...but I fail to see the 3D that was promised by TFA.
Yeah sadly it's the data that's 3D, not the presentation. They located the dark matter in three dimensions, the 3rd being distance according to red shift which is how it's colored. I can see how it's hard to find the explanation, too, what with them breaking up the story every couple paragraphs with a giant bold link to something else. I thought those were different news items at first!
Bad presentation in the article aside, this is pretty amazing work. What a phenomenal instrument we have in Hubble.
The article on the the Hubble site, while similarly lacking a good explanation for the image, actually talks about dark energy more than dark matter. Apparently this data also indicates a universe expanding outward from every point, corroborating that theory, along with some GR experimental validation as well. Not bad for a days work.
So a half-assed internet search uncovered a patent that covers the architecture for networked applications in.NET. And that's not good enough for you? How did that go again? "As far as anyone knows, Mono has no patent issues... except the one I found in two minutes of googling. But I'm sure that's it."
Yeah whatever.
I'm not doing "diligence" because I'd never set my foot in that bear trap in the first place.
Are atheists and scientists so heavily pushed around by religious types (had a nastier expression in here earlier) in America that this is a common reflex?
Sadly, yes. Scientific theories, scientists, and science itself are all under constant assault. The attackers consider scientific theories that disagree with (their particular and frankly bizarre interpretation of) their religion to be automatically false, and the scientists who support these theories to be automatically liars and frauds.
The really fucked up thing about it is that since you still can't get any political traction by coming right out and saying that you don't believe in the science because it contradicts your Sunday School lessons, they try to present their religious-based disbelief as though it were legitimate scientific skepticism. As if they are the true champions of science, and the professional scientists are the ones with religious beliefs.
They accuse the scientists of being dogmatic, of having a-priori conclusions, of not considering obvious alternative explanations because it's all about protecting their sacred beliefs. The hypocrisy is simply staggering. As if science hasn't regularly replaced theories with better ones, as if the most famous names in science didn't become famous for exactly that! And worse is that they argue this in part using a mishmash of extremely poorly understood or simply fabricated science -- usually just a collection of talking points they heard from some anti-science source, which they are completely incapable of going beyond or understanding the flaws in because they never learned the real science they're talking about in the first place.
The first time I ever had an argument where a Creationist argued that evolution was impossible because of the 2nd Law of Thermodynamics, I nearly went into shock. It was wrong on so many levels. But claiming scientists aren't accounting for some obvious principle, a principle the arguer themselves does not understand at all (nor even believe in if it weren't convenient for their argument), is absolutely par for the course.
Then there's things like ID. Intelligent Design is nothing more than a way of dressing up Creationism with a veneer of science-y talk so as to get around our Constitution's separation of church and state and let their religious dogma be taught in science class -- yes, science class -- in public schools. And in some cases, they've nearly succeeded!
So yeah, us science-minded folks (including the ones like me who are also religious) can be very touchy.:)
Which is why the phrase "fudge factor" inspired a rant, but seriously, the people I'm talking about would never take evidence into account in such a way that it could possibly change their mind. No, the next step for them would have been to claim that gravitational lensing itself was a fabrication and thus not evidence of dark matter. Or something dumber, I don't know.
And Mono is, as far as anyone is aware, free of all patented technology.
Or have you found a patent that covers.NET? I haven't. No one else I've asked has. Have you?
Are you fucking kidding me? Are you only just hearing about Mono today? Is everyone you know equally clueless, or did you just never think to try maybe checking the Mono website itself which informs you that it implements patented technology. It's always been known that Mono is not free of patented technology, Miguel has never claimed it was free of patents, he always admitted that it was not.
Oh and yeah before you get to it, we've also known about the Community Promise for a long time and discussed its problems too. Specifically, note that this "irrevocable" promise only applies to things that implement a specific version of the standard, and even then only to the extent that they comply with the standard (as decided by Microsoft), and that any future standard may or may not be covered by the promise.
In other words, at any time they want, MS can decide your implementation doesn't comply, or release a new version of the framework that you are no longer able to comply with and cannot implement without exposing yourself to patent claims.
It's embrace-extend-extinguish like usual, only this time MS tricked part of the Linux community into doing the embracing.
