: Upon impact, comets can create massive vapor plumes that rise thousands of kilometers into the atmosphere, depositing debris that increases opacity and drastically lowers global temperatures. Historical and Theoretical Impacts
: Long-period comets can be pulled apart by the sun's gravity before reaching Earth, potentially hitting as a "cluster" of fragments rather than a single body. Comet Impact
What Is a Comet? | NASA Space Place – NASA Science for Kids : Upon impact, comets can create massive vapor
Scientists have identified several points in history where comet impacts may have reshaped Earth's climate and human society: | NASA Space Place – NASA Science for
Comets, often described as "dirty snowballs" or "icy mudballs," are primitive remnants from the formation of our solar system roughly 4.6 billion years ago. While asteroid strikes are more frequent, a comet impact carries unique risks due to its immense velocity and volatile composition of frozen gases, rock, and dust. The Mechanics of an Impact
: While asteroids typically hit at about 20 km/s, comets can reach speeds up to 71 km/s. Because kinetic energy scales with the square of velocity, a comet can deliver more than 100 times the energy of a similarly sized asteroid.