Researchers Seek Mysterious Dark Matter

[Prrkitty]

I'm not too familiar with the term "dark matter" or what it is, means or etc. ALthough I have heard it many times on shows I watch on the History Channel as well talked about in Sci-Fi movies.

http://www.foxnews.com/wires/2007Aug13/0,4670,DarkMatterHunt,00.html

I take it that "dark matter" is basically... only a theory... at the moment and doesn't actually exist? Or does it exist and we just haven't found it yet?

[Beldaran]

"In astrophysics and cosmology, dark matter refers to hypothetical matter of unknown composition that does not emit or reflect enough electromagnetic radiation to be observed directly, but whose presence can be inferred from gravitational effects on visible matter."

Dark Matter (http://en.wikipedia.org/wiki/Dark_matter)

[Prrkitty]

A comment from the article confuses me all to heck - Knowing that dark matter exists is a far cry from knowing what it is.

Do scientists actually "know" it exists but just haven't found it yet (which is a contraditory statement)? Or do they know what it is and yet still just haven't found it yet?

Sorry if I sound dumb/dense/etc but sometimes my brain has a really hard time wrapping around some things/concepts etc. OH and know ahead of time science is/was probably my worst subject in school (right along with geometry).

[Cloral]

At this point scientists have not made any direct observations of dark matter, because it doesn't give off any form of energy we know how to detect. However, we have observed its gravitational influency on other bodies that we can detect. So we have only observed it indirectly, and as such we don't really know much about it.

[Prrkitty]

So... it has gravitational influency on things that we can observe... but why can't scientists trace along that gravitational influence to the origin of it's affect?

And yes I understand the point that it doesn't give off any form of energy that we know how to detect.

So ... we can see the affect but we can't "perceive/find" where the origin of that affect is coming from because there is no energy for us to be able to find it?

Wow... say/think that five times fast <lol>.

EDIT: Bel, after reading your wiki link ... I'm even more confused <lol>. BUT... I think scientists are just as confused (for lack of a better way to put it) about dark matter. The article talked about ... hot dark matter, warm dark matter and cold dark matter. So I think I understand that there is a LOT of speculation about what just plain 'ol dark matter really is - be it hot, warm or cold?

[Cloral]

I think the basis of it is that distant solar systems and galaxies interact with each other as if they are more massive than what they should be based on the amount of things we've observed in each system or galaxy. So dark matter is the way science currently accounts for the difference. It isn't 100&#37; clear where the dark matter would be, though I do recall reading somewhere that the current thought is that it is located outside of the 'normal' reaches of such things, in a 'halo' of extra matter.

[Lilith]

no offense but I laughed really hard when I saw prrkitty making a topic about dark matter. also fuck dark matter, it's scary shit, kind of like oceans and the sky. I am probably agoraphobic.

[mikeron]

Do scientists actually "know" it exists but just haven't found it yet (which is a contraditory statement)? Or do they know what it is and yet still just haven't found it yet?Observations of the movement of galaxies don't agree with predictions, so "dark matter" is a conjecture used to try to account for the discrepancy. The idea being that it's more sensible to add exotic particles than to alter our view of gravity. What I find interesting is that some of the simulations used to make the predictions of how the galaxies should move were approximations that ignored Relativity.

If you accept that there really is too much gravity there, I think a more interesting explanation is the one that String Theorists have produced (although I'm not a big fan of String Theory). The idea is that some gravity is spilling over into our universe from a parallel one, altering the trajectories of our galaxies.

[Prrkitty]

Observations of the movement of galaxies don't agree with predictions, so "dark matter" is a conjecture used to try to account for the discrepancy. The idea being that it's more sensible to add exotic particles than to alter our view of gravity. What I find interesting is that some of the simulations used to make the predictions of how the galaxies should move were approximations that ignored Relativity.

If you accept that there really is too much gravity there, I think a more interesting explanation is the one that String Theorists have produced (although I'm not a big fan of String Theory). The idea is that some gravity is spilling over into our universe from a parallel one, altering the trajectories of our galaxies.

So what you're saying is that since scientists cannot explain the "gravitational discrepancy" with explanations that can be proved with (for lack of a better word) “stuff” that we already know about… and instead they are willing to change how science views the standard of gravity (views they've held since science basically started and evolved)? And they’re assuming that there is another factor (and they’re calling that factor dark matter) that needs to be inserted into the equation to explain the unexplainable? Yet they have no proof that this “dark matter” even exists?

I feel very thankful that my husband and close friends are always willing to “cuss ‘n discuss” most any subject with me… so that I can learn new things and expand my knowledge of the world around me.

This subject just happens to be one of the ones I’m exploring at the moment. And thank you to all of you that have constructively contributed to this discussion. I initially posted the article because, 1) it interested me and 2) I thought some of you might also be interested in it and might “cuss ‘n discuss” it with me.

[Glenn the Great]

I'd love to discuss this with you. I'd also like to cuss it with you too, but I'm trying not to get slapped with a flaming infraction right now.

But yeah, Dark Matter is a favorite subject of mine.

