Some entirely made-up numbers (for the next 50 years):
Have motivation to destroy earth in indiscriminate fashion (~1)
Have asteroid deflection be within your technological and organizational capabilities (~1/10)
Have asteroid deflection be your easiest method of mass destruction (~1/7)
[Added] have naturally occurring asteroids on close enough trajectories that deflecting them towards Earth is a realistic proposition (~1/20?)
I think I have the least resilience here.
Avoid having your plans to hit Earth with an asteroid detected and disrupted in advance of launch of your asteroid deflection weapon (~1/50)
Redirect the asteroid with probably a large deviation in trajectory onto a very precise collision course with Earth (~1/8?)
Avoid having that trajectory subsequently observed and disrupted by currently existing asteroid observation and deflection infrastructure now operating (~1/10)
I think this is not independent of the previous 3 points, otherwise it’d be a lower probability)
~=1/5,600,000 or 1 in 5.6 * 10^6. However, I think these numbers are a bit of an understatement for total risk. This is because when I was making up numbers earlier, I was imagining the most likely actor to be able to pull this off in the next 50 years. But anthropogenic risks are disjunctive, multiple actors can attempt the same idea.
By contrast, to have asteroid deflection offer a benefit given current information, the requirements are:
There has to be an asteroid on course to hit Earth that we haven’t already detected (~1/1,000,000,000)
(Note this is just numbers I pulled from Shulman’s comment below)
The asteroid has to be of a size class we can build and launch a DART at in time to nudge it anywhere slightly off course (~1/2)
[Added] Just-in-time asteroid deflection without prior experiments are not sufficient (~1/2)
~=1/4,000,000,000 or 1 in 4*10^9.
So overall I’m skeptical that the first-order effects of deflecting natural asteroid risks is larger than the first-order effects of anthropogenic asteroid risks.
A second form of benefit might be
Successfully operating a form of X-risk infrastructure gives a concrete example of something we already do to prevent X-risk and creates a path for government to sponsor more such projects.
I agree with this. If the first-order effects are small, it’s easy for second-order effects to dominate (assuming the second-order effects come from an entirely different channel than the first-order effects).
I appreciate the effort to put some numbers into this Fermi format! I’m not sure whether you intend the numbers, or the result, to represent your beliefs about the relative risks and benefits of this program. If they are representative, then I have a couple points to make.
I’m surprised you think there’s a 10% chance that an actor who wants to destroy the Earth this century will have asteroid deflection within their technological capabilities. I’d assign this closer to a 1/1000 probability. The DART mission cost $324.5 million, was carried out by the world’s economic and technological superpower, and its team page lists hundreds of names, all of whom I am sure are highly-qualified experts in one thing or another.
Maybe North Korea could get there, and want to use this as a second-strike alternative if they can’t successfully develop a nuclear program? But we’re spying on them like mad and I fully expect the required testing to make such a weapon work would receive the same harsh sanctions as their other military efforts.
I’d downweight the likelihood that asteroid deflection is their easiest method for doing so due to the difficulty with precision targeting from 1⁄7 to 1/1000. An asteroid of the size targeted by DART would take out hundreds of square miles (New York is 302 square miles, Earth’s surface area is 197 million square miles). Targeting a high-population area puts even steeper demands on precision targeting and greater opportunity to mitigate damage by deflection to a lower-impact zone. It seems to me there are much easier ways for a terrorist to take out New York City than asteroid deflection.
Since your estimates for the two scenarios are only off by 3 OOMs, I think that these form the crux of our disagreement. I also note that this Fermi estimate no doubt has several conceptual shortcomings, and it would probably be useful to come up with an improved way to structure it.
I appreciate the effort to put some numbers into this Fermi format! I’m not sure whether you intend the numbers, or the result, to represent your beliefs about the relative risks and benefits of this program.
Those are meant to be my actual (possibly unstable) beliefs. With the very important caveats that a) this is not a field I’ve thought about much at all and b) the numbers are entirely pulled from intuition, not even very simple models or basic online research.
