Q uasar is a very energetic and distant active

Info icon This preview shows pages 9–10. Sign up to view the full content.

View Full Document Right Arrow Icon
Q uasar is a very energetic and distant active galactic nucleus. Quasars are among the most luminous objects in the universe due to their high red shift. Most visible from earth. (Question was more in depth than what is listed here) Cepheid - The Cepheid variables are the most important link to galaxian distances. The nearest of these is the Clouds of Magellan and are only about 150,000 to 200,000 light years away from the sun. By determining the absolute magnitudes of Cepheids and other observable characteristics, distances to several neighboring galaxies in which Cepheids can be observed are estimated. Rays/Spectrums: Emission Line is indicative of the emission of light (rather than the absorption), it shows up as a bright line on a spectrum. Absorption lines block particular portions of the light spectrum; they indicate a particular frequency of light has been blocked. In Earth's case, particular frequencies are blocked by substances in the atmosphere, such as ozone (which blocks UV light). Used to analyze the chemical composition of celestial bodies. Electron-positron annihilation accounts for the creation of gamma rays . When an electron and a proton collide, they are both annihilated and this can result in the production of gamma rays. Spectroscope is used to view a spectrum visually; a spectrograph is used to record spectral information Red Shift - Occurs when the frequency of a photon of light is shifted towards the red end of the electromagnetic spectrum. Wave length gets longer. Gamma Rays - have the shortest wavelength on the electromagnetic spectrum. Most gamma-rays are absorbed by the Earth's atmosphere. It wasn't until astronomers were able to put a gamma-ray telescope in space, outside of the influence of our atmosphere, that they were finally able to begin collecting data. 9
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
ASTRONOMY DSST 05Mar2012 X-rays - are also mostly absorbed by Earth's atmosphere, so they need to be observed from high in the atmosphere or from satellites in space. 10
Image of page 10
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern