ago | (#18324297)

The difference is that there are NOT many different studies confirming ESP happens. In fact, there are many studies arguing the contrary (particularly if you focus on studies from reputable sources). There are plenty of people who WANT ESP to be true, but I don't think there are many who have been convinced by the evidence.

One big take home point about dark matter and dark energy is that physicists didn't want them to be true! It took an enormous amount of evidence, with countless independent confirmations over decades to convince the community that they were real. Real evidence can do that - convince reasonable people who begin as non-believers.

Re:Off topic (1)

joto (134244) | more than 7 years ago | (#18324507)

Which studies? How are they confirming "it happens"? What is the "it" they are confirming?

I'm sorry, but if you want to compare the top scientists of this world with a bunch of self-deceiving charlatans and quacks, and fail to find any difference, maybe it's you that need work, and not the world.

Re:Off topic (1)

drinkypoo (153816) | more than 7 years ago | (#18324583)

Well, one (relatively paranoid) theory is that they don't want others getting the technology. "They" in this case is the powers-that-be. The US Government has been experimenting with Remote Viewing [wikipedia.org] for many years now. Some would say successfully so. But frankly there is no good evidence for the existence of any kind of psychic power, at least nothing that I've ever seen. If it's not a controlled scientific experiment, it's useless to science. Of course that doesn't mean that such a power exists and has not been catalogued by science, but there's frankly no good evidence for it whatsoever.

sig (0)

Anonymous Coward | more than 7 years ago | (#18324945)

Cowards need not reply. If you don't care to sign your name, I don't care to believe anything you say.



Fuck you, asshole.

Send them to the Randi foundation, then (4, Insightful)

Moraelin (679338) | more than 7 years ago | (#18324845)

Ok so i know this is off topic, but why are wild hypotheses like this taken so seriously when things like ESP/human mind altering random probability kind of things laughed at so widely when they actually have many different studies confirming it happens?


Heh. Well, then, just send them to the Randi foundation which still has a 1 million dollar prize for anyone who can prove anything like that. The requirements so far have been reasonable too, usually along the lines of having a scientific double-blind test. Nothing you wouldn't expect in normal science. Altering probabilities is even more straightforward, since then you just have to take a large enough sample and do some elementary statistics. So you'd think that if ESP or mind-over-matter or whatever floats your fantasy boat was that proven and working, someone would claim the prize already. But, nah, suspiciously so far what we've had were:

- bullshitters arguing about how unsound scientific testing is, and why they won't take part in it (sorry, if something is only perceived when the test subjects are told and persuaded what they should perceive, then it's probably just make-belief.)

- lame stage magician tricks

- various versions of some global conspiracy to suppress them (funny how noone suppressed them before, then. You'd think the conspiracy would then stop them from publishing books and making faked movies about it too, not just stop them from taking part in a controlled experiment.)

Etc.

Plus, Randi isn't the only one who came up empty so far. What fraudsters are quick to tell you, as if it were some proof of ESP existing, is that both the USA and the USSR were interested in it during the cold war. That much is true. Unsurprisingly, since for example transmitting a message to a submarine by a mean that's (A) not blocked by water or rock, hence receivable from any depth or hole, and (B) impossible to intercept, is any army's or navy's wet dream. What they conveniently ommit there is that both the USA and the USSR, and a few others for that matter, failed to get any results with it.

By contrast, the people with these physics hypotheses tend to actually have some verifiable/falsifiable data, and they give it to you up front. If they did just bullshitting and handwaving like the ESP gang, we wouldn't take them seriously either.

Questions from a B- physics student (1)

landimal_adurotune (824425) | more than 7 years ago | (#18324265)

I'm willing to look like a fool and ask these questions, but I hear about dark matter/energy vs string theory and interesting events like gamma ray bursts and I wonder things but have no one to ask.
- How do they know that the matter is not accounted for?
- Given the absolute vastness of the universe could matter have collapsed into pre-big bang sized chunks very far from each other and things like gamma ray bursts are mini big bangs occuring far away?

