They're confusing comets with meteors. Meteors, or shooting stars, are pieces of space rock, metal and dust left in the wake of comets. We see meteors only when they collide with our atmosphere and are heated to white-hot temperatures. Comets are balls of dirty ice that measure from a few hundred yards to several miles in diameter. They travel in orbits around the sun much like the planets.
Comets appear to hang in the sky, changing position slowly.
Comet orbits are usually elliptical or football shaped with closest approach to the sun occurring at one end of the orbit. As comets travel closer to the sun, sunlight melts some of the ice that holds the dusty ball together. In the vacuum of space, these solid ices are turned directly into gases without first becoming liquid. Rather than a swift ball of fire racing across the sky, even the brightest comets appear as delicate, wispy objects whose motion is apparent only after observing them night after night. Drawing on my own experiences with a few bright comets, they generally appeared as searchlight beams shining through fog.