What caused Halleys Comet?
Halley’s Comet, as well as all comets, are simply dusty icebergs that race around the sun at speeds as fast as 600,000 miles per hour. It is composed not only of frozen water, but other frozen gases, such as ammonia and methane. Most comets are always far from the sun and frozen solid. A few comets, like Halley’s, periodically travel close to the sun. When one of these comets approaches the orbit of Jupiter (or around 500 million miles) it begins to melt from the Sun’s heat. A cloud of gas and dust forms which is called the comet’s coma. The coma is usually larger than the Earth and may be as wide as 500,000 miles. The core of the comet remains solid and is called its nucleus. When the comet gets near the orbit of Mars (150 million miles from the sun) the gas and dirt in the coma are blown away. A long tail forms that may be 60 million miles long. It is the tail that has inspired the continual search to understand comets. Halley’s comet is only one of at least 100 billion comets. It is
