Explanation:
Periodic comet
73P/Schwassmann-Wachmann 3 has fallen apart before.
A cosmic souffle
of ice and dust left over from the early
solar system, this comet was
seen to split into several large pieces
during the close-in part of its orbit in 1995.
However, this time the comet
seems to be rapidly disintegrating
with over three dozen fragments, named alphabetically, now
stretching several degrees across the sky.
Since comets
are relatively fragile, stresses from heat and gravity
and outgassing, for example, could be responsible for their
tendency to breakup in such a
spectacular fashion.
On April 18th, the Hubble Space Telescope
recorded this
sharp view of prolific Fragment B,
itself trailing dozens of
smaller pieces, each with its own cometary coma and tail.
The picture spans over 3,000 kilometers at the comet's April
18 distance of 32 million kilometers from planet Earth.
With its brightest fragment presently too faint to be
seen with the naked eye, comet
Schwassmann-Wachmann 3 will
pass closest to Earth
on May 13 at a distance of about 11 million kilometers.
