Okay guess this is worth a shot

[Hopeless]

Started a thread in the game section after watching a you tube video titled Evacuate Earth and got wondering how to handle this in a game.

However thanks to that thread about plausible space battles I'm now wondering how you'd view this here.

Remember that meteor that was reported in Russia?

What if its was discovered that it was the first of quite a few waves due to bombard the Earth over the course of the next few decades?

By this I mean initially the next say 5 to 7 decades we would have fantastic fireworks going off in the upper atmosphere before the larger meteor showers come on the scene.

If nothing is done pretty much civilisation will end but there's a chance the Earth would survive so it wouldn't be a total extinction event since the world would be devastated but would eventually recover but that still leaves the population of the planet.

Now that video took the view that a neutron star was heading directly for the solar system, my idea was that something would pass close enough to disturb the Oort cloud on the edge of the solar system causing alot of debris to head into the inner system.

Initially most of this is absorbed by the outer planets but eventually larger ones manage to pass into the inner system where they eventually threaten the Earth.

The video came up with the idea of building a ship basically an O'Neill cylinder using a propulsion system that involved nuclear bombs being detonated every 3 seconds behind it propelling it at a fraction of the speed of light to another system where a supposed suitable new homeworld had been located.

Now using that video as a guide I was thinking they'd build underground shelters that would cope with a number of the populace along with an underground starship city as part of a program to build a lunar base intended to help build that O'Neill craft but on the grounds that it could be moved a safe distance away from the meteor showers until they died down and it could return and wait for the Earth to settle enough for them to return down to the planet.

What I'd like to know is your view assuming you were brought into discuss this how would you handle it?

What would be your suggestions?

[erikun]

Remember that meteor that was reported in Russia?

I assume you mean the Tunguska event?

Well, the first problem I see with your idea is that, even disturbing the Oort cloud, and actual object-Earth collision is highly unlikely. Multiple object-Earth collisions, especially in rapid order and starting with the smallest ones first, are basically impossible. The problem is scale. Earth is roughly 12,740 km in diameter while the solar system is roughly 9,006,000,000 km across. We'd need roughly one million asteroids raining through the solar system to have a roughly equal chance of hitting the Earth, and that's assuming the solar system is flat. It most certainly isn't. Being a few thousand kilometers above or below the plane of rotation will mean a complete miss for the planet. So instead, we're talking trillions of asteroids - and given that the Oort cloud is estimated to have "billions" of asteroids, it seems doubtful that Earth would be struck even if all of them spontaneously started heading inward simultaneously - to say nothing of just a few getting toss towards the sun thanks to a passing star.

Second, neutron stars tend to be rather massive, and so would more likely pull parts of the Oort cloud away from the solar system, not throw it towards it. It also wouldn't need to pass through the Oort cloud to do so, as they tend to be more massive than our Sun itself. A neutron star passing through the Oort cloud would likely just destroy everything in its path. Asteroids and material thrown systemward would most likely take up a stable orbit around the sun, although a highly erratic one. Become comets, basically. There's very little chance that any of it would hit a planet or the sun itself.

The Earth has a much larger risk of being hit by a single large-mass asteroid and being destroyed that way, rather than getting bombarded by smaller matter and made inhospitable because of it.


As for the travel idea, if you have a working O'Neill cylinder with a steady population inside, then why bother travelling anywhere? There's no guarantee that your destination will be any more hospitable than what else we have in the solar system currently, and the O'Neill cylinder will need to be self-substaining anyways just to make the journey. Just for an example, the nearest star (Alpha Centauri) is 4.3 light years away, and at the speed of 0.1c (which is quite absurdly fast) we're talking about a travel time of 45 years.

A trip which, I might add, involves passing through said Oort cloud - and if you think a random asteroid strike at slow speeds will cause problems for a 6,583,210,000,000,000,000,000 ton rock, just imagine what they would do to a one-million-ton metal can when moving at a significant portion of the speed of light.

[Hopeless]

Thanks about the information on the meteor showers likelihood, whilst I used that video as an example I meant for something nudging the outer solar system enough to cause such a shower lasting an extended period.

The video suggested transplanting humanity if the Earth was destroyed I was wondering about it being able to remain in the same system but able to move if necessary.