Also, apparently NASA is putting the odds of a collision with Bennu, which is about the same size as Dimorphos, at 1/1750 in the next three centuries. That’s not quite the same timeframe, and this is just a quick Google search result. A more authoritative number would be helpful. Given AI risk and the pace of tech change, I think it makes sense to highly prioritize asteroid impacts this century, not in three centuries.
As have previously been noted, the implicit flattish hierarchy of different points in pro-con lists can sometimes cause people to make bad decisions.
Source: 80000 Hours
Some entirely made-up numbers (for the next 50 years):
Have motivation to destroy earth in indiscriminate fashion (~1)
Have asteroid deflection be within your technological and organizational capabilities (~1/10)
Have asteroid deflection be your easiest method of mass destruction (~1/7)
[Added] have naturally occurring asteroids on close enough trajectories that deflecting them towards Earth is a realistic proposition (~1/20?)
I think I have the least resilience here.
Avoid having your plans to hit Earth with an asteroid detected and disrupted in advance of launch of your asteroid deflection weapon (~1/50)
Redirect the asteroid with probably a large deviation in trajectory onto a very precise collision course with Earth (~1/8?)
Avoid having that trajectory subsequently observed and disrupted by currently existing asteroid observation and deflection infrastructure now operating (~1/10)
I think this is not independent of the previous 3 points, otherwise it’d be a lower probability)
~=1/5,600,000 or 1 in 5.6 * 10^6. However, I think these numbers are a bit of an understatement for total risk. This is because when I was making up numbers earlier, I was imagining the most likely actor to be able to pull this off in the next 50 years. But anthropogenic risks are disjunctive, multiple actors can attempt the same idea.
~=1/4,000,000,000 or 1 in 4*10^9.
So overall I’m skeptical that the first-order effects of deflecting natural asteroid risks is larger than the first-order effects of anthropogenic asteroid risks.
I agree with this. If the first-order effects are small, it’s easy for second-order effects to dominate (assuming the second-order effects come from an entirely different channel than the first-order effects).
I appreciate the effort to put some numbers into this Fermi format! I’m not sure whether you intend the numbers, or the result, to represent your beliefs about the relative risks and benefits of this program. If they are representative, then I have a couple points to make.
I’m surprised you think there’s a 10% chance that an actor who wants to destroy the Earth this century will have asteroid deflection within their technological capabilities. I’d assign this closer to a 1/1000 probability. The DART mission cost $324.5 million, was carried out by the world’s economic and technological superpower, and its team page lists hundreds of names, all of whom I am sure are highly-qualified experts in one thing or another.
Maybe North Korea could get there, and want to use this as a second-strike alternative if they can’t successfully develop a nuclear program? But we’re spying on them like mad and I fully expect the required testing to make such a weapon work would receive the same harsh sanctions as their other military efforts.
I’d downweight the likelihood that asteroid deflection is their easiest method for doing so due to the difficulty with precision targeting from 1⁄7 to 1/1000. An asteroid of the size targeted by DART would take out hundreds of square miles (New York is 302 square miles, Earth’s surface area is 197 million square miles). Targeting a high-population area puts even steeper demands on precision targeting and greater opportunity to mitigate damage by deflection to a lower-impact zone. It seems to me there are much easier ways for a terrorist to take out New York City than asteroid deflection.
Since your estimates for the two scenarios are only off by 3 OOMs, I think that these form the crux of our disagreement. I also note that this Fermi estimate no doubt has several conceptual shortcomings, and it would probably be useful to come up with an improved way to structure it.
Thanks for the engagement! Re:
Those are meant to be my actual (possibly unstable) beliefs. With the very important caveats that a) this is not a field I’ve thought about much at all and b) the numbers are entirely pulled from intuition, not even very simple models or basic online research.
Same :D
Also, apparently NASA is putting the odds of a collision with Bennu, which is about the same size as Dimorphos, at 1/1750 in the next three centuries. That’s not quite the same timeframe, and this is just a quick Google search result. A more authoritative number would be helpful. Given AI risk and the pace of tech change, I think it makes sense to highly prioritize asteroid impacts this century, not in three centuries.