Local Group?
Posted: Mon Mar 29, 2010 7:08 pm
Are the Milky Way and other galaxies in the Local Group considered part of the Virgo Supercluster?
--Bill
--Bill
APOD and General Astronomy Discussion Forum
https://asterisk.apod.com/
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.Wayne wrote:We are gravitationally bound to it but this was not always the case and will not always be the case.
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.Hofi wrote: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...
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.Hofi wrote: 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...