# Evacuating Earth?

1. Apr 16, 2013

### AndromedaRXJ

So I just watched this documentary (or whatever you want to call it) called Evacuate Earth.

It talks about a hypothetical doomsday scenario where a rogue Neutron Star is headed towards the Solar System, and scientist figure this out 70+ years in advanced.

It is a NatGeo documentary, and I know those are almost always very misleading. But I think this one is, at least, a little above average, due to how much they touched up upon. If you've seen this, or are going to watch it, I want to know what everyone thinks of this; in particular, the ship they proposed. And overall, how feasible it would be to evacuate the population in this type of doomsday scenario.

Last edited by a moderator: Sep 25, 2014
2. Apr 17, 2013

### Simon Bridge

Considering the difficulties in evacuating just a city... at best the show is very very optimistic.
But it is pure science fiction.

The idea was to fly to Barnards Star using O'Niel colonies that are accelerated with an Orion-type drive (blowing nuclear bombs up behind it and riding the shock). This drive massively irradiates the place you are leaving but you don't care because the Earth is doomed right? (Never mind the ethics of all those people who will die slowly from the radiation before the star kills them... maybe you launch at the last possible second?)

The time frame used would require most of the mass of the colony to be bomb.
Barnards Star is not a good candidate for planets. The confirmed Earth-like exosolar planets in the habitable zone are lots farther away and you need to go a lot slower unless there is some quite radical development.

And that's just a cursory look.

These shows are not primarily education programs nor science programs, they are primarily entertainment programs. Even being a little better than most still means it is only a little bit less rubbish.

3. Apr 17, 2013

### Staff: Mentor

Not to mention that aside from the issues of building an interstellar craft and getting everyone on it there would have to be huge developments in ecology so that a stable, human carrying ecosystem could be built and maintained on each craft. On top of that you'd have to bring along a sizeable number of humans to meet the specialised labour requirements of a high tech society (and if its living in a space craft holding a closed system ecosystem it's going to be nothing other than high tech). Lastly there's the issue of social set up. There are few examples of social institutions that have survived unchanged and unbloodied for centuries or even millennia. How do you design the set up so as to be sure that in centuries time when the craft arrives at its destination the inhabitants haven't died from fighting or some other social catastrophe?

As Simon says these things are entertainment only with a glimmer of fringe science.

4. Apr 17, 2013

### AndromedaRXJ

Well did you see the entire thing? The ship was assembled in outer space, so that's when they released the bombs for take-off. Would that still irradiate the Earth?

Anyway, I was still surprised with the ship they went with. Coming from a NatGeo documentary, I thought they would go with something more far fetched, like anti-matter propulsion. Which we're probably centuries away from mastering.

I liked that they even had a billionaire privately build a ship that utilized anti-matter, only for it to fail horribly before take-off.

5. Apr 19, 2013

### L4xord

It would depends on how far the ship is from the earth's atmosphere and the direction of the craft. But I reckon Earth would still be affected by a nuclear bomb's radiation.

I think anti-matter is certainly a ridiculous technology that will never be able to be used in the hands of humans. It's just a little too unstable.

6. Apr 19, 2013

### AndromedaRXJ

Never say never. The energy is there. We know that it's only a technological limitation that stops us from using it. Of course it seems impossible now.

Flying once seemed impossible. Now, there's people flying every second of every day. I know we will not use it any time soon, but I think saying we'll NEVER use anti-matter, even within 100,000 years or more, is being a little too..... unimaginative?

7. Apr 19, 2013

### QuantumPion

8. Apr 19, 2013

### Staff: Mentor

I find the "not impossible therefore will happen" argument to be tired. Many things are possible but there are practical reasons why they aren't done. As for antimatter it represents the universes most powerful and easy to detonate bomb. An antimatter rocket capable of zipping around the solar system or even going interstellar might seem romantic but one slip up, deliberate of otherwise, and it's a bomb capable of willing out entire biospheres and devastating the surface of planets.

Given that a usual "space cadet" dream is to have fleets of such craft wizzing around a heavily populated solar system/interstellar nation the danger becomes even worse. Akin to if every aircraft ever built contained a 50 megaton nuclear bomb that would go off in event of mechanical failure or crash. If this were the case I highly doubt we would ever build planes except in the most niche of circumstances, and use them even less.

9. Apr 19, 2013

### AndromedaRXJ

I never said it will happen. I'm saying it may happen. And I'm NOT saying it'll NEVER happen.

I understand, perfectly well, just how unstable and stupendously dangerous anti-matter is. I still don't see how we can just throw the word "NEVER" around, just because we have no idea how we could begin to think about using it today.

