How to defend against an alien invasion.

Note: the alien ships will be capable of travelling through space, and they will have shields of some kind that will be capable of withstanding asteroid impacts at close to light speed. This would make their ships basically invulnerable to nukes.

Note: the aliens are after our resources (water, protein, nutrients). So simply destroying earth is not an option.

What options could the Earth's governments take to eliminate the aliens' threat, assuming that the governments of Earth unite to face this threat.

If I have left out any information that you would need to answer this question, comment and tell. Please don't close this post with out giving me a chance to fix whatever is wrong with it.

More details: Technology is the same as today.

Politically the is United under the newly-formed Earth Parliament. In response to the arrival of the aliens

  1. There are about twelve ships each is roughly the size of small City. Each equipment on nuclear Arsenal, however they are unlikely to use this Arsenal except as a measure of Last Resort and even then probably only against any popular cities. They want to leave the earth resources in intact.

3.there is altogether about twelve thousand aliens and about a third as many robots.

  1. The alien force is not desperate people there merchants who take recourse of resource rich plants and sell them to others that are desperate.

    1. The Aliens have almost as fast as light travel.

    2. On land they use both microwave and projectile hand weapons with mounted laser canons.

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    $\begingroup$ They are pretty much invulnerable to physical attacks -- but how about energy attacks? Laser, focused particle beams, etc.? $\endgroup$ – subrunner Apr 26 '16 at 13:24
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    $\begingroup$ Also: which technology level does Earth have? Today's? 2100? $\endgroup$ – subrunner Apr 26 '16 at 13:25
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    $\begingroup$ Hi, Bryan! You're leaving out quite a few details. As @subrunner asks, please tell us more about the political and technological situation on Earth at the time of the alien invasion. You should also clarify what the alien's technological level and situation is. I know they have ships that travel at the speed of light, but how many of them? Can they bring more, or do they no longer have a home world? Are they a warrior race, or are they attacking us out of desperation? The number of questions I could ask here are nearly endless. You need to give us a good description of the aliens and situation $\endgroup$ – AndreiROM Apr 26 '16 at 13:34
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    $\begingroup$ I'd also like to add that closing the question is exactly so that you have the chance to rewrite it, and flesh it out so don't panic if it is put on hold! Simply edit it, and it will be reopened by the community. $\endgroup$ – AndreiROM Apr 26 '16 at 13:35
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    $\begingroup$ Why would they be after our water : space is full of it without those crayzyyyyyy hiuman triying to nuke you to protect themselves ? $\endgroup$ – MakorDal Apr 26 '16 at 13:44

Stop their ships

Since they seem to withstand not only physical impact at relativistic levels, but also the heat and radiation of nukes, this might be futile but... Try attacking with lasers or other targeted electromagnetic / particle beams. If they've also got shielding against that, you're pretty much SOL with today's technology level -- I'm pretty sure you'd also be SOL with 2100's technology level.

Attack when gathering resources

Depending on how they gather their resources, you might get a chance at harming them that way. If they have to get off their invulnerable motherships to collect water/animals, hit them once they come down into the atmosphere in shuttles. If the shuttles are functionally invulnerable, too, hit them once they leave the shuttles to gather resources. Or hit their resource-gathering machinery.

Poison resources

If they have some kind of beaming technology or are still functionally invulnerable when leaving their shuttles, then contaminate the resources they are gathering to the point that they become unusable for the aliens. Of course, this requires quite a lot of observation to figure out a) when do they gather which resources, b) how to poison them so that it is actually effective against alien biology and technology, and c) how to do all that while keeping resources for humans available.


Contact aliens and figure out if you can't open some kind of trade negotiations. 'We give you x resources, and in turn you leave us alive. We might even farm and harvest resources extra for you. So, if you leave us alive you get a higher yield out of our planet.' It will probably result in some kind of slavery or oppression, but that gives you time to figure out how to really harm them or otherwise get rid of them. Might even give earth time to bootstrap our technology level to the point we can develop weaponry that can actually harm the near-invulnerable aliens.


The answer depends entirely on what assumptions you make about the technology of the aliens.

If the ships are "basically invulnerable to nukes", I'd presume that means they are also invulnerable to any other explosives, and presumably also to kinetic weapons, i.e. bullets, artillery shells, etc. If you start out with the premise that no weapon we have is effective against them, I'm not sure where you go from there.

Maybe Earth invents some new weapon that can penetrate their shields? Without knowing how the sheilds work, I don't know how we could say if that's possible or what it would take.

Well, do the aliens have to leave the ships with the shields to attack? If they're here to steal our resources, can they kill us all from these ships? Or do they need humans for slave labor in the mines?

I think what you're really left with is some sort of trickery or sabotague. Somehow the neogiator or a prisoner smuggles a bomb aboard their ship. Or we use the alien ship that we've kept hidden at Area 51 to bluff our way in, and then upload a virus from our Mac onto the alien computer.


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