How long could humanity survive if Earth were flung out of its orbit?

[Loopus]

Let's say that, for no discernible reason, Earth suddenly flew off on a line tangent to its current orbit at a speed equal to about its current orbital speed. How long would humanity be able to last? Some heat is obviously trapped by the greenhouse effect, but how long would it take to dissipate, and would it be possible to jerry-rig some way of saving some people for longer than the trapped heat would last?

[billfish678]

At at very rough first WAG its going to be the equivalent of deep winter in 3 or 4 months. Another 3 or 4 months and its gonna be like middle of winter Anarctica Cold. And after another 3 or 4 it gets really ugly.

You might be able to have some isolated pockets of people surviving near/in nuclear power plants until the fuel already in the reactor runs out, which might be a few years (or a good bit more if they can eek out the supply).

[Duckster]

If you put a steamy cup of coffee in the refrigerator, it wouldn’t immediately turn cold. Likewise, if the sun simply “turned off” (which is actually physically impossible), the Earth would stay warm—at least compared with the space surrounding it—for a few million years. But we surface dwellers would feel the chill much sooner than that.

Within a week, the average global surface temperature would drop below 0°F. In a year, it would dip to –100°. The top layers of the oceans would freeze over, but in an apocalyptic irony, that ice would insulate the deep water below and prevent the oceans from freezing solid for hundreds of thousands of years. Millions of years after that, our planet would reach a stable –400°, the temperature at which the heat radiating from the planet’s core would equal the heat that the Earth radiates into space, explains David Stevenson, a professor of planetary science at the California Institute of Technology.

Although some microorganisms living in the Earth’s crust would survive, the majority of life would enjoy only a brief post-sun existence. Photosynthesis would halt immediately, and most plants would die in a few weeks. Large trees, however, could survive for several decades, thanks to slow metabolism and substantial sugar stores. With the food chain’s bottom tier knocked out, most animals would die off quickly, but scavengers picking over the dead remains could last until the cold killed them.
http://www.popsci.com/node/24698

The above scenario is if the Sun were to just switch off generating energy. Assuming the Sun continued to exist but its gravity could not hold Earth in orbit as you suggest, probably the same set of events with the initial set of event time horizon (say first 90 days) stretched out a bit. The actual result wouldn't change.

[TriPolar]

Assuming the fling doesn't kill everybody by creating massive earthquakes, eruptions, and tsunamis, then it doesn't matter much. You can dig down, the core will stay hot for a long time, but what is anyone going to eat? The surface temperatures will plummet. Available sunlight will be constantly diminishing, and we're all living underground like mole-people. Providing light to grow food could go on for a short time while electricity can still be generated. But the few people who could survive on the scant resources won't be able to maintain technology for very long. Even the oceans which could maintain a vast food supply will freeze over eventually.

So a few people stay alive for a few years, but before too long everyone dies.

Why do you ask? Did you hear something?

[Boyo Jim]

Part of the answer is dependent of where Earth goes. On a collision course with Mars, maybe? Or a moon collision? I'm curious to what the odds are of getting an Earth-sized planet through the Asteroid Belt without taking some major hits.

I think people could survive for thousands of years if we learn how to tap the heat at the Earth's core.

[Silophant]

Part of the answer is dependent of where Earth goes. On a collision course with Mars, maybe? Or a moon collision? I'm curious to what the odds are of getting an Earth-sized planet through the Asteroid Belt without taking some major hits.


Probably pretty good. Cassini passed through the asteroid belt without coming any closer than 1.6 million miles to an asteroid. (http://uanews.org/node/2841)

[Boyo Jim]

Probably pretty good. Cassini passed through the asteroid belt without coming any closer than 1.6 million miles to an asteroid. (http://uanews.org/node/2841)

Any idea if they planned the course (or the timing) to avoid known objects?

