Part of the dust tail of a comet
that seems to point, often like a spike, toward the Sun.
This rare phenomenon is an illusion caused by the viewing geometry and typically
occurs when Earth crosses the plane of a comet's orbit when the comet is
relatively close to the Sun. Under these circumstances, the cometary dust,
which lies in a thin sheet and lags behind the comet, may be seen edge-on
as an antitail. One of the most prominent antitails ever seen was that of
comet Arend-Roland during its perihelion
passage in 1957.
|Comet Arend-Roland in 1957 with antitail