This is a picture of a Brownlee particle, which may be what a comet is made of.
the National Astronomical Observatory of Japan.

This image shows the ray structure of Halley's Comet.
the National Astronomical Observatory of Japan.

This is a picture of what a comet is made of.
the National Astronomical Observatory of Japan.

The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). © The Regents of the University of Michigan. All Rights Reserved. Site policies and disclaimer