I assume you mean the Tunguska event?

I meant the more recent event when a meteor was reported in Russia and the sonic boom blew some windows and caused enough of a fuss to have phone cameras' recording what happened but Tunguska works just as well!

Still got my answer in any case, much obliged.

[Kato]

Okay, assuming contrary to erikun's argument we would get in such a situation where earth is in imminent danger of getting bombarded by a large amount of dangerous asteroids and we had time to prepare...

There are a whole bunch of factors. Building an O'Neill cylinder or something similar would take a while... probably about as much time as setting up a sufficient defense system, really. And unless we are considering a rather precisely aimed attack on earth - as in, the whole solar system suffers from a huge increase in rogue asteroids - hiding in a rather defenseless metal tube is not that much better than staying on a rather safe planet. (And as erikun mentioned, leaving the solar system is pretty tricky.. Even though I have no numbers on the "density" of Oort's could. )

Unless we can say for sure it's a bad idea I'd try to defend earth and build bunkers instead of running off into space, really. Even waiting outside doesn't seem like a great idea, though you could try to do both and let people decide which they trust more. (I also have no idea on what scale we'd need to build the cylinder to host sufficient people)

[Hopeless]

Okay, assuming contrary to erikun's argument we would get in such a situation where earth is in imminent danger of getting bombarded by a large amount of dangerous asteroids and we had time to prepare...

There are a whole bunch of factors. Building an O'Neill cylinder or something similar would take a while... probably about as much time as setting up a sufficient defense system, really. And unless we are considering a rather precisely aimed attack on earth - as in, the whole solar system suffers from a huge increase in rogue asteroids - hiding in a rather defenseless metal tube is not that much better than staying on a rather safe planet. (And as erikun mentioned, leaving the solar system is pretty tricky.. Even though I have no numbers on the "density" of Oort's could. )

Pretty much yes, figured a majority of the problems is when those stray comets and meteors interact with the asteroid belt between Mars and Jupiter which I suppose would explain why there's a delay before it gets really nasty as the majority to that point is either hoovered up by the outer planets or the Earth isn't in a position to be struck by more than a small number which changes as it heads into an area where this changes significantly.

Unless we can say for sure it's a bad idea I'd try to defend earth and build bunkers instead of running off into space, really. Even waiting outside doesn't seem like a great idea, though you could try to do both and let people decide which they trust more. (I also have no idea on what scale we'd need to build the cylinder to host sufficient people)

That idea came from the video, I thought its construction would be easier if there was a base on the Moon but that doesn't change the fact it would pose serious enough problems that underground shelters would be safer.

However how can anyone be truly sure its safer to stay on the planet if the only evidence that says the Earth will survive doesn't include good odds that humanity can survive what their predecessors the dinosaurs didn't?

Now what was the name of that movie which was done at the shame time as Armageddon?

Anyway still boils down to the original reply that its more likely to be hit by a large asteroid than a series of meteor showers, didn't consider comets and the asteroid belt when I first watched that video though...

[Traab]

Unless the planet itself shatters, couldnt we just board the cylinder, move out of the way, then land back on earth and restart? It would basically be a sci fi noahs arc, with far more than 2 of everything, but still. No need to leave the universe and look to setup elsewhere unless the damage done ruins the planet for the foreseeable future for some reason.

*EDIT* Deep Impact. That was the other movie.

[Hopeless]

Unless the planet itself shatters, couldnt we just board the cylinder, move out of the way, then land back on earth and restart? It would basically be a sci fi noahs arc, with far more than 2 of everything, but still. No need to leave the universe and look to setup elsewhere unless the damage done ruins the planet for the foreseeable future for some reason.

*EDIT* Deep Impact. That was the other movie.

I figured that would be more feasible but exactly how much damage would have to be inflicted to make the Earth uninhabitable?

Could just simply having the moon knocked out of orbit entirely do just that?

Just how much further does our technology level have to improve before off world habitats become viable?

I mean they're already talking about mining the asteroid belt even moving a suitable asteroid where it could be mined more easily so how long before someone seriously thinks about building an O'Neill near enough the asteroid belt to make that a serious business concern?

