Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: Joe L. Ogan on 18/09/2010 15:25:00

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: Joe L. Ogan on 18/09/2010 15:25:00

Dark Flow is a new topic to me.  I had never heard the title until recently.  It is my understanding that scientists are considering this topic and whether or not it has anything to do with the speed of expanding of the universe.  It sounds a lot like Dark Energy to me but that may be because my knowledge is so limited on the subject.  Thanks for comments.  Joe L. Ogan

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: Farsight on 18/09/2010 15:32:57

I have, see http://physicsworld.com/cws/article/news/41984 for example. I wasn't too impressed with the bubbles/cosmic foam/multiverse attention-grabbing presentation. IMHO it's more like an dark-energy anisotropy causing a slightly uneven expansion of the universe, or even something very much simpler.

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: JP on 19/09/2010 03:02:16

All these "dark XXXX" things are a bit confusing.  The word dark is just a place holder to say we can't see what's causing some effect to happen.  Dark flow seems to indicate that somewhere outside of our observable universe, there's a lot of mass tugging at things and causing them to flow in that direction.  This would be new because it's a usual assumption of cosmology that things are pretty well evenly distributed through the universe on a large scale.  Dark flow would seem to indicate this isn't the case.

Dark energy is totally different--the universe seems to be accelerating in its expansion in a way that's not explained by current theories.  The guess is that there's a problem with general relativity or that there's some "stuff" (dark energy) distributed pretty evenly throughout the universe that's causing this to happen.

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: CPT ArkAngel on 19/09/2010 04:03:53

It could be antimatter...

searching about matter antimatter asymmetry, i found that no one can be sure if antimatter has a positive or negative gravitation field... very interesting...

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

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: Geezer on 19/09/2010 06:50:25

Quote from: CPT ArkAngel on 19/09/2010 04:03:53

It could be antimatter...

searching about matter antimatter asymmetry, i found that no one can be sure if antimatter has a positive or negative gravitation field... very interesting...

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

Yes, well I'm fairly sure I could use Wikipedia to prove just about anything. Perhaps you could site something with a bit more substance?

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: CPT ArkAngel on 19/09/2010 07:19:55

I have just read an article about the possibility of antimatter being the Attractor but i lost the link. I am trying to find it...

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: yor_on on 19/09/2010 08:02:14

Dark flow?

A monthly thing? Is it?
If so I've heard about it.

Beware of that subject.

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: yamo on 20/09/2010 00:51:41

It seems to me that Dark Energy, Dark Mass, etc are euphemisms for "I don't know".  They allow theories that have been disproved to survive by a Deus ex machina sleight of hand.  Likewise string theory survives exactly because it cannot be proved.

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: JP on 20/09/2010 04:34:47

Quote from: yamo on 20/09/2010 00:51:41

It seems to me that Dark Energy, Dark Mass, etc are euphemisms for "I don't know".  They allow theories that have been disproved to survive by a Deus ex machina sleight of hand.

Actually, dark energy, mass, and flow are terms for observations that aren't modeled by current theories.  That means that there's something wrong with our current understanding of the universe.  Unless these observations are wrong (and at least energy and mass are strongly supported by evidence), then some new theory is going to be needed--and as usually happens in science there will be several theories and they'll be tested against future observations.  At any rate, no one is seriously using theories that have been proven wrong against observations.  Any theory that accounts for all these dark XXXX effects will have to match previous observations as well as these new ones. 

Title: How many of you here have heard of the topic "Dark Flow?"?
Post by: yor_on on 20/09/2010 06:11:17

Joe, are you thinking of the way it seems that our 'viewable' universe moves?
Like there was some 'mystical attractor' outside our event horizon?

--->       <-----   in between those arrows are we.
What we can see are defined by how long ago since the BB happened. That as the light only can reach a certain distance per year, and that we have a 'limited' amount of time since the BB happened. So if it happened 13 years ago, the light had only had 'time' to travel 13 light years.

Doesn't mean that this is all of the universe though. We talk about an 'inflationary period' very close to the BB, when SpaceTime just 'swissshed away' faster than light, how far nobody knows. If we're referring to the same phenomena that is?

But it's kind'a weird that we then would have such an infinite mass just outside our 'sphere' of observation.. Why? Isn't the universe homogeneous? Having and getting an 'even distribution' through the inflation? Well, more or less.

Maybe it's us, attracting us, like some mirror reflection in some weird mathematical space :)