The aliens have excess nuclear and chemical waste.
According to alien ethical codes, this can only be deposited on a planet with intelligent life. Fortunately, they have detected earth in range of their ships. About once every six hours, a ship will drop a million kilogram payload of highly radioactive waste on earth.
The more stringent aliens (around half of pilots) will responsibly insure their shipment lands on an area of high human inhabitant density. Morally lax aliens will dump at a random location on earth's surface. All aliens are required to approach close enough to earth for the shipment to free-fall, but it is too much effort to approach much closer than that. The only minor concern the alien CEO has is this might destroy human life on earth; if so he will be forced to spend all day locating a new planet with intelligent life.

Waste Quality Information:

Radioactivity levels similar to our own high level waste, may be arranged into chemicals not currently found on earth, may be toxic. It is a mixture of solid chunks, pastes, and liquids.

As long as one human is standing on earth, it is ethical to dump; however the aliens cannot be bothered to take special action to preserve human life.

EDIT: Assume alien sensors can detect any humans present on the planet. On earth, humans are the only species counting as intelligent. The alien technology is sufficiently superior that humanity has no chance of winning a war against them. More aliens ships are continuously sent so a new vessel arrives at earth about once every six hours.
The aliens will dump on the largest population centers until no humans remain there, then switch to the next most populous place until no humans are left alive. While they aren't intending to kill of humanity, they will dump waste in this manner as long as any humans are alive. The only question is how long humans would survive, in our present condition if this kind of dumping happened.

How long can he expect to ethically dump before needing a new planet?

  • $\begingroup$ How good are the aliens at detecting hiding human survivors? $\endgroup$
    – Alexander
    Oct 12 '17 at 22:31
  • 1
    $\begingroup$ This is indeterminable, humans could create a closed biosphere shelter under the crust which would protect them from the dumping. At which point the answer becomes how long till they increase the mass of the planet to affect the tectonic plates. $\endgroup$
    – anon
    Oct 12 '17 at 22:31
  • $\begingroup$ Wait, so the aliens are attempting to kill humans? $\endgroup$
    – Phiteros
    Oct 12 '17 at 22:38
  • $\begingroup$ We would shoot them down, so till we kill all of their ships or pilots. Probably take a few months before the death rate was so high their pilots wouldn't come because they didn't want to die. $\endgroup$
    – cybernard
    Oct 12 '17 at 22:38
  • $\begingroup$ On earth, only humans qualify $\endgroup$
    – Vincent
    Oct 12 '17 at 22:41

It might not kill us.

A million kg is at escape velocity (how fast things hit us if dropped from the farthest away possible) is something like a nuclear bomb.

If they nuke a city a hour (we don't count about the randoms, they probably land in water or a field or mountains) we last six months before they need to find towns smaller than 100k.

So civilization is out, but what about remnants?

You might expect a blast within 100km of you once a year. That is probably survivable long term, but quite unpleasant.

Ok, but can we stop them?

Maybe. We could try to trade waste with the aliens. Conveniently we have a lot of ready-to-be nuclear waste stored in hard to destroy geographically dispersed bunkers, already packaged on top of some of our best rockets. Unfortunately they are not designed for orbit, and so might only be made to go a few km/s which isn't enough to get to where they drop from day one, but we have some experience launching fast enough so the modifications are probably possible.

We could also try exploding the incoming deliveries. If we break them up before they reach the planet then they burn up in the atmosphere and don't smash cities.

But how long could we keep that up?

We have a lot of nuclear weapons, thousands of rockets. Which is enough to last weeks firing one at each incoming delivery. And we could stretch that by ignoring things falling on places we don't care (as much) about. We normally launch nearly 100 rockets a year, so we can make at least that many, but with 15 thousand deliveries a year production would have to increase more than an order of magnitude to keep civilization.

Could we?

Maybe. The last world war saw airplane production jump more than an order of magnitude when that was prioritized over civilian production. And work is already being done on reusing rockets which would dramatically cut into the costs of a large scale project like this.

But what about the poison?

I'm neglect the poison content of the loads since there is something like 10^12 kg of Uranium in the ocean, so a million loads (600 years) to double it. We might have to step up our efforts to avoid destroying our environment to compensate, and extra radiation in the air might cause more cancer depending on the risk model you use, but it's just not on the same scale as space objects falling on us.


You're asking for a logical answer to an illogical question. It's very Douglas Adams-esque. I like it! So, in the spirit of Vogons everywhere (and in a valiant effort to avoid their poetry)...