How long would it take to even begin building large enough underground shelters let alone planning to build an O'Neill?

[The Second]

It is certainly possible that humanity could adapt to a subterranean lifestyle, we have the technology after all, in the form of biodomes. It also wouldn't be too far fetched to imagine a while interconnected series of subterranean tunnels connecting populations together for the purpose of trade and what not.

So long as something didn't come along and shatter the Earth into a few billion pieces, I'd say humanity would stand a good chance of survival without the need for a massive arc that would most likely never be built because of politics.

Edit:

I doubt it would take very long to excavate crude shelters for the population. setting up small biospheres wouldn't take much longer. As for comfortable underground living on par with what we currently enjoy? That could take generations.

[Traab]

I figured that would be more feasible but exactly how much damage would have to be inflicted to make the Earth uninhabitable?

Could just simply having the moon knocked out of orbit entirely do just that?

Just how much further does our technology level have to improve before off world habitats become viable?

I mean they're already talking about mining the asteroid belt even moving a suitable asteroid where it could be mined more easily so how long before someone seriously thinks about building an O'Neill near enough the asteroid belt to make that a serious business concern?

How long would it take to even begin building large enough underground shelters let alone planning to build an O'Neill?

I was more thinking about potential global volcanic and seismic activity that renders the surface unlivable, and likely would also make creating an underground world rather unlikely. Not too mention the ash cloud creating a global winter that lasts who knows how many years.

[erikun]

Could just simply having the moon knocked out of orbit entirely do just that?

The moon would be notoriously difficult to knock into Earth. Randomly smacking an orbiting object would most likely just produce a different orbit, not automatically cause it to spiral into the nearest planet. Orbits are actually rather stable in that regard.

Just how much further does our technology level have to improve before off world habitats become viable?

I mean they're already talking about mining the asteroid belt even moving a suitable asteroid where it could be mined more easily so how long before someone seriously thinks about building an O'Neill near enough the asteroid belt to make that a serious business concern?

How long would it take to even begin building large enough underground shelters let alone planning to build an O'Neill?

Biosphere 2 is the best we've done with creating a man-made self-substaining habitat, as far as I know. It apparently still had problems with the self-substaining aspect, though, requiring a starvation diet and had trouble with some species of plant out-growing the others. (Note that the CO₂ problem was due to a reaction with concrete, not some leak or miscalculation.)

I would have doubts about about a substainable independent biosphere on the Moon or Mars with our current understanding, to say nothing about a spacecraft with no chance of restocking from Earth.

[Thiel]

If we've got 70 years to prepare why not try to defend the earth instead?
We'd have several decades to survey and classify the individual asteroids and develop appropriate countermeasures. If for the sake of argument we spend thirty years developing the rockets and countermeasures, be they nukes, impactors, gravity tractors, lasers or whatever, that still leaves 40 years to launch them. If, again for the sake of argument, we find 10,000 threats that needs dealing with that's still only 250 launches per day. Even if we say the last rocket has to be launched ten years before impact that's still less than one launch per day. If the V2 is anything to go by that shouldn't be an impossible goal considering the managed to make 5200 of them in less than three years with 40ies technology while being bombed and using less than motivated slave labour.

[Traab]

No reason you cant work on both. Im sure a lot of the needed advancements to make it work would also aid in bringing the other plan to fruition. Plus that way you dont put all your eggs in one basket. If it turns out the cylinder is impractical in the time frame required, you still have the worlds most important game of missile command left to play.

[Landis963]

No reason you cant work on both. Im sure a lot of the needed advancements to make it work would also aid in bringing the other plan to fruition. Plus that way you dont put all your eggs in one basket. If it turns out the cylinder is impractical in the time frame required, you still have the worlds most important game of missile command left to play.

Point of order; Missile command has an effectively infinite number of incoming projectiles, any meteor strike would have considerably fewer.

[Thiel]

Point of order; Missile command has an effectively infinite number of incoming projectiles, any meteor strike would have considerably fewer.

I don't get what you're saying.
However there's not going to be an infinite number of targets, only a fraction of the rocks and ice balls out there are large enough to pose a threat and aside from the few really big ones we only have to deal with the ones that are going to hit a populated area.

