Shock Effects on Cometary-Dust Simulants

While comets are perhaps best known for their ability to put on spectacular celestial light shows, they are much more than that. Composed of an assortment of frozen gases mixed with a collection of dust and minerals, comets are considered to be very primitive bodies and, as such, they are thought to hold key information about the earliest chapters in the history of the solar system. (The dust and mineral grains are usually called the "refractory" component, indicating that they can survive much higher temperatures than the ices.) It has long been thought, and spacecraft photography has confirmed, that comets suffer the effects of impacts along with every other solar system body. Comets spend most of their lifetimes in the Kuiper Belt, a region of the solar system between 30 and 50 times the average distance of the Earth from the Sun, or the Oort Cloud, which extends to approximately 1 light year from the Sun. Those distances are so far from the Sun that water ice is the equivalent of rock, melting or vaporizing only through the action of strong, impact-generated shock waves.