Astronomers have calculated that Hale-Bopp will stay millions of miles away. Astronomers think comets occasionally get pulled from their orbital paths by the gravity of stars or some undiscovered planet. Some comets are thrown out of the solar system completely, Thomas says. A few crash into the Sun. When a comet gets closer to the Sun, it heats up.
Many comets also have a tail made of gas.
Gas tails can be hard to see with the naked eye. But some comets, like Hale-Bopp, also have dust tail . Because this tail of rock and dust reflects lots of sunlight, dust tails are highly visible. They base their guesses on three main factors. Astronomers expect Hale-Bopp to glow more and more brightly as it approaches the Sun.