Could life survive if earth was knocked out of orbit

It was discovered by Sir Edmund Halley, though at the time he thought the moon’s orbit was accelerating. Details on it here

I’ve just realised that page doesn’t explain why…Halley and Newton were working out gravity and orbits around this time. Halley used these calculations to predict lunar eclipses. When he worked backwards and compared the calculations with historical observations he realised they were shifted in time. He attributed this to the moon accelarating in its orbit but was unable to explain why this occurred. We now know it is the earth’s rotation that is slowing due to tidal braking.

Wow this sounds just like a discussion I had last week.

In that discussion it was a black hole traveling near the speed of light, (sidebar… If a star the mass of our own sun was accelerated to near light speed would the resulting increase in mass cause it to collapse into a black hole? And then what would happen if it was caused to slow down? suddenly a star would appear out of seemingly nowhere? /sidebar)

A couple of notes form my earlier discussion and the points raised so far:

Weight is inversely affected by the spin of the earth so if the rotation slowed to a stop (and I say if because there is no direct reason that the spin would change just because the orbit did) everyone would get a little heavier in direct proportion to their proximity to the equator. It is the same effect you would get by weighing yourself at the equator and then again at one of the earth’s poles where you would be heavier. However since your boots would weigh more than the actual difference based on the earth’s spin we can disregard this as a significant factor.

The cooling of the earth’s atmosphere and surface would happen very slowly by our standards. Heat would only be lost through radiation not convection so a few well placed nuclear bombs could create what back in the good ole days we called nuclear winter but now refer to as our thermal blanket. Unfortunately the surface would still cool significantly but only slowly descend to –50 and thousands of years later to –100 on the surface.

Mines would be the best place to be as anyone who has been in one can attest to the fact that the deeper you go the warmer it gets. This process can continue for thousands of years as the thicker the crust get the slower the core will cool. We might have millions of years before we lose this as a heat source.

The main things to consider as far as I can tell are these.
Food, Good hydroponics operations would need to be established.
Energy, Some form of energy supply would need to be constructed, Geothermal or Nuclear seem like good alternatives.
Retention of Knowledge, It would be very important to retain what is already known so that we can build on it instead of descending into the Stone Age.
Communication, We would need some way you communicate between the mines so that we can stay one big civilization instead of becoming many small xenophobic civilizations.
Mining ability so that we can grow our subterranean homes and link up with other mines.

Basically we are on a clock we need to survive long enough to find a way off this dirt ball (Greenback wants credit for this statement)

If it would take thousands of years to cool off to -100F, why do some places on earth cool off to -70F after only a few months of being turned away from the sun? And even then they get air currents from other parts of the earth that are getting much more sunlight. Think about how much cooler it gets at night. Even conservatively, most places are at least 10 degrees cooler at night than in the daytime. Now imagine that there is no daytime. Then we might imagine that, at a minumum, we might lose something like 10 degrees of air temperature per day, until the atmosphere starts to freeze out, at which point talking about the air temperature becomes meaningless, since we would be in vacuum.

I agree that it would take months to cool down to Kuiper-belt temperatures. I think we’d also have an inflection point…slower air cooling until the oceans froze over, then much more rapid after that.

I grew up in Fairbanks Alaska. Every winter we’d hit 60 below, after summer temperatures of 80F. And Fairbanks is BELOW the arctic circle, so we never had even one day of absolutely no sunlight. So if we wave a magic wand and make the sun go away, even formerly tropical regions would be hitting 60 below within months if not weeks. Coastal areas will probably stay warmer longer, but when the ocean surface freezes solid you no longer have that heat source. Yes the ground is going to radiate some heat. But that isn’t going to help much. Even if you live near a volcano the temperature gradient is going to be pretty steep, and the spot between the boiling point of water and 100 below isn’t going to be very large and isn’t going to stay in the same place.

Now, would some people be able to survive? It depends on how much warning we get, and if some sort of rescue project is sociologically possible. Yes, with a few years planning the world economy could create an underground habitat for thousands of people, with nuclear reactors for energy, vast hydroponic tunnels with artificial lights, and food stores to last decades, even without hydroponic farming.