Life is unreasonably rare in the galaxy, so when a waste management company gets lucky and finds an inhabited planet, they cherish it and work beyond measure to keep it secret from their competitors and habitally viable for as long as possible. After all, the fees waste management companies must pay to the government to store waste on uninhabited worlds are reprihensible!

Therfore, it is in the best interest of the E'Kathian Secret Brotherhood of Caustic and Indeterminate Waste Storage and Management, LLC to dump waste anywhere BUT inhabited locations on the planet despite the interference of bureaucratic regulation that demands dumping directly on inhabited locations to ensure the longevity of the company's investment and value to its shareholders (whomever they may be in the spirit of free trade everywhere, all praise to E'Kath!)

Offensive bureaucratic regulation demands and imposes the requirement that an intelligent species be one that exhibits "the capacity to modify their environment to the detriment of itself while adjudicating complaint and damage with the greatest possible delay and inefficiency." These Humus (as they call themselves, sounds like some kind of plant to me) exhibit all these characteristics and therefore must meet the interminable regulation that at least three million, seven hundred and forty-six thousand, fourteen individuals must exist at minimum planet wide with a minimum of one hundred ninety-six thousand eight hundred and one in one location, visitation and examination of said planet to be subject to the whim of the Approved and Apparent Disposal of Waste Commission, may they rot in...

But I digress. It is certainly in the best interest of the company (E'Kath!) that we be perceived as complying and, indeed, do so insofar as we are able to milk this sensible disposal site for every G'ham it is worth. Standard corporate entrenchment protocols have been affected with a suitable number of Humus collected and kept in storage to repopulate elswhere with implantable evidence of their capacity to reach said world should the Divine look unfavorably upon us (Say it Ain't So, E'Kath!) and we lose this world.

To do anything less would be entirely unethical.

Sorry, I was having so much fun that I actually forgot to answer your question: Waste disposal can reasonably expect to ethically dump on the planet until caught by the government for violating regulations. The game is to keep that from happening for as long as possible. We Adore You E'Kath!

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    $\begingroup$ This really is the only answer. It can continue until it is uneconomical, and/or the alien government forces the company to stop. $\endgroup$
    – Erik
    Oct 12 '17 at 23:03

A few additional strategies to augment @JBH's excellent answer...

1). Sell doses of Hyronalin to the Humus before and during initial dumping. Check the following list for potential trade goods which the Humus might offer in trade for the life saving/extending drug.

2). Genetically enhance either the Ants or Cockroach to the galactic minimum definition of intelligence. Unsubstantiated rumor has it that the roach's can survive intense radiation, and three million, seven hundred and forty-six thousand, fourteen individuals won't require nearly as much clean-zone and life support as a similar number of humus would.

3). Modify the sensors on the ethical pilots' ships so that they detect human habitations in the ocean trenches and deep deserts. Better yet, buy some service droids from a rival waste disposal company and assign them to gather and carry any ethically dropped waste canisters to said trenches and deserts. If the droids are discovered during a compliance audit, you can always claim that it is an attempt by the competitor to make you look bad.


I think it might not be a big deal if everyone stays cool.

If the aliens are dropping the waste from orbit, much of it will burn up on re-entry and be scattered through the upper atmosphere. It will not hit.

Even a solid chunk of uranium that weight is 52 cubic meters and much will burn away or melt off on the way in.

If the waste is dropped from close enough that it does not pass thru the atmosphere it will not hit with as much force either. It will not make big craters. I estimate the volume of these wads would be between 52 m^3 for uranium and 441 m^3 for carbon. A house is about 300 m^3. The impact would kill the few people beneath it - say 50 at most. People would evacuate. Teams with bulldozers and dump trucks would cover the area hit with soil and sand, or concrete if highly radioactive. I estimate each impact landing in a city would take out a couple of blocks maximum. Cities are big. Landing in a water supply would be a much bigger deal for a city and contamination of a reservoir might make a given city unliveable. Cities which use rivers or wells for water would do better with that aspect. One could take measures to cover reservoirs or store water to ameliorate this danger.

Los Angeles county has a population of 10 million and a deathrate of 600 / 100,000 yearly; so 60,000 per year or 164 every day. Alien dumping would of course be terrifying and newsworthy, and the terror aspect would be disruptive. But an extra 50 deaths here and there and some new unplanned construction would not be a big difference in the workings of US cities if everyone were as blaise about it as they are about car and gun mortality.


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