Fending Off A Space-Alien Invasion

Does the U.S. have the needed weaponry?

Obviously, it depends on the nature of their technology, but I’d say no.

As long as we avoid becoming a spacefaring civilization (as we have been for decades, de facto, with our insane space policy) we will always be on the defense. We need to be able to take the offensive against a space-borne attack, and we don’t even have proper picket lines up in the solar system, which means that there’s a good chance that by the time we find out about them, they’ll be at our front door, and it will be too late.

I do think that we’re good against zombies, though, at least in the U.S.

[Update late Monday afternoon]

Welcome, Instapundit readers! Just a reminder that as long as we obsess about safety in space, we won’t have a chance against an invasion. We’re over halfway to the fundraising goal, with a little less than half the time remaining.

55 thoughts on “Fending Off A Space-Alien Invasion”

  1. Not sure that’s precisely the same as Alien Invasion – How to Defend Earth, but it is by the same authors – and a lot cheaper at $6. (I -think- it’s a Baen reprint of the same material.)

    Our only basic hope at the current state of affair is that they had better want slaves instead of just hitting the reset button on us.

    Or, for some insane reason (Aliens have UN’s too), they decide on a ground war.

    1. Reading the introductory material on the Baen ebooks site, it would appear that the authors teamed up with some others to “popularize” it a bit to get it to a wider audience. The original was more like a Command and Staff College paper geared toward military tech and strategy wargamers. That’s probably why it was so expensive and had such a limited run. I’m all for it, and for only $6 for the non-drm ebook, I bought it and will read it just to refresh my thinking on the topic. Asymmetrical warfare is always something that bears thinking about.

  2. Footfall by Larry Niven and Jerry Pornelle is probably the best Fictional treatment of repelling an alien invasion that I’ve ever read. We beat them of course, but they weren’t really very advanced aliens. And even then the planet was devastated before the war was over. Nukes, asteroid strikes, etc, etc.

  3. Anyone who can command the kind of energy it takes to travel between star systems in a reasonable time also has awesome weapons. We can command at best the kind of energy to travel at 6% of the speed of light, and (supposedly) have the energy to destroy our planet. Anyone who can travel at ~90% of the speed of light probably does have the energy to destroy our planet.

    It almost follows that they could defend against anything we put forth, since to first order, their energy production would require shielding of a kind we can’t imagine.

    However, anyone who commands that kind of energy can do anything they want in the universe, and don’t need to conquer a planet like ours.

    1. Yeah, anyone who can build an interstellar spaceship that can travel 90% of the speed of light could just plow into us without bothering to slow down. At those speeds I think a 500 pound object has the same kinetic energy as the entire US nuclear stockpile (about 2 gigatons of TNT). A WW-II destroyer escort would hit with 7,000 times more energy than the US stockpile, and something the size of an aircraft carrier would hit with 350,000 times the energy we could reply with, and 5 times the kinetic energy estimates of the Chicxulub impact that wiped out the dinosaurs.

      1. 1. No evidence exists for the existence of intelligent extraterrestrials, and both reason and theology argue against the possibility.

        2. If there were ETs, they wouldn’t bother coming here by using rockets to cross interstellar space. Such methods take too long to be useful for any practical purpose (except for possibly the When Worlds Collide “space ark” scenario). Why send a slower-than-light ship on a 500-year journey when some sort of wormhole or warp drive type thingy would almost certainly be invented long before its arrival?

        3. If ETs did exist and did come here, it’s likely their motives and goals would be as incomprehensible to us as our are to lobsters or crickets. We might interpret their rearrangement of our solar system as an attack, never realizing that they are doing so for aesthetic or religious reasons.

        4. If they did seem to bear us deliberate ill will, we’d figure out some way to defeat them, because that’s what we’re built for. Human beings are murder machines.

        5. God won’t let us lose.

        6. 500,000 palm-log war canoes full of spear-carrying natives can defeat a nuclear-armed aircraft carrier.