But would such a colony be feasible? Who gets to live in the colony? More than ninety-nine percent of the world’s population would have no chance of getting into that colony. How many of them are going to work to create colonies for others to live in? If only the people who are going to live in the colony work to build the colony there is no way they can establish self sufficiency. How are you going to prevent armed groups from evicting you from your colony? Soldiers? Are they going to get to live in the colony, or will they have to stay outside and protect it until pretty much everyone is dead?

The point is, if we imagine that the entire world acts selflessly to create arks capable of sustaining a few thousand people, then those people could concieveable live for generations on the donated stored capital of 6 billion unselfish human beings. But I don’t think that is likely to happen. I suppose there are already existing military bases and survivalist shelters that are capable of sustaining human life for a few years after the sun goes away. But the number of people who can fit into those shelters is very few, and they won’t have the capital or labor to create tunnels and nuclear plants. They probably will never be able to set up any significant amount of hydroponic farming, they will be living on stored food. If you have underground bunkers with nuclear power you can last for as long as your food holds out. But that is a function of how many people you cram in there and how much food is stored. You might have years of food. But it will eventually run out. And then humanity becomes extinct.

Hi Lemur,

Thanks for the reply, however as far as cooling goes you are not entirely right. Although the cooling of northern and southern reigons coincides with the reduction of sunlight it is more affected by the location of the Jet stream and localized wind directions than by the heat of the sun.

I will provide you with an analogy which although weak illustrates what I am talking about.

Apollo 13 was without heat in the dead of space -250 C for 3 days. The skin of the capsule was the thickness of tin foil and was not insulated. Yet the astronauts did not freeze.

I challenge you to set up a tin foil tent in Alaska during some relatively mild -25C days and see how long you can keep in warm with body heat.

The diffrence is convection, you can expose bare skin to space and not get freezing for a long time because there is no air to remove the heat, the only heat loss is through radiation.

It is the same as windchill -30 and no wind is safer than -15 with 40 MPH winds because of moving air removing heat. Radiant heat loss does not change.
With the resulting loss in sunlight air currents would change on the earth, this would obvioulsy affect the temperature but not neccesarily in the ways you predicted.

I do not know how complex the cooling model would be but it would be interesting to apply some science to this and see what would actaully happen.

Yes, I agree that wind currents are very important for the local temperature, and that a windy 20 below feels worse than a still 40 below. But in Fairbanks, 60 below happens when the air is absolutely still. Any place that hits 60 below is probably one of the coldest places on the planet. If there is any air movement you will almost certainly get warmer temperatures, since the air coming in must almost certainly be from a warmer spot.

And that was part of my point. Areas of the earth that are warmed by the sun are a mitigating factor for those areas that are turned away from the sun in winter, since air currents frequently bring warmer air to the colder regions. And when you add in ocean currents, and the huge thermal sink of the oceans, and you find that even areas that see no sunlight for a few months don’t usually drop below -60F for very long.

But imagine that every spot on earth is in the same situation as Fairbanks Alaska. They are all radiating heat into the 3K universe. And there ARE no warmer areas to bring heat from, except areas warmed by the oceans. So coastal areas will get some protection for a few weeks, maybe even months. But once the oceans freeze over (which they do every year in the arctic and antarctic) they aren’t going to moderate the air temperature any more, even if a few meters down under the ice there is still liquid water at ~32F, or whatever the freezing point for water at the particular salinity is.

So although air and water currents moderate air temperature on today’s earth, without the sun they wouldn’t have the same effect.

Now, about the vacuum issue. Yes, the earth has a tremendous amount of stored heat that would take billions of years to radiate away into the 3K background of the universe. But that doesn’t mean that the surface of the earth is going to stay warm. Even in the presence of the sun, the earth’s surface is much much cooler than the core. The core will stay warm, insulated from space by the crust, but the surface will get very cold very fast, within months.

