OK, thanks. It appears that my information must be out of date then. (I was taught about nuclear explosions being ineffective due to objects either re-coalescing (long range, rubble piles etc), or being too close to divert from earth (close range).

I was taught that the 'buckshot' effect of a bolide being destroyed via nuclear explosion would only be slightly, if at all (depending on size) preferable to the original impact, given that tracking so many fragments makes evacuation of specific cities/countries etc impossible. There's arguments involved about total kinetic energy transfer from impactor to earth, too.

(I was also taught that other options, propelling the object in a more controlled manner, are terrible in comparison to nuclear explosions, due to the age old limitations of the rocket equation. I'm sure you're familiar. )

However:
Now that we're discussing it, it might well be the case that I was being taught about interstellar objects, since the lecture grew out of a lesson about objects with an orbital eccentricity > 1.

Thanks for your post, I'll find some more recent opinions and info about solar system objects and educate myself further!
(If we have anything like the technology to propel even solar system objects I'll be super-impressed!)

Oh, the 'other thing' -

I certainly didn't mean that I disagreed that an impact could be disastrous. What I disagree with is: The idea that we have become as adept as we are at detecting asteroids and comets, out of a desire to survive.

If you read the other comments in this topic you'll see a few examples of this claim, and it's that I am challenging. (I'm really hoping this is clear now, because I'm trying really hard to state it clearly but it still seems hard to have it land. I really never said what you took me to mean, sorry.)

To clarify again: I believe that we have become as adept as we currently are because of an interest in astronomy, the general desire to understand physics, even geology and the origins of the universe etc! Not out of a desire to survive impacts.

Funding the search effort is no different than funding technology to stop them, if that's the motivation behind the search (I don't believe that it is, I'm counterpointing people that believe that 'it's the life-or-death nature of impacts that make people search' here.)

Ergo, if we really want to survive impacts, we need to work on ways to stop them - our detection is already 10000x further than our ability to stop anything. It's more than good enough for our current abilities to stop anything.

Agreed, but last I checked, any detection is happening way to late to do anything with current technology.

My thoughts are that, if we were truly motivated by the 'life or death' nature of a potential impact as some here implied (I disagree with this reasoning) ; efforts would be going into means of stopping them (we have pretty much none), rather than detection.

8 meter diameter. No mention of speed, but zero consequences if it hit.

(This one was too small to warrant trajectory calculation, since it would be harmless if it hit, but...)

Isn't it still the case that, if there is a potentially disastrous impact detected, knowing doesn't do much good? Its not like you can evacuate a city within a short time frame.

I guess what I mean to ask is - how does knowing about an impact help save us when we can't stop them?

I believe that there comes a point where a minority can be out-voted, by public opinion, to the point where its possible to direct intolerance on them with little more than a protracted campaign of hate speech.

Put another way, when there aren't enough XXX to defend themselves, public opinion can be swayed with little more than 'freedom of speech'.

At that point, the public become willing to vote for INtolerance in that specific case. It's happened many times historically, and is a reason I can get behind both aspects of European hate-speech laws, and aspects of American sue culture.