[Washoe]

In the mid-1970s there was a British documentary series hosted by Martin Landau which addressed this very scenario. Despite the fact that Earth has never been contacted by an alien race in it’s entire recorded history, and the fact that we will be scooting along at a pace that won’t even carry us to the nearest star system for tens of thousands of years, within a matter of weeks we will inundated by visits from alien species of every conceivable form. And since they’ll all be a hell of a lot smarter than we are, they will undoubtedly figure out a way to keep us all alive, if for no other reason than to harvest our internal organs both for food and for replacement parts for their ailing geriatric populations.

[Heracles]

I think people could survive for thousands of years if we learn how to tap the heat at the Earth's core.

... and if we don't lose the can opener. How long does Spam remain edible?

[billfish678]

Lets assume the powers that be set up "survival stations" near/at nuclear plants. Use weapons to kill off any folks not part of the survival plan that try to get in.

You've got about 6 months to a year to get you powered greenhouses up and running and shelter from the intense cold that will be powered by the plant. So far so good.

But, again a rough WAG. In about 3 years give or take its going to get so cold the atmosphere will turn to liquid then solid. Well, thats pretty bad because thats hella cold. But worse than that is the fact you no longer HAVE an atmosphere. So, no its not just damn cold, its like living on the moon. You gotta run around outside in space suits. All your buildings don't just have to be well insulated with power running to them, they gotta be able to be made airtight and able to be pressurized.

I think spurr of the moment hands on work and engineering could get you through the its getting cold then damn cold phase. I don't think you'd have enough time to covert enough buildings to the equivalent of ground based space stations though. Now maybe if this disaster was something we knew was coming for a long time and had time to hash out a plan and get ready.

[Great Antibob]

Any idea if they planned the course (or the timing) to avoid known objects?

No, they didn't.

We like to think of the Asteroid Belt as filled with spacecraft destroying rocks, but it's fairly safe to travel through it.

It's densely populated compared to interstellar space, but it's thinly populated in human terms.

To be honest, it would probably be much more difficult to plan a course that intersected the larger known bodies. Just pick a course at random, and you're facing millions or billions to one odds of actually hitting anything.

There's always been some slight fears about our deep space probes hitting asteroids, but the odds are apparently low (http://www.spacedaily.com/reports/New_Horizons_Crosses_The_Asteroid_Belt.html).

Even something the size of Earth is probably safe. For large scale damage to earth, we'd really only have to worry about hitting larger bodies, and those are rare.

[Francis Vaughan]

One assumes this is based upon A Pail of Air (http://www.webscription.net/chapters/0743498747/0743498747___6.htm) by Fritz Leiber. I remember reading this story when I was quite young, always stayed with me.

(Ha!, and I now notice it is also linked to in the comments to the article Duckster links to.)

[Candyman74]

Survival would be a similar challenge to setting up a colony on some outer planet or a very long-term space flight. If we work out how we could do that on, say, Pluto, we could do it here. But not for many people - we wouldn't be able to convert the entire planet. So 99.9999% of people would die pretty quick.

The problems are gonna be lack of atmosphere, and lack of food. If we have some kinda nuclear power generation keeping us warm in a dome or underground, we can presumably melt and filter ice for water.

But the food's gonna be hard; we'd have to have massive protected greenhouses. Can photosynthesis be achieved with UV lamps? I'm nowhere near enough knowledgeable to answer that.

Power would, I think, have to be nuclear. And most of that would go towards heating. There would probably be conflicts over energy supplies.

Essentially, we'd have to build "arks" on or under the earth, and these would have to be as self-sufficient as a space-travelling ark would be.

[billfish678]

On second thought, large airtight structures might not be a big deal. Earth has no shortage of water. And its gonna get cold. Make giant domes outa ice. Or just melt tunnels into thick layers of ice. Of course you can't let the inside surface get above freezing, but with no wind and decent clothing it wouldnt be bad. And folks could finally make use of all those unwanted tacky sweaters everyone gets as gifts.

