An extinction level impact will occur in 25 years, what options does life on Earth have?

Hypothetically speaking, if an extinction level asteroid/meteor impact was known to occur in ~25 years time, what realistic options does humanity, and life in general on Earth, have?

Could we feasibly design a space operation to alter the course of or destroy the object?

Is it possible to sustain some remnant of life in bunkers/protective shelters for the amount of time that would be needed for the environment to return to a habitable state? Do we have the technology/capacity to store/create enough energy and perishable supplies for this to happen?

Could we feasibly design any sort of space faring colonization mission or long term "housing" in space or on a spacecraft?

Or would we have to resort to launching a probe containing the artifacts (and maybe DNA) of human society for some alien race to find in the future, ala The Inner Light?

Would we be doomed to hoping that a small segment of the population survives and hopefully persists long enough to rebuild civilization as we know it?

What if we had 50 years, does anything change?

 

25 years sounds like easily long enough to save the Earth from a 10km asteroid using current tech - maybe 99% or higher probability of success in preserving humankind.

How about if we only had 25 months, 25 weeks, 25 days, or 25 hours? Survival of the event by any of humankind given 25 months is marginal - maybe 5%.

Survival given 25 weeks or less seems very unlikely. My guess is we'd need 5 years notice to have an evens chance.

I expect someone has already done a proper risk assessment rather than just guessing.

 

We have enough super heavy lift vehicles now to gravity-tractor an object like that way given that amount of time. Hell we might put it in a cycler orbit and mine it.

 

Yes, 50% chance of survival with 5 years notice is probably a tad pessimistic - maybe 80%? Anyway, a mere solar-powered scoop chucking rubble off the surface in a targeted direction could deflect a 10km asteroid sufficiently given a few years.

 

That depends on the asteroid’s orbit, I’d say.
Is it a highly elliptical orbit coming from the distant outer solar system crossing our orbit just once, maybe getting a speed boost from Saturn and or Jupiter on the way, I don’t think we can do much of anything into intercept it.
Assuming this, it would probably be a big fucker, too, given that we could detect it this early.

If it’s an inner solar system asteroid, we are likely to run past it several times till it crosses our orbit for a hit.
We could do plenty with/to it in the mean time.

 

Depends on the nature of the ELE.
Something that sears the surface of the planet, we might be able to survive by putting colonies of humans aboard nuclear submarines and sending them deep underwater. Maybe into caverns or mile deep mines as well. Even with a few days' notice we could make it work. An asteroid impact that smashes the planet, we'd need to get a colony of people into space. That's about 200 people if we want to repopulate. We would need years to design, build, and launch suitable spacecraft. And a gamma ray burst that kills the whole solar system? Sorry, but we're pretty much screwed.

 

Then threw it away because it cost too much to save us.

 

I just read, one of Earth’s mass extinction events can be linked to a supernova.

 

I've made sure that we've painted the asteroid with thousand square kilometres of Vantablack paint. If it holds up to the advertising – and my workers didn't steal any to resell again – it should pass mostly undetected before atmospheric interface. I've fed the gang who stole all the paint used for the proof of concept Microprototype 1 (you may know it as ʻOumuamua) to a gas giant worm, so I think we're safe from theft.

What may spoil the plan is that none of the impactors of 10 km or more we've sent have outright killed everything. Cataclysmic, yes, but the T'Rex kept running around and complaining about the new weather, saying it was nothing to worry about. Will push the V to eleven this time.

 

Yes. We either plop down mass drivers on it, chemical thrusters, nuclear thrusters, bomb it so the orbit shifts, do anything ASAP to alter its course with as little D/v tax as possible. Because the closer it gets, the more D/v it's going to cost. Basically we need to chuck everything at it. A solar sail, nuclear bombs, add mass drivers, everything. But it can be done. As long as it misses, it misses. And it needs to miss - not just be blown up and keep the same orbit, that just means roughly the same amount of destruction, just over a bigger area. It needs to have its orbit changed. But it's doable.