I am by no means a fan of Mono, but I fail to see how it is any different than gcc
Ah well that makes sense. Here it is in a nutshell:
Gcc is, as far as anyone is aware, free of all patented technology, in particular patents owned by companies hostile to free software.
Mono is most definitely encumbered by patents owned by a company that is very hostile towards free software, and has been recently becoming more vocal about alleging patent violations in Linux and threatening legal action.
Mono is not appreciably more vulnerable to attacks from Microsoft than the Linux kernel, or any other major piece of Free Software.
Yes it most definitely is! Because the vulnerability is not hypothetical, it is not a made-up FUD tactic. It's plain as day and undeniable that these patents cover things in Mono, and it is not a simple matter of recoding if MS ever becomes aggressive. There are aspects of the framework that simply cannot be implemented to spec without running into these patents.
Microsoft has no interest in anything cross-platform excepting those that are owned by MS. They have promised not to enforce patents against Mono, but this is not a legally binding promise. The only reason they have to let Mono exist is to waste the time of Linux developers, and to encourage adoption of a framework that is ostensibly cross-platform but can be instantly made Windows-only any time they want.
Oh and I think you're wrong. MS is just as evil as IBM and AT&T. Main difference is that today MS only controls the software while IBM controlled both.
This is absolutely a time bomb and MS is just waiting for the right moment to set it off.
I admit:-) probably a bad choice of words - but gravitational theory is still that - a theory.
Given the evidence the grand parent makes I place much greater confidence in it existing.
An unfortunate choice, since "fudge factor" is what folks say who want to characterize scientists as just making stuff up because they are unwilling to admit that their Holy Gospel is wrong. Of course it's obvious to them that gravity is wrong and dark matter can't exist, because its sounds weird.:P
But since contrary evidence actually affected your opinion, and you were grateful for it, it was perfectly clear that you aren't one of those types. So go ahead and be as un-confident as you want.:) Lots of scientists remain skeptical of new theories for a long time, until the evidence becomes overwhelming.
Still as I'm sure you've heard already, in science a "Theory" only gets to be called that after it has a substantial amount of experimental verification. The Theory of General Relativity is called a Theory because it has been phenomenally successful at making predictions. "Theory" in this sense means "Best working model, because it works, bitches."
It could certainly be disproven (as could Newton's 3rd Law), but it's going to take more than simply GR suggesting a mass somewhere where we don't see any via other means. And it'd be really hard to modify the theory such that it both explains what GR explains, and explains the dark matter observations only without any dark matter.
Modified Newtonian Dynamics(MOND) tried, but the gravitational lensing brought up as dark matter evidence previously can't be explained by MOND without their actually being mass there. I mean it's a basic observation of gravity that masses are attracted to one another, not to random empty points in space. So, like you, the MOND supporters had to admit this evidence supported the existence of dark matter.
You still don't have to think of it as 'fact'. You don't have to think of space-time curvature as fact. But it is probably a good idea to consider these "best working models", and for predictions or inferences made from these theories as pretty good bets.
Or it could be Newton's laws (or General relativity) don't work in this specific context and need to be modified (MOND).
MOND was a plausible explanation for some observed problems of galactic motion that dark matter solves with traditional gravitational theory, but it cannot explain the observed gravitational affects that come from well outside galaxies. Even in MOND, the gravitational force is directed towards the center of mass. Therefore MOND also requires non-baryonic dark matter to work.
It turns out it's really, really hard to come up with a theory that both explains what GR explains extremely well, and the new observations, without inferring the existence of an unseen mass exactly like GR suggests.
As far as I know, neither possibility has been ruled out so far, and there is still no good candidate for Dark Matter.
MOND itself has not been ruled out, but like I said it can't explain our observations without dark matter.
There are certainly good theoretical candidates for dark matter. As I explain elsewhere, one of the top candidates at this time is the theoretical neutralino, a more massive neutrino predicted by Supersymmetry. This particle has not been conclusively found yet, but it's possible it will be soon.
If it's proven to exist, it will be a phenomenal confirmation of Supersymetry and the Standard Model, and GR as well for that matter. If it's not, well, the search will go on, including for alternative theories.
It can go either way, and claiming it's certain the laws are correct denotes a misunderstanding of the concept of Scientific Theory in itself.