[Stranger On A Train]

Part of the answer is dependent of where Earth goes. On a collision course with Mars, maybe? Or a moon collision? I'm curious to what the odds are of getting an Earth-sized planet through the Asteroid Belt without taking some major hits.

I think people could survive for thousands of years if we learn how to tap the heat at the Earth's core.As previously noted, the probability of impact with a solid object should the Earth shoot off in a random trajectory is negligible, likely even less than the probability of impact with a hazardous object in its existing orbit, as it isn't subject to periodic intercept due to orbital resonances. The asteroid belt between Mars and Jupiter is, as noted, almost completely empty space.

Ignoring the issue of sudden release of gravitational energy by from the Earth being relieved of its orbit and just focusing on the thermodynamic effects, there are several previous threads on the topic, such as this one. The estimates that the Earth would be able to maintain habitable conditions for months are hopelessly optimistic. More reasonable estimates are weeks before the atmosphere starts to condense. Once the atmosphere becomes too cold to maintain water vapor, there will no longer be a cloud layer to reflect radiative heat back to the surface. While the CO2 in the troposhpere is opaque to infrared radiation, it is also pretty sparse. Furthermore, without the radiation from the sun to drive atmospheric circulation, layers of the atmosphere will tend to separate, further disrupting the retention of radiative heat. (This will reduce convective loss from the lower atmosphere to the tropopause and up to the stratosphere, but those losses are small compared to radiative losses.)

The proposals for using geothermal or nuclear fission energy sources to support habitation have grossly underestimated the amount of energy required to maintain life in a long term, self-contained environment. The energy we get from the sun isn't just provide warmth and visible light that allows us to see; it provides energy for photosynthesis, which ultimately supports all food production, and the hydrological cycle, which moves, distills, and filters water. Even petroleum and coal that we extract from the ground is ultimately a storage and distribution medium for solar energy that was generated tens of millions of years ago. When you eat an apple, the amount of energy in the entire cycle to produce that apple isn't just the energy stored in carbohydrate chains and protein structure of the fruit itself, but all the energy to construct the tree, provide water, and transport the apple to your grocery store. This totally energy cycle is several orders of magnitude more than the roughly 500 kJ of energy you can actually extract from the apple. Controlled environments may gain some efficiencies over an open cycle, but a self-contained habitat still results in substantial wastage of energy.

Nor do we currently have the capacity to construct complex equipment that will operate for decades, much less millennia, without significant maintenance and external material. Even if you could construct a habitat that would allow you to maintain a civilization indefinitely without a substantial infrastructure to support it. A nuclear fission plant, for instance, would require facilities for the entire fuel extraction, processing, and refinement cycle, as well as periodic replacement of components that fail due to wear, corrosion, and neutron bombardment.

If this type of disaster were to occur, humanity would not be able to survive any significant period. We simply lack the technology, infrastructure, and resources to provide self-sustaining habitats outside of the natural bounty of accessible energy provided by the sun and converted by food plants and animals.

Stranger

[Shinna Minna Ma]

Despite the fact that Earth has never been contacted by an alien race in it’s entire recorded history . . .

Sure we have. It says so right in this (http://en.wikipedia.org/wiki/Chariots_of_the_Gods%3F) book.

[Boyo Jim]

In the mid-1970s there was a British documentary series hosted by Martin Landau which addressed this very scenario. Despite the fact that Earth has never been contacted by an alien race in it’s entire recorded history,...

Obviously you've never seen Nancy Grace nor her spawn.

[billfish678]

Running some very back of the envelope calculations from random info on the net and assuming 2000 square meters per person to grow food the old fashioned in the dirt way but using artificial light for the plants, your 1 Gigawatt nuclear plant could support on the order of 1000 people food wise.

About 300 Gigawatts of current worldwide nuclear power means 300,000 people worldwide. Maybe with hydroponics you can push that up to 3 million? And there well could be other practical considerations that drive the number way lower instead.

Might be able to eek out a handful or two of years till critical stuff in the reactor can't be replaced or fixed. Would the surviving population base be big enough to support specialized industry needed to replace critical parts/supplies? Seems unlikely at first glance to me.

