Are comets disintegrating as they pass by the Sun? What is the ultimate fate of a comet?

The tail of the comet is made up of gas and dust which came from the
comet's solid nucleus, so yes, the nucleus is growing smaller all the
time. When the comet moves to the end of its orbit far from the sun,
its tail will fade out and the disintegration of the nucleus will
virtually stop.

After a few hundred to a few thousand passes around the Sun, comets
either break up completely, lose all their surface ices and become
more like asteroids, or most likely pass close to Jupiter or Saturn
and are thrown out of the Solar System.

Best wishes,
-Neal.

Back to the Ask An Astronomer page.