Slightly more on topic, how much technology would it take to get from another solar system to this one, and how close are we to being able to do something like that ourselves? If an alient space vehicle were to visit us today, what is the minimum technology they would have to have? If they were hostile, is there any chance whatsoever of us resisting?
If they were hostile...chances are they'da blown themselves to bits before ever getting the knowledge to travel between star systems.
As for how much technology it would take...well, technology seems to be something that progresses at geometric rates. If the kinds of advances we've seen during the last 100 years is any indication of what could be accomplished during the next 1000 years...most of us wouldn't comprehend the world of 1000 years hence if we could magically be transported to it.
People of 1909 would have a hard time relating to now...people of 1809 would have had less trouble relating to conditions of 1909...people of 1709 would have had almost no trouble relating to conditions of 1809...and people of 1409 would probably have little trouble relating to conditions of 1709.
Considering conditions in 1909 versus now...just imagine what 2109 will think of what exists today.
My guess...interstellar travel is not that far off. Couple hundred years at the outside would not be an unreasonable guess.