Maybe you could transition to using the liquid part of the ocean to provide power. That power supply might last a fair bit longer until the ice gets too thick to get at the liquid water below.

But it all would probably be like Battlestar Galactica. Things just slowly going to shit with no practical way to stop it.

[enalzi]

Let's say that, for no discernible reason, Earth suddenly flew off on a line tangent to its current orbit at a speed equal to about its current orbital speed.

I got bored and decided to figure out exactly how fast that would take us out of our Solar System, figuring average orbital speed of 107,200 km/h. For this scenario, I also assumed that all the planets were in alignment (because obviously, that's what caused this disaster)


It'll take us almost a month (29 days) to reach Mars.
Then another 216 days after that for Jupiter.
Another 250 days til Saturn.
A year and a half (587 days) till Uranus.
604 days til Neptune.
Another 3 years (1104) days to apologize to Pluto at it's furthest point.
Hang on because it's gonna be about 4 and half years (1802 days) to the heliosheath.
Finally, assuming it stays at it's current speed of 61,420 km/h, 43.4 years after we began our journey through space, we finally catch up to Voyager 1.

[Lemur866]

But are we looking at human extinction within months, years, or decades? What's the over-under for at least one surviving human being at 1 year, 10 years, and 100 years?

[Lemur866]

Might be able to eek out a handful or two of years till critical stuff in the reactor can't be replaced or fixed. Would the surviving population base be big enough to support specialized industry needed to replace critical parts/supplies? Seems unlikely at first glance to me.


Since the nucleus of every group of survivors would be a nuclear power plant, you'd at least have the technicians that run the plant.

Of course, once people realize that, they'll start converging on the plants demanding a spot on the ark. If you could organize the entire industrial production of the planet to create survivable arks, you could do a lot. But this would be impossible, since once everyone realizes that they're doomed they're not going to work like dogs to stockpile an ark for a few thousand strangers. They're either going to try to fight their way in, or give up hope and stop working.

[Loopus]

One assumes this is based upon A Pail of Air (http://www.webscription.net/chapters/0743498747/0743498747___6.htm) by Fritz Leiber. I remember reading this story when I was quite young, always stayed with me.

(Ha!, and I now notice it is also linked to in the comments to the article Duckster links to.)

I hadn't heard of that story, but thanks for the link. I enjoyed it.

I actually got to wondering because I've been reading The Night Land (http://en.wikipedia.org/wiki/The_Night_Land). Since that is a work of fantasy rather than science fiction, I wondered about what would really be involved in losing the energy of the sun.

But, again a rough WAG. In about 3 years give or take its going to get so cold the atmosphere will turn to liquid then solid. Well, thats pretty bad because thats hella cold. But worse than that is the fact you no longer HAVE an atmosphere.

For some reason that didn't even occur to me, but it's a very good point. How thick a layer would the frozen atmosphere form anyway? Considering that by the time the air froze the oceans would be frozen over (thus making Earth's surface 100% land), it seems like it would form a layer over the entire planet of about equal thickness everywhere. Even survivors would find their shelters buried under frozen air. I wonder about the structural integrity that might be required to hold up to that too.

Also, if the atmosphere freezes and falls down in layers, as "A Pail of Air" suggests, it might make it difficult to get through the thickest layer of useless nitrogen to get to our precious oxygen.

I understand at this point, especially from Stranger's post, that human survival for longer that a few weeks is incredibly unlikely. But it's fun to think about. I may have a strange sense of fun. But that's why I like this board.

[billfish678]

I understand at this point, especially from Stranger's post, that human survival for longer that a few weeks is incredibly unlikely. But it's fun to think about. I may have a strange sense of fun. But that's why I like this board.

Strangers post appears to me to be talking about the Sun just going out so to speak. Taking a month or two to get out to Mars and beyond means things start getting pretty chilly soon, but not NEARLY as bad/fast as the not having ANY sunshine.