This fall I'm going to be taking a physics course and an astronomy course and a decade after dropping out of college I'm actually motivated to learn this time.

Re:Questions from a B- physics student (3, Informative)

Gil-galad55 (707960) | more than 7 years ago | (#18324333)

The best way to determine the matter content of the universe is through observations of the cosmic microwave background (CMB). The properties of the plasma that emitted the CMB are well known and be used to predict temperature anisotropies (variations) in it. These show up as peaks and troughs at different angular scales. We know approximately how far away the CMB is in terms of redshift (z ~ 1100... really far!), so these angular measurements give us a distance scale. In a curved universe, the peaks and troughs appear at different angles, whereas those observed are consistent with a flat universe. A flat universe MUST have a certain energy density, but the observed baryon density only accounts for about 4% of that.


This could all be accounted for by dark matter save for the observations of Type 1A supernovae which indicate accelerating expansion, and this requires domination by a state of matter with negative pressure, and this is what's been coined dark energy.

Re:Questions from a B- physics student (0)

Anonymous Coward | more than 7 years ago | (#18324381)

To answer your first question "How do they know that the matter is not accounted for?", here's how we do it:

Step 1. Pick a galaxy
Step 2. Determine its distance using variable stars (stars that change in brightness in well-known methods).
Step 3. Determine the absolute magnitude of the galaxy (how bright it would appear if it was a fixed distance away).
Step 4. Determine how much total mass all the stars in that galaxy have in order to provide that brightness.
Step 5. Observe the doppler shift in the light from the edges of the galaxy (the side rotating toward you will appear bluer than normal, while the side rotating away from you will appear redder that normal) to determine the rotational speed of the galaxy.
Step 6. Determine how much mass must be in the galaxy in order to provide the necessary centripetal acceleration to create the observed rotational speed.
Step 7. Compare answers from Step 4 and Step 6.
Step 8. Smack yourself in the head when you realize the stars in the galaxy only account for less than 1% of the mass required to hold the galaxy together.

Re:Questions from a B- physics student (1)

HomelessInLaJolla (1026842) | more than 7 years ago | (#18324413)

you realize the stars in the galaxy only account for less than 1% of the mass required to hold the galaxy together
You forgot Step 7.5: "Assume that we know everything about all of the forces which hold galaxies together on the astronomical scale."

Re:Questions from a B- physics student (1)

Kagura (843695) | more than 7 years ago | (#18324469)

That's exactly the point he's making, silly.

Same point (1)

HomelessInLaJolla (1026842) | more than 7 years ago | (#18324595)

But he was using it in the opposite direction. The parent asked,"How do we know that dark matter isn't just blah blah blah", and the AC replied,"Because we can calculate blah blah blah", and I pointed out that perhaps the calculations were wrong.

I'm not saying that dark matter is or isn't blah blah blah. I'm just saying that relying on calculations to assert that dark matter is or isn't blah blah blah is the wrong approach.

Nobody is saying you can't own a gun, nobody is saying you can't carry a gun... We're just saying you can't carry a gun in town.

Re:Same point (1)

Kagura (843695) | more than 7 years ago | (#18325199)

If we don't rely on calculations, what are we going to rely on? Magic and hocus pocus, or maybe we'll do our real life-size model milky way to test for it. :)

Do you feel that the entire world's cosmologists and astrophysicists are getting too excited to stop and look at their methodology? I assure you in this one instance you are wrong. :)

Re:Same point (1)

HomelessInLaJolla (1026842) | more than 7 years ago | (#18325427)

Do you feel that the entire world's cosmologists and astrophysicists are getting too excited to stop and look at their methodology?
I'm not saying that they are or aren't back checking their methodology. I am saying that I've seen more than my fair share of legitimate questions get hounded out the door with calculations made by "Essjay" (or his comparable situational counterpart) as the rationale.

maybe we'll do our real life-size m0del milky way to test for it
I often feel that modern physics, both on the astronomical and the quantum levels, needs a thorough code audit and code-cleaning. We can keep our historical observations but we should dump anything which doesn't fit to Heisenberg's Uncertainty Principle. At some point in time too many researchers in too many big-name physics research groups began taking too much LSD and, at that time, they began to needlessly complicate lots of things.

