The first written records of comets date back to nearly 3,000 years ago from China and Europe. The accounts of these comets were believed to be the causes of terrible events that occurred afterwards. In more recent times, however, astronomers have found out what they really are. A comet is basically a mixture of ices, from both water and frozen gases, and dust.
They have also been given the names “dirty snowballs” or “icy mud balls.” The typical comet is less than 10 kilometers across. They spend most of their time frozen solid in the outer parts of our solar system.
Comets are composed of five parts: the nucleus, coma, hydrogen cloud, dust tail, and ion tail. The nucleus is pretty solid and stable, composed mostly of ice and gas with a small amount of dust and other solids. The surface of the nucleus is best described as a black crust. Comet nuclei can range from 1 kilometer to about 50 kilometers across. The black crust on the surface of the nuclei helps the comet to absorb heat, which causes some of the ices under the crust to turn to a gas. Pressure builds up underneath the crust and causes the surface to bubble up in some places. Eventually, the weak spots of the crust break open from the pressure, and the gas shoots outward; astronomers refer this to as a jet.
Dust that had been mixed in with the gas is also pushed out, and as more jets appear, a small gas and dust shell forms around the nucleus, and this is called the coma. The coma, also called the head, is a dense cloud of water, carbon dioxide and other gases and comes off of the nucleus. They can be several thousand kilometers in diameter, depending on the comet’s distance from the sun and the size of the nucleus. The size of the nucleus is important because since large nuclei have a greater surface area facing the sun, which is the side that is the warmest, hence the side where most of the jets are coming from, it means more jets and greater amounts of gas and dust go into the coma. Even though the coma can get to be very large, its size can actually decrease about the time it crosses the orbit of Mars. At this distance the particles that drift out from the sun act as a powerful wind which blows the gas and dust particles away from the nucleus and coma. This is the process, which makes the comet’s tail. The hydrogen cloud is very large at millions of kilometers...
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...elieved that the comet Hale-Bopp was going to cause something very bad to happen, so they all committed suicide. If people can have a better understanding of what comets are, things like this could possibly be prevented. The roles that comets have played in the earth and in life as it is today are really big and important. If it had not been for comets, then life could possibly not have even existed now. Also, many creatures, for example the dinosaurs, have become extinct because of the comets colliding with the earth. If the comets had never made these creatures go extinct, then life would without a doubt be different.
“Works Cited”
Franklin, William. “Small Comets.” Online. Internet. Available:
http://smallcomets.physics.uiowa.edu/
Hamilton, Calvin. "Asteroid Introduction." Online. Internet. Available:
http://www.solarviews.com/eng/asteroid.htm
Laborde, John. “Comet West.” Online. Internet. Available:
http://www.solarviews.com/cap/comet/west.htm
Rondlen, Michael. “Comet.” Online. Internet. Available:
http://windows.ivv.nasa.gov/
Sipes, Russell. “Comet Hale-Bopp.” Online. Internet. Available:
http://www.sipe.com/halebopp/"Comet Hale-Bopp"
Asteroids are tiny, airless rocky worlds orbiting around the sun and most of them are too small to be called planets, yet, some asteroids are too big too not to be acknowledged and are known as planetoids or minor planets. The mass asteroids are puny but despite their size, asteroids can be deadly. The earth has been hit by many asteroids in the past and can potentially be hit by some again. That's one reason why scientists study asteroids and find ways to avoid them from hitting us or at least predict if they are coming.
Many of the heavenly bodies were considered to be the representations of deities. The master of reason, Aristotle, stated once long ago that everything was made of only five elements the final being what makes up the heavenly bodies, after all they lacked the proper technologies to know differently. It was Galileo in 1610, using his telescope, that found dark spots on the sun. So as technological innovations occur our understanding of physics and astronomy grow. Newton in 1687 discovered the laws of gravity, suggested that all the solar and stellar bodies operated the same.
