"Doug Miller" wrote in message
...
"Jim Wilkins" wrote in
:


Second, there is no such thing as "an object approaching along the
line of Earth's orbital
path": the orbital path is an ellipse, not a straight line. The only
way anything can be
*always* in "the line of Earth's orbital path" is if it is in the
same exact orbit -- and if it's in the
same orbit, it can't be approaching us, because two objects in the
same orbit are
necessarily moving at the same velocity.


Okay, I took a nap and daydreamed of orbits, and realized that
anything nudged loose from the Oort cloud would have to pass through
Earth's orbit at a significant angle. The only way to make it tangent
is to assume a high initial velocity as it enters the Sun's gravity
well, so its hyperbolic path grazes our elliptical one.
Observationally that would mean it has higher than Solar escape
velocity.