Once again, I'm saying it may or may not happen. I'm not giving certainty on either end. I don't see how someone could.

10. Jun 10, 2013

### brucemitchell

Call me a pessimist, but if there were some rampant neutron star in our solar system, I think it'd be safe to say that we're all screwed...

11. Jun 25, 2013

### StrayCatalyst

Even with 70 years to prepare, assuming that the majority of the planet's population:
a. has heard of this event,
b. believes it to be true,
and c. lives in a country that is high tech enough to have a space program at all

You're still looking at trying to move (in 70 years, estimated) 8 to 10 BILLION people. In the 50 years or so that we've had space travel, we've not gotten a single person out of Earth's orbit - sending people to the moon isn't going to help, as a neutron star would wipe out the moon, as well. So we aren't looking at just one paradigm shift in space travel (as though one wasn't an impressive accomplishment!) but several. Self supporting colonies - we haven't even succeeded in having these on the surface of the planet, where you can open a window for air, make a phone call to get parts, food, and energy delivered, and gravity is already provided.

If we discover that our planet has a disaster approaching in 70 years, we might be able to launch a few 'seed' colonies - slow ships to other systems, hopefully large enough to contain a reasonably diverse sample of humans, with preserved seeds and embryos to colonize a planet. But you're looking at a tiny percentage of the human race - probably well under a percent, and only from rich nations with technology and money. The three superpowers, plus Europe and perhaps India - maybe five missions, more likely five missions plus some billionaires trying to escape the end of Earth.

But the vast majority of the population would never leave the surface of the planet - we just don't have the resources. If we dedicated all of our efforts to getting each and every person off the planet - where do we go with them? You can't just mag-launch a sealed container of air, food, and people - it has to be a viable colony, with the equipment to stay alive until arriving at a destination, then land there, and then to deal with whatever problems they encounter there. So - assuming no major advances in cold sleep or other means of storing humans like cordwood, you'll need food and air for x number of people for y number of years... plus the ability to navigate in space, AND to have a destination that will support life upon arrival.

IMHO, the only hope would be diaspora - as many colonies as resources will permit, selecting the best of the best that the planet has to offer, sending the ships on the fastest course possible to every viable star (with planets in the Goldilocks zone). And the majority of them would fail - social upheaval, technical failures, design flaws, unforeseen problems, etc - but if two or more ships manage to establish viable colonies, the human race will continue...

minus the unlucky 99.7% that never made it off the surface of the planet.

12. Jan 3, 2014

### Jon Richfield

AndromedaRXJ, don't listen to these guys; they are HOPElessly over-optimistic (or possibly trying to sell you a spaceship). Far from getting a large proportion of the planet into space (never mind going anywhere), you couldn't get them off the planet fast enough to balance the birthrate, never mind dent the population. (Have you checked the birthrate lately? It is nearly 200000 per day, more than 30000000 per year. The whole population of the US in 12 years or so. In a single queue they would have to run past you. Think of that with trying to load them into airliners, even bulk carrier ocean-going ships, let alone spaceships.

Any scheme along those lines would necessarily be on the scale of a small village, not a planetary population. The rest of the planet would never notice you leave. 99.7% indeed!!! Call it a holocaust and you would be close enough for jazz! :D

13. Jan 8, 2014

### StrayCatalyst

Assuming the following:
Every government on Earth knows about the 70 year timeline, believes it to be true, and isn't gripped by religious hysteria that causes them to do nothing meaningful.
The incoming destructive event cannot be slowed down, or caused to change course.
Spending on space exploration eclipses spending on warfare.

At this point, you'd still not be able to evacuate even a significant percentage of the human race - but you might be able to evacuate enough to form viable colonies. Since people understand that anybody left on this planet is doomed, safety may be discarded as a luxury - after all, if a third of the colony ships survive, that's still better than staying at ground zero.

There would be a draconian selection process, of course - why bring HIV to the new colonies? Why bring people who don't meet whatever standards the governments in charge want? Each government that could afford a space program would have different standards for selecting their colonists - some would want rugged, self-sufficient individuals, while others would want quiet, obedient conformists. There'd be no shortage of military types, engineers, doctors, etc but you'd find a lot less artists and dreamers. Assuming that each nation or organization sends their colonies in different directions (not including the three or four closest star systems, which would probably be embroiled in resource wars and territorial battles shortly after the second ship arrived!) the human race would diverge sharply at that point - by the time 'humans' meet again from their travels, they might be so dissimilar as to be unable to breed with each other, or even communicate without difficulty.

