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Comets are small asteroid-like bodies when they are far from the Sun, traveling in highly ellipical orbits about the Sun. When they sweep in close to the Sun, dramatic changes occur as they brighten and develop an extended tail. The nucleus is widely described as a "dirty snowball" composed of ice and some rocky debris.
Halley's CometThere is considerable vaporization as they approach the Sun and they develop ion tails and dust tails. The ion tails are almost straight streamers from the nucleus while the usually brighter dust tails are broad and diffuse and curve slightly, lagging behind the radial direction.
The lighter ionized gas atoms of the ion tale cause it to point outward, directly away from the Sun, because the influence of the solar wind is dominant. I take the lower, more focused part of the tail in the image above to be the ion tail. The dust tail is made up of more massive particles and the role of gravity is important. If particles influenced by gravity are moved to an orbit further from the Sun, their radial direction falls behind that of the nucleus of the comet because their orbital period will be longer. The upper part of the Halley image would then appear to be the dust tail - you can see a slight curvature. In its most visible phase close to the Sun, the comet has a small solid nucleus and a ball of gas around it called the coma. Comas have been found to be on the order of 100,000 km in diameter at their maximum size, comparable to the largest planets. Most aof the light reflection is from the coma. Surrounding the coma and the visible tails is a hydrogen envelope which may extend millions of kilometers. The light from comets is purely reflected light; like the planets, the comets produce no light of their own.
Current models of the nuclei of comets view them as balls of loosely packed ices, a cold mixture containing gas and dust. The dust is thought to be trapped in a mixture of methane, ammonia, and water ice. The smaller moons of the outer solar system are similar in constitution. Since they spend most of their time far from the Sun, their temperatures are thought to be a few tens of kelvins. Chaisson & McMillan suggest a core temperature of 200K and a surface temperature on the order of 350K for Halley when it made its close approach to the Sun.
The short-period comets (less than 200 years) are thought to originate in a region of the solar system out past the orbit of Neptune called the Kuiper belt (30 to 100 AU). Most of them are found to have prograde orbits (in the same orbital direction as the planets) and to be close to the ecliptic plane. The Kuiper belt is described as a region of asteroid-like comets, most of which travel in roughly circular orbits. It may be that occasional close encounters between comets or the cumulative gravitational pull of the outer planets brings one into the higly elliptical orbit which brings it close to the Sun.
Other comets, characterized as "long-period comets", are found in random orientations with respect to the ecliptic plane. They are thought to originate in a large "cloud" of objects in a region perhaps 50,000 AU from the Sun called the Oort cloud. This image of comet Schwassmann-Wachmann 3 taken by Tim Puckett of Villa Rica, Ga. USA. It was obtained with a 12" Lx200 working at f/7. This is a 300 second exposure taken on 12-01-95 .
Comets are small asteroid-like bodies when they are far from the Sun, traveling in highly ellipical orbits about the Sun. When they sweep in close to the Sun, dramatic changes occur as they brighten and develop an extended tail. The nucleus is widely described as a "dirty snowball" composed of ice and some rocky debris.
Halley's CometThere is considerable vaporization as they approach the Sun and they develop ion tails and dust tails. The ion tails are almost straight streamers from the nucleus while the usually brighter dust tails are broad and diffuse and curve slightly, lagging behind the radial direction.
The lighter ionized gas atoms of the ion tale cause it to point outward, directly away from the Sun, because the influence of the solar wind is dominant. I take the lower, more focused part of the tail in the image above to be the ion tail. The dust tail is made up of more massive particles and the role of gravity is important. If particles influenced by gravity are moved to an orbit further from the Sun, their radial direction falls behind that of the nucleus of the comet because their orbital period will be longer. The upper part of the Halley image would then appear to be the dust tail - you can see a slight curvature. In its most visible phase close to the Sun, the comet has a small solid nucleus and a ball of gas around it called the coma. Comas have been found to be on the order of 100,000 km in diameter at their maximum size, comparable to the largest planets. Most aof the light reflection is from the coma. Surrounding the coma and the visible tails is a hydrogen envelope which may extend millions of kilometers. The light from comets is purely reflected light; like the planets, the comets produce no light of their own.
Current models of the nuclei of comets view them as balls of loosely packed ices, a cold mixture containing gas and dust. The dust is thought to be trapped in a mixture of methane, ammonia, and water ice. The smaller moons of the outer solar system are similar in constitution. Since they spend most of their time far from the Sun, their temperatures are thought to be a few tens of kelvins. Chaisson & McMillan suggest a core temperature of 200K and a surface temperature on the order of 350K for Halley when it made its close approach to the Sun.
