OFF: UK Charts (Deep Impact v Armageddon)

[M Holmes]

Carl Edlund Anderson writes:

> On ons 5 aug 1998 19.53 +0100 "Chris Warburton" <desdinova at EARTHLING.NET>
> wrote:
> > BTW I think Texas probably could sneak up - in astronomical terms it's not
> > that big!
>
>      Texas-sized or not, the Earth could easily be hammered by
> a astronomical object that nobody noticed until it smacked into
> us.  I recall there was one that zipped by a few 100k miles or so
> away

There was one about half a million miles away - twice as far as the
Moon.

In 1972 one grazed the atmosphere (say 200 miles up). It was big enough
to swamp every coastal city on the planet if it had hit a deep ocean.

>(gnat's whisker, in astronomical terms) that nobody knew
> about until three days after.  Dunno how big it was, but I
> recall the projected explosive force, had it hit, would have
> outstripped the total nuclear weapons stocks of the planet by
> a very, very large amount.

Anything much over a mile wide would destroy civilisation. There are
estimated to be at least 2000, and almost certainly a multiple of that,
asteroids which cross Earth's orbit. We generally get trashed every
25,000 years or so, and we're about due another one.

Of course this is the first time we've ever had the chance to develop
technologies which might enable us to detect and prevent a hit.

> Carl

FoFP