hey everyone, this is a qualitative question on gravitational orbits: I was going through questions in which the trajectory of the orbiting body is determined based upon the eccentricity of the orbit, e.g. 0<Ecc<1, ellipses, Ecc=1, parabola, Ecc>1, hyperbola. I did the math and found out what the foci where for each case. But I would very much like to know, what is the physical meaning of these foci? Yes, they are points such that the sum of distances from a point on the circumference of trajectory to each focus is a constant. But what do they really mean, in terms of forces or whatever? Okay, thanks!