1) Presumably this will throw the comet off-kilter just enough to smash it into Cozumel or something.

2) You have strange taste in video games.

Ahaha!

Come on -- wouldn't *you* play a game that let you smash thousand-mile-long space objects into one another? Or collide Mars with the Earth?

Woo!

Thanks for the link - at our house, we like that kind of stuff and will surely play the video game when it appears...

An entirely different thought occurred to me when I read the article. Is it smart, or ethical, or forward-thinking, to go smashing things into intact celestial objects? This seems like a pretty primitive approach, like folks who break off fragile stalactites in limestone caves, or who fill in marshland for housing projects. And this is not even to mention the trajectory issue which, I assume (hope?) has been taken into account.

I know we're collecting scientific information here, but we could also find out what would happen if we exploded some nuclear devices on the moon, or threw some biological material onto Venus or Titan.

The interesting question to me is: Is there a line between the hypothetical Moon/Venus/Titan experiments and bowling for comets? If so, where is it and how do we define it?

That's a truly cool question. It seems like this is in the realm of "planetary protection" -- the area of philosophical inquiry (staffed and studied by folks at NASA, the European Space Agency, and elsewhere) that scrutinizes space missions to make sure they do not interfere with any possible life on other planets, nor bring back lifeforms that might infect Earth. (I wrote a piece last year for the New York Times about this.) I know that the ESA has freaked out a lot of planetary-protection experts with its upcoming plan to create a probe that would burrow through the ice on Europa in an attempt to reach potential watery oceans below -- a situation that would be awfully likely to see said water with Earth microbes.

With the comet, they're certain that the impact won't change the orbit to bring it in conflict with Earth, but I have no idea if it'll cause any other long-time problem for it. Me, I don't have any problem with bonking a comet out of alignment so long as it doesn't crash into a planet ... since comets are widely regarded as being highly unlikely sources for life.

There is a position I've heard attributed to Native Americans that sending any spacecraft out of earth's gravity well, much less plonking it into another object that will carry it out of the solar system, is wrong because it diminishes Earth (sending mass/planetary material away).

Wow. I agree, Clive, that there is an eerie beauty to the video. The backlighting is quite pretty. I think that the silence of the video also contributes to the eerie quality. To see an impact like that with no accompanying blast of noise feels very odd to my Hollywood conditioned ears ;)

The confusing sense of speed helps too. With very little background against which to measure the speed of these objects, there is a sense of anticipation leading up to the impact.

Cool stuff.

Yes! The silence makes it particuarly strange -- yet of course certainly realistic, given that there ain't no sound in space.

Or I dunno, would the ejecta carry any "sound" if it collided with a spectator?

Small world - no pun intended - a good friend of mine from college, who I just stayed with recently in Pasadena when visiting LA, is a key team member of Deep Impact. He's been at JPL for 13 years. His past year has been incredibly busy - the team pretty much lives in the lab. July 4 will be his Independence Day indeed.

He was mentioning that the highest resolution camera on the main probe went out of focus, probably during launch, so people are a little bummed by that.

(Separate, but also interesting I think -- I stayed with this friend in Pasadena, but was working during the day at ICT in Marina del Rey. I decided to not to rent a car, but instead commute by Metro train. I had to ride on 4 lines, transferring three times - Gold to Red to Blue to Green. Took 1 hr 20 mins each way, about the same had I driven during rush hour. 50 miles of travel for $1.50. Interesting to see the various demographic changes as I crossed through various LA communities and cultures on my ride - yuppies to financial workers to boisterous south central youths (and older folks tsk-tsking them to themselves) to latino families, and all in between. The whole experience made a not so Small Impact on me.)