[Herra Tohtori]

Quite. If dark matter is not affected by nuclear or electromagnetic forces, it's not going to fuse into atoms.

...which is not surprising, because atoms by definition consist of nucleus and electron layers around it, and nuclei consist of protons and neutrons. And it's not surprising that protons, neutrons and electrons are not dark matter, they are normal matter that is included in standard model of particle physics.


That aside, if we drop "atoms" away from the quoted sentence and replace it with "combined particles", it starts saying something relevant.

Basic interactions include strong interaction, weak interaction, electromagnetic interaction and gravity. Of these, strong interaction (or strong nuclear force), weak interaction (or weak nuclear force) and electromagnetic force has been very accurately combined into one model that utilizes measure bosons as particles that convey these forces. In short, that's what quantum electrodynamics and quantum chromodynamics are all about.

Gravity is a mean bastard, though. It doesn't want to be quantified, but on the other hand, General Relativity does not give accurate predictions at very small ranges.

If some particles are only affected by gravitation, it's indeed very difficult to notice them. Neutrinos are almost like this; they only interact with other universe via weak interaction, which makes them very difficult to detect... And until gravity wave detectors are functional, we have no way of directly detecting dark matter... the only means of doing this would be to look for gravitational anomalies, and that has indeed been the main method of detecting dark matter thus far... in fact, it was found like that.

[Descenterace]

If we ever discover that dark matter does coalesce at the atomic level, you can bet the definition of 'atom' will get a rewrite.

It already includes the antimatter counterpart, which doesn't consist of matter particles...</pedant>

[Herra Tohtori]

If we ever discover that dark matter does coalesce at the atomic level, you can bet the definition of 'atom' will get a rewrite.

It already includes the antimatter counterpart, which doesn't consist of matter particles...</pedant>

Anti-matter belongs to the class of "ordinary matter" in cosmological sense. It is affected by all the four basic interactions just like normal matter is. And anti-matter atoms behave with each others just like normal matter.

From known particles, neutrinos are the ones that are semantically closest to dark matter, but they are not truly dark either, since they interact through both weak interaction and gravity, whence dark matter is hypothesized to only interact with ordinary matter (and itself!) via gravity.

The point is that even if dark matter particles can form structures, it doesn't mean that these structures would be anything like atoms. To be that, they should have very similar properties to protons, neutrons and electrons, and if they had same properties, they would not be dark matter, they would be ordinary matter.

Just like the saying goes - if an Aunt had balls, she would be Uncle.

[Getter Robo G]

Perihelion said, "the rules that govern the universe are actually quite simple"

Amen brother!

One of them is "Do what you want, but if you get out of line some uber race will come around to kick you in the balls..."

So I was wondering... If Dark Matter affects spacial gravity, can we use this somehow to transcend normal space into a sort of SubSpace? (Artifical wormholes anyone? I got dibbs for Wormhole Extreame!) lol

Out!

[perihelion]

Perihelion said, "the rules that govern the universe are actually quite simple"

Amen brother!

That was mostly wishful thinking, and I'll be the first to admit it.  It's just... well, there are parts of Quantum Electrodynamics that have never sat well with me for much the same reasons they never set well with Einstein.  I have a hard time believing in a non-deterministic universe.  The fact that quantum theory comes right out and says that there are some things you flat out cannot know just leaves a bad taste in my mouth.  Not to mention the implication that the universe, at its most fundamental level, is digital!

Thing is, every prediction made by QED has been proven correct thus far.  Maybe human intuition is just no good at the atomic level.  Sometimes I guess I let my desire for things to make sense run too far ahead.  Our collective understanding of physics is getting better (more accurate, probably more "correct") everyday.  But it is also getting so infernally complicated that I wonder if any one person can actually comprehend all of it without becoming the scientific equivalent of a monk.

[Herra Tohtori]

Why is non-determinism such a horror to you?

IMO non-deterministic world is much a relief for me, because should the world prove to be deterministic, it would also mean that there was no free will...

Non-deterministic world allows free will at fundamental level. The power of chance is a good thing to have involved IMO.

Plus, the latest experiments with single foton quantum interference really seem to prove that multiversum interpretation of quantum mechanics is the way to go. There are some phenomena that the "Copenhagen school" of quantum mechanics can't really explain, but the multiversum school can.

[OMFG PWNT]

hey i hate to bring on religions but wat about god?

[Bobboau]

a non-deterministic universe does nothing for free will, it just means stuff is more random, random != willed.

[OMFG PWNT]

no i meant wat herra tohtori said evret (how you spell it?) interpretation is obviously against god and i say its 100% wrong. free will isnt my problem its just the idea is antichrist

[Bobboau]

no, you don't get it, I was ignoreing you because that is beond the point of this conversation.

[Herra Tohtori]

Well, deities are indeed irrelevant to this subject. If we want to bring in theological controversions between predestination and free will, feel free to open a new topic. Besides, predestination is only part of some sects of monotheistic religions (primarily Calvinism and some other protestant forms of christianity), so non-deterministic universe would only be agains their god...

What I simply meant that if the universe is deterministic, everything just happens on a path set to happen in the big bang (or whatever it was). That would mean that free will can not be anything but an illusion.