The short-period comets (less than 200 years) are thought to originate in a region of the solar system out past the orbit of Neptune called the Kuiper belt (30 to 100 AU). Most of them are found to have prograde orbits (in the same orbital direction as the planets) and to be close to the ecliptic plane. The Kuiper belt is described as a region of asteroid-like comets, most of which travel in roughly circular orbits. It may be that occasional close encounters between comets or the cumulative gravitational pull of the outer planets brings one into the higly elliptical orbit which brings it close to the Sun.
Other comets, characterized as "long-period comets", are found in random orientations with respect to the ecliptic plane. They are thought to originate in a large "cloud" of objects in a region perhaps 50,000 AU from the Sun called the Oort cloud. This image of comet Schwassmann-Wachmann 3 taken by Tim Puckett of Villa Rica, Ga. USA. It was obtained with a 12" Lx200 working at f/7. This is a 300 second exposure taken on 12-01-95 .
Comets are celestial bodies composed of ice, dust, and rock. They have highly elliptical orbits that bring them close to the Sun, causing the ice in the comet to vaporize and form a glowing coma and tail. Comets are believed to be remnants from the early formation of the solar system, providing valuable information about its history.
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What is the definition of a comet head?
The comet head refers to the spherical cluster of dust and gas surrounding the comet's nucleus, which is primarily composed of ice, dust, and organic compounds. As the comet approaches the Sun, the heat causes this material to vaporize and form the comet's characteristic coma or fuzzy halo.
Is a comet an asteroid?
Comets and asteroids are the same, but differ in the fact that comets have surface activity with their characteristic tail.
Why is Halley's comet blue?
Halley's comet appears blue due to the emissions of vaporized gases, such as carbon, nitrogen, and oxygen, as it interacts with ultraviolet light from the sun. The ionization and excitation of these gases cause them to emit bluish-green light, giving the comet its characteristic blue glow.
What is a comet a mixture of?
A comet is a mixture of ice, dust, rocky material, and gases such as water vapor, carbon dioxide, and methane. As a comet approaches the Sun, the heat causes these materials to evaporate, creating the glowing coma and tail that are characteristic of comets.
What do you call the piece of a comet that trails behind it?
The piece of a comet that trails behind it is called a tail. Cometary tails are composed of dust and ionized gases that become illuminated by the Sun, creating the characteristic bright streak visible from Earth.
What is the definition of a comet head?
The comet head refers to the spherical cluster of dust and gas surrounding the comet's nucleus, which is primarily composed of ice, dust, and organic compounds. As the comet approaches the Sun, the heat causes this material to vaporize and form the comet's characteristic coma or fuzzy halo.
Is a comet an asteroid?
Comets and asteroids are the same, but differ in the fact that comets have surface activity with their characteristic tail.
What characteristic of Pluto makes it seems like a large comet?
This is because it is made of ice and is smaller than most planets:)
Why is Halley's comet blue?
Halley's comet appears blue due to the emissions of vaporized gases, such as carbon, nitrogen, and oxygen, as it interacts with ultraviolet light from the sun. The ionization and excitation of these gases cause them to emit bluish-green light, giving the comet its characteristic blue glow.
What is a comet a mixture of?
A comet is a mixture of ice, dust, rocky material, and gases such as water vapor, carbon dioxide, and methane. As a comet approaches the Sun, the heat causes these materials to evaporate, creating the glowing coma and tail that are characteristic of comets.
What do you call the piece of a comet that trails behind it?
The piece of a comet that trails behind it is called a tail. Cometary tails are composed of dust and ionized gases that become illuminated by the Sun, creating the characteristic bright streak visible from Earth.
When a comet passes through the sun what happens to the ice?
When a comet passes close to the sun, the intense heat causes the ice and other volatile substances on the comet's surface to vaporize and create a glowing coma around the nucleus, forming the characteristic tail of a comet. This process is called sublimation, where the ice transitions directly from a solid to a gas without passing through a liquid phase.
Is comet a source or form of light?
Comets are not a source of light themselves, but they reflect sunlight. When sunlight hits a comet's nucleus, it causes the surrounding gas and dust to glow, creating the characteristic tails we see from Earth.
What is a ball of ice dust and gasses that travels through space and orbits the sun?
a comet/meteorite
What is a nucleus of a comet?
The nucleus of a comet is the solid, icy core of the comet. It is composed of a mixture of ice, rock, dust, and organic compounds. As a comet gets closer to the Sun, the heat causes the nucleus to release gas and dust, forming the characteristic coma and tail of the comet.
Is Halley's comet a planet or a comet?
It is a comet.
What is a lump of dusty ice?
A lump of dusty ice typically refers to a comet. Comets are made up of rock, dust, water ice, and frozen gases. When a comet gets closer to the sun, the heat causes the ice to vaporize, releasing gas and dust particles that form the characteristic tail seen from Earth.
