[Scenario] We have 4 years.

[megatiger78]

Nuke ti in orbit

[cicatrix]

It wouldn't. There would be deniers, studies, reports, more studies, protests, conferences, political debate, and many hard political decisions to make.

TV shows. Never forget about talk shows.

Everything will be much simpler. They will say on TV that this asteroid will pass 'dangerously close' to Earth and go down in their bunkers in hopes for the best, leaving everyone else to die. No politician will try to save the humanity. Oh well, this world is screwed anyway.

[Starwhip]

Air Blast:

The air blast will arrive approximately 16.8 hours after impact.

Peak Overpressure: 4.59e+06 Pa = 45.9 bars = 652 psi

Max wind velocity: 1700 m/s = 3810 mph

Sound Intensity: 133 dB (Dangerously Loud)

Damage Description:

That sounds decidedly not fun.

[NASAFanboy]

It wouldn't. There would be deniers, studies, reports, more studies, protests, conferences, political debate, and many hard political decisions to make.

Although this is true, it is mostly just a fringe minority in some technologically backward areas in First World Nations. Not everyone cares about them, they don't need to be pleased. Politicans don't accuse each other of being shape-shifting alien lizards while on the campaign trail, and whether or not 9/11 is a hoax isn't a huge subject for debate in American households everywhere (Unless a certain family member is such a crackpot). But radio talk shows. Especially radio talk shows, will attempt to destroy humanity.

It might look obvious that we would all unite under the banner of Humanity in times of crisis, but reality is much harsher when it comes to making the political decisions and reaching agreements, especially when there is so much to lose and nobody wants to lose more than the other guy.

The United States Congress declared war on the Japanese Empire only a day after Pearl Harbor was attacked. We didn't scale over our military, get defense contracts, or haggle over which shipyard would build which troop transport ship and what, we just declared war and did the rest later. An asteroid the size of Pallas likely will send smaller asteroids into the Earth's atmosphere probably years before impact; these asteroids will likely discredit anyone who denies the impact to the extent that simply saying that it won't hit will get you shunned as if you just called the President a shape-shifting alien lizard that landed in Area 51 from the 10th planet Nibru.

[ZetaX]

Still probably not enough but I'd love to see the numbers on a 100 ton fusion bomb... Might be able to nudge it enough with a 10 year lead?

That's, say, 100Mt of TNT. Even at 1Gt, Pallas will laugh meniacly and carry on.

We are talking about changes of maybe picometers or single-digits of nanometers/s here, and the latter sounds already very optimistic.

[Malokin]

Is it possible to redirect the incoming object's trajectory enough to get it to impact the moon? Moon shield for the win. Also, would this cause kessler syndrome to the point of ruining space travel for humanity for 1000 years+?

[Megalodon 720]

Is there any way that we could use the moon? It's much larger that Pallas and could possibly pull it into a different trajectory.

Ninja'd by a very similar post.

[Starman4308]

Still probably not enough but I'd love to see the numbers on a 100 ton fusion bomb... Might be able to nudge it enough with a 10 year lead?

No.

If you can conceive of it: no.

If it could be practically done on current technology on a few years' notice: no.

Just no. We're talking about a rock which, upon being hit a billion-ton impactor at 10 km/s, would change its velocity by a whopping 50 micrometers/second.

The rule of thumb about supernova-related numbers applies here: whatever number you're thinking of, it's too small.

In your case, you're talking about a bomb with the mass of 4 Tsar Bombas. In terms of raw energy, it looks vaguely promising: with 400 MT TNT yield and 100% energy transfer, you could change Pallas's velocity by 12.6 cm/s. Problem is that you aren't going to get anywhere remotely near 100% transfer into kinetic energy: bombs are a terrible way to get kinetic energy. My best estimate (working off what's available from the Wikipedia page on Orion vehicles*) suggests about 0.03% efficiency, and that's with what amounts to a shaped charge firing at a pusher plate designed specifically to absorb that energy.

*0.15kt charges, 4000 ton vehicle, ~10 m/s dV from each charge.

Is it possible to redirect the incoming object's trajectory enough to get it to impact the moon? Moon shield for the win. Also, would this cause kessler syndrome to the point of ruining space travel for humanity for 1000 years+?

Even just avoiding a direct collision is an almost impossible feat, much less trying to get it to intercept the Moon. If we can get a velocity change of a few centimeters/second, that's probably enough. Problem is, we've got nothing to move Pallas by even that tiny little amount, on account of Pallas being so huge that human minds simply cannot grasp the magnitude of it.

Edited December 9, 2014 by Starman4308

[peadar1987]

I thought that if you drilled a bomb under the surface, you could use the ejected material as reaction mass, which would possibly increase the energy transfer. However, Pallas' escape velocity is 300 m/s, so if you do that, most of the energy is just going to fall back to the surface. With a smaller asteroid, that could be a valid way of doing things, using bits of the asteroid as reaction mass. Pallas is just too big. I think if it's going to hit us, we should use the time we have left to design the filthiest, most unsterile probes imaginable, and programme them to land on Mars, Europa, Triton, Callisto, Enceladus, even Titan. Maybe we'll get lucky and life will survive in some form.

