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

[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.)

[retina]

Without all the thousands of minions looking after the power generation plants they will stop producing stable voltages very quickly; within just a matter of hours, so forget about relying upon electricity.

You would have to learn to live off the land or you will die of starvation or thurstation* after a few months. That is if you haven't already died from exposure due to the weather, or animal attack, or accident.

But in general if you leave the barren city and eat the plentiful fruits and meat available elsewhere then you'll be fine physically. Mentally might be a different matter though.

* English needs a single word to describe death from lack of water.

[a1call]

It would be disastrous. There would be no one to read threads like this or reply to it.

I have lived through the ice storm in Montreal where the power was out for days.
Most of my day was spent preparing food and heating it.
Where you live and the timer of the year will make a big difference.
There are native people in central Americas which live in mountains completely off the grid and dine on free fruits they gather from their immediate environment.
Even the native Inuit would probably have little trouble going back to their root living methods and survive easily, as harsh as their environment is.
I doubt it if l would find a new Mersenne prime or be interested to. But I might setup a large computer farm powered by generators and find new record primes of N-1 proven variety.

[jvang]

Originally Posted by retina

You would have to learn to live off the land or you will die of starvation or thurstation* after a few months.
* English needs a single word to describe death from lack of water.

There's dehydration and/or hypernatremia, which would probably be fatal after a couple days

I'm pretty sure that finding a new Mersenne prime is not likely in this new world; like retina said, the power grid would fail in a short time. As far as surviving, you'd have to hunt and/or farm and provide for yourself; perishable foods would spoil very soon without refrigeration and canned food is lame I think mechanical machinery like cars would last for a while, but you'd have to scavenge fuel and parts from all the abandoned stuff. Maybe you could find some solar panels and generate a bit of your own power for simple electronics...

[Chuck]

Find a supply of long-term storage food (I have 30-year cans here at home), and take day trips from there to amuse yourself. The gas pumps won't work after a short time so you'll have to break into cars along the way. I probably have less than 20 years to live so it shouldn't be a problem.

I'd probably want to eventually work my way to a temperate climate.

[axn]

Isn't this the plot of "I am legend" movie?

[VictordeHolland]

This reminds me of a documentary: https://en.wikipedia.org/wiki/Afterm...opulation_Zero
and a movie: https://en.wikipedia.org/wiki/Bokeh_(film)

The biggest problem is your mental health after such a catastrophe.

First day: Arrrrgghhh, cry and curse all day.

After 1 week: Power, water and gas will probably have failed by now. Hopefully nuclear plants have shut down safely. But with so many old reactors and nobody to operate the batteries and diesel generators running the pumps to cools the reactors, the decay heat will melt at least some of the nuclear reactor cores. Better get far away from them. Start planning long term. Hoard as much canned food as you can.

After 1 month: migrated to a milder climate (for instance to the Mediterranean Sea). Find a house with solar panels and get some Tesla (or other electric cars). Why? Because gasoline and diesel start to go bad after a year and become completely unusable in cars after a couple of years.

After 1 year: it's mostly canned food from here on. So you better start thinking about farming if you want any fresh veggies, milk, eggs and meat.

After 10 year: you're completely self-sustainable by now. Your cat will die and cause a complete mental breakdown. What do you do with the rest of your life?
Nature starts to reclaim its ground.

After 50 years: the last person has died. Cities will be unrecognisable. All man-make objects start to erode away.

After 200 years: Atmospheric conditions, forests, wildlife and sea-life will have reverted to the state as they were before humans.

After 100,000 years: After an ice-age, the presence of humans can still be detected by the slightly higher radioactive layer in the soil.

After 100 million years: Plate tectonics will have changed the earth completely.

After 1 billion years: Sun will be 10% more luminous by now. Oceans start to evaporate

After 4 billions years: Milky Way and Andromeda galaxies collide. A spectacular view this must be!

After 5 billions years: Sun will enter its Red Giant stage. Earth will be nothing more than a sea of lava (surface temperature of 2000 C). In the end the Earth will be swallowed by the Sun or evaporated to space.

[Dr Sardonicus]

There was a series some years back called Life After People. Its premise was that, one fine day, the human race simply vanished. Then...

One of the bits I remembered is chronicled in the Life After People Wikia:

1 day after people; As generating plants cease to produce electricity, the last glow of artificial light on earth will be visible southwest of the United States. There, the mighty Hoover Dam can remain operating unattended in weeks, months, or even a couple of years. But in life after people, how long will the Dam still supply power to Las Vegas?

1 year after people; As long as the pipes are open, which carry water to cool the generators that power Las Vegas, the Hoover Dam will still be supplying electricity. But now these generators are about to be brought down by an organism the size of a thumb nail...the Quagga Mussel. These organisms will place on the inside of a pipe, multiply on top of one another, and eventually completely block the diameter of the pipe, preventing cooling water from moving to a generator, and causing the generators to overheat and shut down. Las Vegas now goes dark permanently. With the generators down no water moves through the dam and the Colorado River downstream will run dry until the waters rise high enough in Lake Mead to run through the dam’s spillways like a waterfall.

10,000 years after people; The Hoover Dam, one of the last remnants of modern civilization, finally collapses due to erosion of its concrete and the cumulative effect of seismic activity.

[The Carnivore]

Originally Posted by axn

Isn't this the plot of "I am legend" movie?

The major difference is that you won't need to worry about any zombies, spend time trying to develop a cure, or search for other survivors.

You do need to defend yourself against wild animals, though, which would certainly overrun the cities in a matter of months. Ammunition might not be reliable after a few years, but you'll have enough time to perfect your archery skills by then.

The other concern would be shelter. How long would those McMansions last? Also, without a fire department, things will get tricky, especially if/when a gas line breaks. It only takes one spark from a wildfire, a downed power line, or a lightning strike, and an entire city could go up in flames in a few hours.

You'll be dead long before this, but the last remnants of human civilization would be whatever is etched deeply into stone, like those faces in Mt. Rushmore. I wouldn't be surprised if those stuck around for the next million years.

[The Carnivore]

Originally Posted by Chuck

Take day trips from there to amuse yourself. The gas pumps won't work after a short time so you'll have to break into cars along the way.

If everyone but yourself instantly disappeared, the cars on the road would remain in motion but be driverless. Most of them would be wrecked and blocking the roads. This would be of little concern in a residential area, but the highways would likely be unusable. You'll also have to watch for planes falling from the sky on the first day.

And speaking of roads, how long would they remain driveable? Would weeds and shrubs start growing in the asphalt after the first year? Also, after you've broken into the cars, wouldn't the gas in them have expired if they haven't been used for years?

I think I could last for a few years. I doubt I'll have the resources to find a new Mersenne prime, but if I get insanely lucky and do succeed, I'll carve it into Mt. Rushmore for the next civilization that lands on Earth.

[Chuck]

Since the event happened at midnight, I thought there would be minimal traffic. Probably mostly over the road trucks.

Or maybe the original poster envisioned a "benign" event such as engineered by Klaatu in "The Day the Earth Stood Still".