Your Apollo example is misleading. Yes they were in space without heat. The only loss of heat was through radiation, which is much slower than convection. But they were also GAINING a lot of heat through radiation from the sun, they weren’t in shade during that time. If they were behind a sun shade and not picking up solar radiation they would radiate away the same amount of heat, but get much colder since they aren’t picking up any heat.

So with no sun, the surface is going to get some heat through convection from the core, but is also radiating that heat out to the 3K universe. But the crust is a very good insulator. The air is going to get very cold very soon, since the thermal mass of the air is very small compared to the thermal capacity of the oceans, let alone the crust. So the air temperature will pretty quickly get down to the point where the air freezes out, even though only a few dozen meters down the rocks are above 32F.

You can see this phenomenon in Alaska with permafrost. There is an active layer of soil that freezes and thaws every year. Below that is a permafrost layer, that never melts in the summer and is always below 32F. But below that is a warmer layer, that goes all the way down to the core getting warmer and warmer.

We can easily see that the active layer is there because it picks up heat from the sun in summer time. In the absence of the sun, there is no active layer any more. Instead we will eventually have a layer of solid volatiles (frozen oxygen, nitrogen, water, C02), that is very very cold, not much above 3K. Then we go down into the rock layers, which at the rock/volatile boundary are about the same temperature as the volatiles, but get warmer and warmer as you go down, until you are at molten magma at the core.

So I stand by my prediction of 60 below or colder over most of the earth’s surface in just a few months, certainly within a year the oceans would be freezing over, and then the atmosphere snowing out within a year or so after that. But of course you are right that the total heat budget of the earth will be nearly unchanged, if we take the earth as a whole. But the surface would certianly be affected profoundly.

Of course, someone who has some numbers and a physics background might be able to come up with a much better time frame. But I’m pretty confident that I’m right within an order of magnitude, based on what we already see when portions of the earth are turned away from the sun for long periods of time.

What a great question! I don’t know!

I think that a star, moving at high velocities, would not be collapsed into a black hole. Relativistic mass is something other people perceive. i.e., if I (standing still from my own p.o.v.) watch a 1 Solar Mass star rush by at half the speed of light, I think that it masses 1.4 Solar Masses…but it only perceives itself as having 1.0 Solar Masses.

Am I right, or can anyone here set me straight?


Hi Trinopus,

I may be wrong but I do not believe mass is relativistic.

According to the argument I have heard, you can not accelerate anything to the speed of light because as it approaches the speed of light it’s mass increases and more force is required to accelerate it. So that to reach the speed of light you would need infinite force because mass would be infinite. If this is true the mass would seem to be constant not relative.

If mass is relative it begs a lot of questions, but it sure is interesting.


I will not argue this point with you because you make a good argument, but I sure would love to see a model of this to see what would actually happen.

I should perhaps point out that the OP asks about the survival of life, not necessarily human beings;
there will still be a layer of microorganisms living in the rocks, and probably around the liquid water which would still be pouring around black smokers at the bottom of the frozen oceans.

Earth may well have been frozen once, or a number of times, during the Precambrian era; in those days the sun was a little cooler, and the oceans froze throughout the globe…
after millions of years of outgassing by volcanoes, enough greenhouse gas (mostly CO2) built up to melt the ice. The primitive precambrian biota recovered and developed into our modern world

Such a recovery would not happen if the Earth was in interstellar space, but it does show that life survives for quite a while beneath a frozen ocean.

SF worldbuilding at

Um… You’ve got it halfway right… As something speeds up, its mass appears to increase… That’s why mass is “relative” or “relativistic.” It depends (relates) to the object’s speed…

So, yes, you cannot accelerate a material object (a proton or a galaxy or anything in between) to the speed of light – but you can accelerate it to just about any lesser speed. And when you do, it appears to increase in mass.

An object’s “rest mass” – the mass it would appear to have if observed by someone else who is moving at the same speed and direction – is constant.

I think that the “rest mass” is what is involved in making a star collapse to a black hole, not the relativistic mass… But I’m not sure, and am begging for backup here. (“Tag Team” physics!)


