AGAINST all expectations, NASA’s ageing Deep Space 1 spacecraft captured some
fascinating pictures of Comet Borrelly during its fly-by on 22 September.
Snapshots released last week reveal that the comet is curiously lopsided.
Comets consist of a nucleus of ice and rock surrounded by a cloud of dust and
gas. Images of the cloud of energetic ions around Borrelly show that the nucleus
is off-centre by 7000 kilometres. “It is in the wrong place and we have to
figure out why,” says Donald Yeomans, manager of NASA’s Near Earth Objects
programme at the Jet Propulsion Laboratory in Pasadena, California.
The…
