Science-Help

Your right about when the commet approaches the sun, it becomes warm but as the comment approaches the sun, it forms a glowing tail.

In the cold far reaches of our solar system, in the Kuiper belt and Oort cloud, comets are essentially just small chunks of ice and dust. Comets are nearly invisible except when they get close to our Sun.
As a comet approaches our Sun, it begins to heat up and the ice begins to sublimate — to change from a solid to a gas with no liquid stage. Some of the dust is left behind as the ice sublimates. It forms a dark, protective crust on the surface of the nucleus and slows the melting. In some places the protective layer is thinner, and jets of gas break through. The gas and dust form the cloud of the coma.

Our Sun emits a solar wind, a constant flow of gas and particles (mostly protons and electrons) that streams outward at 350 kilometers (about 220 miles) per second. Sunlight and solar wind sweep the dust and gas of the coma into trailing tails. Because sunlight and solar wind always flow outward from our Sun's surface, the tails always point away from our Sun no matter what direction the comet is moving in its orbit. This means that the tails can be in front of the comet as the comet moves away from our Sun on its return to the outer part of its orbit.

Two distinct tails develop — the plasma tail and the dust tail. The different shapes and angles of the tails are caused by the way different particles are affected by our Sun. The thinner, longer plasma tail forms a straight line extending from the comet. The particles in this ion tail are electrically charged and are pushed away from our Sun by the solar wind. The shorter dust tail is curved slightly. The larger particles in the dust tail do not have an electric charge and are not affected by the solar wind. Instead, the dust particles shed from the comet are repelled by the force of the sunlight and “lag behind” the comet in its movement around our Sun.

Comet tails get longer and more impressive as the comet gets closer to our Sun. As the comet approaches our Sun, it gets hotter and material is released more rapidly, producing a larger tail. Scientists estimate that a comet loses between 0.1 and 1 percent of its mass each time it orbits our Sun.

Most visible comet tails are not that long, but some are. The tail starts forming while the comet is on its way to the sun and gets warm enough to vaporize gas into the tail. When this happns, some dust is also released. As the comet rounds the sun, the tail always faces away from it due to radiation pressure. Halley's comet was much brighter approaching the sun than it was going away, on its last visit. Comet visits are full of surprises.

Most bright naked-eye comets are new discoveries that have never been recorded before. We get one every five to ten years, on average.

Thanks Priscilla. That must have took a lot of time. I really appreciate your help :-)

Thank you drwls. You both are very helpful :-)