        In my uneducated opinion, the only extraterrestrial life we find will be life of Earthly origin spread through space via terrestrial impact debris. I’m guessing Mars is already contaminated with algae or bacteria from Earth, just as Earth has been “contaminated” with (so-far lifeless) Martian debris over the eons.

        1. This scenario has been examined again and again, and the result is always the same.

          The issue is the likely number of civilisations in the Galaxy (best guess is about a million) compared to the lifetimes of star systems capable of supporting life. I’m not going to go through the maths, but the conclusion is that the likely technological gap between civilisations is around a million years. A million years ago humans weren’t human; twenty thousand years ago we were using stone axes. Where we will be a million years ago, if we are still here, is unimaginable.

          If they do exist, and they do come here, and they actually want to, they will squash us like a bug. Don’t know who originally said this, but: “Apes or angels, but never men.”

          To use an example from SF, with a gap of maybe ten thousand years: Care to bet for us against the Culture?

        2. 1. No evidence exists for the existence of intelligent extraterrestrials, and both reason and theology argue against the possibility.

          For “reason”, there is a counterargument. We are an example of intelligent life. So we know the odds of intelligent life occurring are nonzero. Extremely small, but definitely nonzero. Have that happen enough and the odds of more such life become likely.

          For “theology”, consider what we actually see: a universe far larger than anything we could use in theory, even if we were to hop into arbitrary numbers of spaceships that travel at the speed of light. Why? It would make sense that we aren’t the only inhabitants and that the universe is intended to be used for a very long time.

          1. a universe far larger than anything we could use in theory

            Correct at first blush, but contradicts the premise of the Fermi Paradox. I’m not quite the mathematician of Fermi [very huge grin] so I’d have to accept his calculation that if they did exist they would already be here.

          2. Yes, given the expansion of the universe, there will “soon” be an incalculable number of pocket universes (ours will be the Milky Andromeda Galaxy with attendant globular clusters…), way more than there are already. Who did God make those for? Not us.

          3. If we combine Fermi’s Paradox with the theory of multiple universes, maybe the rise of sentient life automatically generates an alternate universe where they are the only form of sentient life?

          4. As a practicing theologian, I say that theology has nothing to do with the size of the universe. As Frank Tipler has pointed out, whether one or a billion planets has life is not relevant to the universe’s size. If no life had formed anywhere, the universe would still be as large as it is.

            There was a push from the University of Paris in the late 13th century – then the leading university in Europe and thoroughly under Aristotelian sway – to have the Church make it dogma that there are no worlds other than our own and that life cannot exist elsewhere.

            This movement was condemned by Bishop Etienne Tempier and was condemned by France’s Council of Bishops in 1277.

            The Church has never held that God has not or could not bring forth life anywhere that God chooses, including other planets.

            Some prominent Christians who embraced idea of life on other worlds include:
            Giordano Bruno and Nicholas of Cusa (15th century)
            Johannes Kepler (16th century)
            American Puritan Cotton Mather (17th century)
            Yale president/minister Timothy Dwight (18th century)

            We do not know whether God created other beings, but cannot be surprised if he did.

            All that being said, a growing number of scientists are concluding that complex life on earth was so unlikely that we may well be it. As Harvard biologist Ernst Mayr has observed, since life began on earth, there have been about 50 billion species. But only one species (us) has developed high intelligence. High intelligence offers no apparent survival advantage for species (just consider the cockroach) and hence is so rare that it (we) may be a “one off.”

            See Peter Ward, paleontologist, & Donald Brownlee, astronomer, Rare Earth: Why Complex Life is Uncommon in the Universe, 2003:
            * Earth’s life-friendly conditions are so unlikely that they may occur nowhere else – hence, “rare Earth.”
            * “Complex” life (more than one cell) is extremely unlikely at all.

            British astronomer John Barrow: “There has developed a general consensus among evolutionists that the evolution of intelligent life, comparable in information-processing ability to that of Homo sapiens, is so improbable that it is unlikely to have occurred on any other planet in the entire visible universe.”

