How does comets tail form

Scientists study the light reflected by different parts of a comet. Gases contain different elements. Each element such as hydrogen , molecule such as water , or ion an electrically charged element or molecule has a distinct pattern of emission or absorption that can be determined in the laboratory; this pattern is known as its spectrum.

By matching patterns between laboratory measurements and comet observations, scientists can determine the composition of the comet. Every comet is made of the same basic ingredients — ice and dust. However, comets probably vary in how much of the ice is water ice and how much is ice made of other substances, such as methane, ammonia, and carbon dioxide.

Comets also vary in the different types of trace elements and hydrocarbons are present. Several space missions, such as the European Space Agency's Giotto mission, have explored comets and provided detailed imagery of comet surfaces. A few missions are intended to sample comets.

NASA's Deep Impact mission will encounter Comet Tempel 1 in July , and will release a projectile into the comet surface to excavate a hole and expose a fresh surface on the nucleus. The spacecraft will collect data on comet emissions and will relay the data to scientists on Earth. While the data from these missions will be from only a few comets and might not be representative, the data will greatly improve our understanding of comet compositions.

What do the orbital paths of comets look like? Based on observations of how comets move through the sky, scientists have determined that comets travel around our Sun in highly elliptical oval-shaped orbits. The time it takes to make a complete orbit is called a comet's period. Comet periods typically range from a few years to millions of years. Where do comets come from? Comets are divided into short-period comets and long-period comets.

Short period comets — such as Comet Halley — revolve around our Sun in orbits that take less than years. Their orbital paths are close to the same plane of orbit as Earth and the other planets, and they orbit our Sun in the same direction as the planets.

Based on these orbital characteristics, short-period comets are believed to originate in the Kuiper belt , a disk-shaped region extending beyond Neptune. The Kuiper belt contains small, icy planetary bodies, only a few of which have been imaged. Occasionally the orbit of a Kuiper belt object will be disturbed by the interactions of the giant planets in such a way that it will have a close encounter with Neptune and either be flung out of the solar system or pushed into an orbit within our solar system.

Their orbital path is random in terms of direction and plane of orbit. Based on calculations from their observed paths, long-period comets are believed to originate in the Oort cloud. The Oort cloud is a spherical envelope that may extend 30 trillion kilometers approximately 20 trillion miles beyond our Sun. Oort cloud objects have never been imaged. 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. Community Leaders: Notable Astronomers. By: Richard S. Wright Jr. November 9, October 19, Astronomy in Space with David Dickinson. By: David Dickinson October 16, By: Monica Young September 28, Imaging Foundations with Richard Wright. September 16, Solar System. Halley's makes an appearance once every 76 years. The comet was named after Sir Edmond Halley. A comet has no light of its own.

We are able to see a comet because of the reflection of the Sun's light off of the comet and because of the gas molecules in the coma releasing energy absorbed from the Sun's rays. A Question As a comet approaches the Sun, does its head or tail lead the way? As it moves around from the Sun, which parts leads? Did you know? The Answer. Show me the Level 1 version of this page.

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