Galaxies in .NET Printing Code 128A in .NET Galaxies

How to generate, print barcode using .NET, Java sdk library control with example project source code free download:
14. Galaxies using visual .net toadd code 128 code set b with web,windows application barcode Figure 14. .net framework USS Code 128 6.

The orbital speed of gas in the spiral galaxy m33. If the mass of the galaxy were all in its center, then we would expect V to decrease. Instead, it is slowly increasing as far out as it can be measured.

The two lower dashed lines are contributions to the velocity from the visible galaxy. The upper dashed line is the de cit that must be made up by invisible mass. Figure from E.

Corbelli and P. Salucci, Mon. Not.

Roy. astr. Soc.

, 311, 441 (2000), with permission of the authors.. 2V. Knowin g the distance to and size of the galaxy (not always easy!) gives us the orbital radius R, and hence the mass M. If the gas or stars whose motion we measure in this way are far enough out from the center of the galaxy, then one would expect that the mass inside the orbit would be fairly constant.

Then, by Equation 14.7, one would expect to see V 2 R constant, or V R-1/2 . What we actually see in almost every case where measurements can be made far from the galactic center is illustrated in Figure 14.

6: V stays relatively constant or even increases as R increases. What are we to make of the rotation curve shown in this gure If V is constant, then Equation 14.7 on the previous page tells us that the mass of the galaxy inside a distance R is proportional to R.

Now, the rotation curves obtained in this way use very weak radio waves from neutral hydrogen gas orbiting the galaxy. This is sometimes detectable two or three times as far from the center as any visible light from the galaxy, in other words in regions well outside the photographic image of the galaxy. They tell us that the mass is still increasing: there is a huge amount of dark matter out there, perhaps two or three times as much mass as one would infer from the photographic image.

What is this missing, or dark, matter No one yet knows, despite years of investigation. We will return to this question after the next section, once we have seen that the spaces between galaxies hide even more missing mass than the galaxies themselves do..

In this se USS Code 128 for .NET ction: galaxies often come in groups called clusters, with hundreds or thousands of members. These clusters provide additional evidence for missing matter, and they also give clues to how galaxies were formed in the very early Universe.

Figure 14.7. The central portion of the Virgo Cluster of galaxies.

The elliptical galaxy m87 illustrated in Figure 14.1 on page 164 is at the center of this picture. Several hundred galaxies of various sizes may belong to this moderately rich cluster.

Use of this image is courtesy of the Palomar Observatory and Digitized Sky Survey created by the Space Telescope Science Institute, operated by aura, Inc. for nasa and is reproduced here with permission from aura/stsci..

Gangs of g alaxies The ever-attractive nature of gravity makes it inevitable that galaxies are not spread out uniformly through the Universe. Instead they tend to group together in what are called clusters of galaxies. Our own Local Group is a small, loose cluster consisting of 3 spiral galaxies (Andromeda, the Milky Way, and a smaller spiral called m33, illustrated in Figure 14.

6), several minor galaxies, and many satellite galaxies such as m32 and the Magellanic Clouds. There are many clusters that are much more populous, having 100 to 1000 members. The nearest big cluster of galaxies is the Virgo Cluster, at a distance of about 18 Mpc, containing a few hundred galaxies.

Figure 14.7 is a photograph of this cluster. The elliptical galaxy m87 shown in Figure 14.

1 on page 164 is a giant elliptical in the center of the Virgo Cluster: it may well have been formed by the merger of two or more spirals that were brought to the center by the collective gravitational force of the whole cluster. Clusters also group into superclusters; we will discuss these in 25. When we try to estimate the masses of clusters, we nd further evidence of even.

Copyright © . All rights reserved.