[ 79 ] Earth and Space Science GED ® TEST SCIENCE FLASH REVIEW • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • What was one of the characteristics that caused Pluto to lose its status as one of the planets of our solar system? Which of the following statements about comets is NOT true? A. A comet is a small, icy celestial body that, when passing close to the sun, may display a tail. B. Comet tails are caused by solar radiation and solar wind. C. Comets range from a few hundred meters to tens of kilometers across, and are composed of loose collections of quartz, diamond, and silicate. D. The orbit of a comet can last a few years to several hundred years. For example, Halley’s comet is visible from Earth about every 75 years. Its next appearance should be in 2061. What is the main difference between an asteroid and a comet?