Chondrules make up a large portion of chondrites. The millimeter-sized spherical objects originated as molten droplets in space. Most chondrules are rich in olivine and pyroxene. Chondrites also contain refractory inclusions (including Ca-Al Inclusions), which are among the oldest objects to form in the solar system, particles rich in metallic Fe-Ni and sulfides, and isolated grains of silicate minerals. The remainder of chondrites consists of fine-grained dust, which is either present in the matrix of the rock or forms rims or mantles around individual chondrules and refractory inclusions[11]. The geologic and cosmologic communities generally accepts that these spheres were formed by the action of a shock wave that passed through the Solar System, although there is little agreement as to the cause of this shock wave.[12]
Furthermore, the group said its understanding of suicide was not at all conventional: ''The true meaning of 'suicide' is to turn against the Next Level when it is being offered.'' In the group's thinking, a spaceship, thought to be following in Hale-Bopp's wake, would be offering just such an opportunity.
Stars explode at the end of their lifetime, sometimes when they explode the stars leave a remnant of gasses and, dust behind. What the gasses come together to form depend on the size of the remnant. If the remnant is less than 1.4 solar masses it will become a white dwarf, a hot dead star that is not bright enough to shine. If the remnant is roughly 1.4 solar masses, it will collapse. “The protons and electrons will be squashed together, and their elementary particles will recombine to form neutrons”. What results from this reaction is called a neut...
Solar nebula is a rotating flattened disk of gas and dust in which the outer part of the disk became planets while the center bulge part became the sun. Its inner part is hot, which is heated by a young sun and due to the impact of the gas falling on the disk during its collapse. However, the outer part is cold and far below the freezing point of water. In the solar nebula, the process of condensation occurs after enough cooling of solar nebula and results in the formation into a disk. Condensation is a process of cooling the gas and its molecules stick together to form liquid or solid particles. Therefore, condensation is the change from gas to liquid. In this process, the gas must cool below a critical temperature. Accretion is the process in which the tiny condensed particles from the nebula begin to stick together to form bigger pieces. Solar nebular theory explains the formation of the solar system. In the solar nebula, tiny grains stuck together and created bigger grains that grew into clumps, possibly held together by electrical forces similar to those that make lint stick to your clothes. Subsequent collisions, if not too violent, allowed these smaller particles to grow into objects ranging in size from millimeters to kilometers. These larger objects are called planetesimals. As planetesimals moved within the disk and collide with one another, planets formed. Because astronomers have no direct way to observe how the Solar System formed, they rely heavily on computer simulations to study that remote time. Computer simulations try to solve Newton’s laws of motion for the complex mix of dust and gas that we believe made up the solar nebula. Merging of the planetesimals increased their mass and thus their gravitational attraction. That, in turn, helped them grow even more massive by drawing planetesimals into clumps or rings around the sun. The process of planets building undergoes consumption of most of the planetesimals. Some survived planetesimals form small moons, asteroids, and comets. The leftover Rocky planetesimals that remained between Jupiter and Mars were stirred by Jupiter’s gravitational force. Therefore, these Rocky planetesimals are unable to assemble into a planet. These planetesimals are known as asteroids. Formation of solar system is explained by solar nebular theory. A rotating flat disk with center bulge is the solar nebula. The outer part of the disk becomes planets and the center bulge becomes the sun.
...ymbolism and presents God as a main aspect of this event. This topic helped me reflect on how this event would differ or cease to exist if our government was different, the role of nature and the concept of an ultimate being presented in this event. It is amazing how life can be turned upside down by reflecting on the freedoms and nature that we have now and how life and even cultural events such as this could be so different if our concepts and attitudes towards things were what they are now.
