Collision & Space Travel

[centaurwind]

I have read on some books about deep space observer increasing its velocity through collisons with the gravity fields of planets. Its about the problem of momentum but I am not clear about how it really works, can somebody explain it to me?

[Guille]

is it about the collision of the planets due to gravity?

of the observer with the planets due to gravity?

or of the observer with gravity and/but not the planet?

if it's the last one, how can something "collide" with gravity?

[AntonioLao]

I have read on some books about deep space observer increasing its velocity through collisons with the gravity fields of planets.

I think what you mean is gravitational slingshot. See it at
http://www.mathpages.com/home/kmath114.htm

[centaurwind]

Thanks for the link.

[Guille]

Antonio,

does the gravitational slingshot also work and can be understood in the quantum scale?