The Gravity Tractor

[lizzie]

http://news.nationalgeographic.com/news ... d_tug.html

A spacecraft could use a gravity "towline" to alter the course of an Earth-bound asteroid, a new study by two NASA astronauts suggests.

Previous schemes to deflect an incoming space rock range from landing a spacecraft on the asteroid and pushing it off course to blowing it up with nuclear weapons. The new plan takes a gentler approach. A spacecraft would hover above the asteroid and gradually pull it off course using nothing more than the gravitational attraction between the two bodies.

"If an asteroid is found to be at an impact trajectory with Earth … you will have many decades of notice. And it turns out that you only need to change its velocity by a very small amount in order to prevent a collision," said Edward Lu, a NASA astronaut at the Johnson Space Center in Houston, Texas.

[redeye]

crash asteroids into the Earth

The link above takes you to the NASA near Earth asteroid homepage. I had some fun terrifying my colleagues at work by smashing asteroids into the planet using this program. Try choosing 6344P-L and fast forward to OCT 12th 2054, Doomsday!

The thing is gravitational systems are chaotic, It's not really possible to predict the exact location of any planetary body and it gets harder to predict the farther into the future you look.

I don't think we'll have years to prepare for an incoming bolide, more like seconds.

Cheers!

[nick c]

Redeye wrote:
The thing is gravitational systems are chaotic, It's not really possible to predict the exact location of any planetary body and it gets harder to predict the farther into the future you look.

A skeleton in the closet of clockwork, gravity-only celestial mechanics!
[url2=http://cosmicvariance.com/2006/07/23/n-bodies/]The N-body Problem[/url2]

Nick

[redeye]

Thanks Nick, fascinating article.

The gravitational fascism displayed by modern cosmologists bemuses me, especially with regards to Saturn's ring system. The Saturnian system, with over 60 moons, should be utterly chaotic, yet it contains the most stable structure in our Solar system - Saturn's rings.

Daphnis and the Keeler gap

The image at the link above seems to show that the rings on either side of the Keeler gap are rotating at different speeds, i would further this speculation by stating that I believe that the reason the rings look different is due to rotational speed rather than particle size.

Cheers!