An asteroid is another kind of rocky object, or small solar system body. Most asteroids orbit the sun between Mars and Jupiter. Comets are objects made of rock, ice, and frozen gases from the far edge of the solar system, with very elliptical orbits. We can see them from Earth when they are close to the sun. Some have long tails of dust that resemble feathers in the night sky, and others have such large elliptical orbits that they come near us only once in a thousand years. Meteors are smaller rocks and pebbles that sometimes hit the Earth's atmosphere, though most burn up from friction before they can reach us. We call their streaks of light "shooting stars," or meteorites. Sometimes, about once every hundred thousand years, a large meteor hits the Earth; the impact can blow open a huge crater on the Earth's surface. Such huge meteor strikes can change the atmosphere of the planet. A meteor crash millions of years ago may be what killed the dinosaurs. If astronomers see an object made of ice and rock with a long dust-tail approaching, it is most likely a(n) ________.
a) comet
b) asteroid
c) meteor
d) dwarf planet