[GoSlash27]

The opening lines of the book I'm currently engrossed in are incredibly appropriate here...

I'm pretty much farked. That's my considered opinion. Farked...

Seriously, there's not a blessed thing we can do about something like that. We can try to divert it, but we will fail. We can try to get humans off the planet, but they will only die in space. We can try to hunker down in shelters and try to survive long enough for life to reestablish itself outside, but we would merely go extinct.

All I can think of worth doing is to stockpile seeds and animals, enough humans and supplies to make it until the sun comes back and then immediately begin repopulating.

Best,

-Slashy

[Starman4308]

The opening lines of the book I'm currently engrossed in are incredibly appropriate here...

Being stranded on Mars does tend to give you that impression of one's situation, doesn't it?

Also, being blessedly unaware of what the impact would do, I'd be cautiously optimistic about deep-underground or underwater shelters opposite the impact site to wait out the apocalypse.

[Wanderfound]

Already mentioned, but for reference: http://www.antipope.org/charlie/blog-static/2007/06/the_high_frontier_redux.html

Self-sustaining off-world colonies are far-future SF.

[Mazon Del]

The opening lines of the book I'm currently engrossed in are incredibly appropriate here...

The Martian, right?

[EzinX]

Why not build orion drive spacecraft and move to the moon? 4 years is enough time to develop them if there's no expense spared, is it not? And you could carefully select a group of enough people to have every skill covered, and then pack enough equipment and supplies to actually build a self-sufficient industrial infrastructure using lunar ore.

[Skyler4856]

Why not build orion drive spacecraft and move to the moon? 4 years is enough time to develop them if there's no expense spared, is it not? And you could carefully select a group of enough people to have every skill covered, and then pack enough equipment and supplies to actually build a self-sufficient industrial infrastructure using lunar ore.

Yeah, it may be advantageous to look into in orbit options, simply because of the lower demands of boosters.

[LordQ]

I have to say that an in orbit solution seems the most practical. But wouldn't ejecta from the impact damage the station?

[EzinX]

The problem with in-orbit is simple. You only have the raw materials you brought with you, and the only way to get any more requires using technology that you brought with you. If you, say, had to wait a century for the earth to cool down (literally! from all the volcanic activity!) you'd be returning with century old reentry vehicles.

If you're on the moon, it takes more delta-V, but you can in principle continue to expand your civilization and build new tools with the lunar ore. It's still a precarious situation - run out of spare parts for a critical system and everyone dies before you can develop the infrastructure to build new spare parts. However, in theory, if you bring enough equipment and machine shops and furnaces and so on along you could mine lunar ore and turn it into almost anything you needed.

Certain things would be incredibly tough to make in this situation, microchips and imaging sensors seem like obvious examples. However, maybe there's a crude way you could keep your civilization running with cruder mechanical and vacuum tube based electronic systems in order to control the various compressors you need to run your life support systems. I wonder what you would do when your lunar solar panels begin to die, making them in-situ sounds incredibly difficult.

You could build horizontal centrifuges to expose your population to a full gravity at least some of the time.

[NASAFanboy]

Is there any way that we could use the moon? It's much larger that Pallas and could possibly pull it into a different trajectory.

Ninja'd by a very similar post.

It would be easier to use a screwdriver to deflect the asteroid than the Moon. At best we'll put a new debris field around the Earth and change the lunar inclination by a miniscule bit, at worst we'll look stupid to future historians (if any) and any watching aliens (if any) and have wasted our resources.

Why not build orion drive spacecraft and move to the moon? 4 years is enough time to develop them if there's no expense spared, is it not? And you could carefully select a group of enough people to have every skill covered, and then pack enough equipment and supplies to actually build a self-sufficient industrial infrastructure using lunar ore.

It took ten years for America to go to the Moon, and that was with a pretty big budget and the threat of Soviet nuclear moonbases. While I'm certain we can get to the Moon earlier today, you're talking about refurbishing a design that has not been tested for fifty years and then building a giant spacecraft with it. We would'nt even get the spacecraft prototype constructed in four years, let alone testing it. Sure, engineering projects can be rushed, but there is a limit as to how much you can rush a engineering project. Yes, you can put in unlimited money, yes, you can pour in all the manpower and resources, but engineering requires intelligence and experience, and you can't find that in unlimited quantities to asign to all the programs and side projects.

Edited December 10, 2014 by NASAFanboy

[Whirligig Girl]

It wouldn't. There would be deniers, studies, reports, more studies, protests, conferences, political debate, and many hard political decisions to make. It would take months or years before we actually reach a consensus that something needs to be done NOW (or 4 years ago). Then you have to make all the tough political decisions about WHAT to do exactly. Even in this thread we can't agree on a common course of action, so imagine what it would be like in an emergency G8 or UN conference.