[Landis963]

I don't get what you're saying.
However there's not going to be an infinite number of targets, only a fraction of the rocks and ice balls out there are large enough to pose a threat and aside from the few really big ones we only have to deal with the ones that are going to hit a populated area.

That's essentially what I'm saying.

[Traab]

Point of order; Missile command has an effectively infinite number of incoming projectiles, any meteor strike would have considerably fewer.

Pfft, fine then, the most important ROUND of missile command ever played. Damn accuracy nazis.

[Landis963]

Pfft, fine then, the most important ROUND of missile command ever played. Damn accuracy nazis.

I resent that! If Indiana Jones has taught us anything at all, it's that the Nazis were anything but accurate!

[Kislath]

The 15.0+ Richter earthquakes that would shake the whole world for weeks would render it not very likely that a series of underground cities would be able to remain connected by tunnels, and those bunkers themselves would take a lot of damage too, probably. We would lose most of them, I'd bet.
Still, some would survive.

[Hopeless]

Given how things stand do you think the various military commands could organise the diversion of a meteor shower coming on a far greater frequency over the following decades?

My original idea was that the Oort cloud was disturbed showering the system with debris which is increased once it hits the asteroid belt between Mars and Jupiter.

Assuming most are initially swept up by the outer planets the Earth's orbit around the sun would eventually leave it open to showers, but how important is it between how many actually hit, how large assuming hopefully those that do make it into the inner system are smaller barring whatever is dragged along from the asteroid belt?

Would the effects on the Oort cloud be detectable on Earth?

Is it more likely humanity would have headed out into the rest of the solar system before this becomes a valid threat?

[Kislath]

Most of the Oort cloud is just dust. Large particle dust, but harmless enough for the most part. Most of the Oort stuff would probably get pulled away toward a passing large body anyway, instead of pushed toward the sun.

As for the bigger Oort chunks, they'd have to get past the Kuiper Belt. Sedna, Thalia, Pluto...and probably hundreds of other planetoids would be our first line of defense, capturing much. The greater outer planets could likewise block more, but they would admittedly miss much more than they caught.

Okay, by then they'd start getting close enough for us to even notice them. Let's face it; the odds of us even realizing that there is a problem before the coming swarm reached Saturn are pretty low. So, by the time we see that there are thousands of little rocky & icy chunks the size of office buildings coming at us, we won't have very much time available to do anything about it. We'd never have time enough to build much of a defense.

We would probably never even know that some large rogue mass passed by our system anyway, unless it was really huge or we happened to get lucky.

As for the military... hehe.. it would probably be a battle of wills between the military and the politicians, one side wanting to nuke the incoming threats and the other side complaining of radiation and smaller, more numerous rocks falling on us. Each side would think the other side idiotic, and there would be much fuss.
Eventually common sense would win out, and the missiles would launch when people finally realized that having two dozen kilometer-wide pieces hit us would be far preferable to having a single two-dozen kilometer wide chunk hit us. Let's just hope that they figure this out in time to divert the objects completely.

No, I don't think it's at all likely that humanity would try to evacuate the planet. To go out into space where the likelihood of the ships being pummeled by all the debris that would have missed Earth would be foolhardy, and let's face it; there are just too many people. To even make the attempt would be to invite world war as people fought over who would leave and who would die.
The Uber-wealthy Richard Branson types would possibly launch a few little ships of their own, but they'd only take a handful of people.

[Kato]

Okay, by then they'd start getting close enough for us to even notice them. Let's face it; the odds of us even realizing that there is a problem before the coming swarm reached Saturn are pretty low. So, by the time we see that there are thousands of little rocky & icy chunks the size of office buildings coming at us, we won't have very much time available to do anything about it. We'd never have time enough to build much of a defense.

While I have to agree I don't quite see how likely a huge gravitational object would direct much stuff to fly into the solar system, I think if it had this effect we would notice because we are still (for whatever reason) leisurely tracking the outer planets' orbits and we would notice them being disturbed. Likely, such a massive thing coming our way we would notice quite a bit in advance. While I really don't have a good scale for movement in space I guess we'd have a few months or so at least, assuming these things move at reasonable speeds.