British plan to tackle asteroids

 One of these could really spoil your day

Have you seen that article on the BBC's website: "British plan to tackle asteroids"?

First, I have a confession to make. I know little or nothing about the detailed science - all I can offer is my gut feeling.

A couple of weeks ago I was reading the excellent Bill Bryson book : A Short History of Nearly Everything. He devoted a couple of pages to the threat from asteroids. It did not make for easy reading. It's reckoned that a relatively small asteroid, eg a kilometre or two in width - would be sufficient to extinguish life - or at any rate- most life  (certainly ourselves)  on Earth. What's more, its approach speed is so great that we would probably have only minutes - or seconds warning - of its approach.

So when the BBC article says that the threatening asteroid would have to be detected 15 years, no less, before its ETA,  time  in which for us Earthlings to mount our defences and  launch a so-called "tractor",  then it hardly inspires confidence.

But there's worse to come, at least where the science is concerned. The article says a space craft would be sent up that would park itself alongside  the asteroid.  It's mere presence would gradually make the asteroid veer off course due to the small amount of gravitational attraction between craft and asteroid.

Hold on a minute. The asteroid is vastly bigger than the craft.  The asteroid will pull the craft towards it with far greater force than vice-versa. The only way a small craft can act as a gravitational magnet would be if it had a propulsion unit that kept it at a constant distance, fighting the gravitational force. But that would surely require an input of energy - for 15 years or more. Is that why the article threw in a brief mention of solar power? Well, I say - that's one super Duracell battery.

I may be completely wrong, but my initial reactions are that this scheme is hare-brained - or maybe there's a lot more untried technology involved than the authors - or the BBC journalists-  are letting on. The BBC, to its credit,  inserts a little caveat - "No prototype have as yet been tested".   Pie in the sky?  Sci-fi hardware in outer space?

Tell me: are there any other kindred spirits out there who share my profound scepticism with what looks at first sight like silly season gimcrack "science".