Well good thing that I didn't say it's certainly correct, now isn't it? I said it works extremely well, which is a true statement and the test by which all hypotheses and theories are measured. I said that this means that dark matter is a prediction based on a theory that already has an outstanding record of successful prediction.
Further observation could certainly demonstrate general relativity to be incorrect, and in fact I would wager that is highly likely though it's probably going to involve more precision, not completely changing the relationship between mass and gravity (like, by having the gravitational force *not* point at the mass as would be required to explain away dark matter).
Weakly interacting does not mean that it interacts via the weak interaction.
That's right that is a possible English interpretation of "weakly", which is why what I quoted explicitly explained that the acronym "Weakly Interacting" came from their "expectation of the weak interaction" at the Electro-weak scale, to make it clear they don't mean "weak interaction" as in "not very strong", but rather the Weak Force, one of the unified fundamental forces of the Standard Model.
That is why direct detection experiments look for elastic interactions between a dark matter particle and a nucleus in the experiment. This is why you have to minimize the background as much as possible.
It's because the weak interaction is relevant only at such a close distance between particles that a neutrino-like particle has to basically directly impact a nucleus, which is a ridiculously tiny target in ordinary matter where nuclei are held apart by the electromagnetic force. It's mostly empty space to uncharged particles. That's why the probability of an interaction in an object the size of one of our detectors is so low that it takes years of measurement to be sure you've really seen one, and a deep hole to make sure it's not overwhelmed by noise.
Read the Ars and the Berkeley article, they explain all the findings there. Yes the actual discovery is still only a modest probability, but it's clear the theory it's based on is a mass-full particle that interacts through the Weak Force.
No, the neutralino does not interact through the weak interaction.
They really do. To quote the Berkeley CDMS website linked from the Ars article about possible (but very speculative) dark matter detection, who are trying to detect WIMPS and in specific neutralinos:
Specifically, a cross section for interaction between a neutralino and a nucleon in ordinary matter of the order of the electro-weak scale would be consistent with a meaningful cosmological role for the particle. This expectation of a weak interaction together with the expected mass range of the neutralino, 10 to 1000 GeV, produce the acronym "WIMP": Weakly Interacting Massive Particle.
So that and other usages of "weak interaction" lead me to believe neutralinos interact via the weak interaction.
I would expect there to be differences in the experiment, but the overview seems very similar: Put an extremely sensitive detector as far down in the earth as you can to shield yourself from as many normal cosmic rays and particles as possible, and wait for years to see enough events to say you've got a decent probability of having actually seen something real.
That's right. At least not in the same way as 'normal' matter via electromagnetism. Obviously it interacts gravitationally; that's how we discovered it.
Depending on what it is, it might interact via the Weak Force. But the weak force is extremely short-range -- and I don't mean short-range in an astronomical sense, I mean short range in an sub-atomic sense. Neutrinos for example only interact via the weak force, and they can easily pass through our entire planet without coming close enough to an atomic nucleus to interact. Kinda makes them a bitch to detect, but we've done it.
So if dark matter is something like neutrinos, then that would explain both why we can't see it and why it seems to be able to pass through an entire galaxy unperturbed.
They already knew they were there, they just hadn't actually seen them yet.
Another way of looking at it, is that they were only able to see 1/100'th of the universe before, now they can see 1/10'th of the universe.
Exactly.
It's as if by looking at the 1/100th of the universe we could see, we calculated a rough density of the universe. You then extrapolate based on the principle that our section of the universe isn't special, and you thus expect to find lots of galaxies out there.
Unless these galaxies are so far away they are outside the universe and don't contribute to whether the whole universe is gravitationally open or closed, they have just invalidated that argument, period.
You don't understand the most basic aspects of this situation, period. These galaxies were already believed to exist, but were not seen. Estimates of the mass of the universe are not based simply on counting galaxies we've found in telescopes. The estimate for the total mass of the universe does not increase every time Hubble takes a Deep Field picture and astronomers count up the galaxies. So finding these galaxies that we already expected to be there does not change the argument for dark matter one iota.
By the way, I was third poster to this thread, after two people basically shouting FRIST PSOT! If anyone wants to mod me wrong, fine, but redundant is simply cowardly and a gross abuse of the system.