Re:Same point (1)

rasputin465 (1032646) | more than 7 years ago | (#18325379)

I'm just saying that relying on calculations to assert that dark matter is or isn't blah blah blah is the wrong approach.

You can't say it's the 'wrong' approach, because it's the only approach we have. The problem we're faced with is: in order for something to produce the effects we see today, what properties must it have, and what properties must it not have? Science history has demonstrated time and again that whenever we see some observations that seem to contradict a theory, 99% of the time the theory is correct, it just needs to be modified slightly. For example, when they noticed a 'wobble' in Uranus' orbit that seemed to contradict the orbit predicted by Newtonian theory, it turned out that Newton's theory was fine, they just needed to modify their model of the solar system to include the effects of [previously unknown planet] Neptune. Of course our calculations could be wrong, but that doesn't mean we can't make correct calculations.

Re:Questions from a B- physics student (1)

aristotle-dude (626586) | more than 7 years ago | (#18324473)

To answer your first question "How do they know that the matter is not accounted for?", here's how we do it:

Step 1. Pick a galaxy
Step 2. Determine its distance using variable stars (stars that change in brightness in well-known methods).
Step 3. Determine the absolute magnitude of the galaxy (how bright it would appear if it was a fixed distance away).
Step 4. Determine how much total mass all the stars in that galaxy have in order to provide that brightness.
Step 5. Observe the doppler shift in the light from the edges of the galaxy (the side rotating toward you will appear bluer than normal, while the side rotating away from you will appear redder that normal) to determine the rotational speed of the galaxy.
Step 6. Determine how much mass must be in the galaxy in order to provide the necessary centripetal acceleration to create the observed rotational speed.
Step 7. Compare answers from Step 4 and Step 6.
Step 8. Smack yourself in the head when you realize the stars in the galaxy only account for less than 1% of the mass required to hold the galaxy together.
That is all well and good but it may be that the need for "dark energy" and "dark matter" may be the result of sloppy science. If scientists cannot tell the difference between a distant giant galaxy and a nearby dwarf galaxy, how can you believe a word they say about missing mass?

http://www.space.com/scienceastronomy/070312_giant _dwarf.html [space.com]

I rest my case.

"Normal?" (5, Insightful)

Flwyd (607088) | more than 7 years ago | (#18324267)

If dark matter makes up most of the mass in the universe, wouldn't the kind of matter we're familiar with be the abnormal kind?

Re:"Normal?" (1)

suv4x4 (956391) | more than 7 years ago | (#18324649)

If dark matter makes up most of the mass in the universe, wouldn't the kind of matter we're familiar with be the abnormal kind?

No, because we, as sentient beings on planet Earth define what "normal matter" is. Universe doesn't care at all.

My point being, don't you begin thinking we're some sorta odd artifact in the universe. It's the wrong way to think about it. Not to mention I believe all this "dark matter" and "dark energy" scientists are looking for is a result of improper equations which make us believe it exists (I can be wrong, but my bias is towards: it doesn't exist).

Re:"Normal?" (1)

GroeFaZ (850443) | more than 7 years ago | (#18324651)

Wow. If I shall ever see something more politically correct than this statement, I can die happy.

Re:"Normal?" (1)

R3d M3rcury (871886) | more than 7 years ago | (#18325291)

Well, I could complain that "abnormal" implies "bad." Therefore, he should not have used the term "abnormal" but, instead, the politically correct "Differently Normal."

