An asteroid from deep space is sighted from the earth moving on a parabolic path with the

Question:

An asteroid from deep space is sighted from the earth moving on a parabolic path with the earth at the focus. When the line from the earth to the asteroid first makes an angle or 90° with the axis of the parabola, the asteroid is measured to be 40 million miles away. Flow close will the asteroid come to the earth)? Treat the earth as a point.