That may have been true when you clicked the reply button, but by the time you posted you were about the 5th top-level post to ask if this disproves dark matter. It may seem unfair since you did write up more than just "I don't believe in dark matter and am now proven right", but it's not really an abuse.
I knew about the fudge factor we needed to get the equations to work - I didn't know we have actually seen something like that.
It was never a "fudge factor" to make the equation of gravity "work". It was a prediction of the already extremely well-working equation. Not "Oh noes gravity is broken, we need 'dark matter' to fix it." Rather "Huh, gravity implies there is a mass here that we can't see with our electromagnetic detection devices".
Think of it this way. You're walking around a room blindfolded with a cane that has a pressure sensor on the end that uses a voice synthesizer to tell you the readings. You notice that all along a large flat plane the pressure sensor detects pressure equal to that with which you push. Newton's 3rd Law tells you that for this to happen, something must be pushing back with equal force. Something like a wall.
Now, do you say that the wall is a fudge to make Newton's 3rd Law work? Or do you say that Newton's 3rd Law implies that there is a wall there?
I mean you might as well say that the existence of the Sun is a fudge to make electromagnetic and gravitational equations work.
I'm not trying to rag on you or anything (I mean you said 'thank you' for evidence after all), just trying to clear up a misconception that I think has lead to a lot of unnecessary skepticism of dark matter.
The missing mass is comprised of all the socks that have slipped through the spacetime continuum
True. But one of the biggest mysteries in astrophysics right now, just after the prevalence of matter over antimatter, is why it's always the left sock.
it is matter that is fundamentally different and doesn't appear to interact with regular matter at all, except gravitationally.
More specifically, it doesn't appear to interact electromagnetically. Which just happens to exclude all of our direct detection methods (i.e. telescopes).
One candidate for dark matter is the neutralino, which is predicted by Supersymetric Theory and is basically a neutrino but heavier, and like a neutrino interacts through the Weak Interaction which allowed us to find neutrinos, and maybe even actual dark matter.
Is that what he did? I remember long, in-depth justifications from him and others. Endless debates on slashdot with Miguel personally arguing in dozens of threads.
Yeah, I personally argued with him, and yes, I think that's an accurate characterization of his response to the patent issues. He couldn't deny that patent issues existed, so instead he simply claimed that they would not be a problem. After all, Microsoft had promised. So we were just being paranoid.
Miguel was enamored with a lot of the technology behind ".NET", and thought he could outsmart Microsoft, in a sense. He thought he would be pragmatic and non-religious about the technology and adopt it.
I've been saying it for years -- real pragmatism must always include consideration of the practical realities surrounding a tool or technology. Like, who is providing it, what are the terms under which they provide it, could those terms change and how would that affect your use of the tool? Or as you point out, how does the technology you like (C#) fit into the larger strategy being pushed (.NET)?
Many engineers tend to want to ignore those aspects and focus solely on the qualities of the tool itself. They say they just want something that "does the job", and thus fail to consider how those factors affect the tool's ability to do the job. Because, being technically-minded people, they want the technical factors to be the only ones that matter. They call this "pragmatism" and being "non-religious".
Which just goes to show how even people who value pragmatism and rationality more than anyone can still be completely irrational. Ignoring the important external factors because you really wish they weren't important is not rational!
Rationality is simply a useful trick that our mammalian brains have picked up. But at the end of the day we are still emotional animals, and even when expending great effort to force ourselves to think rationally we can't eliminate the effect of our emotions. Much of the time "rationality" is simply a way to justify what we've already decided based on emotion.
Ergo the worst thing a person who values rationality can do is tell themselves that they are completely rational and uninfluenced by emotion. I think there's an important lesson to be learned here, even for those of us who saw this situation coming from a mile away.
Slashdot Mirror
Wikipedia also says you can only write about things you don't actually have any real knowledge of... I don't think we're quite that bad. Yet.
Well, it's not an official policy here at /. More like an unspoken ideal.
...but I fail to see the 3D that was promised by TFA.
Yeah sadly it's the data that's 3D, not the presentation. They located the dark matter in three dimensions, the 3rd being distance according to red shift which is how it's colored. I can see how it's hard to find the explanation, too, what with them breaking up the story every couple paragraphs with a giant bold link to something else. I thought those were different news items at first!