Scientists could be considered justified in their attempts to explain gravitational discrepancies by assuming the existence of undiscovered particles as opposed to changing the accepted laws of gravity. This is because of the discoveries that have been made in the past century.

This past century saw the great expansion of the field of particle physics. Before the 1900s, people only knew about protons, neutrons, and electrons as being the components of the universe.

Then we learned that there were literally hundreds of other particles out there. A lot of them are very hard to detect and to individually isolate.

Neutrinos are a very good example of this. They are a by-product of radioactive events. The are point-sized, electrically neutral like a neutron, and are believed to contain a VERY tiny amount of mass per particle, many times less than that of an electron. These things were all around us, and we never realized it, as they showed almost no interaction with their surroundings. It is estimated that a neutrino could pass through many light-years of concrete before being brought to a stop.

We had to construct a massive underwater particle-collecting tank and have it operate for many years only to identify half a dozen Tau Neutrinos, which are apparantly all around us in an uncountable number.

Particles like neutrinos, and yet others we haven't detected, could add up in a big way considering the size of the universe, making large-scale effects that we wouldn't predict with our laws of gravity.

[Gleeok]

That's ridiculous, everyone knows that Dark matter is the excrement of the Nibblonians, and that each pound weighs over 10,000 pounds. What do you think aliens use as starship fuel when they travel to Earth so they can ubduct imbred hillbilies for anal experimentation? Hmmm?

[mrz84]

OK. I like Gleeok's idea of Dark Matter better than that of the scientists. It's funnier. :kitty: On a more serious note, what I've heard about from a magazine I read at the library because I was board is that is some sorta particle that counters regular matter or whatever and that it had something to do with the creation of our universe. Meh. I can't remember even half of the atricle I read. It was back in May I think. Meh.

[{DSG}DarkRaven]

That's ridiculous, everyone knows that Dark matter is the excrement of the Nibblonians, and that each pound weighs over 10,000 pounds. What do you think aliens use as starship fuel when they travel to Earth so they can ubduct imbred hillbilies for anal experimentation? Hmmm?


OK. I like Gleeok's idea of Dark Matter better than that of the scientists. It's funnier.

That's because he stole it from Matt Groening (http://www.imdb.com/title/tt0149460/).


Astrophysics is a complicated subject that, admittedly, I haven't read up on much lately. But as has been explained in long form during this thead, basically, Dark Matter is a product of our own ignorance. It's something that we think exists because it theoretically explains what we don't currently know.

[Prrkitty]

I found this article http://hubblesite.org/newscenter/archive/releases/1996/29/astrofile/ when I put into google (dark matter building block).

And there they go again talking one of the 3 versions of dark matter they think exists... this time it's cold dark matter.

It just boggles my mind that the scientists don't know what it is... but they've identified 3 versions of this item they don't know <giggle>.

It's just very interesting to me... much as I know ahead of time that it's WAYYY over my head (especially since those that have SERIOUS degrees in science can't understand it either).

[AtmaWeapon]

The current models of astrophysics weren't really working when applied to observed universal movement. "I don't know" doesn't make a very good paper in the journals, and neither does "God made it that way", so people tossed ideas around and it just so happens that "dark matter made it that way" works.

It's also really convenient when the substance that makes your theory work includes the property "impossible to detect"; it reminds me of the aether that the Michelson-Morley experiment (http://en.wikipedia.org/wiki/Michelson-Morley_experiment) accidentally disproved or the possibility of other beings, divine or simply otherworldly, that we spend so much time arguing about.

That's actually a particularly sarcastic observation though because there is very little doubt in my mind that dark matter exists because in general this many scientists don't get excited about something unless there is compelling reason to believe it. Honestly it's not uncommon for a great discovery to come about from a random guess that was then verified as the right answer, in fact I'd wager it's actually easier to guess correctly than to prove your guess is correct. Heck it doesn't even have to be all formal, Steven Kistler accidentally invented Aerogel (http://en.wikipedia.org/wiki/Aerogel) on a bet with a friend, and I swear at one point I read a direct quote from him that suggested weed was involved :cool:

So basically I'm kicking back and letting the science guys figure this all out and when they do I'll be glad to hear their explanation. At this point I'm pretty sure they are on to something but I still chuckle at the notion that there's something oddly familiar about seeking a force that is impossible to detect yet holds great influence over cosmic events...

(of course the difference is the existence of dark matter is an actual scientific concept that we will conceivably one day be able to prove or disprove so it's not exactly a wasted effort to devote research into it)

[Dechipher]

Isn't Jesus Dark Matter?

[AtmaWeapon]

Isn't Jesus Dark Matter?A similar joke got a chuckle out of my Physics teacher. He was pretty informal and put up with a lot, and had just spent a lot of time discussing the background for why dark matter had to exist but hadn't introduced dark matter itself. He got to the point where he was discussing what percentage of the universe must be comprised of matter, then asked what we thought the rest should be.

I couldn't resist and ventured "God" as a guess, and it was well-received. I tended to attempt (and fail) to use "God made it that way" as a sarcastic answer to difficult questions and it was usually good for a laugh.

I should have put it for the answer to some exam questions; the results would have been the same :*(