Oh, another core of short term survivors. Nuclear sub crews. They dump all those missiles, cram the sub full of canned goods and submerge. They might make it a couple of years.

My guess is the frozen atmosphere would be about 50 feet thick give or take.

[Elmer J. Fudd]

... and if we don't lose the can opener. How long does Spam remain edible?

It just occurred to me that food might not be very high on the list of problems. Wouldn't most of the world's biomass freeze and be preserved soon after death? Accessing it might be difficult but the planet would hold the equivalent of trillions of tons of frozen steak and veggies.

[billfish678]

Accessing it might be difficult but the planet would hold the equivalent of trillions of tons of frozen steak and veggies.

Good point. It might be easier time/energy wise to "mine" food than to try to grow it. But I sure as hell wouldnt eat anything/anybody dug up along the Jersey Shore.

Unless of course the "situation" was desperate :)

[engineer_comp_geek]

At at very rough first WAG its going to be the equivalent of deep winter in 3 or 4 months. Another 3 or 4 months and its gonna be like middle of winter Anarctica Cold. And after another 3 or 4 it gets really ugly.

I would think it would be a lot faster than that. The air can cool down quite a bit just overnight. I'm thinking you're going to be in deep winter by the end of the first week, which is a lot faster than your WAG. Of course, this is still a WAG on my part too.

[Arrendajo]

One assumes this is based upon A Pail of Air (http://www.webscription.net/chapters/0743498747/0743498747___6.htm) by Fritz Leiber. I remember reading this story when I was quite young, always stayed with me.

(Ha!, and I now notice it is also linked to in the comments to the article Duckster links to.)

The thing that bugged me about A Pail of Air, even when I first read it as a kid, is that they had the survivors bringing in pails of frozen oxygen, then thawing it beside the fire. Oxygen + fire = instant disaster.

[billfish678]

I would think it would be a lot faster than that. The air can cool down quite a bit just overnight. I'm thinking you're going to be in deep winter by the end of the first week, which is a lot faster than your WAG. Of course, this is still a WAG on my part too.

How much less sunlight is the Earth going to get one week out? About 10 percent less.

How much less sunlight does a hemisphere get in dead of winter vs middle of summer? Very rough number is 50 percent less. At mid latitudes you get about 16 hours of light a day during the summer and more like 8 during the winter. Then there is that whole angle of the sunlight on the surface thing too.

So its going to take something like a month (and more like 2) to get total sunlight intensity due to increasing distance down to winter levels. Then there is the thermal lag. It does take some time to cool the air, ground, and water down. Average coldest day is something like a few weeks to a month after winter solstice, even though the amount of sunlight received after the solstice is increasing during that time.

Then there are the oceans. Once you try drive the temps way down (like antarctica cold) the oceans will start to freeze. That will slow the cooling down till most of the ocean surface freezes to a decent thickness, so that probably also slows down things a bit for a few weeks.

Add all that up and its 2 to 3 months.

Or to take another tact, IIRC the standard line is that Mars would be chilly but liveable if it had a nice thick earth like atmosphere. If the Earth for some reason just keeps going straight in its orbit (tangential to its orbital path) at any point, its going to take like 2 months for the Earth to be same distance from the sun as Mars. This estimate jives with the first one.

Now, if you happen to be in the hemisphere thats in the dead of winter when the big fling happens you probably have more like just a month before things get ugly.

[engineer_comp_geek]

For some reason, it stuck in my head that the reason the earth had gone off on a tangent was because the sun had disappeared, and that stayed in my head even as I skimmed down the thread. So sorry, brain fart. Carry on.

[TriPolar]

It kind of means the Sun isn't exerting a gravitational force anymore. Since we're assuming all sorts of things here, I think it's fair to assume that the combined efforts of mankind could create a deep underground chamber where a bunch of people could stay alive for a while before the food or heat runs out. But that just prolongs the inevitable. Everybody is going to die eventually.