Everybody dies. How do they look?
October 12, 2009 7:16 AM   Subscribe

I'm toying with an idea for a short story or maybe a long story or maybe no story, but the idea has led me to a point where I have a question for those of you who have some knowledge about science and biology. Read on, brave adventurer!

So, let's say I have a magic button, and I press that button and every single living thing on the planet dies instantly. I understand that the definition of what is "alive" is a subject of some debate for certain corner cases, but since I am not a scientist and I lack the knowledge necessary to carry on an informed debate on the topic, let's just assume that by "alive" I guess I mean that "it is a commonly held belief among people who study such things that this thing is alive."

So, I would think that this would include people, plants, animals, bacteria, and a laundry list of other things I'm not thinking about.

Ok, so we have our magic button and we know what it does.

Let's say I press that button and everything drops dead where it stands. Hooray!

Now, I know that when a person normally dies, there is a process of decay that works to erode the integrity of said corpse over time.

My question is, how would this process be altered by the lack of any other living things existing? It would be my assumption that this would largely apply to bacteria and things that maybe eat away at a body after it is no longer alive?

So, maybe to phrase it a better way....

Let's say I was able to magically visit this now-dead Earth some 20 or 30 years after I had pressed my magic button. If I encountered the body of a person who had dropped dead on the street in Anytown, USA, what is it likely to look like? I assume that perhaps the elements - sun, rain, snow, wind - might have served to work it down to a skeleton regardless of any other living factors. Right? Ok, but let's say a person dropped dead while being largely protected from the elements - like in a house or in an office or something. What is it likely to look like? Would the lack of bacteria and such work to preserve it such that it would look almost freshly dead? Or would it perhaps look mummified?

Maybe you get the idea. I want to visit a dead planet some decades after the "event" - and I'm curious about how I would find the people and animals and such to look. Get it?
posted by kbanas to Science & Nature (19 answers total) 4 users marked this as a favorite
Let me try and rephrase it: Normally the process of disintegration and decay is carriend out by biological, physical and chemical processes. In this case you only have physical and biological processes.

Physical processes such as heat and cold will damage the body and in my opinion the body will be better preserved in the absence of bacteria but will not look 'freshly dead' for too long. The speed and extent of changes depend on the temperature and other environmental factors.

There should be some work on what will happen to a body left on the moon or in space where you have the physical factors but not the biological factors.
posted by london302 at 7:24 AM on October 12, 2009

Let me try and rephrase it: Normally the process of disintegration and decay is carriend out by biological, physical and chemical processes. In this case you only have physical and biological processes

Do you mean only physical and chemical there?
posted by biffa at 7:42 AM on October 12, 2009

In drier environments, I'd expect dessicated bodies. In more humid and wet environments, maybe something like a bog body.
posted by DarkForest at 7:51 AM on October 12, 2009

Lots of mummification. But if you yourself are not wearing a environment/space suit, you are going to be shedding all kinds of microbes into the environment, so if you come back 20 or 30 years after your first visit, you may find the planet overrun by the microbes you left behind.
posted by fings at 7:57 AM on October 12, 2009

I think london302 is on the right track. There are circumstances in which bodies have been preserved from biological decay agents (known as "mummification"), such as the Tollund man man. In a peat bog, acid penetrates living tissue and creates an environment in which bacteria cannot survive, resulting in the preservation of flesh. However, a body left out in the open wouldn't look quite the same as one buried in peat. You can also take a look at bodies that have been preserved in ice, which is another environment in which bacteria can't cause decay. For instance, Otzi the Iceman, a 5,000 year old human body. More recently, a man named Ernest Munn crashed on a glacier during WWII. His body was discovered mummified by the cold (I can't find any pictures, probably out of respect for the more recently deceased and his relatives).

I would expect the most evident change after a decade or two would be dehydration. Except for bodies actually in water at the time, I would expect much of the water to leave the body, resulting in a shriveled appearance. Depending on the amount of wind and other erosion factors, the tissue will eventually begin to slowly break down on its own. Perhaps some skin would start to break and flake/peel off.

There's a lot of useful info in the mummification article in wikipedia.

Very interesting and creepy scifi idea! Good luck!
posted by Salvor Hardin at 8:00 AM on October 12, 2009

every single living thing on the planet dies instantly

The mechanics of how everything dies is probably important as well. There are many ways that individual cells can die, and how they die would affect what the dead organisms would look like. If the magic button causes all of the cells to burst, for example, that would look a lot different than other methods (such as depriving cells of food/oxygen, vaporizing them, etc.)
posted by burnmp3s at 8:06 AM on October 12, 2009

People Jerkey
posted by Gungho at 8:08 AM on October 12, 2009

Response by poster: The mechanics of how everything dies is probably important as well.

Let's assume it is a metaphysical event. That something from the cosmos comes down and simply and instantaneously removes from everything that intangible something that makes it alive. It sucks out the life force, if you will. It is non-destructive in a way, while obviously being incredibly destructive in another way.
posted by kbanas at 8:08 AM on October 12, 2009

Response by poster: So I get the impression that "people jerky" and "mummification" are basically what we're talking about. The links you guys have provided have been excellent thus far. Thanks!
posted by kbanas at 8:09 AM on October 12, 2009

Would the lack of bacteria and such work to preserve it such that it would look almost freshly dead?

Even without bacteria, all the moisture content is still going to eventually evaporate into the air, so I would be thinking images of dried fruit or beef jerky clinging to a skeleton. It would definitely look shrunken and gaunt, not at all lifelike.
posted by Rhomboid at 8:14 AM on October 12, 2009

You might be somewhat interested in the book "The World Without Us". It's more about buildings than bodies though.

