[Ford Prefect]

Actually no...
The sky is freaking HUGE and we can only monitor about 3% of it at a time.

The truth is that a gigantic metoer could come any second and kill us all without us even knowing..now THAT is scary.

Yes, that's true. There have been at least a couple cases recently where huge ass mother****ers missed us by less than a million miles and we only saw them after they passed.

[karajorma]

Originally posted by TrashMan
Actually no...
The sky is freaking HUGE and we can only monitor about 3% of it at a time.

The truth is that a gigantic metoer could come any second and kill us all without us even knowing..now THAT is scary.

Sorry but no. The Spaceguard Survey estimates the size of a gloabal killer would be at least 2km in size. If you're trying to tell me that an asteroid that size could approach Earth and only be detected on the day before impact then I've got a bridge I'd like to sell you.

What can't be spotted easily are the smaller asteroids which wipe out a city. Those are dangerous and really should be protected against (cause nukes are useful against something that small).  But an asteroid that can kill us all? We'd not be hearing about that one the day it impacts.

[Black Wolf]

Originally posted by karajorma

 But an asteroid that can kill us all? We'd not be hearing about that one the day it impacts.

In all likelyhood, we probably would be, just to prevent the mass rape and stuff, but we'd definitely be detecting it on time. Keep in mind that there are millions of semi amateur astronomers looking into the sky every night, as well as the global astronomies, as well as the skywatch programs designed to look for these things. Someone would see it.

And, oh yeah. Stupidity. I'd believe my teachers at assembly over the past several days worth of newscasts full of "New Diet sweeps the nation" stories or whatever.

[Ford Prefect]

Two kilometers is nothing in space. We simply don't see everything at once. Like I said before, very large things have gone by us without us seeing them until after they pass. And in addition, the objects that we do detect have to be spotted a very long time in advance for us to do anything about it.

[Flipside]

All I'll say from that point of view is that we've got by for the last several million years without anyone looking out for them

Cataclysmic asteroid collisions are not, I'm pleased to say, a common occurence among the inner planets. And, of course, we have a moon, take a look at the surface of that to find out where a lot of Earth-bound dangers ended up

Oh, and to put things into perspective, yes, we would see anything that was going to hit us, since, it order to be able to do damage it needs to have one of two things, mass or speed. Both of these create phenomenon that are detectable from long range over a wide are.

The Comet that hit Jupiter exploded with a force of 1 triliion megatonnes, it would have cracked the moon in two. However, something of that mass and speed would never get caught in the Earth's gravity well, and for a direct hit... well, imagine playing 3D zero-gravity, no-friction snooker on a table that is 200 km cubed with sawdust on the felt, and you'll have a rough idea of the chances

[Lightspeed]

But still, it is possible

[Flipside]

Yes, it is When you have literally Billions upon Billions of years leeway, even those long shots come up from time to time. However, if we saw a Comet of that magnitude coming towards Earth, the only effective action we could take is to put our heads between our legs and kiss our asses goodbye

[karajorma]

Originally posted by Ford Prefect
Two kilometers is nothing in space. We simply don't see everything at once. Like I said before, very large things have gone by us without us seeing them until after they pass. And in addition, the objects that we do detect have to be spotted a very long time in advance for us to do anything about it.

I never said we'd be able to do anything about it. Just that we'd know it was coming before the day before it hit us.

[Lightspeed]

Originally posted by Flipside
Yes, it is When you have literally Billions upon Billions of years leeway, even those long shots come up from time to time. However, if we saw a Comet of that magnitude coming towards Earth, the only effective action we could take is to put our heads between our legs and kiss our asses goodbye

Uh, it's pretty much random. That means, you don't need much time for it to happen. Heck, it could happen thrice in a row in very little time

It's just not very likely.

[Flipside]

LOL Mathmatically very true, theoretically we could be bounced all over the solar system by errant comets and through sheer fluke end up in the same orbit as we started.

[aldo_14]

Tunguska stands as a good example, of course.

[karajorma]

Rather worryingly Tunguska isn't the most recent of the incidents either. The Amazon Basin was hit in the 30s and Canada just escaped being hit only a few years back.

[Flipside]

Small impacts are going on all the time, look at how many meteorites have been dug out of the Arizona desert

Tunguska is one of those wierd ones, which is only 'probably' an impact iirc? There were some strange peculiarities about the blast zone?

Oh, they'll hit us from time to time, but they are coming through one of the thickest atmospheres (relative to size) and hitting the densest planet in the Solar System (Yes, this is true, might even explain our evolution a little). Earth, for all it's upheavals, is a tough little nut

[karajorma]

Originally posted by Flipside
Tunguska is one of those wierd ones, which is only 'probably' an impact iirc? There were some strange peculiarities about the blast zone?

The whole standing trees bit? That's cause the Tunguska asteroid didn't actually hit the ground in one piece. Experiments showed that an asteroid fragmenting about 8 miles up would have that effect and would produce the same "butterfly" observed at the blast site.

[Flipside]

Ah right, they cleared that one up

Last time I read about it, to be honest, was in Arthur C Clarkes mysterious World

[kode]

this just goes to show that you in fact should not believe everything the authorities say.

having said that, the 14 year olds are either exceptionally stupid or the teacher is exceptionally skilled in rhetorics, or a combination of both.

[Flipside]

'War of the Worlds' syndrome

[kode]

Originally posted by Flipside
'War of the Worlds' syndrome

with the slight difference that orson welles was a ****ing genius, and it was back in 1938 which was a time when there were fewer instances of the fourth branch of government around.

[Flipside]

That is true, but, we have been made hyper-aware of these threats from Outer Space, even on this board people consider it a thing to be concerned about in the short term when far more local global catastrophes threaten us. We have been led to believe that these things could hit at any time.

People can be just as stupid and gullible when they buy their opinions in the papershop every morning

[karajorma]

What scares me is the small metalic asteroids rather than the big dinosaur killing ones. The asteroid that created the Wabar impact for instance was only 10m in diameter. There are millions of those in Earth crossing orbits IIRC.