            British cosmologist and ETI enthusiast Paul Davies: We have just three options when deciding how we got here:
            1. A fluke (random chance). Davies says this is the “ultimate just-so story.”
            2. Unknown laws that make life a cosmic imperative, but says Davies, empirical data point the other way; science does not support the inevitability of life forming anywhere
            3. A miracle? Davies is not religious and so doesn’t delve into this.

            My personal view is that if there is another life form about as intelligent as we are, the odds are long in favor that it is located in another galaxy altogether. If there is one, but only one, such species in each galaxy, intelligent life would seem very rare but actually there would still be hundreds of billions of such species. But I would also say that not only would crossing intergalactic space be impossible, it would be entirely pointless.

            So IMO, not one single dime needs to be spent on worrying about defending against alien marauders. There ain’t any.

          5. We do not know whether God created other beings

            Scripture says he did, they are called angels. Only in popular myth are angels confused with people, a separate creation. The question then becomes, did he create any other?


            worrying about defending against alien marauders

            What if we are the only sentients, but that includes a earlier human civilization that left a fallen earth population that has come back to conquer us? Let’s call them Atlanteans.

        3. We might interpret their rearrangement of our solar system as an attack, never realizing that they are doing so for aesthetic or religious reasons.

          Alien feng shui?

        4. 1. Reason does not remotely argue against intelligent extraterrestrials, though it suggests we have no reason to believe any are here now.

          Theology is irrelevant – whose are we using, and what’s the basis for that? None of the theological source materials I’m aware of even mention the rest of the universe meaningfully – as they wouldn’t, as it’d be utterly irrelevant to the recipients even if they were Inspired By A Living God.

          2. That assumes FTL is actually possible. If it isn’t, then it’s slow ships. That does admittedly make it much, much, much, much (rounds to zero) less likely we’d ever have to defend against them, so it’s a fair point.

          3. Irrelevant, since it’s the effect that matters, not the motive.

          4. Does not follow.

          5. Assumes facts not in evidence.

          6. Not arguably a good analogy. Also not actually necessarily true; the carrier can swamp them and they can’t climb up into it.

    2. Anyone who can command the kind of energy it takes to travel between star systems in a reasonable time also has awesome weapons. We can command at best the kind of energy to travel at 6% of the speed of light, and (supposedly) have the energy to destroy our planet. Anyone who can travel at ~90% of the speed of light probably does have the energy to destroy our planet.

      Not necessarily. It could be that interstellar travel requires incredibly small amounts of energy using some technique we do not know of. However if that is true our planet should have been visited already.

      The best thing we can do to protect from an attack is to map the universe and work on interstellar travel ourselves. Any means of defense we do have may not work. Static defenses can be bypassed or destroyed by an invader. They also take large amounts of resources to build. Better to use the resources on a mobile attack force.

  4. What they may want is to make sure we never are a threat. Best to exterminate us before that happens. Unless we’re tasty. In which case, earth becomes a feedlot.

  5. Well, I can’t think of any realistic SF stories in which the primitives beat the interstellar conquerors without resorting to magic.

    1. Poul Anderson wrote one 40? 50? years ago about mediaeval Englishmen beating aliens and taking over the galaxy – I think it was called “Three Hearts and Three Lions”. It was a fun book

      1. Whoops – my memory failed me – that’s what happens when you are about to have your 70th birthday.
        It was Anderson’s “The High Crusade” published 1960.

  6. As far as Hollywood’s use of “Space Aliens” as the villain it is the last PC villain it can use. Soon even fighting NAZI hordes will be off limits as the “history will be changed”.

  7. Probably best is to surrender and be enslaved or worse. If you can buy time, buy it.
    To have a chance we need to be interplanetary. And confrontation lightyears away is much better than less the light minutes away.

    There is no need for space aliens to engage us within our atmosphere.
    They could simply block out our sun. One space rock could kill us. Or a few space rocks could make the idea of any resistance, wildly silly.

