So you're calling it a "crisis" that people will be better informed of the risk they've always faced? Seems to me we should use that media coverage to build political support for a real asteroid defense system.
If the media does not contextualize risks correctly, as it never does, it's absolutely a crisis—a crisis of a poorly-informed, panicked society lashing out and doing irrational things.
It's not a costless error if a warped illusion of risk drives countries to, i.e., deploy nuclear-tipped space weapons for asteroid defense, which then precipitate a genuine crisis. It's not obvious that having more defenses is obviously safer than having less; some thoughtful people have argued the opposite:
>"In our view, development of this asteroid-deflection technology would be premature. Given twentieth-century history and present global politics, it is hard to imagine guarantees against eventual misuse of an asteroid deflection system commensurate with the dangers such a system poses. Those who argue that it would be prudent to prevent catastrophic impacts with annual probabilities of 10^-5 would surely recognize the prudence of preventing more probable catastrophes of comparable magnitude from misuse of potentially apocalyptic technology."
In this case, the context is "we face the same risk all the time, from asteroids we don't see." I'm not convinced that's reassuring.
The Sagan paper concerns much larger asteroids, which are correspondingly more rare. For asteroids in the 8MT impact range, it doesn't make much military sense to launch deep space missions to divert them years in advance, rather than delivering nukes directly with ICBMs in minutes. Given any competent asteroid defense system, an asteroid diversion would be detected immediately and countered, and the perpetrators would face consequences.
In fact, since we already have rockets that can reach asteroids, I'd say the possibility of malicious diversion makes a defense system more important.
- "The Sagan paper concerns much larger asteroids, which are correspondingly more rare."
That's a fair distinction—the paper predates the modern telescope surveys that are discovering all the small ones.
- "rather than delivering nukes directly with ICBMs in minutes"
You'd still need multiple years for those nukes to have a useful effect. (The change in velocity is instant; the change in position is not). They wouldn't be ICBM's, either: we'd need a new type of deep-space delivery vehicle, far larger than a suborbital ICBM. That'd probably trigger a new type of nuclear arms race.
Sorry, what I mean is: why would I use my rocket and nuke to divert an asteroid years in advance, when I can drop an 8MT nuke on you directly in 30 minutes with much more accurate targeting?
One possible reason is plausible deniability, but that goes away if we have a good asteroid defense system with an emphasis on early detection.
For one thing, you could weaponize asteroids as a second-strike response, if there's an imbalance where one superpower has asteroid deflection and one does not. Even if it's delayed by months, the certainty that the asteroid will eventually hit establishes a deterrent against attacking the asteroid-controlling country. If there's defenses against ballistic missiles, this circumvents those.
For another, the asteroid-deflecting nukes are dual-use as weapons themselves. A nuclear warhead in deep space defeats conventional ballistic missile defenses. If that warhead is turned towards Earth, that (first-strike) attack's not visible to the adversary until a few seconds before impact—unlike an ICBM launch, which has tens of minutes of warning, enough to launch (conventional) interceptor missiles.
I don't think a second strike from asteroids would work. You can't just arbitrarily redirect an asteroid towards Earth whenever you want. You need one that's already going to pass nearby. You might have to wait decades for it to hit, and during that time your enemy can send their own nuke and nudge it away.
But if you could do second strikes with asteroids, that would be a good thing. Second strike capability helps prevent nuclear war. Effective first strikes are what's destabilizing.
Which brings us to your second point. I agree that stationing nuclear warheads in space is a bad idea. But we don't have to do that. With years or decades of advance warning, we can just launch them from Earth.
- "Second strike capability helps prevent nuclear war. Effective first strikes are what's destabilizing."
I don't disagree!
- "You need one that's already going to pass nearby."
There's a very large number of these already, within a small delta-v of Earth. We don't know where they are yet (it was a show-stopping issue with NASA's Constellation (?) program, when they wanted to demonstrate capturing an asteroid, but couldn't find one), but that's going to rapidly change.
- "and during that time your enemy can send their own nuke and nudge it away"
That's pretty useful: that brings it to a point where the defender has to invest an amount of resources comparable to the attacker. That's a win for the economically stronger country. If the difference grows large enough, they can simply overwhelm them with numbers.
That's even before opening the technological possibilities of stealth asteroids.
Eh, we already have steath aircraft that could slip in past air defenses and drop a nuke with next to no warning. We probably have a stealthy hypersonic that can also do so. That doesn't negate a nations second strike ability.
Part of the reason the US, Russia and China have vast land based missile fields is to visibly show the enemy that they're gonna have to wipe out huge swaths of land with hundreds of nukes (and THEN sink our boomers) to have a successful first strike.
Right; but if the enemy thinks that's likely to happen, it'd only take them 15 minutes to nuke that one airbase that stores all the B-2's. Strategic bomber aircraft aren't very useful weapons for superpowers fighting each other (or else we'd have a lot more B-2's).
