If you were the last person on Earth, how long could you survive?

[M344587487]

I'd probably last a few years until my sanity came into question, I'm picturing a scenario like in the 1985 film The Quiet Earth. Zero chance of finding a mersenne prime but solar panels would be useful for power.

[kriesel]

Originally Posted by MooMoo2

Suppose an alien or a God were to instantly rapture all of humanity except for yourself. What's left is everything that was not worn by anyone at the time - houses, vehicles, animals, and pretty much everything in the malls and stores. This event occurred at midnight when you were asleep. When you wake up, you find a brief note stating that everyone has vanished, and that nobody will be returning regardless of what you do.

How long could you survive, and what would you do? Without anyone to maintain the infrastructure, how long would it be until the water and power grids fail, and is there anything you can do to delay it? Can you get a semi-dependable food source before the groceries in the stores go bad? For the medium and long-term, could you perform medical care on yourself, and would you relocate to a more hospitable area?

Bonus question: Do you think you'd have a reasonable chance of finding a new Mersenne prime before you die? You'd have access to all of the computers in the world that aren't password-protected, but you still have to focus on survival, and the Internet might go down or be inaccessible within weeks.

(note: This is somewhat similar to: http://www.mersenneforum.org/showthread.php?t=22778 . In that scenario, the man-made objects disappear while the people stay, but in this scenario, the people disappear while the man-made objects stay.)

Read the book One Second After for some ideas. See the Martian. No showers, baths, or flushing when the power goes out. Results could range anywhere from a full life expectancy, to 90 days if diabetic (insulin goes bad, you run out of it, you run out of ice to lengthen its potency with, etc), to less than a week if water's unavailable or you panic and don't realize nearly every house has a nice big tank of it called a water heater. In an ordinary utility interruption scenario, and apartment living, it's a good idea to have some bottled water already on hand, maybe run the tub full before the water tower gets empty and throw the shower curtain over it to keep dust out and evaporation in. A full cupboard is a good idea too. And in the specific scenario, last man on earth, the house next door's tank is available too with a little effort. And the next, and the next... Each could provide more than a month's drinking water.

For hunting, "modern munitions are built to outlive the people who purchased them" if properly stored. http://concealednation.org/2015/05/d...s-take-a-look/

Gardening gets to be more work without any power tools to till the soil. But a productive garden may make small game hunting easier; rabbits come for your lettuce, and end up staying for dinner after some time cooking on the wood stove. In the short term one could harvest cattle, and each would provide a lot of meals. Refrigeration is an issue, but supply is not. Learn how to make jerky. After a couple generations of game life span, hunting becomes easier because few of the game animals have ever encountered a human and their numbers increase considerably. Fisheries should also bounce back. Feral dogs could be a serious threat. Having a large dog of your own may not be worth the effort of feeding it. Native Americans made dog stew. Wood gathering becomes a lot of work when the grid's down & there's no usable gas for your generator or chain saw. Axes and falling trees also present the possibility of going to an ER staffed by only you. Cut wood only keeps so long unless it's protected from rain and snow and bug free and dry enough. Moldy wood is not healthy to have around and becomes wetter as it breaks down.

A bicycle in good condition would be a good thing to have, for the occasional trip to the sporting goods or hardware store. Also a bike-towable light trailer would be good. Bike tires are made of rubber and will slowly deteriorate over decades. Good ones can still be ridden after a few decades of hanging on a rack if properly and carefully inflated. (Dry and dark helps.) Where I live, bars, grocery and convenience stores, gas stations, liquor store, pharmacy, village library, and hardware stores are all in walking distance, as are farm fields, orchards, and lakes. Bank branches too but they become irrelevant. Solar panels plus an inverter would allow some limited daytime computing, but with no internet availability, it might be hard to know what primes to test. Battery life is only a few years typically, and there won't be any new ones getting made. Once 220ac goes away or the well pump fails, water's a problem here. Back to the sporting goods store for water purification tools and supplies. Water storage technique is important. It doesn't take long for a bit of algae to make an illuminated bottle of water quite unpleasant (smelly) and perhaps unsafe.

The far future timeline someone posted could also include, 600 million years, the end of multicellular life on earth due to a shortage of carbon in the biosphere due to weathering of rocks to carbonate.

The article quote saying the big pipes from Hoover dam are to _cool_ the generators was amusing. I remember seeing pictures of the generators, and they appeared to be air cooled. The water is what _powers_ (turns) the generators' turbines; flow rate times gravity head which at Hoover is a quite considerable height, minus the frictional loss of head in the pipe. https://www.quora.com/How-are-the-el...ver-Dam-cooled

[Dr Sardonicus]

Originally Posted by kriesel

The article quote saying the big pipes from Hoover dam are to _cool_ the generators was amusing. I remember seeing pictures of the generators, and they appeared to be air cooled. The water is what _powers_ (turns) the generators' turbines; flow rate times gravity head which at Hoover is a quite considerable height, minus the frictional loss of head in the pipe. https://www.quora.com/How-are-the-el...ver-Dam-cooled

Looks like the History Channel really fouled up that time. Sheesh.

I don't know what the time line is for Mr. Sun getting bright enough to warm things up too much for us to survive, but IIRC present thinking has it in the hundred-million year range.

I heard somewhere that humans can't survive indefinitely in an ambient temperature of 130 F (54-55 C) or higher.

[Chuck]

I just came back from my two morning walks, one to Lowes and the other to the Publix supermarket. Both of these stores are within 15 minutes walking distance. The grocery has a large diesel generator, but I probably wouldn't be able to operate it or get fuel.