Thank you robby you are indeed courteous. This is Great Debates, to start with.

Now, the Earth is pushed out of its orbit. What happens to the moon? What happens to Venus? What happens to Mars? What orbit does it resume?

The Earth is falling and pulling away from the Sun, which, itself is falling and pulling away from some further point. So what orbit does the Earth take once it moves away from this current multiple rotational field?

Nothing has posited exactly what force is going to be strong enough to push the Earth out of this orbit. . .

So let’s say, just for hypthetical, because I don’t know what I’m talking about, and you, of course, do. The earth somehow is pushed out of its orbit. And begins falling toward the Sun. . .the next densest object. and in that process it stops spinning. So it sits like the moon. No rotation. So what happens to the Weather? Which is related to the atmosphere and the heating and cooling and solar winds, and water vapor, etc? One cold side, one hot side. That’s going to be one massive weather system, I’d think. Do you really think the earth is going to maintain this atmosphere? Because it has a certain mass?

Oh that’s what the lab experiments showed?

And what is this new orbit going to look like? Since we’re being hypothetical. . .let’s say it goes out to Plute at its furthest, and in to Mercury at its nearest to the sun. . .

None of this is going to happen. If something large enough, strong enough occurs to push the earth out of its orbit, this solar system is done for. Life, as we know it is done for.

Or, perhaps you can build a space ship that is merely a ball with atmosphere. . .

You’ve managed to mangle the OP and orbital mechanics to a degree I’ve never seen before.

There are no rotational fields. There are a number of interacting gravitational fields. Typically they are dwarfed by the Sun’s. Besides the OP posted the Earth got kicked out and the sun disappeared. A number of people pointed out the sheer impossibility of such an occurrence.

Nope. Someone pointed out that an extremely massive object passing through the solar system could potentially perturb the orbits of the planets.

Saturn could float in water, Mercury is denser than the Earth.Size means nothing. Mass does. The sun is the most massive object in the solar system. You would have to change the velocity of the Earth by about 30 km/s to “fall” into the sun. Additional velocity would move us away from it.

Yeah, because physics is funny about not caring what you think. Escape velocity is dependant on mass, gas velocity id dependant on the square root of temperature (and molecular mass). A singled side heating might raise the temperature high enough to help boil off some gases, however the far side would effectively act as a condenser and the atmosphere would freeze out on the far side.

Sure, magnetically contain the cloud and then punt it through a galaxy sized rail gun. Oh I have no idea, sounds good though. :slight_smile:

Hroeder, here’s how to think of it.

Hold up a ball. Now let go. The ball falls to the floor. Why? Because the mass of the earth pulls on it. We call this gravity. The more mass an object has, the more it attracts other objects, and the closer the object is to the mass the more it is attracted. The earth is very massive, and it is very close to the ball. So balls fall towards the earth.

Now imagine that there are lots of balls falling towards the earth. Some hit the ground. Others can’t hit the ground, since there are so many of them. They pile up into a layer of balls. The balls are held to the earth, but there are layers of balls covering the ground.

Now imagine that there are millions of balls, enough to cover the whole earth. Gravity holds them down. The earth’s spin, the sun, the moon, none of it matters. Balls fall down because of gravity. If there are lots of balls, they pile up. All the balls want to fall, but if there are too many, they are stopped.

Now imagine that each ball has a little vibrating motor. They all wiggle around in the piles. Drop them and they fall to the ground and bounce around, forming a wiggly layer over the earth.

Now imagine that the balls are very very very very very very small. As small as a molecule of oxygen. Drop an oxygen molecule and it will fall towards the earth, because of earth’s gravity. But there are so many wiggly oxygen molecules near the surface of the earth that the oxygen molecule will bounce off a lower molecule before it hits the ground. There are layers of oxygen molecules bouncing around near the earth’s surface, all trying to fall to the ground, but they can’t because there are too many and they bounce off each other.

And that is why our atmosphere stays on our planet. Because gravity pulls it there.