The ionized gaseous tail of any comet is quite
large, sometimes extending over millions of miles. Here we see a
small fragment in the center and on each side ionized gas molecules
which have spread out over the entire hemisphere of Earth. The
atmosphere will absorb these ions, or they will eventually fall to the
surface if heavy enough. The lightest ions are farthest away from the
fragment since they most affected by the solar wind. The crop circle
is obviously manmade due to its poor construction.