Bad presentation in the article aside, this is pretty amazing work. What a phenomenal instrument we have in Hubble.
The article on the the Hubble site, while similarly lacking a good explanation for the image, actually talks about dark energy more than dark matter. Apparently this data also indicates a universe expanding outward from every point, corroborating that theory, along with some GR experimental validation as well. Not bad for a days work.
So a half-assed internet search uncovered a patent that covers the architecture for networked applications in .NET. And that's not good enough for you? How did that go again? "As far as anyone knows, Mono has no patent issues... except the one I found in two minutes of googling. But I'm sure that's it."
Yeah whatever.
I'm not doing "diligence" because I'd never set my foot in that bear trap in the first place.
Are atheists and scientists so heavily pushed around by religious types (had a nastier expression in here earlier) in America that this is a common reflex?
Sadly, yes. Scientific theories, scientists, and science itself are all under constant assault. The attackers consider scientific theories that disagree with (their particular and frankly bizarre interpretation of) their religion to be automatically false, and the scientists who support these theories to be automatically liars and frauds.
The really fucked up thing about it is that since you still can't get any political traction by coming right out and saying that you don't believe in the science because it contradicts your Sunday School lessons, they try to present their religious-based disbelief as though it were legitimate scientific skepticism. As if they are the true champions of science, and the professional scientists are the ones with religious beliefs.
They accuse the scientists of being dogmatic, of having a-priori conclusions, of not considering obvious alternative explanations because it's all about protecting their sacred beliefs. The hypocrisy is simply staggering. As if science hasn't regularly replaced theories with better ones, as if the most famous names in science didn't become famous for exactly that! And worse is that they argue this in part using a mishmash of extremely poorly understood or simply fabricated science -- usually just a collection of talking points they heard from some anti-science source, which they are completely incapable of going beyond or understanding the flaws in because they never learned the real science they're talking about in the first place.
The first time I ever had an argument where a Creationist argued that evolution was impossible because of the 2nd Law of Thermodynamics, I nearly went into shock. It was wrong on so many levels. But claiming scientists aren't accounting for some obvious principle, a principle the arguer themselves does not understand at all (nor even believe in if it weren't convenient for their argument), is absolutely par for the course.
Then there's things like ID. Intelligent Design is nothing more than a way of dressing up Creationism with a veneer of science-y talk so as to get around our Constitution's separation of church and state and let their religious dogma be taught in science class -- yes, science class -- in public schools. And in some cases, they've nearly succeeded!
So yeah, us science-minded folks (including the ones like me who are also religious) can be very touchy. :)
Which is why the phrase "fudge factor" inspired a rant, but seriously, the people I'm talking about would never take evidence into account in such a way that it could possibly change their mind. No, the next step for them would have been to claim that gravitational lensing itself was a fabrication and thus not evidence of dark matter. Or something dumber, I don't know.
And Mono is, as far as anyone is aware, free of all patented technology.
Or have you found a patent that covers .NET? I haven't. No one else I've asked has. Have you?
Are you fucking kidding me? Are you only just hearing about Mono today? Is everyone you know equally clueless, or did you just never think to try maybe checking the Mono website itself which informs you that it implements patented technology. It's always been known that Mono is not free of patented technology, Miguel has never claimed it was free of patents, he always admitted that it was not.
Oh and yeah before you get to it, we've also known about the Community Promise for a long time and discussed its problems too. Specifically, note that this "irrevocable" promise only applies to things that implement a specific version of the standard, and even then only to the extent that they comply with the standard (as decided by Microsoft), and that any future standard may or may not be covered by the promise.
In other words, at any time they want, MS can decide your implementation doesn't comply, or release a new version of the framework that you are no longer able to comply with and cannot implement without exposing yourself to patent claims.
It's embrace-extend-extinguish like usual, only this time MS tricked part of the Linux community into doing the embracing.
I am by no means a fan of Mono, but I fail to see how it is any different than gcc
Ah well that makes sense. Here it is in a nutshell:
Gcc is, as far as anyone is aware, free of all patented technology, in particular patents owned by companies hostile to free software.
Mono is most definitely encumbered by patents owned by a company that is very hostile towards free software, and has been recently becoming more vocal about alleging patent violations in Linux and threatening legal action.
