From J. WHITMAN
There has been much discussion recently of possible cosmological causes
of global catastrophe over the Earth’s recent history. Random comets from
the imaginary Oort cloud and rogue asteroids are popular enemies.
The recent precise measurements of the velocity of the star Lalande
21185 (New Scientist, Science, 1 August) suggest that a complete star system
may arrive in our midst in under 30 000 years. Now that should produce
some interesting effects.
J. Whitman Barnham, West Sussex
