Asteroids as powerful as NUCLEAR BOMBS strike Earth TWICE YEARLY

Dumb Luck?

Talking statistics is talking rubbish.

The article says that none has ever seen any sign of thes things until after they happen. How the hell do they manage to miss every one of them when they are as common as solstices?

And how come none of these things have ever hit the moon?

Or did you all think that lunar craters are nearly perfectly symmetrical because that how meteor strikes operate on the moon as opposed to the ones that hit earth?

Re: er ... wot?

Wanderers? Wasn't that the other planets?

Yes that's right, when viewed from this planet. And if you go stand on Mars you'll see that Earth wanders across the stars just like the other planets do.

Re: yeah, well - @David Pollard

You're looking at things on the wrong scale.

The evidence for the Big Bang lies in things like the cosmic background microwave radiation, and galactic red shift. If the laws of physics were slightly different, there could have been a Big Bang which did not result in star formation - except nobody would be around to observe it.

The evidence doesn't only come from very large scales - particle physics shows that, for the present range of known particles to exist, at some time the universe was very hot and dense (replace "very" with "inconceivably" for best effect.) That's because, if that wasn't the case, there would never have been a stage at which the necessary quark soup existed to crystallise out into hadrons as the universe cooled. It is exactly the same way that we can tell that certain rocks were once extremely hot, because of the way that they have crystallised.

From different ends, then, we know that at one time the universe was extremely small and hot, and that it is currently expanding; we can also detect the fossil radiation from the extremely hot stage. There are plenty of books which give a much, much fuller explanation, and I'm only posting this extremely superficial overview because without it you might not realise the kind of evidence they will be discussing, and how compelling it is.

Re: yeah, well

If the causal connection can't be established, then how can we know with any certainty that the big bang occurred?

I don't even know that YOUR MOM occurred, so what are you on about?

Re: Maybe we need a couple hits near some major cities

"The other danger, not mentioned above, is what might happen if a meteor strike devastated (say) Karachi. Would it be mis-identified, leading to an all-out nuclear strike and counterstrike in the following minutes? Indeed, are we sure that the USA or Russia would correctly identify what nature could throw at Washington or Moscow or other major cities?"

Fortunately nuclear detonations have a very distinct 'double-flash' that asteroid strikes do not. The outer flash is caused by the air itself being superheated by the release of hard radiation, the second by the expansion of the actual fireball, composed of the physical material of the bomb itself. Although facts don't automatically prevent the human element of panic, confusion and impulsive decisions I suppose.

Re: The odds are not too shabby

I nominate Bilbyville.

(Unless Bilby lives in Queanbeyan.)

Re: The odds are not too shabby @ Bilby

I think for Britain this would be Milton Keynes, or possibly Slough.

( One could argue for Central London on a busy day with parliament in full session. But while that would raise the average IQ of the nation by quite a bit, it would also destroy some beautiful Old Stuff that *would* be missed. )

Re: The odds are not too shabby

Actually two per year, so four per century.

These are not even the big deal. They are the biggest deal we can look for because they recur on a period where we can look.

The big deal is that our sun is flying through a cloud of rocks that don't circle it. Most of the time it is less dense like now, but other times it is quite dense. In those times the speed of the worst possible sun-orbiting asteroid seems but a gentle kiss compared to an interstellar comet's smack. These threats don't recur, and there is no way to look for them. They will come, or not. The only way to deal with this threat is with distributed backups.

Re: The odds are not too shabby

That's the odds for hitting an urban area. It isn't the odds for hitting your urban area. Those odds are significantly longer.