Figure 1
This image taken by NASA's Spitzer Space Telescope shows the comet Encke
riding along its pebbly trail of debris (long diagonal line) between the
orbits of Mars and Jupiter. This material actually encircles the solar
system, following the path of Encke's orbit. Twin jets of material can
also be seen shooting away from the comet in the short, fan-shaped
emission, spreading horizontally from the comet.
Encke, which orbits the Sun every 3.3 years, is well traveled. Having
exhausted its supply of fine particles, it now leaves a long trail of
larger more gravel-like debris, about one millimeter in size or greater.
Every October, Earth passes through Encke's wake, resulting in the
well-known Taurid meteor shower.
This image was captured by Spitzer's multiband imaging photometer when
Encke was 2.6 times farther away than Earth is from the Sun. It is the
best yet mid-infrared view of the comet at this great distance. The data
are helping astronomers understand how rotating comets eject particles as
they circle the Sun.