Mono is not appreciably more vulnerable to attacks from Microsoft than the Linux kernel, or any other major piece of Free Software.
Yes it most definitely is! Because the vulnerability is not hypothetical, it is not a made-up FUD tactic. It's plain as day and undeniable that these patents cover things in Mono, and it is not a simple matter of recoding if MS ever becomes aggressive. There are aspects of the framework that simply cannot be implemented to spec without running into these patents.
Microsoft has no interest in anything cross-platform excepting those that are owned by MS. They have promised not to enforce patents against Mono, but this is not a legally binding promise. The only reason they have to let Mono exist is to waste the time of Linux developers, and to encourage adoption of a framework that is ostensibly cross-platform but can be instantly made Windows-only any time they want.
Oh and I think you're wrong. MS is just as evil as IBM and AT&T. Main difference is that today MS only controls the software while IBM controlled both.
This is absolutely a time bomb and MS is just waiting for the right moment to set it off.
I wonder what the state congressmen (or whatever they are called up there) got in return for this sweet deal... Money? Drugs? Sex? Free Computers?
They were promised unlimited free porn for life, and eagerly agreed. Then MS sent them a download link for Internet Explorer.
So the answer would be "No, if you're asking in the context of the 1800s." :)
I admit :-) probably a bad choice of words - but gravitational theory is still that - a theory.
Given the evidence the grand parent makes I place much greater confidence in it existing.
An unfortunate choice, since "fudge factor" is what folks say who want to characterize scientists as just making stuff up because they are unwilling to admit that their Holy Gospel is wrong. Of course it's obvious to them that gravity is wrong and dark matter can't exist, because its sounds weird. :P
But since contrary evidence actually affected your opinion, and you were grateful for it, it was perfectly clear that you aren't one of those types. So go ahead and be as un-confident as you want. :) Lots of scientists remain skeptical of new theories for a long time, until the evidence becomes overwhelming.
Still as I'm sure you've heard already, in science a "Theory" only gets to be called that after it has a substantial amount of experimental verification. The Theory of General Relativity is called a Theory because it has been phenomenally successful at making predictions. "Theory" in this sense means "Best working model, because it works, bitches."
It could certainly be disproven (as could Newton's 3rd Law), but it's going to take more than simply GR suggesting a mass somewhere where we don't see any via other means. And it'd be really hard to modify the theory such that it both explains what GR explains, and explains the dark matter observations only without any dark matter.
Modified Newtonian Dynamics(MOND) tried, but the gravitational lensing brought up as dark matter evidence previously can't be explained by MOND without their actually being mass there. I mean it's a basic observation of gravity that masses are attracted to one another, not to random empty points in space. So, like you, the MOND supporters had to admit this evidence supported the existence of dark matter.
You still don't have to think of it as 'fact'. You don't have to think of space-time curvature as fact. But it is probably a good idea to consider these "best working models", and for predictions or inferences made from these theories as pretty good bets.
Until contrary evidence comes along. :)
Or it could be Newton's laws (or General relativity) don't work in this specific context and need to be modified (MOND).
MOND was a plausible explanation for some observed problems of galactic motion that dark matter solves with traditional gravitational theory, but it cannot explain the observed gravitational affects that come from well outside galaxies. Even in MOND, the gravitational force is directed towards the center of mass. Therefore MOND also requires non-baryonic dark matter to work.
It turns out it's really, really hard to come up with a theory that both explains what GR explains extremely well, and the new observations, without inferring the existence of an unseen mass exactly like GR suggests.
As far as I know, neither possibility has been ruled out so far, and there is still no good candidate for Dark Matter.
MOND itself has not been ruled out, but like I said it can't explain our observations without dark matter.
There are certainly good theoretical candidates for dark matter. As I explain elsewhere, one of the top candidates at this time is the theoretical neutralino, a more massive neutrino predicted by Supersymmetry. This particle has not been conclusively found yet, but it's possible it will be soon.
If it's proven to exist, it will be a phenomenal confirmation of Supersymetry and the Standard Model, and GR as well for that matter. If it's not, well, the search will go on, including for alternative theories.
It can go either way, and claiming it's certain the laws are correct denotes a misunderstanding of the concept of Scientific Theory in itself.
