[rl41]

Extraterrestrial life may not just be separated from us by space -- time is also a huge issue here. Long ago I heard an explanation from Neil DeGrasse Tyson on this, though my google skills are failing to excavate it. I'll make an attempt to explain the idea...

The amount of time for which life exists on a planet, from genesis to extinction, is extremely small on a universal scale. Intelligent life may not persist on a planet long enough to develop a means for intergalactic expansion. Even if they succeed in this endeavor, it is likely that they will be wiped out eventually by some means.

Basically, the likelihood of multiple intelligent species existing simultaneously and within adequate proximity for one to make contact with the other is extremely small. It's hard to overstate how lucky we would have to be.

[c1u]

A "warp drive" is a time travelling device as much as it's a space travelling device.

Travelling to Alpha Centauri in 2 weeks means travelling about 4 years 3 months into the past. If that holds true then leaving today, spending 6 months "at warp", you could look back on Earth in the early 1960s. After a 2 year journey Earth could be seen in the early 1800s. Travel for 25 years, and see Earth in 500BC.

[rl41]

This is true, though you still have to be lucky enough for a civilization to be existing at your destination in both space and time. Perhaps a civilization could exist at your destination in the perceived time when you depart, but upon arrival you end up at a time when they do not.

I think the point of my comment still stands regardless of this revision. If you could choose exactly the position in time at which you'll land, then we have a different story (though this would likely require unreasonable travel speeds).

[c1u]

I see your point, but we don't know. A one in a million event happens about once a month (Littlewood's law). It might be that there are many more rocky wet worlds than we now think there are, but we dont know that either. But we do know FTL travel is also time travel. Being able to tug big telescopes and look back and study our own stages of civilization would in itself be pretty amazing.