When an asteroid a few dozen meters in diameter whizzed past the earth
earlier this month nobody was the wiser until a few days after the near
miss. Some scientists think it would be well worth some research expenditure
to begin a more systematic head-counting of loose cannon on the earth’s
orbital plane in order to have a better chance of predicting future
collision possibilities.

Astronomers at the CNRS/Paris Observatory’s
Celestial Mechanics Institute are preparing a project to fill in the holes
in what is currently the only serious attempt to cast a visual net through
the solar system for “catching” asteroids, Linear, an American program
employing automatically controlled twin telescopes. The French team is
concerned that Linear can only pick up objects of more than a kilometer in
diameter, does not see anything in the southern hemisphere sky, nor can it
track accurately any body whose trajectory lies even partly in the southern
skies. Moreover, it takes Linear a month to complete its bit-by-bit scan,
during which an asteroid could easily appear and disappear, thus escaping
detection. Their first priority is a proposal to the European Southern
Observatory to install a 3-4 foot telescope to begin automatic scanning from
Chile, to complement Linear’s northern lookout, then they plan to call for
several 10-15 ft telescopes to begin searching the heavens for smaller
asteroids still of a size to inflict a good deal of damage.

¿Sb`nterviewed in
the daily press, one the team’s leaders criticized the scoffing of certain
public figures at such a waste of money, pointing out that the costs are
minimal (a few hundred thousand euros annually) compared to the enormous if
slight risk surveillance would help avoid. In answer to the obvious question
of what good a warning would do, most scientists suggest that as the
catalogue of asteroids grows the chances increase that that information
would be available several decades ahead of time, thus permitting clever
earthlings enough time to dream up a suitable way to divert the menace. (Le
Monde, June 28, p23, Pierre Barthélémy)