Space-based weapons (which are banned by treaty) are more like submarine-basing, in that the enemy isn't necessarily sure where they are; but, in addition to that, they have potentially very short warning times before a strike. No one actually wants that unstable dynamic, with the short/no-warning; which is why all the nuclear powers have (so far) agreed by treaty not to build any.
edit: But if someone were to build a civilian spaced-based asteroid defense, which involved sending nuclear weapons into space... that could get destabilizing fast. Whether or not Sagan can predict specifics, the big-picture idea of humans not trusting each other with apocalyptic weapons is not wrong. (Worth recalling the USSR genuinely mistook the civilian US Space Shuttle for a nuclear weapons platform).
Forgive my naivete, but do we really have the precision measurements and kT payload calibration needed to alter an asteroid's trajectory and speed to the point that we can target specific (even very large) country landmasses as the Earth's rotation exposes them to the oncoming projectile?
Nuclear second strike has always been from the submarines, which guarantee a response within minutes.
Versus your proposal here of launching a highly visible rocket, to manipulate a highly visible object, with a flight time measured in days to weeks that's mostly ballistic.
The physics of tomorrow though will be the physics of today however: a many months flight time out to an orbital object to affect trajectory change is a response time so far away as to be meaningless: any opponent with an ICBM strike capability on Earth could happily blast away your entire civilization, and reasonably expect to use the same technology that enables that ICBM capability to blast away (or deflect) your asteroid.
Put it another way: for considerably less expenditure of effort, you could just build a hydrogen-bomb large enough to obliterate Earth's biosphere completely[1]
Consider that ICBM's might not work forever. If e.g. new types of anti-ballistic missile defenses were to become cheap and reliable, then ICBM/SLBM's could even become obsolete (say, within the century). If that happened, there'd be a slew of new arms races, which are unimaginable to us, being beyond our technology horizon.
Physics isn't changing over time, but engineering is.
>we'd need a new type of deep-space delivery vehicle, far larger than a suborbital ICBM.
Like...starship?
> That'd probably trigger a new type of nuclear arms race.
Why on earth would there be an arms race on something designed to deliver nuclear payloads to deep space? The only way I could see that happening is if we had nuclear armed deep space colonies? (See, the expanse)
This. It’s a crucial step for our civilisation to be able to protect earth from any incoming dangers be it asteroids or Umuamua type objects. There must be a global effort with all countries to build such a system.
Good luck with that... currently we are failing to muster a global effort for tackling climate change, which is a much more pressing issue than an asteroid which may or may not hit us. I know https://en.wikipedia.org/wiki/Don%27t_Look_Up is satirical, but reality often outdoes satire, so I wouldn't be surprised if things would play out exactly like in that movie...
This pessimism has its place, but in this specific case, it is not accurate.
Congress did decide that NEO's are an important problem, and eventually money was appropriated to address it, and a technical solution to the detection problem has been found. (https://en.wikipedia.org/wiki/NEO_Surveyor)
There is an open doubt whether a fully functional coffee machine is currently orbiting Venus, however one of these hypotheses is different than the other.
Hint: expertise matters, evidence matters, and in a field where buildings/laws/fields of study get named after successful contrarians, a long streak of effectively unanimous consensus should not be undervalued.
The coffee machine has no implications on my current life span. It may be true, but who would waste their time caring about this?
Show me the /unanimous/ consensus that this is an immediate /existential/ issue. I don't believe such a thing exists. When attempting to understand the difference between those who care about an asteroid and climate change, which was the question, this is the critical point to concern yourself with.
Overwhelming agreement among experts is as gold as standards get.
But FWIW, I don't think anyone believes that climate change is a quick duration species-existential event. Massive slow-roll geopolitical destabilization leading to societal collapse? That's definitely on the table.
Hmmm… what level of agreement would constitute sufficient cause for massive change?
Eventually happen? What percentage of the Great Barrier Reef is gone?
How about this every single climate change skeptic I have offered this wager to has declined to take me up: if in the next calendar year, the average global temperature for a given month is below the average global temperature of that month in the year you were born I will pay you 10 times the amount you are willing to wager. If the opposite is true, that the month this year is warmer than the same month in the year you were born you must pay me the amount you are willing to wager.
> by doubting, you've already ruled it out, haven't you?
So you are attempting to create an environment where reasonable doubt is impossible. This behavior is actually part of the reason I have doubts.
> we know corals will be dead in the next few decades
Do we?
> The mass extinction event is underway and we aren't doing enough to stop it.
This is a clever dodge of the original question. Can you explain to me when our current inaction reaches a point where no response will ever be able to overcome the drivers of this mass extinction? Do you have an estimate you can share?
The good news is that the near-unanimous consensus among experts is that climate change is not an existential issue. Almost no climate scientist thinks that climate change could wipe out the human race. (That's compatible with it having very large effects on human welfare, substantial percentages of global GDP.)
