A chalazion is a small bump that appears on your eyelid because of a blocked oil gland.It can develop on the lower or upper eyelid, and it often disappears without treatment in about one month. chalazion is a small bump that appears on your eyelid because of a blocked oil gland.
Artist's conception of a white dwarf accreting hydrogen from a larger companion. A nova (plural novae or novas) is a cataclysmic nuclear explosion on a white dwarf, which causes a sudden brightening of the star.Novae are not to be confused with other brightening phenomena such as supernovae or luminous red novae.he recurrence interval for a nova is less dependent on the white dwarf's accretion rate than on its mass; with their powerful gravity, massive white dwarfs require less accretion to fuel an outburst than lower-mass ones.
Comets are icy bodies of the solar system. They consist of frozen gas, dust particles and stones or rocks of various sizes from dust size to hundreds of meters. They are distinguished from asteroids by the presence of a coma (the shiny tail).They are of two types.es a nucleus of a comet is made of ice because a comet nuclei are  loose collections of ice, we need to break down the three main  parts of a comet a nucleus, coma, and the â¦ tail.