Sabdy Mariscal
IPC-4B
Astronomy
Astronomy is the science of space beyond earth’s atmosphere like stars, comets, galaxies, nebula, and comets – as well as the large scale of properties of the universe also known as the big picture. However I’m only going to write about stars, comets, galaxies, and the nebula because I think those are the most interesting aspects of astronomy.
Stars have different size, color, and temperature. There are different types of stars; some are smaller than the earth and even bigger than the sun, so there are a variety of stars. Scientist have placed stars on groups based on how they are the same and how they are different. The brightness of a star depends on their surface temperature so the blue and the white stars
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Comets are made out of dust and ice, and they can only come from two places the Kuiper belt and Oort cloud. Comets spend billions of years in their homes when they approach the inner solar system they start to melt and then grow a tail. The tail can be in front or behind the comet depending where the sun is located at.
The galaxy is a system of millions and even billions of stars, with gas and dust, held together by gravitational attraction. There are many galaxies in the universe and only three different types the spiral, elliptical, and irregular. The spiral galaxy has long twisting arms and has areas where stars are being formed. The elliptical galaxy are close together making the center look like an enormous star, but you can only find old stars creating the elliptical galaxy. The irregular galaxy can look like anything and have different characteristics.
The nebula is a cloud in outer space made of gas and dust and stars are being made in there. There are three types of nebulas the emission, reflection, and planetary. The emission nebula shines with its own light. The reflection nebula is a cloud made of gas and dust and it doesn’t create its own light, but shines from the reflection of nearby stars. The planetary nebula is a ring-shaped nebula formed by an expanding shell of gas around an aging
Every day we look into the night sky, wondering and dreaming what lies beyond our galaxy. Within our galaxy alone, there are millions upon millions of stars. This may be why it interests us to learn about all that we cannot see. Humans have known the existence of stars since they have had eyes, and see them as white glowing specks in the sky. The mystery lies beyond the white glowing specks we see but, in the things we cannot see in the night sky such as black holes.
What is astronomy? Astronomy consist of a lot of things that make up our solar system such as: the nine planets, asteroids, meteorites, the moon and the sun. Astronomy is also a fascinating hobby that can be followed by anyone. You do not need to be, as some people seem to imagine, ‘mathematically-minded’ , in order to start, or even to become a very experienced observer. Yet astronomy is one of the few hobbies where not only can you gain great enjoyment, but if you feel want to can very easily make observations of great scientific value.
The Orion Nebula contains one of the brightest star clusters in the night sky. With a magnitude of 4, this nebula is easily visible from the Northern Hemisphere during the winter months. It is surprising, therefore, that this region was not documented until 1610 by a French lawyer named Nicholas-Claude Fabri de Peiresc. On March 4, 1769, Charles Messier inducted the Orion Nebula, M42, into his list of stellar objects. Then, in 1771, Messier released his list of objects for its first publication in Memoires de l’Academie.1
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.
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...
2. Comets are similar to asteroids, however they are covered in particles like as ice and gas compounds.
The Milky way is a band of light that has millions of stars that are combined together and that spans 100,000 light years away. They say the Milky Way is about 14 billion years old. How they figured this out by measuring the ages of each star. They have found trace elements of hydrogen and helium so we know that the Milky Way was formed and early in the history. Another good way to find the age of the stars in the Milky Way is measuring thorium because it has a half-life of 14 billions years after 14 billion the thorium should decay in another element. The formation of the Milky way started by observations concerning chemical abundances in stars and gas using
1. Where do comets come from in the Solar System? Comets come from the outer Solar System, existing well beyond the planets. Most of the comets come from the Oort Cloud, a collection of comets, amounting to possibly a trillion comets.
Comets are made up of four distinct features. The first is the nucleus. The nucleus is made up of frozen gases, mostly water vapor with lesser amounts of carbon dioxide and carbon monoxide, and imbedded in the frozen gases are interplanetary dust and tiny fragments of stony and metallic meteoric material. Some comets, the larger ones, have a nucleus of 10 kilometers (Schweighauser 22).
A galaxy, also called a nebula, consists of billions of stars, interstellar gas, dust, and dark matter which are all bound to form a massive cloud in which we live in. Although it cannot be very well explained, dark matter makes up at least 90% of a galaxy’s mass. Galaxies also contain billions upon billions of stars and their diameter can range from 1,500 to 300,000 light years. That’s huge! The Milky Way, the galaxy in which we live in, is one of about 170 billion galaxies in the observable universe. Our Sun is one of the billions of stars in our galaxy, and our eight planets revolve around this star in only a tiny part of our galaxy. “The Earth’s solar system is believed to exist very close to the Galaxy’s galactic plane, due to the fact that the Milky Way essentially divides the night sky into two virtually equal hemispheres” ("All About the Milky"). It definitely makes people second guess the fact of there being life on other planets.
The Universe is a collection of millions of galaxies and extends beyond human imagination. After the big bang, the universe was found to be composed of radiation and subatomic particles. Information following big bang is arguable on how galaxies formed, that is whether small particles merged to form clusters and eventually galaxies or whether the universe systematized as immense clumps of matter that later fragmented into galaxies (Nasa World book, 2013). A galaxy is a massive area of empty space full of dust, gases (mainly 75% Hydrogen and 25%Helium), atoms, about 100-200 billion stars, interstellar clouds and planets, attracted to the center by gravitational force of attraction. Based on recent research, 170 billion galaxies have been estimated to exist, with only tens of thousands been discovered (Deutsch, 2011).
A very small solar system body made mostly of ices mixed with smaller amounts of dust and rock. Most comets are no larger than a few kilometers across.the main body of the comet is called the nucleus, and it can contain water, methane, nitrogen, and other ices. When a comet is heated by the sun, its ices began to melt off. The mixture of ice crystals and dust blows away from the comet nucleus in the solar wind, creating a pair of tails. The dust tail is what we usually see when we view comets from earth. The tail happens when gas molecules interact with the solar wind. The tail is not usually seen by the naked eye but can be imaged. Comets normally orbit around the sun and have come from the further outer solar system.The nucleus of a comet
Most spirals consist of a rotating flat disc containing stars, dust and gas, and a central collection of stars known as the bulge. Hubble itself classified the various spiral galaxies into groups of Sa, Sb, Sc and so on. This naming is in accordance with the decreasing order of the importance of the central bulge compared to the surrounding disc and this can be inferred from the fig. Milky Way and our nearest galaxy M31 belong to the group Sb. Some spirals have a bar-shaped structure in their central region.
Ever since the beginning of time there have been stars. Not only stars in the sky, but moons, planets, and even galaxies! Astronomy is defined as the branch of science that deals with celestial objects, space, and the physical universe as a whole. In other words it is the study of space, planets, and stars. Throughout the ages, many people have used astronomy to help them learn about the universe, our own planet, and even make predictions about life itself. Understanding astronomy means understanding where it originated, the different groups/cultures that used it, and modern purposes of the science of the stars.