The Solar System


What are some characteristics of Halley’s comet?

Scientists think that Halley’s comet is similar to all other comets, except perhaps that it is larger and closer to the Sun than most. In 1986 the European Space Agency’s probe Giotto took pictures and other data of the center of Halley’s comet. The images showed that the comet was about nine miles (fifteen kilometers) long and six miles (ten kilometers) wide, coal-black, and potato-shaped, marked by topological features that look like hills and valleys. Two bright jets of gas and dust, each about eight miles (fourteen kilometers) long, shot out of the comet. The surface of the comet, and the gas in its coma and tail, contained water, carbon, nitrogen, and sulfur molecules.


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