# The earth is flung into deep space

a binary pair of black holes is cruising into the solar system, and threatens to slingshot the earth out into deep space

That's got me thinking, is there any chance of survival beyond a few days/weeks when the atmosphere freezes? (Would it freeze?)

Just off the top of my head, I suppose a nuclear submarine parked near some geothermal vents (where the water hopefully wouldn't freeze) could last until the food ran out. The folks on the ISS wouldn't have sunlight for power so they wouldn't last too long.

Obviously we'd be looking at either nuclear or geothermal energy sources to keep us going, coupled with some closed loop life support systems. To be sustainable (both short term for food and long term for population), it'd have to be fairly large-scale.

In The Martian, Mark Watney is nearly self sufficient. He'd need more space to grow food, plus some nuclear power would help. Would that system scale? We have the advantage of earth's mineral resources that may still be accessible to an extremely well-equipped band of survivors.

Let's assume we have plenty of warning that the earth is going to be ejected (say decades).

Is there any possibility for humanity to survive long enough for us to develop advanced enough technology for our own deep space-capable ships (so, permanently)?

• VSauce sun disappearing - basically the same effect Just watched this video again, and as usual Michael tells the story in an interesting way. He is no scientist, but he checks his stories pretty carefully. Mar 24, 2016 at 8:26
• There's a story called A Pail of Air. Mar 24, 2016 at 17:23
• @GaryWalker Though captivating, Even Michael at VSauce is mortal. Was the filling of the Three Gorges Dam's impact on the Earth's rotation rate detectable?
– uhoh
Oct 10, 2018 at 17:29
• @JDługosz, I thought of that too but that isn't a winning proposition since they were mostly scavenging. The only reason they lasted so long is that they were the only ones around to scavenge food and fuel. Oct 19, 2018 at 22:01
• If we accelerated the Earth quickly to 99.999% speed of light with Heisenberg Compensators (so the Earth doesn’t collapse under such acceleration), we could probably make it to the next star without the complete collapse of the biosphere. Humans outside bunkers would NOT be part of the survival group.
– SRM
Oct 21, 2018 at 9:08

Lets take a look at this mathematically:

First off, take a look at Earth's energy budget. The incoming solar radiation is $\approx 240~\frac{\text{W}}{\text{m}^{2}} = 1.73 \cdot 10^{17}~\text{W}$ total. Imbalance between incoming and outgoing is about $\left(0.60 \pm 0.17\right)~\frac{\text{W}}{\text{m}^{2}}$, so relatively insignificant. This means that Earth radiates about $1.72 \cdot 10^{17}~\text{W}$.

Earth's oceans are a significant heat regulator for the planet, and contain about $1.4 \cdot 10^{21}~\text{kg}$ of water (source). This means a change of 1 °C in the oceans is equivalent to about $6 \cdot 10^{24}~\text{J}$ of heat energy. From this we have:

$$\frac{6 \cdot 10^{24}~\text{J}}{1.72 \cdot 10^{17}~\frac{\text{J}}{\text{s}}} \approx 3.5 \cdot 10^{7}~\text{s}=405\,days$$

So it would take a little over a year for the ocean temperature to drop by 1 degree Celsius.

For the purpose of the question, let's assume the majority of Earth's readily available heat is contained in the ocean, such that the ocean temperature directly correlates to the atmospheric temperature. This is an oversimplification, but not to far off (and in reality, the ground also stores a significant quantity of heat, so this will likely lead to an overestimate of how quickly the temperature drops).

This result means we would actually have quite a bit of time (on the order of years) before Earth became unlivable. Likely, we would see an immediate drop in temperature such that the mean temperature becomes about the same as we would expect for nighttime temperature. After this, we would see a more gradual decline corresponding with the loss of heat from Earth due to radiation. People in northern latitudes or desert regions would likely be in immediate danger, but tropical regions would likely remain livable for quite some time, and you are not in danger of the atmosphere freezing for a couple centuries at least.

The other immediate danger would be massive plant die-offs (due to lack of sunlight) followed by massive animal die-offs due to loss of food sources. The plant die-offs would have an interesting side effect of increasing carbon dioxide concentration in the atmosphere, leading to a stronger greenhouse effect and reducing the atmospheric heat loss.

Given the relatively slow heat loss, we should have enough time to build enclosed habitats powered by geothermal energy (coal, oil, and nuclear are all still options as well, but if you are already underground geothermal is quite convenient). There would still be significant casualties, but the short term effects would be at least as survivable as a nuclear winter.

Longer term (after about a century), the oceans would eventually freeze, followed by the atmosphere. At this point the surface would be completely inhospitable, and we would have to rely on underground habitats to survive.

So, given sufficient organization, yes, the human race should be able to survive.