    Our inability in terms of space capability could grounds for us being so useless as to have no reason to seek our surrender. They could completely ignore us or kill all of us.
    But why would come here? Maybe they have some interest in the life on earth and even the sentient life on earth.
    A basic question is do they have AI; are they AI. If they lack AI, humans could used as substitutes for AI.
    If they have/are AI, they could possible have some use for humans.

    But at the moment, we stuck on one planet which requires a considerable effort to leave, and making much harder to leave the earth, would be easy.

    What make more difficult is if humans were scattered all over our solar system. It still wouldn’t be too difficult, but at least their some risks for them. The problem is everyone scattered all over the solar system, would be fairly easy to detect. So they could know say the 10,000 locations of human activity. But if we had means of some sort of stealth, then that is adding some level of complexity for them.
    Of course if already had some experience fighting ourselves in space, then we could be much harder target. Though of course any human war in space, could have some pretty frightening consequences.
    But maybe if such consequences were seriously considered, war gaming them might as good as actual warfare.
    So in other words if serious and various deterrence were to be established making it hard to start and “win” a war, then switching from an internal threat to an exterior threat could be achieved. And one of those deterrences, would probably include stealth, similar to our use of nuclear subs. Plus capability to block sunlight and somehow counteract that.

  8. The only defense against R bombs(relativistic kinetic energy weapons) is do unto them before they do unto us. See Charles Pellegrino’s “Flying to Valhalla”.
    Charlie is my favorite paranoid.

    1. I keep toying with the idea of writing a story where a race of smug aliens launches a Pellegrino weapon at us… only to see it bounce harmlessly off the planet-girdling artificial event-horizon force field field defense shield humanity developed during the course of the r-missile’s 1,500-year flight.

      Cue opening can of interstellar whoop-ass…

    2. Why bother developing a defense? After all, in only x years, we’ll already render it obsolete… Enough thinking like that, and we’d still be in the Paleolithic.

  9. If they come here, it’s probably because there is something here they want. If that something is on the Earth, they’ll probably not destroy the planet in the course of destroying us. If that something is not on Earth, why bother with us? What are going to do to interfere with them on our own moon, never mind anywhere else in the solar system?

  10. The only reason any alien would invade is if they had an exchange economy where human and Earth artifacts had trade value (genetics, new species, music, art, information, history, etc). Otherwise the Earth is just one of trillions of trillions of useless rocks to them.

    If they have an exchange economy they will see the wisdom of exchanging with us on a voluntary trade basis (it’s more efficient to rely on the natives who already possess information about items worth trading). If they engage with us in voluntary trade we will convince them to use PayPal.

    Elon Musk wins again.

    1. It really is the safest way to pay. You wouldn’t give your credit/debit card info to some guy in Russia/Eastern Europe/Nigeria, let alone for some green bug-eyed monster…

      (dayum — spear-phishing from the Gamma quadrant is gonna be brutal…)

  11. The best way to prepare for defense against aliens is to study the Japanese interaction with the west. They avoided colonization by rapidly quickly picking up the aliens technology and adopting parts of their culture. Their big mistake was to try to mimic the west’s politics and found themselves 50 years behind the times – adopting imperialism when it had already become naughty and joining up with the wrong allies.

  12. All we need to do is call upon Gaia to swarm the puny aliens with bears and mountain lions or something like that. This trick has worked at least once, in my recollection.

  13. Probably the most realistic First Contact story ever written was “Call of Cthulhu”.

    1. You should read “The Kraken Wakes” by John Wyndham. Without delay.

  14. Well we would have no chance vs someone with relativistic space flight capability. Though don’t think the space ark, generational ship is that unfeasible , there can be some disaster or pressure to force the generational ship instead of waiting for more favorable travel capabilities. Now what are the odds of a generational ship would be close enough to come to Earth extremely low, and even them the alien civilization should have a order of magnitude of energy usage capability over us. I would guess a low Type 1 civilization.

  15. I’ve seen a few ideas but what about this?
    A civilization so far advanced to be able to travel between solar systems would be so far removed from us, as someone intimated, as we are from lobsters. Maybe they would just be curious.

