Originally posted by: Rats in the walls
I hate to be a killjoy, but back-and-forth interstellar travel in realtime is just not physically possible. What the trekkie nerds fail to grasp is that as an object approaches the speed of light, it becomes light, i.e. it disintegrates on the subatomic, then the sub-subatomic level, and then finally becomes pure energy: light. Nothing else can travel at the speed of light but light itself. This is as reversible a process as burning a newspaper and expecting to put it back together and reading it again.
So there will never be any social, back and forth travel or communication between planets like in the movies unless the same star system is lucky enough to have two or more habitable planets that just happen to produce intelligent and technologically advanced civilizations, which is very, very rare, exponentially more rare than having life at all, but even this probably does exist somewhere as there are so many stars as to make the odds pretty good. Which is awesome for them, but not for us, since we don't.
What is possible though, and what could account for a visitation to us or some day by us, is some kind of seed ship, sent on a one-way trip to their/our best guess of what might be a habitable system by the time its hundred thousandth generation descendants got there, but that would still be a crap shoot because remember, most of the images of stars that you see are snapshots of thousands, hundreds of thousands, sometime millions of years past, so who knows what the planned destination would look like by the time such travelers arrived.
However, I am completely confident, based just on the enormous numbers alone, that there is in fact life on other planets in the universe, that some of this life is technologically advanced, that some of it travels between planets, and that some, perhaps on the verge of their star dying, sends/sent ark-ships out into space. I would guess that the oldest parts of the universe would have a few such flying dutchmen of some sort, ghost ships dead and adrift, and perhaps even a few that got lucky and successfully transferred life from one star system to another in this fashion; again, the sheer numbers make this likely. For us, the most productive place to look for something like this would be coming from the oldest parts of our own galaxy, the outermost arms, and most likely placed on a heading inward toward younger stars like our own, just to hedge their bets. That's still plenty of choices for origin and for destination, as all the stars you can see in the night sky with the naked eye are stars in our galaxy, so that's still pretty good odds. In fact, some credible theoretical astrophysicists recently published a calculation in the journal nature based on recent spectral analyses and image mapping that they believe that there are at least 3,000 and as many as 30,000 planets with life on them in the Milky Way alone. Pretty cool, but sadly, still out of reach.
Originally posted by: tom.
click here for link