Well good thing that I didn't say it's certainly correct, now isn't it? I said it works extremely well, which is a true statement and the test by which all hypotheses and theories are measured. I said that this means that dark matter is a prediction based on a theory that already has an outstanding record of successful prediction.
Further observation could certainly demonstrate general relativity to be incorrect, and in fact I would wager that is highly likely though it's probably going to involve more precision, not completely changing the relationship between mass and gravity (like, by having the gravitational force *not* point at the mass as would be required to explain away dark matter).
Weakly interacting does not mean that it interacts via the weak interaction.
That's right that is a possible English interpretation of "weakly", which is why what I quoted explicitly explained that the acronym "Weakly Interacting" came from their "expectation of the weak interaction" at the Electro-weak scale, to make it clear they don't mean "weak interaction" as in "not very strong", but rather the Weak Force, one of the unified fundamental forces of the Standard Model.
That is why direct detection experiments look for elastic interactions between a dark matter particle and a nucleus in the experiment. This is why you have to minimize the background as much as possible.
It's because the weak interaction is relevant only at such a close distance between particles that a neutrino-like particle has to basically directly impact a nucleus, which is a ridiculously tiny target in ordinary matter where nuclei are held apart by the electromagnetic force. It's mostly empty space to uncharged particles. That's why the probability of an interaction in an object the size of one of our detectors is so low that it takes years of measurement to be sure you've really seen one, and a deep hole to make sure it's not overwhelmed by noise.
Read the Ars and the Berkeley article, they explain all the findings there. Yes the actual discovery is still only a modest probability, but it's clear the theory it's based on is a mass-full particle that interacts through the Weak Force.
No, the neutralino does not interact through the weak interaction.
They really do. To quote the Berkeley CDMS website linked from the Ars article about possible (but very speculative) dark matter detection, who are trying to detect WIMPS and in specific neutralinos:
So that and other usages of "weak interaction" lead me to believe neutralinos interact via the weak interaction.
I would expect there to be differences in the experiment, but the overview seems very similar: Put an extremely sensitive detector as far down in the earth as you can to shield yourself from as many normal cosmic rays and particles as possible, and wait for years to see enough events to say you've got a decent probability of having actually seen something real.
Oh man, I'm so hoping the next one is the Flabbergastingly Large Telescope.
Simply Staggeringly Large Telescope?
That's right. At least not in the same way as 'normal' matter via electromagnetism. Obviously it interacts gravitationally; that's how we discovered it.
Depending on what it is, it might interact via the Weak Force. But the weak force is extremely short-range -- and I don't mean short-range in an astronomical sense, I mean short range in an sub-atomic sense. Neutrinos for example only interact via the weak force, and they can easily pass through our entire planet without coming close enough to an atomic nucleus to interact. Kinda makes them a bitch to detect, but we've done it.
So if dark matter is something like neutrinos, then that would explain both why we can't see it and why it seems to be able to pass through an entire galaxy unperturbed.
Er, but I'm guessing it was something to do with the seventh-generation iPhone.
A 7G iPhone? Is it the model with the ham dispenser?
*note: goats.com has nothing to do with certain horrific things that have goats in the name.
You're just putting the left sock on your right foot.
Today I'm wearing two right socks because I lost the last of my left socks in the wash the other day.
They already knew they were there, they just hadn't actually seen them yet.
Another way of looking at it, is that they were only able to see 1/100'th of the universe before, now they can see 1/10'th of the universe.
Exactly.
It's as if by looking at the 1/100th of the universe we could see, we calculated a rough density of the universe. You then extrapolate based on the principle that our section of the universe isn't special, and you thus expect to find lots of galaxies out there.
Unless these galaxies are so far away they are outside the universe and don't contribute to whether the whole universe is gravitationally open or closed, they have just invalidated that argument, period.
You don't understand the most basic aspects of this situation, period. These galaxies were already believed to exist, but were not seen. Estimates of the mass of the universe are not based simply on counting galaxies we've found in telescopes. The estimate for the total mass of the universe does not increase every time Hubble takes a Deep Field picture and astronomers count up the galaxies. So finding these galaxies that we already expected to be there does not change the argument for dark matter one iota.
