Starship Asterisk*

[quote="Hofi"]
I think that this statement depends on how you define "gravitational bound". All massice objects are affected by others' gravity. If there's a lot of empty space around the cluster, the gravitational bound of a galaxy to the group is stronger because there's no opponent.
Otherwise if there are a lot of clusters around it, the gravitational obligation is not so strong...[/quote]
As Chris has said, there's no real "how you define" for gravitational binding. An object either is, or it isn't. If an orbit is hyperbolic or parabolic, there is no binding. It the orbit is elliptical (i.e. closed) then the object is bound. However, this is an instantaneous state as future interactious can change whether the object is bound or not, the object can be ejected.

Globular clusters, for example, are comprised of bound stars (and make an excellent model for superclusters), but they leave trails of stars behind them or even orbit within arcs of stars which they have ejected.

[quote="Hofi"]I think that this statement depends on how you define "gravitational bound". All massice objects are affected by others' gravity. If there's a lot of empty space around the cluster, the gravitational bound of a galaxy to the group is stronger because there's no opponent.
Otherwise if there are a lot of clusters around it, the gravitational obligation is not so strong...[/quote]
I don't think there are different ways of defining "gravitationally bound". Whether the binding is weak or strong doesn't matter; if you are gravitationally bound to something, your speed with respect to it is less than its escape velocity. In other words, you are in some sort of closed orbit.

[quote="Wayne"]We are gravitationally bound to it but this was not always the case and will not always be the case.[/quote]
I think that this statement depends on how you define "gravitational bound". All massice objects are affected by others' gravity. If there's a lot of empty space around the cluster, the gravitational bound of a galaxy to the group is stronger because there's no opponent.
Otherwise if there are a lot of clusters around it, the gravitational obligation is not so strong...

That very much depends on your definition of "part of". We are gravitationally bound to it but this was not always the case[1] and will not always be the case[2].

For example, between us and the Virgo Cluster is the Canes I Group and the M81 Group.

[1] We're on the very outskirts, which likely means we've either been captured or are just doing a pass or two before being ejected
[2] Small clusters, such as the Local Group, are tossed around between superclusters or even intergalactic space quite often. Then there's the future fun that dark energy will have.

Thank you! Good source of information and an excellent map.

--Bill

Looking at [url=http://www.atlasoftheuniverse.com/virgo.html]this image[/url], I would say that we are as near the middle of [url=http://www.universetoday.com/guide-to-space/galaxies/virgo-supercluster/]it[/url] as we are the middle of our own galaxy. Part of the Virgo Supercluster but not the [url=http://en.wikipedia.org/wiki/Virgo_Cluster]Virgo Cluster itself[/url] which lies in the center of the supercluster

Are the Milky Way and other galaxies in the Local Group considered part of the Virgo Supercluster?

--Bill