From Peter Slessenger, Reading, Berkshire, UK
It is suggested that the orbits of planets in our system would probably be unaltered by a star passing at about 100 astronomical units from the sun. But what of the many Oort cloud and Kuiper belt objects? They would be much closer to the passing star and more easily disturbed (9 December, p 12). Could the planets expect a bombardment of comets and asteroids?
