4D dark matter

[El_Machinae]

So, this is a 2D picture, but it represents a 3D image. Few people have trouble imagining the 3D picture it represents (my apologies to those who cannot).

But it's a 3D snapshot of dark matter; but this dark matter image represents data from different time periods. The left-side is 'now' and the right side is 'way back when'. It's in essence, a blurred photo of something moving.

It's a 2D picture of a 3D snapshot representing a 4D image.

I just thought it was cool that we're learning more and more about dark matter; in a decade or so, I can attend a couple-day seminar, and learn (easily) what's taking people decades to put together.

http://www.msnbc.msn.com/id/16515562/

This illustration shows the three-dimensional distribution of dark matter in a patch of the universe, going back from a nearby region in recent time (on the left) to a distant region about 6.5 billion years ago (on the right). The chart indicates that the distribution of mass has become increasingly clumpy.
...
Just collecting the data required nearly 1,000 hours of observations using the Hubble Space Telescope's best camera, representing 10 percent of the past two years' available observing time.

 

[Abaddon]

Bought New Scientist the other day, as wll as in independant.. had interesting articles about this.

 

[Brighteye]

but it's not representing a conventional 3D image if right to left is representing time rather than space. Therefore it's a 2D image representing a 3D image that represents a different 3 dimensions.

 

[Urederra]

So, what does it mean? Dark matter interacts with itself forming clusters, like stars or planets? what force makes it form clusters over time? some sort of gravity? same gravity as the one that forms planets and stars or other type of force?

 

[El_Machinae]

Brighteye, it's a 3D image of what we see today, but we have to keep in mind that everything far away is actually much older than it is now.

Urederra: I think it's just good 'ol common gravity that causes it to clump. I might be off my rocker, but some people might think that 'regular' matter clumps more easily (density?) and then attracts the dark matter

 

[Golden Touch]

dark matter is possibly the stuff that holds the rest of the universe together. you canny see it, only judge the shape etc by the impact is has on visible things. intesting stuff! was in new scientist, trhough admittedly I did skim read it a wee bit. Revising for chemistry finals is bad enough!

 

[WerBackIII]

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This^ is something like a wormhole. Scientific thing that it's possible:
We're are living into another Dimension. 4D. Wormholes, get it?

 

[Sidhe]

There's a bit of an argument at the moment between the MOND(Modified Newtonian Dynamics) It could be that dark matter isn't the answer, however this said I'm not banking on MOND panning out.

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

Interesting picture, most people can't imagine objects in 3D let alone 4.

Here's a 4 D rubiks cube

http://www.plunk.org/~hatch/MagicCube4dApplet/

 

[Swedishguy]

I have a bit trouble looking at that picture, yes.

It might have been Internet slang for 'for the dark matter'.

 

[Eran of Arcadia]

Yeah, unless it is animated it is 3D, time replacing one of the spatial dimensions.

 

[Valka D'Ur]

I don't know if this is a stupid question or not (physics isn't my strong point), but is it possible for dark matter to become any other kind of matter? Can it change its form or properties?

And if it's so clumpy, can it be "unclumped"? The best analogy I can think of right now is when you have some kinds of cooking ingredients like brown sugar or rice that tend to become clumpy over time, but you can unclump them to make them usable.

 

[Sidhe]

Yeah, unless it is animated it is 3D, time replacing one of the spatial dimensions.

You can represent time on a graph or picture with 3 spacial dimensions (x,y,z) and one time(imaginary axis) Using Imaginary numbers, to represent time. Time however decreases with any movement in the other axis(time dilation)

Of course animation is the easier method.

The problem with diagrams like this are they break down in any but simple non varying speed diagrams because of the nature of gravity and it's bending of space time.

It is very difficult to conceptualise 4D, because we cannot actually see it as such. Imagine a 2D being trying to comprehend the 3rd dimension and you'll see what I mean.

 

[Elrohir]

I have a question about Dark Matter that's probably really stupid, but I'll ask it anyway: If there's so much of it out there, why don't we see things colliding with it? A moon suddenly changing course, or an asteroid breaking apart when it hasn't hit anything that we can see, that sort of thing. Could spaceships in the future face the problem of accidentally colliding with large masses of dark matter because they can't detect it?

 

[Sidhe]

I don't know if this is a stupid question or not (physics isn't my strong point), but is it possible for dark matter to become any other kind of matter? Can it change its form or properties?

And if it's so clumpy, can it be "unclumped"? The best analogy I can think of right now is when you have some kinds of cooking ingredients like brown sugar or rice that tend to become clumpy over time, but you can unclump them to make them usable.

No one knows, by it's nature it is invisible to methods of viewing it, but WIMPS(Weak Interacting Massive Particles) Such as Neutrinos, because they only interact through the weak force and gravity and not through electromagnetism they can't be seen. And MACHOS have been suggested, large clouds of gas invisible to telescopes and also weakly interacting.

Of course dark matter is only 22% of matter in the universe and ordinary matter about 4%, with the rest being made up of dark energy 74%.

The non visible nature of this matter makes MOND a fairly popular alternative, this suggests that at a distance the force of gravity may become stronger, but it's also plagued with having little to support it, at the moment the dark matter has some inferred evidence with photos of colliding galaxies, but to be honest neither is really that strongly supported by evidence atm.

 

[Brighteye]

I have a question about Dark Matter that's probably really stupid, but I'll ask it anyway: If there's so much of it out there, why don't we see things colliding with it? A moon suddenly changing course, or an asteroid breaking apart when it hasn't hit anything that we can see, that sort of thing. Could spaceships in the future face the problem of accidentally colliding with large masses of dark matter because they can't detect it?

I believe that dark matter has as one of its properties that it does not interact with real matter except through gravity. We don't see sudden changes of course because dark matter is collected in such large clumps that they're galazy-size, and therefore the effect is not a sudden one.

 

[Elrohir]

I believe that dark matter has as one of its properties that it does not interact with real matter except through gravity. We don't see sudden changes of course because dark matter is collected in such large clumps that they're galazy-size, and therefore the effect is not a sudden one.

How can it not interact with regular matter? It's made up of physical particles, correct? Then why can't those physical particles hit other particles from regular matter? The whole thing sounds really weird.

 

[Godwynn]

I found this nice 4d animation on wiki.

 

[Sidhe]

I've seen that before, it's excellent I tried looking for it earlier but couldn't find it, seeing in 4 dimensions would send you nuts.

Erin if the interaction isn't large, basically it's hard to determine if it's dark matter or something else. As Brighteye says the only time we've inferred it so far is by massive collisions of matter, and then only in the last few months. There was a thread about it I'll try and find it.

http://forums.civfanatics.com/showthread.php?t=183311&highlight=Dark+matter

 

[Unser Giftzwerg]

Neat stuff! Thanks for all the various links ... and that cool rotating cage thingie.

 

[CoolioVonHoolio]

Ive always been very interested in this sort of stuff but never fully understood it... like.. what the freak is 4 dimensional.. and how is that even possible??