In the endless expanse of intergalactic space, stars are in every stage of being born, radiating huge amounts of energy, transforming and dying. When one finds out more about how stars are formed, what they are made of, and how they die one cannot help but to be awed by the complex processes and vast transformations that take place in the lifecycle of a star. A star's life begins in a nebula, which is an interstellar cloud made up of dust, hydrogen and helium gas, and plasma. Nebulas have been called "Stellar nurseries" because they contain just the right conditions and materials for the formation of a star. These clouds are sometimes disturbed by turbulence caused by gravity from nearby phenomenon like asteroids or supernovae. This turbulence creates instabilities in the spin of the cloud and cause clumps of denser matter to begin to form. Three-dimensional computer models of star formation predict that the spinning clouds of collapsing gas and dust may break up into two or three blobs (NASA). Gravity then makes these clumps of matter contract into a large mass where increased density and pressure create heat. This hot dense core of matter is known as a protostar. A star spends most of its life as what is called a main sequence star. Our sun is currently a main sequence star that has a mass of about 1030 kg, or about 333,000 times the mass of the earth (swin). This mass is often used as a convenient unit for expressing the mass of other stars and is called one solar mass. A star like our sun takes about 50 million years to become a main sequence star, and it finally reaches that stage when the temperatures in the protostar reach roughly seven million degrees kelvin. At this critical temperature, Hydrogen begin... ... middle of paper ... ...ms a disk that is heated to enormous temperatures and emits large amounts of x-ray and gamma-ray radiation. This radiation can tell the scientists that there is a black hole at the center of the disk. This essay has provided some small glimpses into the fascinating world of stellar astronomy and stellar evolution. It has shown how a star is born and what its existence is like as a main sequence star. It has explored some of the most common final transformations and the resulting stellar remnants. This essay has also presented insight into a variety of the nuclear fusion reactions that take place as stars die and given the reader information about how long stars exist in various states. As one learns more about the lifecycle of stars, one cannot help but to be awed by the vast transformations and complex internal reactions that take place during their existence.
Brown dwarfs are objects in space that sit between the lines of being a star and a planet. This object is dim and hard to distinguish from low mass stars at the early stages of the dwarf’s life. They are often called failed stars because they start their life the same way as regular stars. However, in some stage, they just didn’t have enough mass gathered to generate the fusion-powered energy of a star. Scientists are certain that brown dwarfs are the missing link between stars and planets but the formations of dwarfs are still a mystery.
Dyson, Marianne J. Space and Astronomy: Decade by Decade. New York: Facts on File, 2007. 14+. Print.
Black holes - the strange scientific phenomenon that has astounded physicists and astronomers alike for decades. Popular subjects in science fiction novels, black holes are one of the greatest enigmas of the scientific world. Even today, the concept of a super-dense ball of matter that not even light can escape from is somewhat farfetched, and many scientists disagree with each other about nearly every aspect of a black hole. This project will attempt to shed some light on these mysterious formations, and will inform you the reader of the most popular and widely accepted theories surrounding them.
Imagine a massive celestial object in space, so densely packed with matter that nothing can ever escape it, not even light- that’s what black holes are. They are formed by large stars- stars that are way larger in size (20 times or more) than the sun. When such massive stars run out of fuel in its course, it can no longer sustain its heavy weight. They rapidly collapse causing colossal of explosions called supernova.
Just recently a major discovery was found with the help of a device known as The Hubble Telescope. This telescope has just recently found what many astronomers believe to be a black hole, After being focuses on a star orbiting empty space. Several pictures of various radiation fluctuations and other diverse types of readings that could be read from that area which the black hole is suspected to be in.
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.
The idea of interstellar space travel has been discussed for many years between many scientists and engineers since 1950s (Adelman, 180). It has not only been discussed but also demonstrated in science fiction literature. By getting the knowledge of interstellar travel, people wonder when will we be able to travel between stars and if it is even possible to reach another star other than the sun. However, others wonder “what is the point of spending so much money on something that it isn’t possible?” or “why do we have to study another star when we have the sun that light our day?” The answers to those two questions are; one day our sun will become a red giant and end the life of earth and the second reason a nearby supernova can affect our solar system (Mallove, pg .4). In order to escape from these tragedies, we need to find a way to be transported to another star. Dr. Leslie Robert Shepherd, nuclear physicist and member of The British Interplanetary Society, first published a paper on “Interstellar Flight” in 1952. From then on The British Interplanetary Society kept the research on “Interstellar Space Travel” throughout its history (The Telegraph, 2012). Our research question is “Can we ever reach other stars other than the sun?” This paper will explain the challenges of interstellar flight, ways to travel into space and finally projects that had appeared during the years of research.
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).
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 Big Bang, the alpha of existence for the building blocks of stars, happened approximately fourteen billion years ago. The elements produced by the big bang consisted of hydrogen and helium with trace amounts of lithium. Hydrogen and helium are the essential structure which build stars. Within these early stars, heavier elements were slowly formed through a process known as nucleosynthesis. Nucleosythesis is the process of creating new atomic nuclei from pre-existing nucleons. As the stars expel their contents, be it going supernova, solar winds, or solar explosions, these heavier elements along with other “star stuff” are ejected into the interstellar medium where they will later be recycled into another star. This physical process of galactic recycling is how or solar system's mass came to contain 2% of these heavier elements.
Supernovas are extremely powerful explosions of radiation. A supernova can give off as much energy as a Sun can within its whole life. A star will release most of its material when it undergoes this type of explosion. The explosion of a supernova can also help in creating new stars.
The idea behind the Solar Nebular Hypothesis is that the solar system was condensed from an enormous cloud of hydrogen, helium, and a few other elements and rocks. Around five billion years this cloud of materials began to spin and contract together into a disk shape under their own gravitational forces. The particles started combined together, protoplanets, to eventually form planets. A great mass of the material eventually began to form together, protosun, and make up the sun.
In their idea, a spinning cloud of dust either shrank under its own pull of gravity or collapsed under the explosion of a nearby star. Whether it shrank from gravity or collapsed upon itself, most material in the aftermath gathered around the center, and the cloud began to spin faster. The material compressed, causing temperatures to rise dramatically and the chemical process of hydrogen fusion to take place, thus allowing the sun to form. Much of the material combined to form a large disk surrounding the sun, but friction within the disk caused mass “whirlpools” to break away, which shrank into compact protoplanets. These protoplanets joined together to form the eight planets and their moons, and all uncollected material left over from the disk formed comets, meteoroids, and
The education system in India is based on forced learning that kills student’s spirit and zest of learning. In the film “Like Stars on Earth,” we look specifically at the draw backed role played by parents and teacher in Indian education system. We follow the story of a dyslexic Indian boy, Ishaan, who always had trouble coping with his studies, but in the end with the help of an understanding teacher he is able to study normally and catch up with his peers. We will analyze this film using the concepts from Practices of Looking to explain our thesis. Eddie will cover the concepts of encoding and the ideology surrounding Indian education; Kiranjot Singh will explain the concepts of punctum, negotiated reading and producer’s intended meaning;