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Ask Slashdot: How Could We Actually Detect an Alien Invasion From Outer Space?
First time accepted submitter defiant.challenged writes As I was watching another sci-fi blockbuster about aliens wanting to harvest the life stock population on earth for their energy since we are such a robust species, I was wondering how likely and easy/difficult it would be currently to actually detect an outer space invasion (fleet). I am a firm believer that if we would be invaded, we would not stand a chance and would probably not even hit a single ship when it comes to fighting them. The aliens in the movie had the capability to space-jump right into our solar system and even very close to earth. My question is how good are we at the moment in detecting an alien ship/fleet that jumps into our solar system. Do we have radio dishes around the globe such that we can detect objects in space in all longitude and latitude degrees? I know we have dishes pointing to the skies but how far can they reach? Do we have blindspots perhaps on the poles? I also wonder if our current means, ie radio signals, are relatively easy to be compromised with our current stealth technology? To formulate it in more sci-fi terms, how large is our outer space detection grid, and what kind of time window can they give us?
Just because the hypothetical aliens are ahead of us in some respects (e.g. the ability to practically travel across interstellar distances) it does not necessarily follow that they would be ahead of us in all others.
Uh, yes, it absolutely does. If they have mastered interstellar travel, then then there is no way that they will be behind us in any other aspect.
On the positive side, this also probably means that they'd have nothing to gain by coming here or killing us off.
If physics doesn't allow for it, it doesn't allow for it anywhere. It doesn't matter how large the Universe happens to be.