Could a single dark matter particle be light-years wide?

[Dogmudgeon]

This is truly weird.

http://www.sciam.com/print_version.cfm?articleID=00084A33-908A-111B-87CB83414B7F0000

In 1996 Discover magazine ran an April Fools' story about giant particles called "bigons" that could be responsible for all sorts of inexplicable phenomena. Now, in a case of life imitating art, some physicists are proposing that the universe's mysterious dark matter consists of great big particles, light-years or more across. Amid the jostling of these titanic particles, ordinary matter ekes out its existence like shrews scurrying about the feet of the dinosaurs.

This idea arose to explain a puzzling fact about dark matter: although it clumps on the vastest scales, creating bodies such as galaxy clusters, it seems to resist clumping on smaller scales. Astronomers see far fewer small galaxies and subgalactic gas clouds than a simple extrapolation from clusters would imply. Accordingly, many have suggested that the particles that make up dark matter interact with one another like molecules in a gas, generating a pressure that counterbalances the force of gravity.

The big-particle hypothesis takes another approach. Instead of adding a new property to the dark particles, it exploits the inherent tendency of any quantum particle to resist confinement. If you squeeze one, you reduce the uncertainty of its position but increase the uncertainty of its momentum. In effect, squeezing increases the particle's velocity, generating a pressure that counteracts the force you apply. Quantum claustrophobia becomes important over distances comparable to the particle's equivalent wavelength. Fighting gravitational clumping would take a wavelength of a few dozen light-years.

Such a particle would have a very low mass, "about 10 E-23 electron volts (compared with the proton's mass of 10 E+9 electron volts)" (exponential notation edit by bkl)

That ... that's homeopathic!

But try letting a pill that size dissolve under your tongue, eh? :)

--bkl

[bemildred]

1. Saw that, thought it was wierd too.

But hey, this is quantum mechanics, it's all wierd.

[Swede]

2. It's all counter-intuitive.

It seems so unlikely,yet the quantum theory works.

[wurzel]

3. Is this saying galaxies are in some kind of Dark Matter particle?

And, like everything else there is a limit to how small something can get. So a Galaxy cannot be any smaller than the limit of a dark matter "particle"?

[bemildred]

4. Nope. Dark Matter(tm) is "dark", can't see it.

But is has gravitational effects, so you can see the
results of it's presence in the "clumping" of visible
matter. I wonder what the mass of such dark matter
particles would be? Seemingly large.

Edit: says in the article, mass is very small, because of
the long wavelength, mea culpa.

[wurzel]

5. You mean if galaxies were "inside " a dark matter "particle"

or "bubble", we wouldn't be able to see the galaxy?

[bemildred]

6. A wavelength of a "few-dozen light-years" would not seem

big enough for a galazy to fit in, and in any case these
hypothetical particles would not block light, and the assumption
would seem to be that things interpenetrate each other, like
light going through glass for instance (sort of). A real physicist,
which I am not, might have more to say, but might be even harder
to understand.

[wurzel]

7. So it becomes a matter of "resolution"?

No pun intended.

[bemildred]

8. Yes, that seems right.

You could say they are using a quantum effect to explain
the apparent "resolution" of the clumpiness of matter in
space by positing a particle of the right sort to explain
it. (Or I could be full of it, but thats what it sounds
like to me.)

[wurzel]

9. It kinda makes sense though. In a way. Sort of. Ya know what I mean?