New Proof Unknown "Structures" Tug at Our Universe

National Geographic ^ | 22 March 2010 | NatGeo

[Feline_AIDS]

"Dark flow" is no fluke, suggests a new study that strengthens the case for unknown, unseen "structures" lurking on the outskirts of creation.

In 2008 scientists reported the discovery of hundreds of galaxy clusters streaming in the same direction at more than 2.2 million miles (3.6 million kilometers) an hour.

This mysterious motion can't be explained by current models for distribution of mass in the universe. So the researchers made the controversial suggestion that the clusters are being tugged on by the gravity of matter outside the known universe.

Now the same team has found that the dark flow extends even deeper into the universe than previously reported: out to at least 2.5 billion light-years from Earth.

[brytlea]

Fortunately, most of the time they'll accept whatever B.S. answer we give. When it's all said and done, we look like geniuses to them. Suckers! :-)

Is this an exact quote from Pelosi?

[Magnum44]

No, I dont think so, but the state where the universe was all energy with no mass was only the tiniest fraction of a second. As soon as it converts to mass its slowing down very rapidly. Red shift today is a small fraction of speed of light. So very early on in the 13 or so billion years since the big bang, I suppose you could have relative velocities in opposite directions that exceed light, if you ignore the relationships with gravity and time that Einstein tells us need to be included.

Einsteins theory of space-time would say that the traveler on a ship moving at the speed of light outward in the universe would still see the light moving away on the other side of the universe doing so at the speed of light....yeah its strange. I think its because the travelers time is now infinitely slow.

I took my cosmology (yes, thats what the study of the origins of the universe is called...its not about cosmetics) classes many years ago, and its not the field I work in today, so if someone more experienced with Einsteins theory can elaborate, I am happy to be refreshed. :)

[SunkenCiv]

Thanks Kevmo! This is pingworthy on another list as well.

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[SunkenCiv]

Thanks Kevmo!

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[bert]

.......So the researchers made the controversial suggestion that the clusters are being tugged on by the gravity of matter outside the known universe. .......

I concur, that is the most likely possibility.

The smoking gun that might propel them outward is missing.

[stripes1776]

Gravity is the weakest force in nature and does not control the cosmos, period.

It is true that gravity is a very week force. But it does becomes important when there is a large mass.

The gravity between atoms is insignificant because the mass is so mall. Between atoms electricity is a greater force, the source of chemical reactions. And at the subatomic level, gravity again is very insignificant because the mass is so small. Between subatomic particles, nuclear forces are extremely powerful, but they operate over very short distances.

But when there is a large mass like the sun, then gravity becomes a significant force in the surrounding space. And the gravitational force operates over very large distances. Over those large distances, electrical and nuclear forces are insignificant.

[stripes1776]

Einsteins theory of space-time would say that the traveler on a ship moving at the speed of light outward in the universe would still see the light moving away on the other side of the universe doing so at the speed of light....yeah its strange. I think its because the travelers time is now infinitely slow.

In Newtonian physics, space and time are constant, but the speed of light is relative. So OneWindgedShark, when you added the two speeds of light, you were using Newtonian physics.

But from experiments in measuring light, we know that the speed of light is constant for all observers, regardless of their frame of reference or the source of the light. So Einstein in his theory of relativity simply stated the results of observation: space and time are relative, but the speed of light is constant. So Magnum44, are are mostly correct, and time does slow as you approach the speed of light. But infinite limits can only be approached; you can never get there.

[OneWingedShark]

>In Newtonian physics, space and time are constant, but the speed of light is relative. So OneWindgedShark, when you added the two speeds of light, you were using Newtonian physics.
>
>But from experiments in measuring light, we know that the speed of light is constant for all observers, regardless of their frame of reference or the source of the light.