All the stores are going to be closed up since the event happened at midnight. I will be breaking in the next day, probably using a long wrecking bar to get in. I will need to board up any broken glass to keep animals out.

Without refrigeration, the grocery store will soon become unpleasant with all the rotting meat and other perishables. I will probably want to spend the first days hauling out canned foods and other non-perishables and bottled/canned drinks. I will select the largest nearby house for canned goods storage and empty it of spoilable items. I'll select another house for trash dumping.

I have Derek Humphry's book Final Exit which details the drugs needed for assisted suicide, so I will be sure to lay in a supply from a nearby pharmacy.

[Uncwilly]

Originally Posted by Dr Sardonicus

I heard somewhere that humans can't survive indefinitely in an ambient temperature of 130 F (54-55 C) or higher.

If everything is continuously above say 115, it becomes hard to ingest fluids that are effective to sweat. If you can keep the fluids coming in at a low temperature (<37C) it can help. I haven't been up that high (130), but have been out in the desert above 120 F. Shade is important.

I have removed items from a 550C furnace before with my bare hand. (But that is a story for another day.)

Originally Posted by Chuck

I have Derek Humphry's book Final Exit which details the drugs needed for assisted suicide, so I will be sure to lay in a supply from a nearby pharmacy.

Just hope they don't go bad by the time you chose to use them.

[Chuck]

After a little further thought, why not just take the drugs after a couple of days (I'm already approaching 70)? Have a good feast from the grocery while the meat is still good and the ice cream is still frozen. There's really no point in running around hoarding supplies.

[Dr Sardonicus]

Originally Posted by Uncwilly

If everything is continuously above say 115, it becomes hard to ingest fluids that are effective to sweat. If you can keep the fluids coming in at a low temperature (<37C) it can help. I haven't been up that high (130), but have been out in the desert above 120 F. Shade is important.

I have removed items from a 550C furnace before with my bare hand. (But that is a story for another day.)
Just hope they don't go bad by the time you chose to use them.

I heard, many years ago, about a man who deliberately subjected himself to a temperature of 400 degrees F for, if memory serves, 20 minutes. There was even a video. The "oven" he was in was a small cubicle, heated by a large number of incandescent light bulbs. He said afterwards that they could have baked a batch of cookies in the oven while he was in there.

Also IIRC, it was for a Guinness World Record. Guinness subsequently dropped the whole category of life-endangering stunts, which probably helps explain my lack of success in finding anything about it on line.

The highest temp I have willingly endured for any length of time is in saunas. Some would be at least 200 degrees F, and I'd sit in there, sweating profusely, for maybe 20 minutes. Of course, saunas are fairly dry. Putting a bit of water on the heat creates steam, and that really packs a wallop. Especially if you're near the ceiling...

There was a sign in one large sauna I used, warning people not to lie down on the benches. The nail heads were really hot, but I think the real reason for the sign was, if you did lie down, you might not be able to get back up.

[retina]

Originally Posted by Dr Sardonicus

There was a sign in one large sauna I used, warning people not to lie down on the benches. The nail heads were really hot ...

It isn't that the nail heads are hotter than the other things, it is the amount of heat energy they can transfer to your skin. It is all about thermal conductivity.

[Uncwilly]

Originally Posted by Dr Sardonicus

I heard, many years ago, about a man who deliberately subjected himself to a temperature of 400 degrees F for, if memory serves, 20 minutes. There was even a video. The "oven" he was in was a small cubicle, heated by a large number of incandescent light bulbs. He said afterwards that they could have baked a batch of cookies in the oven while he was in there.

Also IIRC, it was for a Guinness World Record. Guinness subsequently dropped the whole category of life-endangering stunts, which probably helps explain my lack of success in finding anything about it on line.

There was more than one experiment. It was the US military that did the endurance testing. They did 'heavily clothed' and unclad tests. If memory serves the clothed record was over 500 F. I have an older GBWR 1983 at home and will look into it when I get a chance.

[xilman]

Originally Posted by Dr Sardonicus

The highest temp I have willingly endured for any length of time is in saunas. Some would be at least 200 degrees F, and I'd sit in there, sweating profusely, for maybe 20 minutes. Of course, saunas are fairly dry. Putting a bit of water on the heat creates steam, and that really packs a wallop. Especially if you're near the ceiling...

There was a sign in one large sauna I used, warning people not to lie down on the benches. The nail heads were really hot, but I think the real reason for the sign was, if you did lie down, you might not be able to get back up.

I frequently spend 20+ minutes at 85-95C, lying down. If a bench has exposed metal it needs fixing. Nothing to do with lying down --- a nail head is painful wherever it touches.

The hottest at which I've spent any significant time is around 110C to 115C.

With an unlimited supply of cold water to drink I could spend much longer times in a sauna.

At the other end of the thermal spectrum I've removed items from buckets of liquid nitrogen. The secret is to have dry hands and not to hold on to metal for more than a small fraction of a second.

[Uncwilly]

Originally Posted by xilman

At the other end of the thermal spectrum I've removed items from buckets of liquid nitrogen. The secret is to have dry hands and not to hold on to metal for more than a small fraction of a second.

Much the same from the furnace. Dry hands are important and the thermal mass and conductivity are vital. I have put things (crucibles, evaporating dishes, and weighing dishes) in a 550 C furnace several times barehanded. I have only removed the little aluminum weighing dishes (photo) with my unprotected paw. The little tabs that stick up are very thin, so the contact area is small, if one grabs them by the edges, and they have a very low thermal mass. We often times squared up the dishes to fit them in trays, so they had corners. The heat load was higher, but still quite ok. A few calluses on the fingertips would help.

One can find videos of individuals passing clean hands through molten metal.