• The ocean won't help nearly as much as you hope because it will take time for the heat to propagate to the surface. Once ocean ice forms, insulation will further retard the heat flow. The temperature difference between winter and summer should be a clue that your analysis is unrealistic. I can find projections from scientists of about -100 F to -150 F for surface temps after 1 year of losing the sun. Don't know if they modelled carefully or just took a guess though, but it seems much more likely to be accurate to me. Mar 24, 2016 at 7:45
• I feel the temperature loss risk is underestimated. I've heard that a 1-2°C increase in temperature in the oceans bleaches coral on a large scale, see skepticalscience.com/coral-bleaching.htm. While that's a climate change related problem and warming, not cooling, the ecological wrecks caused by a plant based CO2 increase and temperature decrease in the oceans could imbalanace lots of things. Consider that water can dissolve more CO2 at a lower temperature, for instance. Oct 22, 2018 at 1:20

No, if we lose the sun, we are done for. Simple as that.

1- We don't know what effect the gravitational slingshot would have on Earth's rotation. Earth is currently rotating at 360° per 24 hours. Which gives it a speed of 1675 km/h (reference). Any sudden difference in this would be quite catastrophic and would probably end humanity.

2- Sunlight is extremely important for human (and other mammals') health. "According to epidemiologist Robyn Lucas at Australian National University, analysis of lifespan versus disease shows that far more lives worldwide could be lost to diseases caused by lack of sunlight than to those caused by too much, and it is inappropriate to recommend total avoidance of sunlight." Also: Multiple sclerosis (MS) is least prevalent in the sunniest regions. Exposure to the ultraviolet-B radiation of sunlight appears to be most important and this may operate via vitamin D synthesis. (Wikipedia Article). And of course don't forget that sunlight is required for the synthesis of the vitally important vitamin D. (Also read this article for a quick idea of how essential sunlight is).

3- Remember chilling winter nights? Well, without the sun it is going to be one unending chilling winter night forever. No math required. And this chilling winter night would grip Earth as a whole. With no sunlight, the temperatures would plummet quickly. The mean temperature in deep space is barely higher than absolute zero (-273° C) and a cozy mean 24°C of Earth would drop dramatically in the absence of the sun. This is a chart of ocean depth versus temperature, present on wikipedia.

Mean ocean depth is 3000 meters and the temperature below 1000 meters is less than 6°C. Furthermore, water is a bad conductor of heath and if moon is shot away from Earth, a layer of ice would quickly form on the tide-less oceans, trapping the heat below from radiating into the environment. And in the presence of a moon (and tides) the motion of top layers of water would quickly radiate away their heat in the chill of deep space. Damned if you do (have a moon) and damned if you don't!

4- Did I mention that sunlight exposure is vital for children? Children deprived of essential time under sunlight develop short-sightedness. If we survive for 40 years (extremely, extremely improbable), 70% of the next generation people would have severe cases of myopia and rickets. The rest 30% would be frighteningly ghastly and barely able to feed, let alone actively work.

5- We cannot grow crops in the absence of sunlight. No, not with artificial lighting. First of all, how would we establish hundreds of thousands of miles of fertile, underground farmlands when we ourselves would have barely the liveable space? Secondly, how are we going to provide sufficient lighting to this enormous area? The sun provides Earth with 1,575 x 10$$^{18}$$ joules per year. This is several times greater than the combined energy consumption of the world and this is how plants get vast amounts of free energy. (Reference). So no, you cannot hope to grow crops underground in the absence of sun. At all not.

# Conclusion

No, we cannot survive in the long run (more than a few weeks) without the sun.

• We can simulate pretty well the sun light, so the health problem is somewhat solvable. The point about velocity il true, but i suppose that the question imply that earth survive the slingshot aspetto well as humans Mar 24, 2016 at 8:22

The amount of time humanity would have would largely depend on the velocity of the earth after the slingshot and/or the time it takes for the slingshot to occur. The thing to keep in mind is the sun wasn't snuffed out, the earth is just moving further and further away from it. The sun will still provide light and heat just in lower and lower amounts as the distance the earth travels from its normal orbit increases.

Think about how long it takes for a spacecraft to reach say the orbit of Mars from earth orbit. Some of the faster craft would take several months at closest approach, but if you are bearly hitting solar system escape velocity, it would take closer to a year.

If you had a slow enough escape velocity you would have time to implement drastic plans to buy you even more time to build colony ships, underground or underwater cities, etc. For example, you could intentionally release as much greenhouse gasses as possible in the atmosphere to offset the cooling for a time by doing drastic things like burning all the forests on the planet (they were going to die anyway) or converting chemical plants into massive greenhouse gas emitters, etc.

Also, there is the possibility that the slingshot would take the earth closer to the sun for a time before it passes the sun and continues on to escape the solar system. So you could have the opposite effect where the earth superheats for a while and then dies an icy death.

Either way, you should have more than a few weeks if you assume the slingshot was not so powerful it killed all the people on the planet by its self.