There are eight stars within 10 LY of Sol, and that number increases by 33 at 15 LY. Assuming that colonies are established at several of these - the colonies will spend generations surviving, world-building, and establishing themselves in their new home. Some will find that the "Goldilocks" planet they expected to find is in some way unsuitable - too hot, too radioactive, covered in Venus-like acidic clouds, etc - most of those colonies will die out rapidly, though a few will be able to refuel and pick another destination, to arrive after several more generations of travel.

So, by the time the surviving colonies are well established enough to worry about the other branches of the human race, they'll have gone through a unique set of evolutionary factors - first the selection process that got their ancestors into the colony ships, then the generations that passed during the trip ( Ships are highly unlikely, when evacuating a planet, to travel with so much room that there can be unrestrained breeding!), then arriving at the destination planet and facing its challenges... two colony ships that start off from the same nation, with the same selection process, will still end up with different cultures by the time they've returned to space. Two colonies that start from different nations will most likely not share a language, and the rest of their culture would be even less similar.

One other major difference - the colonies that started off in the first decade or so would be lower tech but probably have the benefit of the time they were able to take before departing - plans, equipment, training, psychological testing, etc. The ships that leave in the last few years before the disaster, on the other hand - they'll be the desperate ones, the ones who take enormous risks as there's no plan B - it's get into space or lie down and die. The last ones leaving will be the ones taking the biggest risks - better a one in four chance of having your ship survive, than a 100% chance of dying with your doomed planet.

P.S. FTL communications would change the whole equation, as the dispersed branches of the human race could still communicate and share their cultures, technologies, and discoveries. At that point, the human race might biologically change (based on local conditions) to such an extent that they'd be too different to interbreed, but no branch of the human race would think it was the only branch remaining.

Last edited: Jan 8, 2014
14. Jan 8, 2014

### phinds

This is adding science fiction to science fiction.

15. Jan 8, 2014

### .Scott

I don't have youtube available right now. Are we assuming that Mars is not an option?

16. Jan 8, 2014

Staff Emeritus
This has moved from science fiction to fantasy.

The US spent $25B on Apollo, and managed to get 24 people to leave Earth orbit. So it's$1B per head in 1973 dollars, or $5.9B per head in today's dollars. The suggestion was made to divert world-wide military expenditures ($1.7T) to this, so over 70 years we could get 20,000 people to leave Earth orbit. If we want to send them farther, it costs more.

The ratio of distances between the nearest stars and the moon is the same between the moon and how high you can jump.

17. Jan 8, 2014

### phinds

Well said.

18. Jan 8, 2014

### D H

Staff Emeritus
Surely you exaggerate, V50!

Most of that expenditure was learning how to do it. Presumably it won't cost near as much per person once we've learned how to do it. Let's say that we get a two order of magnitude increase on your 20,000 people every 70 years, so 2 million people every 70 years.

At that rate, it will take a mere quarter of a million years to evacuate the Earth. No problem!

There are three key assumptions regarding this number: That we have a quarter of a million years lead time on the impending disaster, that people stop breeding like rabbits, and that we learn how to do it. All of these are dubious.

19. Jan 8, 2014

### phinds

I think that "dubious" is a very generous overestimate of how likely they are.

20. Jan 9, 2014

### Jon Richfield

DH, DUBIOUS???? Dubious like honest politicians with brains maybe. Or sane humanity.
People are not breeding like rabbits anyway; we are only producing babies a little faster than two per second, which is a lot slower than 7 bn rabbits could manage. We could hardly reach a production rate of 70000000 per year currently, which is only a few orders of magnitude faster than 2000000 per 70 years. Let's not be negative. If we can speed that up a little we could leave earth by climbing the pile of babies.
Straycatalyst, I think you need to pay a bit more attention to the perspective of numbers and logistics. Last night I read of th crushes and paralysis that developed, not in trying to leave EARTH by space, but just a few 19th century Mississippi towns when the yellow fever struck. No special transport needed, no technology gap, no crowded territory, just a few tens of thousands of people stampeding out of by our current standards, rural Memphis and surrounding towns.
Have you ever got caught in a crowd crush?
The only way you would get anything to work would be to keep the reason for the exodus under wraps, sell the secret to Bill Gates and a few pals, and aim for getting a small population of the rich and select to go nowhere in particular, leaving the trash (that is you and me mate!) to burn or rot on Earth, while the rich guys burn or rot a bit further out in space.
In other words, don't let it bother you; if there is something you can't change, it isn't a problem; it is reality.