Will mankind destroy itself?

[Gawdzilla Sama]

Okay then.

[JimC]

Math is not reality.

Neither are the words we type onto this forum reality. Nor are our ideas as presented any reality. These are all merely models of reality, which is what my maths are, also. The maths is just as relevant and as much a part of the discussion as any ideas you, or anyone else puts forward.

Very true.

Mind you, much of this has to do with perception, and how an assessment of risk may or may not change behaviour. BG is not denying that an asteroid impact is possible tomorrow, just looking carefully at past events to get a perspective. Whether his perfectly valid analysis of the probabilities involved is a useful datum for anybody considering such issues is up to them.

He is denying it won't happen soon. Which is bullshit.

Turn that statement on its head. If, as you assert, "not happening soon" is bullshit, then you seem to be implying that it will happen soon.

Of course, none of us know whether event X will or will not occur, but assigning probabilities based on past records is really all we can do, other than waving our hands in the air and saying "Darwin knows"...

[Gawdzilla Sama]

Jim, there's a difference between those two. First, I don't assert that it will happen at all. But I don't assert that it won't happen soon either. We don't know when it will happen, and the math doesn't tell us WHEN.

[Gawdzilla Sama]

*cough*

http://www.msnbc.msn.com/id/49155837/ns ... nce-space/

[JimC]

Jim, there's a difference between those two. First, I don't assert that it will happen at all. But I don't assert that it won't happen soon either. We don't know when it will happen, and the math doesn't tell us WHEN.

And it never will, and never can...

However, if you were on a planet in another solar system, much nearer a dangerously active asteroid belt, with a past record of major impacts every 500 years, the probability you would assign to a strike in the next year would be much, much higher...

In fact, I'd prefer to have my trusty survey ship well off planet, ready for a reasonable chance of filming a big one...

[Gawdzilla Sama]

Did you read that link?

[JimC]

Did you read that link?

Have now, and it's always interesting to hear about such events.

However, it is well understood that the smaller the class of object, the more frequent are the occasions when they head towards Earth (whether they burn up or not). There are a lot more small rocks than big ones...

Dinosaur busters are vastly bigger than the example in the link, and their average frequency of impact is correspondingly vastly lower...

If not, Earth would be not as it is today...

[Blind groper]

Gawdzilla

If you are talking of smaller strikes, the probabilities change again. The spectacular over the UK was of rather tiny strikes, which happen all the time.

As I said before, the one I would worry about is another Tunguska type strike (http://en.wikipedia.org/wiki/Tunguska_event), which some authorities have estimated happens about every 100 years. So another one could happen any time soon with reasonable probability. Most likely, it would happen over the ocean, or a sparsely populated area, but there is a solid chance it might happen over a populated area, in which case we have a major tragedy.

Of course, a Tunguska strike will not be an extinction event, which is what we have been talking about.

[Gawdzilla Sama]

So show me where the math says there won't be a strike tomorrow.

[Blind groper]

Gawdzilla

We covered that earlier. There will be a strike tomorrow, guaranteed. In fact, hundreds of strikes. Small ones. Go outside on a clear night and look up. Roughly every 30 minutes, plus or minus a bit, a shooting star can be seen. Each one is a minor strike of a space rock against the Earth.

As far as a big dinosaur killer strike is concerned, I cannot say yea or nay, but I can calculate (roughly) the odds against it, which I have done, several times.

[Gawdzilla Sama]

That's where we have reached a sticking point. Odds don't mean it won't happen tomorrow.

[Blind groper]

Gawdzilla

I have never said that. Of course it can happen tomorrow. Vanishingly unlikely, but it could happen. But, as I told you, I am not going to worry about such an incredibly low likelihood.

[Gawdzilla Sama]

Gawdzilla

I have never said that. Of course it can happen tomorrow. Vanishingly unlikely, but it could happen. But, as I told you, I am not going to worry about such an incredibly low likelihood.

Same likelihood as any other day. And you said it probably won't happen in the next hundred years.

[Blind groper]

Each day has the same very, very, very low odds. But the odds are greater for a 100 day period. Greater for 10 years. Greater still for a million years. Even that 100 year period is still a very small time period compared to an event that strikes once each 100 million years. So, yes. it probably will not happen in the next 100 years. It probably will not happen in the next million.

Until you get to rather high numbers, the odds are still too small to worry about.

[MiM]

If one were about to hit tomorrow, it would probably have been spotted already