By the way, I was third poster to this thread, after two people basically shouting FRIST PSOT! If anyone wants to mod me wrong, fine, but redundant is simply cowardly and a gross abuse of the system.
That may have been true when you clicked the reply button, but by the time you posted you were about the 5th top-level post to ask if this disproves dark matter. It may seem unfair since you did write up more than just "I don't believe in dark matter and am now proven right", but it's not really an abuse.
I knew about the fudge factor we needed to get the equations to work - I didn't know we have actually seen something like that.
It was never a "fudge factor" to make the equation of gravity "work". It was a prediction of the already extremely well-working equation. Not "Oh noes gravity is broken, we need 'dark matter' to fix it." Rather "Huh, gravity implies there is a mass here that we can't see with our electromagnetic detection devices".
Think of it this way. You're walking around a room blindfolded with a cane that has a pressure sensor on the end that uses a voice synthesizer to tell you the readings. You notice that all along a large flat plane the pressure sensor detects pressure equal to that with which you push. Newton's 3rd Law tells you that for this to happen, something must be pushing back with equal force. Something like a wall.
Now, do you say that the wall is a fudge to make Newton's 3rd Law work?
Or do you say that Newton's 3rd Law implies that there is a wall there?
I mean you might as well say that the existence of the Sun is a fudge to make electromagnetic and gravitational equations work.
I'm not trying to rag on you or anything (I mean you said 'thank you' for evidence after all), just trying to clear up a misconception that I think has lead to a lot of unnecessary skepticism of dark matter.
The missing mass is comprised of all the socks that have slipped through the spacetime continuum
True. But one of the biggest mysteries in astrophysics right now, just after the prevalence of matter over antimatter, is why it's always the left sock.
Some say the two are related.
it is matter that is fundamentally different and doesn't appear to interact with regular matter at all, except gravitationally.
More specifically, it doesn't appear to interact electromagnetically. Which just happens to exclude all of our direct detection methods (i.e. telescopes).
One candidate for dark matter is the neutralino, which is predicted by Supersymetric Theory and is basically a neutrino but heavier, and like a neutrino interacts through the Weak Interaction which allowed us to find neutrinos, and maybe even actual dark matter.
If anyone would like to read a somewhat middle-of-the-road (neither "IV IS GREAT!" nor "IP is the DEVIL!")
As a Satanist, I would like to say that I find your usage of those two ideas as extreme opposites offensive.
However, as a Satanist, I find causing offense to be commendable. So, carry on!
You can teach a monkey to do a lot of useful things, except care that you don't want it to poop everywhere.
Is that what he did? I remember long, in-depth justifications from him and others. Endless debates on slashdot with Miguel personally arguing in dozens of threads.
Yeah, I personally argued with him, and yes, I think that's an accurate characterization of his response to the patent issues. He couldn't deny that patent issues existed, so instead he simply claimed that they would not be a problem. After all, Microsoft had promised. So we were just being paranoid.
Miguel was enamored with a lot of the technology behind ".NET", and thought he could outsmart Microsoft, in a sense. He thought he would be pragmatic and non-religious about the technology and adopt it.
I've been saying it for years -- real pragmatism must always include consideration of the practical realities surrounding a tool or technology. Like, who is providing it, what are the terms under which they provide it, could those terms change and how would that affect your use of the tool? Or as you point out, how does the technology you like (C#) fit into the larger strategy being pushed (.NET)?
Many engineers tend to want to ignore those aspects and focus solely on the qualities of the tool itself. They say they just want something that "does the job", and thus fail to consider how those factors affect the tool's ability to do the job. Because, being technically-minded people, they want the technical factors to be the only ones that matter. They call this "pragmatism" and being "non-religious".
Which just goes to show how even people who value pragmatism and rationality more than anyone can still be completely irrational. Ignoring the important external factors because you really wish they weren't important is not rational!
Rationality is simply a useful trick that our mammalian brains have picked up. But at the end of the day we are still emotional animals, and even when expending great effort to force ourselves to think rationally we can't eliminate the effect of our emotions. Much of the time "rationality" is simply a way to justify what we've already decided based on emotion.
Ergo the worst thing a person who values rationality can do is tell themselves that they are completely rational and uninfluenced by emotion. I think there's an important lesson to be learned here, even for those of us who saw this situation coming from a mile away.