The Great Attractor

[All Seeing Eye]

I've had a book on my shelf for quite a long time and decided to sit up in bed and read it last night because I couldn't get to sleep. There was section about something called 'The Great Attractor', it says that our entire local group of galaxies including the Virgo supercluster which our local group is connected to is falling or moving towards it.
Now it is believed that this 'Attractor' is dark matter or dark energy.

Is it possible that we aren't being pulled toward dark matter/energy but instead we're simply orbiting something else? like a black hole the size of which has never been known before?

Also apparently the Andromeda Galaxy is falling toward the Milky Way. How are people sure that Andromeda is falling toward us and not the other way around?

 

[scotthm]

apparently the Andromeda Galaxy is falling toward the Milky Way. How are people sure that Andromeda is falling toward us and not the other way around?

Because Andromeda is 'UP' in the sky, and we obviously can't be falling up.

---------------

 

[All Seeing Eye]

There is no up or down in space.

 

[Chaos Descending]

Also apparently the Andromeda Galaxy is falling toward the Milky Way.

Yes.

How are people sure that Andromeda is falling toward us and not the other way around?

There's no difference. They are the same thing.

 

[Verteron]

There is no up or down in space.

There's also no 'stopped' and 'moving' -- things only move relative to eachother. So we can say Andromeda and the Milky Way are getting closer as time goes on, but it's an invalid question to ask which of us is creeping up on the other.

I suppose you could try to measure the motion of both the galaxies relative to the Cosmic Microwave Background or the average positions/velocities of other galaxies in the local group, but honestly this kind of thing is pretty slow and practically immeasurable, the only reason we know Andromeda is approaching us is that it's blue-shifted instead of red-shifted like most objects in the universe.

 

[iguana_tonante]

I've had a book on my shelf for quite a long time and decided to sit up in bed and read it last night because I couldn't get to sleep. There was section about something called 'The Great Attractor', it says that our entire local group of galaxies including the Virgo supercluster which our local group is connected to is falling or moving towards it.
Now it is believed that this 'Attractor' is dark matter or dark energy.

Is it possible that we aren't being pulled toward dark matter/energy but instead we're simply orbiting something else? like a black hole the size of which has never been known before?

Well, technically there is little difference between a fall and an orbit: the only discriminant is the proportion between gravitational pull and tangential velocity.

The black hole explanation is unlikely: we are talking of something with the mass of a galaxy supercluster, that is mind boggling (above 10^15 solar masses). I'm too lazy to make calculations, but a black hole with such an high mass would have incredibly severe tidal effects on the surrounding matter, and its presence would have very noticeable effects on light coming from that direction.

Plus: dark energy, as we understand it now (i.e. not much, but some) does not play a role in gravitational attraction, but it's believed to explain the increase in the rate of expansion of the universe. The only link with dark matter is that they both are "dark" in the sense that they are not directly observable.

Also apparently the Andromeda Galaxy is falling toward the Milky Way. How are people sure that Andromeda is falling toward us and not the other way around?

Sorry, could not resist.

 

[Lindley]

I'm too lazy to make calculations, but a black hole with such an high mass would have incredibly severe tidal effects on the surrounding matter,

Are you sure? I was under the (admittedly ill-informed) impression that tidal effects were a bigger problem on low-mass black holes than on the really big ones. Counterintuitive, I know. Something about the event horizon being farther away from the singularity.

and its presence would have very noticeable effects on light coming from that direction.

Well, that's certainly true.

 

[iguana_tonante]

I'm too lazy to make calculations, but a black hole with such an high mass would have incredibly severe tidal effects on the surrounding matter,

Are you sure? I was under the (admittedly ill-informed) impression that tidal effects were a bigger problem on low-mass black holes than on the really big ones. Counterintuitive, I know. Something about the event horizon being farther away from the singularity.

Yeah, you are right: I checked my books and they agree with you. Tidal effects are the results of changes in attraction over distance, so the absolute value of the attraction is not really a factor. Since less massive black holes have smaller event horizons (via the Schwarzschild equation), the "spaghettification" occurs when the falling matter is still well outside it. There are other second order effects, however, like frame dragging, that should depend directly on mass.

 

[All Seeing Eye]

and its presence would have very noticeable effects on light coming from that direction.

Well, that's certainly true.

If galaxies are orbiting a blackhole larger than anything ever before discovered then the blackhole isn't in the direction of this so called great attractor, truth is there aint no great attractor and the blackhole is therefore somewhere else in the void between Galaxies and we're not looking in the right direction, infact it's probably completely unviewable.

 

[yellowdingo]

I've had a book on my shelf for quite a long time and decided to sit up in bed and read it last night because I couldn't get to sleep. There was section about something called 'The Great Attractor', it says that our entire local group of galaxies including the Virgo supercluster which our local group is connected to is falling or moving towards it.
Now it is believed that this 'Attractor' is dark matter or dark energy.

Is it possible that we aren't being pulled toward dark matter/energy but instead we're simply orbiting something else? like a black hole the size of which has never been known before?

More likely the Black hole...

The Ultimate Conclusion of String Theory is that the Universe is Debris of Change in Possibility, Time is Continuous change in Possibility, and a Singularity a point of Change in Possibility...That describes a situation where our entire Universe is debris of change in Possibility orbiting/anchored to a moment of change (a Singualrity). You will never percieve this black hole because it is outside the limits of Possibility (the Possibility our Universe makes due with). The from this conclusion being that Strings (A) collide with Mirror Strings (/A) and [cease to exist] not quite cease to exist - forming a Kobject/Singularity but leaving unconnected Debris Strings (our Universe)- while the Kobject separates into a new Possibility.

Unfortunately for all our existing Sciences and Philosophies; String Theory invalidates Religion and Evolution.

