Essay, Pages 4 (779 words)
The Milky Way is a whitish stripe in the nightsky, especially visible in the night without the moonshining. This is because in autumn evenings it runsacross the sky from northeast to southwest, itroughly coincides with the routes of migratory birdspaths. According to written sources, the first attemptwas made to scientifically explain the Milky Way inancient Greece. What is actually the Milky Way, thefirst to understand Pythagoras in the VI centuryB.C. He insisted that it was a pool of many weakstars whose eyes could not be seen in isolation.
G.Galilee proved it by looking at the Milky Waythrough his invented telescope. (Fig. 1.)Fig. 1. Milky Way as seen from our planet – Earth the stars in the Milky Way were of the samedensity and if the interstellar space were transparent,the Milky Way would look like a strip. However,the density of stars is uneven, and there are cloudsof light-absorbing dust in the interstellar space. As aresult, the Milky Way looks like a bright strip ofvery irregular contours, narrowing, widening orsplitting into several furrows.
Fig. 2. Milky Way and two neighbouring Galaxies -compared (LMC and Antlia 2) Milky Way is narrowest and shinesweakest in Winter and Spring. The Sagittariusconstellation of the Milky way is widest andbrightest, there is the Galactic Center. In theopposite direction there is so called – the anticenterand it is at the limit of the Auriga and Taurusconstellations. Approximately in the middle of theMilky Way is the Galaxy halfway.That the Milky Way is a projection of a giantstar system in the sky, was proved by the Englishastronomer William Hitchel in the 18th century,relying on the stars’ calculations in variousdirections of the sky.
The first true model of this starsystem was created only in the 20th century. Thegalaxy consists of hundreds of billions of stars, theirswarms, interstellar gases, and dust clouds, calledthe Nebula. Similar galaxies that are spreaded in alldirections from Milky Way is a lot. So this galaxy isno different in the universe. (Fig. 2.)The sun is running with its planets around theMilky Way in the direction of Sagittariusconstellation that is away from us at 28,000 LightYears. The stars of the galaxy are the most denselyclustered at disc-shaped space part. The diameter ofthis disc is about 100,000 Light Years. Because theSun is inside it, the other distant disc stars cometogether in a glowing circle – the Milky Way, thatdivides the sphere of the sky into two approximatelyequal parts.Fig. 3. Milky Way Galaxy from the side. We can see thinedges and thickening at the center of Galaxy. ExplanationCorrect answer:b) Millions of stars within the galaxy can beobserved with telescopes.What is actually the Milky Way, the first tounderstand Pythagoras in the VI century B.C. Heinsisted that it was a pool of many weak stars whoseeyes could not be seen in isolation. G. Galileeproved it by looking at the Milky Way through hisinvented telescope.Wrong answersa) All the stars in the Milky Way Galaxy can beseen with naked eye. – It is impossible to see allstars with bare eye, even with telescopes it is notpossible to see every single star. With our bare eyeswe can see only the brightest and biggest stars.c) The Sun orbits the galaxy approximatelyevery 10,000 years. – “The Sun takes 225 millionEarth years to make one rotation. This period oftime is called a cosmic year.”Kerrod, Robin. Encyclopedia of Science Heavens 2.New York: MacMillian Reference USA, 1997: 35.3. Discussion and ConclusionsMilky Way is not just an enormous view of theaccumulation of stars from the cluster inside. At thesame time, it is projection of many stars in the sky.The three-dimensional system of those stars iscalled the Galaxy (greece. – galaktikos – milky,dairy) – that is the most probable reason why ourgalaxy was called Milky Way, from greek wordgalaktikos that means dairy, milky. It has about 300billion stars.There are more similar galaxies to Milky Waythat are spreaded in universe in different directionsfrom ours. If you glance at the galaxy from greatdistance – from the side it would look like anenormous lean-to-edge lens that has about 120,000light-years from one edge to another. At its edges,thickness reaches just a few hundred light years. Inclose proximity to the center, this “lens” thickens,turning into a large 3000-6000 light-years ball.(Fig. 3.)All galaxies whose structures can be seen,consists of stars: this shows that the formation ofstars in the gas cloud, when the material reaches acertain density, is very likely to happen. Apparently,it is caused by crashes, caused by impact waves -like a snowball, they are triggering a chain-claddingprocess – the more mass of the cosmic crowngrows, the stronger thrust is and the more it attractsthe new surrounding material. And the pressuredmaterial in the center of the bulge is of hightemperature, and the nuclear reaction begins – thestar lights up