Imagine the problem of evacuating North America, since it's going to be turned into a giant crater. Does the US Congress peacefully and unanimously agree to dissolve the USA, give away their assets (including military stuff) and send everyone abroad? How many countries are going to agree to accept the millions of refugees? Under what conditions? What about land owners, corporations, financial interests, insurance companies? Who defines who the winners and losers are going to be after such a devastating event?

If the decision is made to attempt to deflect the asteroid, there are the questions of who is going to pay, which companies get the contracts, who commands the mission, and what happens if it fails. The simple act of nominating a science committee to evaluate solutions will require months of negociation.

It might look obvious that we would all unite under the banner of Humanity in times of crisis, but reality is much harsher when it comes to making the political decisions and reaching agreements, especially when there is so much to lose and nobody wants to lose more than the other guy.

At a certain point the object would be clearly visible in the night sky. Although I suppose that would mean it's too late.

[Whirligig Girl]

Even if Pallas completely misses Earth, it's still probably an extinction event. Pallas is not small, and the tidal buldges it raises as it passes Earth may by itself be enough to cause massive earthquakes and volcanic eruptions. I read once that a near miss by Mars would turn Earth's surface entirely molten from the deposited tidal energy, but I don't know if that scales down to Pallas too. Still, it would NOT BE GOOD.

Secondly, it may change Earth's orbit enough to significantly alter the climate.

Finally, a near miss does not erase the possibility of a future impact. In the "best" case for negating the possibility of a future impact, where Earth ejects Pallas from the solar system entirely, could mean that Earth deposits so much of its orbital energy into Pallas that our perihelion is too close to the Sun for Earth to remain habitable. Even as it currently stands, Earth is supposedly just inside the inner edge of Sol's habitable zone. If we got just a bit closer, the planet will supposedly go into runaway greenhouse mode, like Venus.

Pallas is not small, but it's only a tiiiiiny fraction of the mass of Mars. Earth's orbit would be changed enough for astronomers to notice, we may need an extra leap day every hundred years or something. Pallas' gravity wouldn't disrupt the Earth nearly as much. The tidal wave caused by a near miss certainly would not cause a mass extinction event. If you can get it from a grazing impact to... say... half of geosyncronous orbit, then Earth will probably be fine... until Pallas' next approach.

[Whirligig Girl]

It would be easier to use a screwdriver to deflect the asteroid than the Moon. At best we'll put a new debris field around the Earth and change the lunar inclination by a miniscule bit, at worst we'll look stupid to future historians (if any) and any watching aliens (if any) and have wasted our resources.

I don't think he means crashing Pallas into the Moon, just swinging it by. But it'd still be rather extremely hard to do that, because (and the calculations are precise, so without human intervention everything has been taken into account of the predicted arrival date, time, and location) the Moon would obviously not be interfering with the orbit much already.

[Whirligig Girl]

wonder what you would do when your lunar solar panels begin to die, making them in-situ sounds incredibly difficult.

Actually, it's far easier on the Moon than on Earth! Solar Panels are already made out of the same stuff as the moon's regolith, and a vacuum is needed to make solar panels, so it's really easy to make solar panels on the Moon, as long as you have a robot to do that for you.

[NASAFanboy]

I don't think he means crashing Pallas into the Moon, just swinging it by. But it'd still be rather extremely hard to do that, because (and the calculations are precise, so without human intervention everything has been taken into account of the predicted arrival date, time, and location) the Moon would obviously not be interfering with the orbit much already.

I thought he mean't changing the lunar trajectory to make Pallas miss (Thus the whole debris field and new crater, nuclear warheads). Unless the Moon was already going to interfere and make Pallas hit, we have nil chance of making it do that if it doesn't. The Moon is pretty large; we have the largest Planet:Moon mass ratio in the entire solar system and sometimes are called a "dual planet system" by some astronomers. Have fun with that.

[Whirligig Girl]

For the record, even though SLS will ideally be ready in four years, I seriously doubt that the launch vehicles for this endeavor will come from America. (Although we do have some Saturn V Hulls and engines which could potentially be cleaned up)

The Proton could be used, but it's not even as powerful as some of the ULA vehicles like Delta IV Heavy. The best bet is probably to try and refurbish any Heavy-Lift-Launch-Vehicles that lie in mothballs/museums to working order.

[Whirligig Girl]

The Moon is pretty large; we have the largest Planet:Moon mass ratio in the entire solar system and sometimes are called a "dual planet system" by some astronomers. Have fun with that.

Interesting you mention that. I am totally aware of the moon's amazing size, however we are not considered a binary system because the Earth-Moon barycenter rests within the Earth itself. Pluto and Charon, meanwhile, are definitely a binary dwarf planet system. Charon needs to be taught in schools just as much as Pluto. Charon and Pluto have a much closer mass ratio than that of the Earth and Moon.