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Dark Matter's Profile Discovered?
pingbak writes "According to New Scientist, astronomers may have potentially discovered dark matter's EM profile (story). For the rest of us, this means astronomers may have just discovered all of the extra force holding the galaxy(-ies) together, which is not currently explainable though gravity and black holes at the center of universes alone. Since dark matter doesn't interact with ordinary matter, it's almost directly undetectable -- but now, physics and astronomy may just have had an awesome breakthrough. Nobel Prize material if it proves correct!"
Um... perhaps I'm very much misinformed, which is entirely possible, but the article submission makes the claim that Dark Matter doesn't interact with regular matter.
WTF? I thought the reason we're looking for Dark Matter is because the matter we *know* about doesn't add up to cause the gravetic interactions that we can observe. I thought Dark Matter was just matter we couldn't observe just yet, not some exotic "doesn't work the same as other matter" matter.
Am I totally wrong here?
"Times have not become more violent. They have just become more televised."
-Marilyn Manson
I, for one, welcome our new dark matters. Er, masters.
Previous statement makes no sense until it is explained later that they started down the course of thinking dark matter has a mass far less then previously postulated.
What they mean by "weakly interacting" is similar to how neutrinos are described - it doesn't have much of an electromagnetic impression, so it doesn't block light or smack into a detector in an earthbound observatory. Unlike neutrinos, it does posess a significant mass and is affected by gravity. And while that is "exotic", astrophysicists were only forced to consider this sort of thing when all previous efforts to explain some pretty obvious mis-matches in the numbers didn't work.
Now I'll let someone else explain about "dark energy"...
Perfectly Normal Industries
In other news, dark matter's IM profile has also been found:
Name: Matter, Dark
Nick: d4rkm4tt3r
Age: ~15 billion years
Likes: Vast emptiness of the cosmos.
Dislikes: Peeping-Tom astronomers.
Bio: I generally keep a low profile, out of sight. Maybe one day, the matter of my dreams will see me for who I really am.
Gotta love it.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
http://www.astro.queensu.ca/~dursi/dm-tutorial/dm0 .html
From the link above there is:
1. cold dark ordinary matter(baryonic)
2. Non baryonic(exotic) dark matter both hot and cold
The article seems to indicate wilp(weakly interacting light particles instead of (in addition to) wimps(weakly interacting massive particles. Wilp's are like neutrinos. We have not discovered any wimps yet.
IANAHEP, but is there anypossibility that an electron and a positron could orbit one another with a reasonably long half-life?
"Provided by the management for your protection."
The assumption that these photons have anything to do with dark matter, though, has more to do with fashion and funding than actual science. It's cool and helpful to have your new observation associated with something everybody's already keen on. What they do know, though, is that whatever's producing the photons is distributed like the galaxy's mass is, not like the visible stars are.
Some references...astronomy.net and the referred to article
http://www.arxiv.org/PS_cache/astro-ph/pdf/0309/03 09686.pdf ... this must be a draft there's a typo in their ackowledgments (I checked all the equations and they look OK though ;0)>
In the conclusions they appear to be saying that some new interaction is happening due to ('mediated by') exchange of a light gauge boson (translation: low-energy force-carrying integer-spin-particle)
Alternatively a new heavy fermion (neutrinos are fermionic, spin-1/2) mediates in the interaction: their words "could be responsible". So you might not be far off (if there second guess is correct).
Start talking Nobel prizes when CERN/Fermilab find either of these particles.
[... I've not done any particle physics for 5 years so this could be baloney.]
There are many reasons, but one which you might look at is the large amounts of radiation coming from the galactic nucleus. As you may know, electrons absorb radiation and gain energy (velocity) when they do so.
Another explanation, if you take away the radiation, would involve a huge fermi sphere of electons which would require that only very few of them are sitting in that big gravity well with no kinetic energy.
There are other reasons why electrons would be very unlikely to be found at rest at the galactic core, but I think these will do.
Daniel
Carpe Diem
And more to the point, how do they find the centers?
You just keep licking them and you eventually get to the centers.
- Hail to our fearless misleader! Fool speed ahead!
Dark Matter's profile.
There have been two leading candidates for dark matter: WIMPs and MACHOs. Each camp have had their proponents.
WIMPS: Weakly Interacting Massive Particles. Neutrinos on steriods. Since they only interact through the weak and gravitational forces, they are by definintion dark in EM. But, we haven't found any in colliders.
MACHOs: MAssive Cosmic Halo Objects. You're describing MACHOs. Ordinary, cold, dark matter. But there's probably too much of it to be this. It should have been swept up into stars.
Frankly, I think that the energy levels detected will prove to be not what we're seeking here. It's too much of a coincidence that it is the e/e-bar annilation energy. OTOH, if there were a WILP which did have such a mass, we'd probably never see it thinking we were looking at e/e-bar reactions.
I have discovered a truly marvelous sig, unfortunately the sig limit is too small to contain i
According to my friend the physicist, every point is the center, from that point's frame of reference. (I should point out, of course, that he's a relativist, rather than dealing too much with quantum scales)
-1, "1337" speak