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Dark Flow
Posted: Sat Oct 31, 2009 9:46 am
by The Code
Hi folks
Somebody else pointed this out to me.
http://www.space.com/scienceastronomy/0 ... flows.html
Is the bubble about t
How can something be on
Has the b
Mark
- Is the Bubble about to Burst? Another baffling cosmic puzzle has been discovered.
How can something be on the out side of our universe, be pulling things with-in?
Has the Big Bang, Just got more complicated?
Re: Dark Flow
Posted: Sat Oct 31, 2009 10:20 am
by makc
mark swain wrote:How can something be on the out side of our universe pulling things with-in?
I'm with mark here, being able to see effects of things outside the horizon means causality violation.
Re: Dark Flow
Posted: Sat Oct 31, 2009 2:19 pm
by bystander
mark swain wrote:How can something be on the out side of our universe pulling things with-in?
makc wrote:I'm with mark here, being able to see effects of things outside the horizon means causality violation.
Just because objects are outside our observable universe doesn't mean those objects can't affect objects within our viewing area, does it? Why would that be a causality violation?
Re: Dark Flow
Posted: Sat Oct 31, 2009 4:30 pm
by Chris Peterson
makc wrote:mark swain wrote:How can something be on the out side of our universe pulling things with-in?
I'm with mark here, being able to see effects of things outside the horizon means causality violation.
Not exactly. We can be seeing
past effects of something which is
now outside our horizon; that doesn't violate causality. It is rather certain that we were affected in the past by energy and matter which is now outside the observable Universe.
Re: Dark Flow
Posted: Sat Oct 31, 2009 4:40 pm
by Chris Peterson
mark swain wrote:How can something be on the out side of our universe pulling things with-in?
First of all, that is only one suggested explanation. It is far from certain.
Second, you should be more careful in your choice of words. "Our universe" should be "the observable Universe", and you need to consider that every point in the Universe has its own observable universe. So something outside
our observable universe can be inside the observable universe of something we observe far away. And those distant objects will have had a history of interaction with parts of the Universe that our outside our horizon.
In fact, it doesn't seem remarkable to me at all that we should see these kinds of fossil motion, given the assumption that the Universe is much larger than the observable Universe.
Re: Dark Flow
Posted: Sat Oct 31, 2009 7:02 pm
by bystander
![Image](http://imgs.xkcd.com/comics/dark_flow.png)
xkcd.com - A WebComic - Dark Flow
Scientists Detect Cosmic 'Dark Flow' Across Billions of Light Years
Goddard Space Flight Center - Press Release 08-83 - 2008 Oct 23
It seems to me to be somewhat analogous to black holes. While we can't see past the event horizon of the black hole, we can directly observe the effects of the black hole on the surrounding space. It's those effects that allow us to determine the properties of the black hole.
It also seems similar to the
Great Attractor
Re: Dark Flow
Posted: Sat Oct 31, 2009 7:23 pm
by The Code
What can pull, 1 billion light years from where it is located. 1000's of galaxies to a speed of 2 million mph?
I admit, i am no mathematician but even i can tell what ever this baby is, its going to break all the rules.
: Quote
''last year. Dark flow joins other cosmological mysteries, including dark matter and dark energy, none of which are easily explained by Einstein’s general theory of relativity, our current best theory of how gravity and the universe itself work. Solving even one of these riddles could turn physics on its head''.
''They can’t see anything that would cause this bulk motion, so it may suggest that there is a very massive structure lurking beyond the edge of the visible universe pulling the galaxies toward it with its gravity''.
They also said, there is nothing like it it the known visible universe that could replicate it. I assume they also include an 18 billion solar mass black hole that we all know about.
http://www.popsci.com/military-aviation ... w-revealed
Chris Peterson wrote:Second, you should be more careful in your choice of words. "Our universe" should be "the observable Universe", and you need to consider that every point in the Universe has its own observable universe. So something outside our observable universe can be inside the observable universe of something we observe far away. And those distant objects will have had a history of interaction with parts of the Universe that our outside our horizon.
agreed, but we only have 13.7 billion years. we running out of time Chris. and if this object is 70 billion solar masses we may need to find some ''time'' from somewhere.
![Smile :)](./images/smilies/icon_smile.gif)
Re: Dark Flow
Posted: Sat Oct 31, 2009 8:35 pm
by Chris Peterson
mark swain wrote:agreed, but we only have 13.7 billion years. we running out of time Chris. and if this object is 70 billion solar masses we may need to find some ''time'' from somewhere. :)
Keep in mind that large masses rarely suck things into them. Other masses tend to orbit around them, and I see no reason to think this would be any different. It is entirely likely that we would orbit harmlessly forever around a 70 billion solar mass structure.
