When I began research for this week’s topic, my first quest was learning the difference between an asteroid and a comet. Here’s what I discovered. Comets (dirty snowballs) are primarily composed of ice and dust. As they near the sun, the heat melts the comet’s ices and releases the dust particles we view as the comet’s tail. Asteroids (minor planets) are large rocks ranging in size from a few feet to several hundred miles across. Ready to learn more?