Another thing to consider is the effect of sunlight. These bodies that were protected from the weather but exposed to light would eventually have their organic-based pigments (like melanin) bleached out. Skin and hair might be bleached white. But there's still the iron in one form or another in the body that would lend some coloring. Exactly what color though probably depends on what sort of chemical reactions the iron undergoes (oxidation?).

I'd speculate that sunlight would eventually break down all organic chemicals in the body, leaving just bones and inorganic dust. But I think that's probably more on the order of hundreds or thousands of years. Most bodies would possibly be buried before this would occur.
posted by DarkForest at 8:33 AM on October 12, 2009

I'll chime in to agree with the others. Pretty much all of the decay that we see in dead things is the direct result of other, living, things trying to eat them. Largeish creatures (lions down to insects) eat big chunks, digest it and excrete it as faeces. Smaller creatures (bacteria and fungi) secrete various enzymes that liquify the dead animal/plant, esentially digesting it before ingesting the resulting nutrient-rich gunge.

We do occasionally see the consequences of death in places where no life can flourish. The two main ones -- falling into a peat bog and dessification -- have already been mentioned. In a peat bog various factors (mostly lack of oxygen and acidic conditions, I think) mean that bacteria can't survive, so plant and animal matter survives, soggy but more or less intact, until we dig it up. In very dry conditions (examples have been found in dry, hot places like egypt and dry, cold places like the arctic), the lack of available water means that the environment is basically sterile. Again, dead plant and animal matter dries out and shrivels up a bit, but otherwise survives basically forever.

I guess the question is which way it'll go (soggy or dry), and I suspect it'll depend on the climate. In dry or moderately humid parts of the world the body would probably dessicate and start to look mummified. To keep the corpses looking fairly fresh but not soggy, I think you'd need very stable, very humid conditions. An environment that has cycles (e.g. humid summers, dry winters) would give a constant hydration/dessification cycle, which would probably cause a lot of wear and tear.

You might want to consider the influence of UV light. UV is damaging to all sorts of materials given enough time: plastics tend to yellow and go brittle, pigments (in paints and in animal/plant tissue) lose their colour, etc. So if part of your sterile world was exposed to regular bright sunlight for a few years, you might expect all the preserved corpses to look bleached. If your timescale is decades or longer, stuff built from plastic might be broken, especially if it's built of metal that expands and contracts with heat combined with increasingly brittle plastic. A lot of painted or dyed objects might start to lose their colour but, with synthetic paints, that should take a much longer time, possibly in the order of hundreds of years.
posted by metaBugs at 8:38 AM on October 12, 2009

(And if you do go ahead with this, please let us know.)
posted by IndigoJones at 8:45 AM on October 12, 2009

I would guess sort of mummified. High Mountain Mummies from Peru.
posted by bdc34 at 8:49 AM on October 12, 2009

A double-talk mechanism for your magic button: it causes the entire surface of the planet to be hit with a huge burst of gamma rays.
posted by Chocolate Pickle at 9:15 AM on October 12, 2009

Hmm, no one's mentioned it yet so I'll just toss out the observation that living cells contain their own digestive enzymes, mostly corralled inside subcellular vesicles called lysosomes. When cells die, the lysosomal membrane can rupture and spill the enzymes out into the cytoplasm. So your dead bodies in a sterile world might undergo some auto-digestion from their own enzymes.

There's another pathway for programmed cell death called apoptosis, which normally does useful things like removing damaged or virally infected cells. (Also, in plants, it's what lets trees drop their leaves in autumn, and why truly ripe fruits separate from the stem with a clean scar rather than a torn stub of stalk - look for that scar when you buy tomatoes and melons!) Anyway, I'm no expert on apoptosis but it's conceivable to me that this pathway might get triggered here and there as part of a last-ditch "gotta clean up all these nasty dead cells" effort.

So you might get some patches of oozy messiness before dessication shuts everything down.
posted by Quietgal at 9:21 AM on October 12, 2009 [1 favorite]

oops sorry, i did mean physical and chemical.
posted by london302 at 9:41 AM on October 12, 2009

Mechanism: It could be any number of things. If you wanted a slow death giving time for the plot to evolve you could use apoptosis as someone suggested it. If you wanted it to be fast you could use a meachanism which interferes with oxidative phosphorylation. The challenge will be to distribute the substance which causes the widespread death. Getting this chemical or even gama rays to deep into the oceans and rainforests etc.

Apoptosis needs energy so dead bodies may be more likely to go down the lysosomal digestion path than apoptosis. Someone might be able to calculate the total amount of enzyme in all lysosomes and total amount of protein in human body and give a sense of how much degradation can happen that way.
posted by london302 at 9:58 AM on October 12, 2009

Digestive enzymes, such as those found in lysosomes, are sensitive to pH. They don't operate well outside of lysosomes, which are kept at a lower pH relative to the cytosol. Note that once respiration (and thus ATP production) ceases, the proton pumps maintaining this pH difference will stop working, and pH will normalize between the lysosomes and the cytosol. But given that the volume of the former is much, much smaller than volume of the latter, the pH of the cytosol will lower very little.

Enzymes are also sensitive to temperature. Remember that they're optimized to function at the normal temperature of the organism. Once the body dies and starts to lose heat, the activity of the enzymes will drop (though not to zero).

Also keep in mind that once a certain degree of water loss occurs, the enzymes will lose structure and functionality. So even if some degree of self-digestion did occur, it would not continue indefinately. I'm guessing dehydration would halt the process with a week or two.
posted by dephlogisticated at 4:23 PM on October 12, 2009

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