U08a1 Galaxies Review Coursework Example | Topics and Well Written Essays - 750 words

U08a1 Galaxies Review - Coursework ExampleThe gravitative influence of mass father uped inside an orbit of a particular size determines the drive (and therefore period) of that orbit. So by measuring the period and size of the orbit, we can determine the mass inside the orbit. This is one mode you can use to determine the mass of Jupiter (by looking at the orbits of its moons). Mathematically, the expression for the mass enclosed indoors an orbit of radius r is M = v2r/G, where G is Newtons gravitational constant and v is the orbital speed of a star at outperform r. This c erstwhilept works equally well for the orbits of stars and gas within lock galaxies. By looking at the mass inside the orbit of stars or gas at different distances from the center of the galaxy, the mass of a galaxy as a function of radial distance from the center can be obtained from the rotation curve of the galaxy. 7. What are cosmic rays, and where are they thought to baffle from? Cosmic Rays are extre mely high energy charged particles (usually protons) that travel the Universe at just about the speed of light. Most galactic cosmic rays are probably accelerated in the blast waves of supernova remnants. This doesnt lowly that the supernova explosion itself gets the particles up to these speeds. The remnants of the explosions, expanding clouds of gas and magnetic field, can last for thousands of years, and this is where cosmic rays are accelerated. Bouncing seat and forth in the magnetic field of the remnant randomly lets some of the particles gain energy, and become cosmic rays. Eventually they build up enough speed that the remnant can no longer contain them, and they escape into the Galaxy. Because the cosmic rays eventually escape the supernova remnant, they can only be accelerated up to a certain maximum energy, which depends upon the size of the acceleration region and the magnetic field strength. 11. How do we know that spiral build up do not rotate like giant pinwheels? What makes spiral arms bright? voluted arms are regions of stars that extend from the center of spiral and barred spiral galaxies. These long, thin regions resemble a spiral and thus give spiral galaxies their name. Either way, spiral arms contain a smashing umteen young, blue stars (due to the high mass density and the high rate of star formation), which make the arms so remarkable. We know that the spiral arms cannot rotate like pinwheels around the center of the galaxy because the cozy stars would finish several orbits while the outer stars complete one. This would wind the spiral pattern up, which we do not see. The arms appear bright because of the enhanced star formation in them. The bright, bluer stars in particular make the arms bright since these stars do not live long and so die before bed covering far from the arm in which they create. Therefore spiral arms are bright because they contain many short-lived blue stars that shine for only a few million years. 21. The carbon in my adamant ring was once part of an interstellar dust grain. The carbon in my diamond ring was once part of an interstellar dust grain. This statement is sensible. Much of the carbon in the interstellar medium is in the form of dust grains, so the carbon in the interstellar cloud out of which the Earth formed must also have been largely in the form of dust grains. 36. We measure the mass of the smuggled hole at the galactic center from (a) the orbits of stars in the galactic cente