The phrase "giant comet" refers to a very large, icy object in space that resembles a comet, which is a space rock made up of ice and dust.
Sentences with «giant comet»
Boyajian's original hypothesis was that transiting swarms of giant comets caused the star's dimming. (scientificamerican.com)
Larger bodies, such as giant comets, asteroids, and protoplanets, must have coalesced from the original disk and then crashed into one another. (discovermagazine.com)
Astronomers now think they were once all bits of a single giant comet that fragmented in the distant past. (space.com)