The Comet of Death

Ok, so I'm reading this science book by Bill Bryson called 'A short history of nearly everything' and I get to a chapter about comets. Bill asks a scientist how much warning we would have if we knew a comet was going to hit the Earth. 'Oh, probably none' the scientist says. Apparently scientists can't really track comets or asteroids as they're so hard to see and you wouldn't actually be able to see one until it started heating up in the Earth's atmosphere which is about 1 second before it hits the Earth.
When asked to describe the events that would happen as the comet hit the Earth, the scientist described it like this:

'An asteroid or comet travelling at cosmic velocities would enter the Earth's atmosphere at such a speed that the air beneath it couldn't get out of the way and would become compressed... compressed air grows swiftly hot, and the temperature below it would rise to 60,000 Kelvin, or ten times the surface temperature of the sun. In this instant of its arrival in our atmosphere, everything in the meteor's path - people, houses, factories, cars - would crinkle and vanish like cellophane in a flame'

This follws with:

'Now every living thing within 250 that hadn't been killed by the heat of the entry would now be killed by the blast, and everything after that would witness a flash of blinding light, followed by 'an apocolyptic sight of unimaginable grandeur: a rolling wall of darkness reaching into the heavens... its approach would be eerily silent as it would be moving far beyond the speed of sound... anyone in a tall building would see a bewildering veil or turmoil followed by instantaneous oblivion.' Pretty much everything within a 1,500 km radius of the blast would be flattened and on fire, and ripped apart by debris and flying projectiles.

The worst thing about this is that we have no technology capable of stopping any of this from happening. All that bullshit about sending a team into space or firing a nuclear missile to break up the comet in movies like Deep Impact and Armageddon is just fanciful rubbish as for one, we don't actually have any working rockets capable of leaving the Earth's atmosphere right now (the last one, the Saturn 5, was retired in 2005) nor the technology to guide said missile over millions of miles of space and even if we did hit the comet with a nuclear warhead, we'd just make a string of comets that would slam into the Earth one after another and now they'd be intensely radioactive leaving us to die slowly and horribly.

This information really ruined my day. Thanks Bill, you bastard.