...Yes, actually. Now I'm a bit biased. I come from survivalist militia stock. I spent most of '99 preppin' for Y2K and then '01+ after 9/11 in bunkers. Just get the nation to subsidize Mountain House, hook up a nuclear reactor, and keep digging in mountains somewhere, this is the simplest option. The Bunkers in...Armageddon, was it? Totally doable. You nationalize everything, you put the world on war footing, you shove people down there, as much as possible. This is the simplest option, and can be done concurrently with the orbit changing mission above - have NASA and ESA and CSNA and ISRO and Roscomos work on altering the orbit, everyone else doesn't just sit around, they make vaults.

It won't be comfortable, however.

Last I heard, the most a submariner was down in the depths, back to back, was around 120 odd days. Four months. People have been in space for a year and a half or more, but are always doing something and talking to a living world.

Now, theoretically, you can stay down there for a longer time, but it's going into uncharted territory real fast. I hope the government leaves them construction equipment to keep on expanding the base, stock it full of teachers, give everyone courses, anything to keep them occupied.

I'm gonna say No. Not without our tech. We don't have a handle on ECLSS yet, nor anything more than just making, basically, a bunker, and putting it on the Moon or Mars (Just do the Far side of the moon). And for what? If you can make a nuclear-solar powered bunker-in-a-box, just do it here. A bunker on earth for 10 years is far more preferable than a bunker on the Moon for a year.

A complete waste of time. Better spent on shoring up defenses here or focusing on a more active mission.

If it's a planet killer, many will die. Even in the developed world. It's impossible to shove everyone down there, or support them. I would say a few million, at most. People will try to make it through on cans in backyard bunkers, and if the dust subsides within two, three years, they can make it. But not much longer. The more ornate bunkers can make it a few decades (Mountain House has a shelf life of thirty years...mmm), but the sooner they come out, the better, while using the Bunkers as new capitals and cities to spring out from. But most people are goners. Starvation, the breakdown of logistics, crime, warfare...but humanity, as we know it, technologically, can survive. It just depends on how much we really give a damn about saving it.

In 50 years? Certainly. However at that point malaise and economic ups and downs have their way. Oh, at first people will build bunkers, look into space tech, but then it becomes someone else's problem, funding dries up. A few missions. Then when it's 10, 5 years away people care again.

 

25 years would be enough, I think 5 years would just be doable, 3 years would probably make a lot of people sweat, 1 year, if everything works out, less than one year.. I think I'd take that bunker.. my two cents

 

A last gasp of flood basalt volcanism worries me. No deflecting that.

 

Do we have the technology to avoid/survive that? Yes, for sure.

He problem is that we wouldn’t have the political will to do it!
Just look at the current crisis, where even problems months away are ignored until they are upon us already. During the first 24 years and 10 months some politicians would use the impending doom as a scaremongering device to obtain popularity while the opposing parties minimized the situation and talked about it being a “hoax” for the same exact reason.

When destruction is weeks, of not days, away governments would start taking the situation seriously...And by then it will be too late. Bye everybody.

 

...much like anthropogenic climate change then...

 

Remember that it's not just about capacity, but also motivation. We put a man on the moon within 8 years, using 1960's technology. We could put a small colony in space with 2020's tech, I think. Armageddon makes a great motivator.

 

If the event is an extinction level event, then there will be humans left. Maybe some of the most wealthiest and, their most trusted and some of the most trusted workers, would go deep underground. But an extinction level event means that all life is eradicated.

The only way to really avoid an extinction level event on Earth is to build and maintain colonies on the Moon that can sustain themselves for at least 250 years without any assistance from Earth.

 

Problem is, "extinction level event" covers a wide array of possibilities, from "wipe out unprotected human life on earth" to "obliterate everything within light years". One could be survived by a select group with a few days of prep time. The other, no hope at all.

 

Well, all we can hope for then is that Hugh Everett's relative-state formulation (or something akin to it) of quantum mechanics is correct and that humankind continues to exist in other branches of the multiverse.

 

New super white paint might help with that, according to next big future

 

Potentially more harmful substances strewn around the environment that degrade and find their way into the food chain - is that a good idea?

ETA: I assume the technology being referred to is this one:

https://www.bbc.co.uk/news/science-environment-54632523

Given the problem, this would be akin to using a sticking plaster to fix a breach in a dam. It'll help but it isn't sufficient. We should be switching to renewable energy sources and striving for carbon neutrality much faster than we are at present. Carbon sequestration would also help but as this paint might be attacked by acid rain, could it actually end up releasing carbon dioxide into the atmosphere?