    “So, xyzkdyl, what do we have here on the third planet?”
    “Interesting, lmluhyl, a group of life-forms calling themselves ‘intelligent life-forms’.”
    “Hmm, send someone down to investigate and study, maybe we’ll get the prize from The Great Pbpbpb, for the most interesting display.”

    So maybe it would just be curiosity, or maybe they know all about us already and leave us alone out of kindness. Maybe they send silent sentinels to observe and report, rather like an interstellar reality show. I mean, it could be.

    That’s more or less why I was sent here…

  16. Anyone capable of traveling here would be capable of either cutting off our sunlight or irradiating us with deadly radiation. Most likely, though, they would just eat us and mine the planet for its minerals and move on to the next planet.

    1. Since it looks like every star has a dust cloud surrounding it like our own Ort cloud, made of up billions of rocks, a species would likely have to exhaust that source first before leaving their own star system, not to mention all the moons they would probably have around gas giant.

  17. Are you sure we haven’t been invaded already?

    If the goal is to exterminate, rather than colonize, there’s no need to send an expensive starship. A small probe carrying microbes or nanites could do the job for .0001% the cost. Such an attack could be incredibly subtle.

  18. Everyone seems to assume we’re going to be invaded (if at all) by some race of beings that is “like us”; they either come with guns and technology or otherwise exist/communicate on some paradigm akin to humanity’s.

    John Wyndham wrote books like The Kraken Wakes and Trouble With Lichen, both of which involved extraterrestrial invasions by (at least in the Kraken; can’t remember details of the Lichen book) superior intelligent beings. Imagine, though, what we’re dealing with is a sort of snail or something; where to begin trying to communicate? Or a plantlike alien? What if they don’t come on starships and hover over DC or Johannesburg but come in like twinkling red lights across the sky that disappear into the deep ocean, or on the wind like dandelion seeds?

    In terms of likelihoods, I suppose everyone’s full of crap including myself but I’d imagine we’ll see that sort of “organic” alien invader that will conquer our planet and supplant us at the top of the chain well before anyone shows up with plans to blow us up and put in a transterrestrial freeway.

    Maybe that’s how the dinosaurs bit the dust, too. Who really knows yet?

  19. Either they need our planet because they destroyed their planets orbit by changing the mass of their planet. Or they wiped themselves out by not realizing that shooting mass off their planet would destroy their orbit. Silly humans, you can’t leave the planet or change its mass without wrecking its orbit.

  20. Evidently nobody remembers the old Safeguard ABM system. The bigest difference between that and the current one under development is that Safeguard one used nuclear warheads; you only had to be close enough, you didn’t need a direct hit. But one of the two missiles was the Sprint missile, which, near as I can estimate based on quoted speeds and distances could accelerate at 800 to 1000 gravities. It could move. Do the math. That was 1960’s technology. But we discontinued deployment of that system. We also signed an ABM treaty with the Soviets.
    One of the paths of research in Reagan’s “Star Wars” was the development of “Third Generation” nuclear weapons, see Theodore B. Taylor’s article in the April 1987 Scientific American for hints about what was possible. Combining directed, high energy nukes with updated ABM missile technology, we could do a lot of hurt, real fast, at a pretty fair distance to aliens trying to invade the earth. If we were willing to build it.

  21. I suspect the only effective defense would be to be strong and technologically capable enough to be capable of offense.

    Not doing so, strictly, but capable.

    Otherwise, the fact that they were able to get here suggests we couldn’t win, if they were aggressive, even if we had, say, Lunar and Martian colonies.

    (Contra AC, I don’t think missiles are likely to do much good; we now have laser-based, speed-of-light-tracking systems that can shoot down a missile almost-reliably. Not one as fast as a Sprint, but it’s not relativistic, so it’s not too fast for a laser to track.

    Hostile aliens, well… if they’ve given any thought to the matter, I suspect they can swat down a missile, assuming we can even find them to target them.)

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