What’s bugging me is the diameter gap between the figure in the model and the figure given for the time span such an endeavor would actually have at its disposal before impact. 200 m is not “less” but massively less than 500 m. And to introduce the argument of economic feasibility at this point—the whole point of the proposal is its feasability, isn’t it?—strikes me a bit as, well, moving the goal posts.

^_^J.

For a 200-metre-wide asteroid, the spacecraft would need to weigh about 20 tonnes and lurk 50 metres from its target for about a year to change its velocity enough to knock it off course.

This idea was devised by Edward Lu, a NASA scientist and astronaut.

See also
http://www.b612foundation.org/about/foundation.html

Seriously, though, since I’ve gotten a bit wary by now: can anyone do the math on this “tractor trick” Easterbrook brought forward, and verify that there are possible cases in which this scenario would actually bear out? How much mass/weight would a probe have to have, in order to get an asteroid that’s on collision course with Earth with a given diameter and a certain speed to change its course for some degrees, of fractions thereof, and how far away would that have to happen? Lots of variables to deal with here, but it should be possible to calculate some average cases, no?

Cheers,
^_^J.

As I called him a crank; I too was commenting on the messenger, not the message.

Glad we could help make you see the light! I dunno where Easterbrook gets off calling out Hawking. I suppose, the he has several degrees in theoretical physics and he just writes sports stuff for some extra cash.

Zeb

read the links I posted for gyokusai. They might help clarify things.

I no longer support the space program. What a bunch of jerks.

I would accept your criticism willingly were it not for the fact that I didn’t just say he was a tool… I provided examples, quotes and references to the fact.

As Torbjorn pointed out, he mutilated an article on quantum physics with a complete lack of understanding of some very basic principles of physics… and then went on to make the argument that physicists had it all wrong… I wish I could find the article to link it to… I think it was in the Atlantic several years back.

Saying he was a crank without providing evidence to back it up would have absolutely been ad-hominem, and you would be right to point it out. But in this case, we’ve got facts to back the statement up. If you wish, feel free to take a read of some of the articles we’ve pointed out here, or do a search and see for yourself… I’m fairly confident that in short order you’ll agree with what we’ve been saying.

By the way, I’m not lashing out against the message in this case… more the messenger in the form of Easterbrook… I’d rather see someone with some actual scientific credentials present the case and argument.