Alien Invasion-proof Earth

This week I’ve read Larry Niven’s Footfall and watched Spielberg’s War of the worlds, and I was thinking, in reality, mankind wouldn’t have much of a chance against alien invaders with the technology to move between the stars and the ultimate strategic high ground.

Anyway, in order to make a discussion of this, super advanced defence satelites from a long-dead ancient civilisation orbit most lifebearing planets, including Earth which neutralise all forms of orbital bombardment. Automatic inteligence gathering over an Alien world triggers them and in the year 2012, they give the UN general a superduperly-convincing recorded message imploring them to ready Earth for a alien invasion in 30 years.

What happens?
What can Earth do to prepare?
What would be the best outcome for the people of Earth?

Earth has no knowledge about the incoming threat beyond speculation and theorising.

Start digging, we are going to need lots of places to hide.

Can’t do much. I guess we could push Project Sipapu, the alleged planned orbital particle beam weapon. I once saw a TV special on future tech which claimed a properly built Sipapu “could control (i.e, destroy) everything between here and the orbit of Mars.”

Put as many of those particle beam weapons up there as you can. Then put a whole bunch of dummy targets up there with them, in the hope that it will take invaders long enough to target then all that we’ll get some shots off.

This. Lots of bunkers, lots of wired communications systems between the bunkers; there’s no way we’re going to take them out in space so if defense is possible, it’s going to be guerilla war-style a la what Hezbollah did in southern Lebanon in 2006.

I for one embrace our new insect overlords.

We can just fill the near orbit area with tons of space junk. They can still drop missiles on us or use death rays, but we could make it near impossible to get a landing craft through safely. If they have transporters., there’s not much we can do. Still, there’s hope. A documentary I saw indicated that alien mother ships tend to leave an unsecured modem line open and their computers can be easily hacked. So our socially unadapted teenagers could save the day. Also when firing the space gun at the aliens, shoot up through the roof of the bunker instead of dragging the gun out in the open where they can hit you.

Space is big I’m afraid. Really big. And even if somehow you could fill low earth orbit with junk to a depth where nothing could get through (imagine coating a sphere the size of the earth completely with junk), life on earth is very partial to the sunlight it would be blocking.

I doubt there is much we could do but hide. But if the aliens were coming in something big that we could catch in an unmaneuverable deceleration phase from high sub light speeds we could try putting junk in its path.

That socially unadapted teenage kid had some inside help from a failed astronaut-wannabee. We can’t be sure it will work that way next time. And the aliens only leave their modems unsecured one day a year, on July 4. I’m sure that documentary you saw mentioned those details.

We don’t make a sphere of junk around the planet. We just fill it with lots of small high velocity pieces. So something could get through, but it risks getting punctured by small pieces of space junk. Eventually it may turn into a layer of space dust as the bits collide with each other. So we’d have to keep sending up pieces of junk to restock. Hoperfully we let the ISS guys come home first.

Stones --and lots of them-- piled high around the walls of our huts.

Two (2!) spears for every warrior.

Develop powerful drugs for better dreams and visions.

We beat the Martians more than 100 years ago and they haven’t bothered us since!

Nope, I specified in the OP that there’d be no orbital bombardment just to make this remotely fair.

Ok, then we’re fine with just the space junk cloud. We could also send up some brilliant pebbles ahead of time as a first line of defense. They should be small enough to launch them through the junk cloud with a fairly low failure rate. Instead of sending all the junk up from earth it might be easier to take chunks of the moon or asteroids and put them orbit preloaded with explosives to form the junk cloud on demand.

We could paint the Earth pink and erect a simple SEP field. They would never notice us

CAPT

Or make it look like it is on fire.

That might work.

Nah, who would pass up a free barbeque?:stuck_out_tongue:

They got here through interstellar space, which–while we think of it as a vacuum–is hardly empty. The space junk isn’t going to make a whit of difference to their shields/ablative layers. Best case, they have nudge an asteroid through first to clear an orbit, and we survive a couple extra hours.

Well it’s true they’d have to be able to deal with all the crap in space on the way here. But the chances of something intersecting their spaceship as they traveled with some shield in front of them is pretty low. But the space junk around earth won’t be sitting still. All of it will be moving in different directions at over 20,000mph. Even sending something ahead of them to clear a path won’t stop pieces of junk from intersecting their lander from all different directions. Now if they can land a heavily armored craft that can take the hits, then we don’t have a chance.

Now my alternate plan involves a really big blue space balloon with big letters that spell EARTH on the side. I have to flesh out the details, but I think it’ll fool out-of-towners for a while.

And where do these objects acquire their ‘high velocity’? Because unless these things are orbiting the earth several times a second my point stands. You are going to have to blanket the sky with them.

A documentary I watched pointed out that there’s no vehicle so high-tech that it can’t be destroyed by two logs (suspended on ropes) crashing together.