Asteroids are sexy again.
Sure, in 1998 we had two blockbuster movies ("Armageddon", which sucked, and "Deep Impact" which was excellent) showing us that asteroid and comet impacts could generate giant tsunamis, wipe out all life, cause lots of quick-cut camera shots, make Ben Affleck cry, and so on, but in the intervening years they haven't gotten as much attention. There have been documentaries on TV and some coverage in the dead tree media, but that's about it.
But most likely it was the reporting on findings from panels of top-level scientists on the topic that's caused a mini-flurry of stories. The BBC news had a story on it just the other day. They interviewed Professor Richard Crowther, chair of the UN Working Group on Near Earth Objects (NEOs); and as you might expect, his conclusion was that we need to get off our asteroids and do something:
The document says most asteroids entering the Earth's atmosphere are small and burn up before reaching the surface. But it is the larger ones - perhaps 200m or more across - that would need to be deflected away from a collision course with the Earth.
Even a rock 50 meters across could take out a city, exploding high in the atmosphere and generating a devastating shock wave and fireball. But it's literally impossible to find asteroids that small very long before impact. 150 meters or so is a reasonable size to find, and that's also about the size where they start doing damage on a large scale.
The UK newspaper The Guardian also picked up on this story, talking about (what I think is) a different group called the International Panel on Asteroid Threat Mitigation:
The international community must begin work now on forging three impact prevention elements - warning, deflection technology and a decision-making process - into an effective defence against a future collision,' said the International Panel on Asteroid Threat Mitigation, which is chaired by former American astronaut Russell Schweickart. The panel made its presentation at the UN's building in Vienna.
This is an important point, We need to find these suckers, we need to understand what to do, and we need to understand how to do it. Think of it this way: we find an asteroid 300 meters across, and calculate it will hit in Germany. Uh oh! So we launch a rocket, use our tech, and push it out of the way... kinda. Something goes wrong, and it only gets nudged. We recalculate the path... and find out it will now hit Pakistan. Oops! Their government might be a little ticked over such a thing, so we need to have some sort of process in place to deal with these (fairly realistic) issues.
I'm glad that scientists are able to get their reports out to the public, and I certainly hope the UN takes the threat seriously -- they will meet in February to discuss the issue. This is a global problem, and needs to be dealt with on an international scale.