Isn't M-theory and the multiverse idea a bit discouraging?

[reoffender]

I have been reading about the multiverse idea recently and when I came to think of it , as much as I find it extremely interesting, isn't it a bit discouraging as well? I mean, if there was "time" before the big bang and if there are infinite number of other "bubble" universes in the "11th dimension" colliding with each other to form "other" universes, There should be almost infinite number of "extremely extremely advanced" civilizations in technology in the other universes, who already understood this idea and one of them should have reached "our universe" somehow to discover. I mean I know that it depends on when these "bubble universes" were there in the first place, but I am assuming they were always there? So might that not imply that traveling between universes is almost impossible? Ok, I am a bit confused and I need your help :)

 

[Forestman]

Who said they hadn't been here.

 

[Coin]

I don't think "there should be many advanced civilizations in the braneworld multiverse, surely one of them would have found us by now?" follows any more than "there should be many advanced civilizations in the visible universe, surely one of them would have found us by now?". Especially because our knowledge of physics allows for travel between planets whereas traditional M-theory, as I understand, says that nothing travels between branes except sometimes gravitons.

(By the way, while we're on the subject, something that still confuses me rather badly-- does the M-theory bulk actually have "time"? That is to say, we talk about branes "colliding and then separating" from one another, or gravitons "leaking off" of a brane-- this kind of language seems to imply events that follow from other events, or "time". But surely under M-theory what we call "time" is just a geometric feature of the manifold of our universe, and in turn a feature of the brane[s?] that our strings are stuck to. How does it make sense to talk about time, or use language implying time, when discussing the interactions of branes floating out there in the bulk?)

 

[Orbb]

(By the way, while we're on the subject, something that still confuses me rather badly-- does the M-theory bulk actually have "time"? That is to say, we talk about branes "colliding and then separating" from one another, or gravitons "leaking off" of a brane-- this kind of language seems to imply events that follow from other events, or "time". But surely under M-theory what we call "time" is just a geometric feature of the manifold of our universe, and in turn a feature of the brane[s?] that our strings are stuck to. How does it make sense to talk about time, or use language implying time, when discussing the interactions of branes floating out there in the bulk?)

At low energies, M Theory is described by branes embedded into a 11 dimensional Minkowski space. A p-dimensional brane traces out a p+1-dimensional worldvolume during its time evolution, just as a point particle traces out a one-dimensional worldline. It is therefore the bulk already that contains the time coordinate.

 

[Naty1]

I thinkit was Hawking who pointed out we would likely be overrun with extrterrestrial observers if large numbers of advanced civilizations existed...on the other hand it always seemed to me that we might well be unaware that we are being observed...

Do ants know we watch them? I doubt any solider ants race back with the message "There was a scientist out there just now watching us." Seems likely advanced civilization extraterrestrials could easily watch us and we'd never be aware...