Edit I just noticed that you mentioned decades of warning. I think with decades of warning there would be a much higher chance of humanity surviving. I think you would see a massive global mobilization akin to going into a world war as every nation begins working on massive projects to delay the cooling, create colony ships, and/or go underground with zero regards to environmental contamination. Think world-wide Manhattan project for a minimum of 20years (warning period) with maybe 5 years twilight period (extended time till the surface of the earth is unliveable despite all intervention) with like 90+ percent of the GDP going to collosal extinction prevention projects.

• Finally a sensible answer :-) Oct 20, 2018 at 8:36

There's actually a popsci article about exactly this.

Pertinent:

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.

Also pertinent:

Humans could live in submarines in the deepest and warmest parts of the ocean, but a more attractive option might be nuclear- or geothermal-powered habitats. One good place to camp out: Iceland. The island nation already heats 87 percent of its homes using geothermal energy, and, says astronomy professor Eric Blackman of the University of Rochester, people could continue harnessing volcanic heat for hundreds of years.

It would be a miserable existence, but potentially sustainable with sufficient warning.

If humanity were to survive, there would need to move underground. They would need some sort of power. Some that could last a long time probably some form of nuclear power.You Could probably grow food using artificial sunlight the main problem would who got to live in these underground shelters and who didn't. Overpopulation and Limited resource could also be a problem long turm.

But I guess the overall answer to your question is yes. As long as you have a source of power to produce light and heat, and plants growing under artificial sunlight. Then yes it is possible that human life would continue.

Could humanity survive?

Yeah, in theory. You probably hit the nail on the head right in your own question. Large nuclear powered closed-loop systems could be built and stocked with fuel and other consumables with present-day technology and enough advance warning.

Would humanity survive?

These types of shelters would take a tremendous amount of input to build, and it is certain that most people would be left out in the cold - literally. Consider the reality of being a person on Earth when this advance warning is given. You are almost certainly not in the select (intelligent/wealthy) group that will be chosen to survive in the shelters. Would you accept dropping everything in your life for the next two decades to contribute to a project that, at its fruition, will literally shut the door in your face? Would you accept a majorly decreased quality of life as the worlds economies crumble due to a large majority of resources being poured into a single project that has nothing to do with market forces? Would all of humanity drop everything in the face of certain death to give a chance to a select few? I would like to think that humanity is capable of selecting the best people and sacrificing the rest of us to give them a chance, but I am not sure when push came to shove that it would work that way. See the "Remembrance of Earth's Past"/"Three Body" trilogy for (one author's) pretty in-depth exploration of this concept.

Say Humanity Survives - Then What?

You are probably right that eventually humanity will have to venture out into the void in search of resources. However, it is still easier to survive on a sunless, frozen Earth with all its resources (nuclear fuel, geothermal energy, water, oxygen) than to survive in deep space. If the goal is to get to a new, more habitable planet that's fine, but humanity would still need to find a target and then live for (many, many) generations on a (massive) spaceship. In addition, the research, experimentation, and industry necessary to develop deep space capabilities would be gargantuan. Depending on how many people can be sheltered and what their resource situation is, this may be too large of an undertaking.

So?

Hope I'm not sounding too pessimistic here. I think the answer to your question is a very slight maybe. I can't immediately rule out the possibility of long-term survival, but I sure wouldn't bet on it.

Without the sun, humanity has lost.

The reason for that is simple: The sun powers everything. Without it, we don't get the heat to keep all those processes working that make Earth be the place it is. First, the atmosphere would probably freeze or just become liquid. Then, when the Earth is in vacuum, the oceans wouldn't help anymore at all. This is because in vacuum, water simply doesn't want to exist in the liquid state - if it doesn't freeze it automatically starts to boil (even at, like, 1 degree Celsius).

Then, we wouldn't have anything anymore that could balance the temperature out. Furthermore, we would have to filter the air that we could preserve in underground bunkers or the like and at some point, we would run out of supplies. At this point, the normal folk would be long dead.

To conclude this, it would certainly be an interesting topic to write about, if it doesn't bother you that at the end of the book, everyone would be a really cold, frozen ball of frozen meat and blood. You know, frozen. It would certainly involve a lot of cold and death.

• I have edited your post to remove the unnecessary fluff sentence and to split the post into paragraphs. As I said in the edit summary, you need two enters to separate into paragraphs. Oct 19, 2018 at 21:55
• See the phase diagram for water. (Also e.g. here.) For water to boil at +1°C, you need a pressure of about 600 Pa = 0.6 kPa, compared to the International Standard Atmosphere 101.325 kPa. At a pressure of 1 Pa, water boils (actually, sublimates, as it doesn't have a liquid phase at that pressure) at about -55°C-ish.
– user
Oct 19, 2018 at 22:26

My assumption would be that the timeline for such cosmological events from detection to eventual causation would be in decades or a century. Even the dislodgement and slinging would be a slow process in human scale.

At these scales we would be able to bio engineer us out of the situation. We probably won't be the same species. Other questions is would Earth be alone in this journey. Will there be other planets ,gravitationally locked to us. Could then we convert Jupiter into a mini sun like in the space Odyssey book.