Comet

A comet is a small, icy body orbiting the Sun that becomes visible from Earth when its trajectory brings it close enough for solar heating to vaporize its frozen surface, creating a luminous head and distinctive tail. These "dirty snowballs"—mixtures of rock, dust, and volatile ices—have captivated observers for millennia, often interpreted as omens before modern physics revealed their celestial mechanics.

Comets follow highly elliptical orbits, some returning periodically (like Halley's Comet, visible roughly every 76 years) while others arrive from the distant Oort Cloud on one-time trajectories. As a comet nears the Sun, solar radiation ablates its nucleus, releasing gas and dust that stream away due to solar wind, forming the comet's characteristic tail—always pointing away from the Sun regardless of orbital direction.

These icy messengers have scientific significance: their composition preserves volatile compounds from the early Solar System, offering clues to planetary formation. They also pose modest impact hazards, though catastrophic strikes are extraordinarily rare. Comets have inspired art, mythology, and models of Orbital mechanics, bridging ancient wonder and modern understanding.

Related

Asteroid, Meteorite, Orbital mechanics, Solar System, Halley's Comet, Oort Cloud