A few weeks back we had read a short story by H.G. Wells called “The Star.” This story is about the anticipation and consequences of a comet or “star” collision with Earth. On its way through the solar system, the comet also struck other planets. A mathematician after studying the occurrence makes a few predictions about how the encounter with the star will be fatal for Earth and its inhabitants. Some of these predictions were ice in Greenland melting, colder English winters and typhoons in the Pacific. Despite the catastrophes and chaos, Earth manages to survive. Even though a mathematician made the predictions, there is not much of a scientific base behind them.
Our Sun continuously converts hydrogen into helium and with this process it provides the essentials for life processes. In doing this it controls “our climate, provides light, raises tides, and drives the food chain” (Schaefer 34). Our Sun also has influenced many beliefs now and in the past. History has documented Sun worshipping religions while many current societies use solar calendars (Schaefer 34).
Most big asteroids are ball shaped. Smaller asteroids, which are usually broken off of a larger asteroid, come in a lot of different shapes. All asteroids have craters that form when they bump or crash into other asteroids. The older the asteroid, the more times it has been hit and the more craters it has.
A star begins as nothing more than a very light distribution of interstellar gases and dust particles over a distance of a few dozen lightyears. Although there is extremely low pressure existing between stars, this distribution of gas exists instead of a true vacuum. If the density of gas becomes larger than .1 particles per cubic centimeter, the interstellar gas grows unstable. Any small deviation in density, and because it is impossible to have a perfectly even distribution in these clouds this is something that will naturally occur, and the area begins to contract. This happens because between about .1 and 1 particles per cubic centimeter, pressure gains an inverse relationship with density. This causes internal pressure to decrease with increasing density, which because of the higher external pressure, causes the density to continue to increase. This causes the gas in the interstellar medium to spontaneously collect into denser clouds. The denser clouds will contain molecular hydrogen (H2) and interstellar dust particles including carbon compounds, silicates, and small impure ice crystals. Also, within these clouds, there are 2 types of zones. There are H I zones, which contain neutral hydrogen and often have a temperature around 100 Kelvin (K), and there are H II zones, which contain ionized hydrogen and have a temperature around 10,000 K. The ionized hydrogen absorbs ultraviolet light from it’s environment and retransmits it as visible and infrared light. These clouds, visible to the human eye, have been named nebulae. The density in these nebulae is usually about 10 atoms per cubic centimeter. In brighter nebulae, there exists densities of up to several thousand atoms per cubic centimete...
The last of the features of the comet are the tails. Most comets have two tails. One tail is made from dust particles and the other, called ion tail, is made gases. As a comet approaches the sun, the frozen gas becomes unfrozen which causes the dust particles to become free. Light pressure from the sun and some other forces cause these materials to move away from the head of the comet and in the opposite direction from the sun. According to Charles A. Schweighauser in his book, entitled Astronomy from A to Z: A Dictionary of Celestial Objects and Ideas, he states that we see comet heads and tails because they not only reflect sunlight, but they also fluoresce—give off their own light—when comets are near the sun. The tails from the comet may be up to 150 million kilometers long each or together.
Stars are born in the interstellar clouds of gas and dust called nebulae that are primarily found in the spiral arms of galaxies. These clouds are composed mainly of hydrogen gas but also contain carbon, oxygen and various other elements, but we will see that the carbon and oxygen play a crucial role in star formation so they get special mention. A nebula by itself is not enough to form a star however, and it requires the assistance of some outside force. A close passing star or a shock wave from a supernova or some other event can have just the needed effect. It is the same idea as having a number of marbles on a trampoline and then rolling a larger ball through the middle of them or around the edges. The marbles will conglomerate around the path of the ball, and as more marbles clump together, still more will be attracted. This is essentially what happens during the formation of a star (Stellar Birth, 2004).
Nuclear fusion occurs when two atomic nuclei collide with enough energy to bind together to form one nucleus. Nuclear fusion occurs in the core of our sun, and is the source of its tremendous heat. In the sun hydrogen nuclei, single protons, fuse together and form a new nucleus. In the conversion, a small amount of mass is converted into energy. It is this energy that heats the sun.