* Outgassing: As a comet approaches the sun, its icy surface heats up and begins to sublimate (turn directly from solid to gas). This process releases gas and dust into space, forming the comet's characteristic tail. This loss of material reduces the comet's overall mass.
* Solar Wind: The constant stream of charged particles from the sun, known as the solar wind, can also erode the comet's surface, further contributing to mass loss.
While comets might occasionally pick up a small amount of dust or other debris in their travels, the amount gained is negligible compared to the mass they lose through outgassing and solar wind erosion.
Therefore, it's safe to say that comets generally decrease in mass with each orbit around the sun.