Yes, and if you add two constants together you get twice that constant. You HAVE to do this if you are measuring the expansion (either from the ‘center’, or ‘outside’) of that said universe in that said dimension. At no point is there ever any object in the model which exceeds the speed of light, in fact because the only objects ARE photons the only objects ARE traveling at the speed of light; the expansion is a concept, not an object.

>So Einstein in his theory of relativity simply stated the results of observation: space and time are relative, but the speed of light is constant. So Magnum44, are are mostly correct, and time does slow as you approach the speed of light. But infinite limits can only be approached; you can never get there.

What of light? That is, by definition, traveling at light-speed. I fail to see how considering light itself can invoke slower-than-light arguments/rules.

[brivette]

I’ll ask my daughter-in-law, she has a masters degree in astro-physics.

[wendy1946]

Gravity is only meaningful in closely confined systems like our own solar system or like one of us walking around on the surface of a planet. There isn’t any way gravity could hold two stars like our sun and AC together from 4 light years distance.

[stripes1776]

Gravity is only meaningful in closely confined systems like our own solar system or like one of us walking around on the surface of a planet. There isn’t any way gravity could hold two stars like our sun and AC together from 4 light years distance.

The rate of velocity at which the observable universe is expanding is increasing rather than decreasing. That rate should be decreasing, but it is not. So how would you explain the increase in the rate of acceleration?

[Rebelbase]

"Must...keep...this..'structure' from poking the universe"

[oldvike]

Please do. And then ask her to explain it to me in simple terms with lots of pictures. :0)

[onedoug]

Theoretical physics has totally gone to hell.

It seems that way sometimes. But theory must remain connected to what is more firmly established, even if it often seems wild. In other words, M-Theory, for example, connects to General Relativity in a very natural way at low energies. But M-Theory's dynamics would only be manifest at energies much higher than anything we can perhaps ever achieve. But it's a very beautiful theory. And beauty is one of the central aspects that it seems God structured the universe around.

[Magnum44]

I think the original question was how fast the universe, ie some mass objects can expand, but you postulated:

... if you add two constants together you get twice that constant....

and the the problem is that even if you are moving at near the speed of light away from the opposite direction of light, when you measure it, it will still be the constant. If you are standing still it is still the constant. So while it seems that you could add the two opposite velocity vectors, you cant, because when you start moving, the speed of light remains constant in all frames.

Again this is my best understanding of how space-time works.

[wendy1946]

There are two elephant-in-the-living-room kinds of problems with what Einstein had to say about gravity.

One is that gravity has been known for centuries to propagate instantaneously to within our ability to measure while Einstein claimed that information cannot be transmitted faster than C.

Two is that you cannot start with Einstein's claim that gravity amounts to any sort of a four dimensional differential geometry kind of thing and believe it ever could have changed very much near the surface of our own planet. Yet it is an easy demonstration that it has, and that the super animals of past ages count not live in our present world, in fact that they would be immediately crushed by their own weight in our present world.

[editor-surveyor]

"Two is that you cannot start with Einstein's claim that gravity amounts to any sort of a four dimensional differential geometry kind of thing and believe it ever could have changed very much near the surface of our own planet. Yet it is an easy demonstration that it has, and that the super animals of past ages count not live in our present world, in fact that they would be immediately crushed by their own weight in our present world."

What Sci-Fi pulp rag did you swipe that bit of absurdity out of?
.

[Magnum44]

I have no idea what you’re talking about...and I am certainly not going to argue against Einstein...LOL

[Magnum44]

...and by the way...gravity does not propogate

[OneWingedShark]

>and the the problem is that even if you are moving at near the speed of light away from the opposite direction of light, when you measure it, it will still be the constant. If you are standing still it is still the constant. So while it seems that you could add the two opposite velocity vectors, you cant, because when you start moving, the speed of light remains constant in all frames.

...*sigh* by that logic E = mc^2 shouldn’t EVER work because there is no way to alter/manipulate [anything involving] a “c term” so that you can get a “c squared.”