Re: Dark Flow
Posted: Sat Oct 31, 2009 9:05 pm
by The Code
Chris Peterson wrote:Keep in mind that large masses rarely suck things into them.
Large masses got large in a undisclosed time scale . and are large for a reason.
Chris Peterson wrote:Other masses tend to orbit around them
Space time is curved, due large masses. It also bends light.
Chris Peterson wrote:and I see no reason to think this would be any different.
But maybe a slight difference. Our planet is a bit of dust.
Chris Peterson wrote:It is entirely likely that we would orbit harmlessly forever around a 70 billion solar mass structure.
Black holes and all larger bodies consume there food through a straw. They strip them particle by particle. and they decide via mass, what distance.
Thanks for your input Chris.
Well I,ll leave you to it then, I,m off .
Re: Dark Flow
Posted: Sat Oct 31, 2009 9:51 pm
by canuck100
The Milky Way is moving at 630 km/s relative to the local Hubble flow, according to Wikipedia which is 1.4 million miles per hour.
Perhaps this puts the 2 million miles per hour into a different context.
Also, this story as reported on a NASA web site at
http://www.nasa.gov/centers/goddard/new ... _flow.html states that
"The clusters show a small but measurable velocity that is independent of the universe's expansion and does not change as distances increase," says lead researcher Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md.
Yes, they quote the 2 million miles per hour number but they themselves say that this velocity includes only a "small but measurable" additional, unexplained velocity.
And as Chris says, it's one set of observations, one study. I think that this is a bit of a leap as well
What's more, this motion is constant out to at least a billion light-years. "Because the dark flow already extends so far, it likely extends across the visible universe," Kashlinsky says.
To say that being constant over 1 billion light years when the observable universe encompasses 6 billion light years seems like a lot of enthusiasm.
Who know what else they will find?
They discovered "The Great Attractor" in the 1970s and then in 2005 they reported that it had 1/10 of its originally estimated mass. If I remember correctly, they think that this great attractor is a very large, old galaxy cluster. Perhaps we have an even bigger, even older one here, who knows?
Re: Dark Flow
Posted: Sat Oct 31, 2009 10:27 pm
by The Code
canuck100 wrote:To say that being constant over 1 billion light years when the observable universe encompasses 6 billion light years seems like a lot of enthusiasm.
1 Sixth of what we can see, Mind blowing. thanks canuck100
Mark
Re: Dark Flow
Posted: Sun Nov 01, 2009 5:46 am
by harry
Chris said
Keep in mind that large masses rarely suck things into them. Other masses tend to orbit around them, and I see no reason to think this would be any different. It is entirely likely that we would orbit harmlessly forever around a 70 billion solar mass structure.
Reading this tells how little you know about Cosmology, Astrophysics and the evolution of stars and galaxies.
Where do you get your information from?
Re: Dark Flow
Posted: Sun Nov 01, 2009 10:17 am
by canuck100
mark swain wrote:canuck100 wrote:To say that being constant over 1 billion light years when the observable universe encompasses 6 billion light years seems like a lot of enthusiasm.
1 Sixth of what we can see, Mind blowing. thanks canuck100
Mark
Sorry mistake - typo i was in a rush. The universe is not 6 billion LY. That was how far away their galaxies were.
The observable universe is 13.7 billion light years in radius so 27+ billion LY in diameter . . . which is not accurate either.
When we view the outer edge, we are seeing it as it was 13 billion years ago . . . but they have been moving away from us all that time . . . so, according to the well sourced Wikipedia article (I checked)
Re: Dark Flow
Posted: Sun Nov 01, 2009 2:00 pm
by Chris Peterson
harry wrote:Chris said
Keep in mind that large masses rarely suck things into them. Other masses tend to orbit around them, and I see no reason to think this would be any different. It is entirely likely that we would orbit harmlessly forever around a 70 billion solar mass structure.
Reading this tells how little you know about Cosmology, Astrophysics and the evolution of stars and galaxies.
Where do you get your information from?
I get my information from scientific sources, not from pulp science fiction, as you apparently do. Collisions between massive objects are exceedingly rare in this Universe. The behavior of massive objects is to orbit their center of mass; they do not fly into each other. Thus, from planets to black holes to galaxies, none of these objects suck distant things into them. Actual collisions only happen in the very unusual cases where the objects are moving exactly towards each other.
Re: Dark Flow
Posted: Mon Nov 02, 2009 5:40 am
by harry
G'day Chris
What ever you say, the Universe will be there next week.
Do a bit of reading and ask around about your logic.
You will find that you are wrong.
Gravity is one of your problems.
Re: Dark Flow
Posted: Mon Nov 02, 2009 5:44 am
by Chris Peterson
harry wrote:What ever you say, the Universe will be there next week.