Human free will might or might not be illusion, independent of whether the world itself is or isn't deterministic. But if the universe was deterministic, there wouldn't be even the chance that free will existed.

In a non-deterministic world, things do not happen in predestined path, so there is always a choice. In a deterministic world, there are no choices, only an illusion of making a choice. In a deterministic world, if you had sufficient information and sufficient calculation power, you could calculate what will happen to you from this day on.

And a billion year ago some sentient being could've predicted with absolute certainty that one day you'll be making those calculations.

But in a non-deterministic world, the choice is always there, randomizing events and making it truly impossible to achieve absolute accuracy with any matter whatsoever. That's what I mean with "free will". Randomized illusion of free will is more free than absolutely predictable free will.

So, in reality the human consciousness is always limited to existing possible states, but they still can't be accurately predicted.

I guess you could call human free will as "semi-free" in a non-deterministic universe. But in a deterministic universe, it's not even that, because there's only one possibility for the course of any action.

[Bobboau]

I fail to see how the theoretical ability to calculate the future or not makes free will any less illusionary. on the microscopic scale things are still happening acording to simple rules, it's just that there might be a bit of randomness involved makeing a definate answere imposable to predict with absolute certanty.

now this all said I am what I call a mechanicist or quasi-determinst, I beleive in a universe that is run by rules, though those rules may be probabalistic in nature. I am also oddly someone who argues in favor of free will, but that is partly a function of how I have free will defined, which I don't feel like going into elaborate detail on explaining, but I think of it more of an ability of a system to learn and use past experience to make judgements about current situations, even if the choice one makes can be precisely calculated by my definition it's still free will. and I know that's not how phylosophers have it defined, but I disagree with them.

[Flipside]

Well, Free Will is defined by our own interpretation of Free Will. The Murderer/Victim argument is the famous example, but to break it down, we all have things we want to do, Free Will can be defined as both the urge to do it and the choice not to. However, there are some elements of Free Will that are not nearly so 'free' as we think. If you see a car coming towards you, how much choice do you think you have as to whether your body tries to get you out of the way?

If someone tries to kill you, you will use as much force as possible in return and worry about whether you killed them or not afterwards. This is why the 'Self Defence' laws are so tricky to maintain, because no-one stops and thinks 'Is this appropriate Force?' they tend to think 'Arrrrrrrgggh!' at around that stage.

And, not going too philosophical, but 'Arrrrrrrgh!' has had far more to do with human development than any other thought.

[spartan_0214]

Enough about Deities! ! !

Dark matter has to exist, because matter doesn't have an opposite. Let's see, there is: White and Black, Good and Evil, Spartan_0214 and Dark Hunter, Macintosh and PC, you name it, it has an opposite. Dark Matter must exist. . . .

[Flipside]

Not neccesarily, after all, you get things like 'Cold', 'Silence' etc, which are an absence of something, heat and sound in these cases, there is no such thing as 'Cold Energy' (Well, yes, Quantum Physicists would disagree, but that's a different sort of Cold Energy) all there are is Materials without any heat energy.
You could say that the opposite of Matter is Vacuum.

Theres no reason why Dark Matter cannot exist, it is simply mater that has congealed too far away from a light-source to be illuminated, but until our ability to detect it improves greatly, I will remain sceptical as to just how much of it is out there.

[Nuke]

stop defining the universe in a human centric manor. the universe operates independant of human belief and pholisophy.

[spartan_0214]

  centric or eccentric? 

[perihelion]

@ Flipside:

While it is possible to explain some of the missing mass of the universe away as normal baryonic matter that simply is not sufficiently illuminated to be seen (i.e., brown drawfs and other dwarf stars, cold interstellar gas and dust, neutrinos, etc.), most of that missing mass simply cannot be explained without either seriously rewriting general relativity or the presense of a very large quantity of matter which does not interact with visible matter in any way other than gravity.

http://en.wikipedia.org/wiki/Dark_matter

It's not the most rigourous article out there, but it does cite some good references and gives a good introduction to most of the theories out there.

[Flipside]

Yup, though personally, I'm not against looking at the laws of General Relativity. Personally, I find it more believable to think there is only one 'kind' of matter in the Universe and we just don't understand every aspect of it yet rather than start inventing new kinds.

I may be wrong, I'm no scientist, but as a scientist said 'When physicists start talking about matter who's only proof of existence is the fact it is almost impossible  to detect, you can almost smell the paradigm shift coming one way or another.'

[Ford Prefect]

now this all said I am what I call a mechanicist or quasi-determinst, I beleive in a universe that is run by rules, though those rules may be probabalistic in nature. I am also oddly someone who argues in favor of free will, but that is partly a function of how I have free will defined, which I don't feel like going into elaborate detail on explaining, but I think of it more of an ability of a system to learn and use past experience to make judgements about current situations, even if the choice one makes can be precisely calculated by my definition it's still free will. and I know that's not how phylosophers have it defined, but I disagree with them.

There are about as many definitions of free will as there are philosophers. You could define free will as "a purple banana" and there would be a philosopher (probably some twentieth-century scholar of epistemology) who would be right there with you.