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Understanding stellar evolution
Understanding stellar evolution
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Recommended: Understanding stellar evolution
Understanding stellar evolution is important to astronomers because it allows them to estimate star age using spectroscopic studies, even though a star might be isolated and not part of a cluster. Star clusters form when an interstellar cloud collapses and fragments. Stars evolve within a cluster with the most massive stars evolving the fastest and creating the heaviest elements in their cores; although lower-mass stars take longer to evolve, they can also create heavy elements. Newly formed elements are scattered into the interstellar medium as the result of supernovae in the case of high-mass stars and in the case of low-mass stars when they shed their envelopes in the form of planetary nebulae. Star formation, evolution, and explosion is a continual process that imbues the interstellar medium with heavy elements and enables the formation of new stars. There would not be life on Earth without the elements generated by supernovae (McMillan, 2011).
After a high-mass star explodes in a supernova all that is left intact is a relatively small, about the size of a small asteroid, very massive ball of neutrons. This remnant is called a neutron star, even though it is not actually a star. New neutron stars rotate very rapidly and have extremely strong magnetic fields with hot spots localized near the magnetic poles where radiation is emitted in concentrated beams of light that radiate through the cosmos like a revolving beacon. If the neutron star is positioned so that the beam passes across the Earth, the light is seen as pulsing and the neutron star is called a pulsar. While all pulsars are neutron stars, not all neutron stars are seen as pulsars because in time a neutron star’s intense magnetic field and rapid rotation ...
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...can contribute energy to the remnants for a long time after the explosion, which is what astronomers believe is the case in the Crab Nebula (Rothstein, 2003).
References
McMillan, C. (2011). Astronomy today (7th ed., Vol. II). Boston, MA: Addison-Wesly.
Rothstein, D. (2003, May). How long do supernova remnants last. Retrieved March 5, 2014, from http://curious.astro.cornell.edu/question.php?number=533
Sometimes the final stages of the life of a star result in violent explosions. (n.d.). Retrieved March 4, 2014, from http://ircamera.as.arizona.edu/natsci102/natsci102/lectures/supernovae.htm
Stromberg, J. (2013, July 17). All the gold in the universe could come from the collisions of neutron stars. Retrieved March 4, 2014, from http://www.smithsonianmag.com/science-nature/all-the-gold-in-the-universe-could-come-from-the-collisions-of-neutron-stars-13474145/?no-1st
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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.
The American scientist John Wheeler coined the phrase “black hole” in 1969 to describe a massively compact star with such a strong gravitational field that light cannot escape. When a star’s central reserve of hydrogen is depleted, the star begins to die. Gravity causes the center to contract to higher and higher temperatures, while the outer regions swell up, and the star becomes a red giant. The star then evolves into a white dwarf, where most of its matter is compressed into a sphere roughly the size of Earth. Some stars continue to evolve, and their centers contract to even higher densities and temperatures until their nuclear reserves are exhausted and only their gravitational energy remain. The core then rushes inward while the mantle explodes outward, creating neutron stars in the form of rapidly rotating pulsars. Imploding stars overwhelmed by gravity form black holes, where the core hits infinite density and becomes a singularity (some estimate it at 10^94 times the density of water).
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...
Nebula away so that it can avoid certain things. In the short story, “The Star,” the priest stated,
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.
Black holes are incredible processes that happen in space that are capable of crushing anything unlucky enough cross paths with them. Black holes have caught the attention of millions of people around the world because of their incredible strength and the fact that so much is unknown about them. The theories of possible outcomes resulting in traveling into a black hole has been used in many science fiction stories, but what we think is science fiction could actually exist. With black holes being out of our reach, and even difficult for our greatest minds to understand, what happens within them may just stay science fiction. The more we learn about black holes the more questions we ask.
Shklovskii, Iosif S. Stars: Their Birth, Life, and Death. Moscow: Central Press for Literature in Physics and Mathematics, 1975.
...e times the mass of the sun. In this case gravity is overwhelmingly strong and is able to crush the neutron star towards zero mass. The result is a black hole with a gravitational field strong enough to not even let light escape (Brusca, 2004).
After a supernova, the core is likely to travel someplace else within space. When the core is less size than about 5 solar masses, the neutrons will halt the collapse of the star. This will create a Neutron Star. Neutron stars are observed as pulsars or X-ray binaries. When the core is very large, nothing that h...
In an article in Scholastic, David Fisherman states, “Within seconds the fireball ejected matter/energy at velocities approaching the speed of light. At some later time—maybe seconds later, maybe years later—energy and matter began to split apart and become separate entities. All of the different elements in the universe today developed from what spewed out of this original explosion” (Fishman). The diagram above shows how vastly and rapidly the universe was created. During the inflation of the universe, it grew rapidly and doubled in size at least ninety times. While hot and dense, the universe expanded rapidly. Denise Chow wrote on space.com, “for the first 380,000 years after the Big Bang, the intense heat from the universe’s creation made it essentially too hot for light to shine. Atoms crashed together with enough force to break up into a dense, opaque plasma of protons, neutrons, and electrons that scattered light like fog” (Chow). After cooling, it allowed energy to be converted into particles such as protons, neutrons, and electrons. Within minutes after the Big Bang, atomic nuclei formed, but it took thousands of years before electrically neural atoms were first formed. The majority of atoms that formed were hydrogen, helium, and traces of lithium. Gravity caused the hydrogen and helium has to form giant clouds that will become galaxies, the smaller clouds broke apart to form stars, which was when the universe came out of its dark ages. Planets were formed by the first stars dying and releasing heavy elements into
Life is lost without love, but what is love without desire? Could it be that love is an arguable thought, something that is not as strong as what we perceive it to be? Could love be merely an instrument used by society to justify their foolishness? Is it true that this idea we call love, is nothing but a fabrication of the mind fueled by the intense desire to posses?
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.