 

[iguana_tonante]

If galaxies are orbiting a blackhole larger than anything ever before discovered then the blackhole isn't in the direction of this so called great attractor, truth is there aint no great attractor and the blackhole is therefore somewhere else in the void between Galaxies and we're not looking in the right direction, infact it's probably completely unviewable.

Yes, but it still has to be somewhere. Sure, it may be in a position that it's hardly detectable (even if I think that, given the masses involved, it would be pretty bizarre), but the question is: why? You have to put yourself in a corner to justify such alignment. Why go with a weird and untestable hypothesis when you have a perfectly fine explanation as it is? I think that you are thinking too much about this so-called "Great Attractor" because it happens to have a funny name: there is nothing weird and exotic about it, it just happens to be the dynamical centre a somehow big cluster of galaxies (with its associated dark matter halo, just as any other galaxy cluster). We see a lot of them around in the sky: nothing special about it, except probably it's the nearest respect to our position.

The Ultimate Conclusion of String Theory is that the Universe is Debris of Change in Possibility, Time is Continuous change in Possibility, and a Singularity a point of Change in Possibility...That describes a situation where our entire Universe is debris of change in Possibility orbiting/anchored to a moment of change (a Singualrity). You will never percieve this black hole because it is outside the limits of Possibility (the Possibility our Universe makes due with). The from this conclusion being that Strings (A) collide with Mirror Strings (/A) and [cease to exist] not quite cease to exist - forming a Kobject/Singularity but leaving unconnected Debris Strings (our Universe)- while the Kobject separates into a new Possibility.

Unfortunately for all our existing Sciences and Philosophies; String Theory invalidates Religion and Evolution.

 

[Icemizer]

String Theory?? Bwahahahahahahaha. I sure hope someone is working on something else because thats not the answer.

 

[iguana_tonante]

String Theory?? Bwahahahahahahaha. I sure hope someone is working on something else because thats not the answer.

Uhm, why you say that? I think string theory (especially the braneworld explanation about the question why gravitation is much weaker than other forces) could be quite on the right track.

I'm not entirely convinced (and the mathematics required is entirely out of my league and just keep whooshing over my head no matter how many times I try to understand it), but I think it looks promising.

 

[farmkid]

I've had a book on my shelf for quite a long time and decided to sit up in bed and read it last night because I couldn't get to sleep. There was section about something called 'The Great Attractor', it says that our entire local group of galaxies including the Virgo supercluster which our local group is connected to is falling or moving towards it.
Now it is believed that this 'Attractor' is dark matter or dark energy.

Is it possible that we aren't being pulled toward dark matter/energy but instead we're simply orbiting something else? like a black hole the size of which has never been known before?

More likely the Black hole...

The Ultimate Conclusion of String Theory is that the Universe is Debris of Change in Possibility, Time is Continuous change in Possibility, and a Singularity a point of Change in Possibility...That describes a situation where our entire Universe is debris of change in Possibility orbiting/anchored to a moment of change (a Singualrity). You will never percieve this black hole because it is outside the limits of Possibility (the Possibility our Universe makes due with). The from this conclusion being that Strings (A) collide with Mirror Strings (/A) and [cease to exist] not quite cease to exist - forming a Kobject/Singularity but leaving unconnected Debris Strings (our Universe)- while the Kobject separates into a new Possibility.

Unfortunately for all our existing Sciences and Philosophies; String Theory invalidates Religion and Evolution.

Is this translated via Babelfish from some other language?

 

[iguana_tonante]

More likely the Black hole...

The Ultimate Conclusion of String Theory is that the Universe is Debris of Change in Possibility, Time is Continuous change in Possibility, and a Singularity a point of Change in Possibility...That describes a situation where our entire Universe is debris of change in Possibility orbiting/anchored to a moment of change (a Singualrity). You will never percieve this black hole because it is outside the limits of Possibility (the Possibility our Universe makes due with). The from this conclusion being that Strings (A) collide with Mirror Strings (/A) and [cease to exist] not quite cease to exist - forming a Kobject/Singularity but leaving unconnected Debris Strings (our Universe)- while the Kobject separates into a new Possibility.

Unfortunately for all our existing Sciences and Philosophies; String Theory invalidates Religion and Evolution.

Is this translated via Babelfish from some other language?

Yes, most probably Balderdashese...

 

[yellowdingo]

String Theory?? Bwahahahahahahaha. I sure hope someone is working on something else because thats not the answer.

Its OK LT, I understand...its been a long long time since you were offered the secret to the Universe.

I may have the answer thats umpalatable to the other six billion rubes on this rock...but I'm buggered if I know how to make it propel a space craft...How do I twist all the strings in opposition to the Gravity induced by their current twist anyway?

 

[All Seeing Eye]

^ wuh?

 

[yellowdingo]

^ wuh?

Which bit Admiral TS? The bit where gravity is a consequence of the twist in the strings common to your planet, or the idea that you can do antigrav by twisting them strings counter-earth-wise?

 

[All Seeing Eye]

^ wuh?

Which bit Admiral TS? The bit where gravity is a consequence of the twist in the strings common to your planet, or the idea that you can do antigrav by twisting them strings counter-earth-wise?

and where did you obtain this bit of information? from the hitchikers guide to the galaxy?

 

[yellowdingo]

^ wuh?

Which bit Admiral TS? The bit where gravity is a consequence of the twist in the strings common to your planet, or the idea that you can do antigrav by twisting them strings counter-earth-wise?

and where did you obtain this bit of information? from the hitchikers guide to the galaxy?

I was reading something on stringtheory. I'll look around and see if I can find an online source. Mostly I solve these things myself and instead of publishing in Magazines to my intellectual inferiors I pass it out to ordinary people in forums...