Not if you're right! We'll all die very soon as the Earth is sucked into the Sun by its massive gravity, and then the Sun is sucked into the massive black hole at the center of the Milky Way, and then the galaxies of the local group collide... soon the Universe will be reduced to a single black hole. I guess we're doomed by this odd sort of gravity you imagine.
Re: Dark Flow
Posted: Mon Nov 02, 2009 6:55 am
by harry
G'day Chris
Mate, please do a bit of research.
Our solar system as every other part in the spirals of the MW are moving towards the centre.
Do you need information to confirm such simple information.
If you did a bit of galaxy evolution you would understand.
Re: Dark Flow
Posted: Mon Nov 02, 2009 9:05 am
by makc
holy crap so many responses, where do I start...
Just because objects are outside our observable universe doesn't mean those objects can't affect objects within our viewing area, does it? Why would that be a causality violation?
They can affect, but we cannot see it. If we could, it means we received information from them faster than light.
Not exactly. We can be seeing past effects of something which is now outside our horizon; that doesn't violate causality. It is rather certain that we were affected in the past by energy and matter which is now outside the observable Universe.
I remember you, Chris, saying at this forum that nothing ever crossed the horizon from here to there; it appears that you have now reversed your position?
still, if they ever were here anywhere within 13bn years, should not we still see light coming from them?
Re: Dark Flow
Posted: Mon Nov 02, 2009 9:42 am
by harry
G'day makc
Holy crap is a good word(s)
Re: Dark Flow
Posted: Mon Nov 02, 2009 2:33 pm
by Chris Peterson
harry wrote:Our solar system as every other part in the spirals of the MW are moving towards the centre.
And the Earth is always falling in towards the Sun. But we also have lateral motion, which is why we never hit it. The Solar System is
not moving towards the center of the Milky Way in any sense other than the fact that we are in orbit. It's a complex orbit, that looks somewhat scalloped, but we are not going to ever collide with the center of the Milky Way. Likewise for the rest of the stars in our galaxy (or any other).
And the fact that parts of our observable universe are moving in some common pattern does not mean they are going to collide with anything anywhere (even assuming that common motion is caused by a large attractive mass somewhere).
Re: Dark Flow
Posted: Mon Nov 02, 2009 3:14 pm
by The Code
makc wrote:still, if they ever were here anywhere within 13bn years, should not we still see light coming from them?
Thanks makc
13.7 is the End of the line. ding ding, Folks. nothing to see here. er How did that huge thing get there?
Great big things do not get made in a day.
And then there is the 1bn light years flow.
Mark
Re: Dark Flow
Posted: Mon Nov 02, 2009 3:32 pm
by Chris Peterson
makc wrote:I remember you, Chris, saying at this forum that nothing ever crossed the horizon from here to there; it appears that you have now reversed your position?
still, if they ever were here anywhere within 13bn years, should not we still see light coming from them?
I don't recall saying exactly that, although if I did it might have been in a slightly different context. It is believed that the Universe underwent early, rapid expansion. This would have stretched regions that had been causal into distances that no longer are. So stuff that we might have seen 13 billion years ago could easily be beyond the observable Universe now- and presumably actually is.
Re: Dark Flow
Posted: Mon Nov 02, 2009 4:22 pm
by The Code
Chris Peterson wrote:This would have stretched regions that had been causal into distances that no longer are. So stuff that we might have seen 13 billion years ago could easily be beyond the observable Universe now- and presumably actually is.
What?
The universe got stretched?
13.4 is as far as we can see. There should be nothing past this marker. but we now know there is. and its huge. how did it get past 13.4 billion years ago? It should not be there.
Mark Swain.
Re: Dark Flow
Posted: Mon Nov 02, 2009 4:38 pm
by Doum
mark swain wrote:Chris Peterson wrote:This would have stretched regions that had been causal into distances that no longer are. So stuff that we might have seen 13 billion years ago could easily be beyond the observable Universe now- and presumably actually is.
What?
The universe got stretched?
13.4 is as far as we can see. There should be nothing past this marker. but we now know there is. and its huge. how did it get past 13.4 billion years ago? It should not be there.
Mark Swain.
And that question was answer in an earlyer post:
Chris Peterson wrote:makc wrote:mark swain wrote:How can something be on the out side of our universe pulling things with-in?
I'm with mark here, being able to see effects of things outside the horizon means causality violation.
Not exactly.
We can be seeing past effects of something which is now outside our horizon; that doesn't violate causality. It is rather certain that we were affected in the past by energy and matter which is now outside the observable Universe.
No stretch there
Re: Dark Flow
Posted: Mon Nov 02, 2009 5:52 pm
by The Code
Doum wrote:And that question was answer in an earlyer post:
No . The visible universe is 13.4 billion light years . And according to the big bang, There is nothing past that time.
Except, What ever this huge thing is, we can not see. Matter and huge black holes do not jump behind the horizon faster than light speed.
Mark