Re:"Normal?" (0)

Anonymous Coward | more than 7 years ago | (#18324937)

When coming up with a definition of "normal", it's all relative.

heh, why bother, i've already found both (1)

dlasley (221447) | more than 7 years ago | (#18324273)

dark matter = stuff at the bottom of my laundry sucking up available light

dark energy = abundant local olfactory distortions generated by the stuff at the bottom of my laundry

mystery solved, case closed ...

but the science geek side of me wants to see them prove the existence of (not) "normal" dark matter or dark energy because it's just plain cool. and i want my personal teleportation device that skirts the fringes of the space-time continuum!

How do we know we do not know how to know it? (1)

Normal Dan (1053064) | more than 7 years ago | (#18324311)

... maybe this next round of evidence will have to be not only beyond anything we know but also beyond anything we know how to know.
What does that even mean? As if it is so complex we would not be able to understand it if we were given all the details. This sounds like an explanation for God. "God is so beyond our understanding there is no way we will ever understand him. So we might as well just accept and believe in him."

hrmmm...

God is not... (1)

rmdyer (267137) | more than 7 years ago | (#18324601)

God...

* is not "a him".
* is not even "an it".
* doesn't even have a definition that makes sense.

So...

* how can you "believe" in something you cannot accurately describe?
* how can you "believe" in an idea that doesn't make sense?
* Does believing that blue is red make it true?

Does anybody know what they are talking about when they say the word "God"? Because I certainly don't understand what people are talking about when they utter that cobbled word.

Re:God is... (1)

bladx (816461) | more than 7 years ago | (#18324761)

Hey, there is still time for you to find out who God is and time to seek.

Re:God is... (0)

Anonymous Coward | more than 7 years ago | (#18325293)

god is a who? Well which is it? I feel like I'm playing charades.
And who pray tell figured out that a god is a who?
Is he from "who'ville"?
And what's time got to do with anything?
Does anybody really know what time it is?
Does anybody really care?
If so I can't imagine why.

So is it tenoric or sopranic? (0)

Anonymous Coward | more than 7 years ago | (#18324321)

Or perhaps altic?

Oh, "non-baryonic", I read it as "non-barytonic". Sorry!

-L

I still want to know.... (1)

NoseBag (243097) | more than 7 years ago | (#18324393)

...what color dark matter is? God, I hope its not beige.

Re:I still want to know.... (0)

Anonymous Coward | more than 7 years ago | (#18324753)

...what color dark matter is? God, I hope its not beige.

It's dark beige.

This made me laugh (1)

fredrated (639554) | more than 7 years ago | (#18324531)

FTA: "If so, such a development would presumably not be without philosophical consequences of the civilization-altering variety."

Yeah, like my mocha java is going to go up in price, or maybe the prime lending rate?

"beyond anything we know how to know" (1)

GroeFaZ (850443) | more than 7 years ago | (#18324547)

Good to see that Rumsfeld has found a new job that lets him exercise his poetic skills.

Socrates called it thousands of years ago. (1)

had3l (814482) | more than 7 years ago | (#18324837)

"I know nothing except the fact of my ignorance."

We will never know everything, and the more we run after knowledge, the farther it will gets from us.

Once (If we ever do) conjure up a decent theory that explains what this Dark Energy and Matter fuss is all about, we will realize that there is even more we don't know than we thought.

This is the curse of knowledge, I for one blame Eve for eating that damn apple.

Nibbler poop. (1)

fahrbot-bot (874524) | more than 7 years ago | (#18324867)

And whatever it is that dark energy involves, we know it's not 'normal,' either.

Nibbler knows what it is and from where it comes...

frZist st0p (-1, Troll)

Anonymous Coward | more than 7 years ago | (#18325393)

Ugg (1)

TopSpin (753) | more than 7 years ago | (#18325463)

"It's a ridiculously simple, intentionally cartoonish picture," Perlmutter said.
Way to arm the Intelligent Design crackpots.

He may mean our interpretation is cartoonish, but it doesn't parse that way.

Dark matter is just matter... (0)

Anonymous Coward | more than 7 years ago | (#18325493)

Where the entropy is measured to infinity, hence the creation of an event horizon.

it's a fudge factor that the layman can understand (e.g. it's the opposite of matter).

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