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Quasars or quasi-stellar radio sources are the most energetic and distant members of a class of objects called active galactic nuclei (AGN). Quasars are extremely luminous and were first identified ...

Space Quotations: Astronomy & Cosmology Quotes


Now appear before You with a new contrivance of glasses [occhiale], drawn from the ... for example, nine miles appear as though they were only one mile distant. ... but when I follow the serried multitude of the stars in their circular course, my ... of the heavens very much like its center; in size and distance it has the ratio of a ...

How We Found the Most Distant Quasar (Yet) Known - Space.com


Feb 9, 2015 ... The vast majority of these objects were ordinary sunlike stars in Earth's own ... In many cases, that host galaxy is so faint it is not detected, leaving only the quasar visible. ... (The finite speed of light means that larger physical distances ... small size of quasars also means they appear star-like when viewed ...

Quasar - New World Encyclopedia


Jun 19, 2015 ... Quasars were first identified as high-redshift sources of electromagnetic ... In optical telescopes, quasars look like single points of light (i.e. point ... Astronomers detected what appeared to be a faint blue star at the ... moot and today the cosmological distance of quasars is accepted by almost all researchers .

Galaxies, Clusters, and Quasars - sci.astro - Astronomy Net


Apr 27, 2003 ... H.01 How many stars, galaxies, clusters, QSO's etc. in the Universe? ... does this mean they are that far away now or were that far away when the light left them? ... for example, for every Sun-like star there are about 200 faint red M dwarfs. ... enough to see nearby, much less at large cosmological distances.

An overview of active galaxies: View as single page


Initially only AGN which were detected as radio sources were called quasars ... the spectral lines did not appear at appropriate wavelengths for atoms of any ... In each case shown in Figure 5 faint nearby emission was discovered from stars in a galaxy. ... The distance between the quasar and the galaxy is one-seventh the ...

Chapter 15 | SixDay Science


Some of these milky nebulae have spiral shapes to them and others look like ... The distances between galaxies are large and are often measured in megaparsecs. ... Those favoring a large Milky Way with the spiral nebulae inside it were ... little dust and gas left between the stars; (c) this means that they have no new star ...

Observed Characteristics of Quasars


More specifically, this means that being less— perhaps far less—than half a second of arc ... The radio appearance of a typical quasar is relatively similar to the ... Ordinary stars have a continuous energy distribution in their spectra to a first order ..... If cosmological distances for quasars offered no difficulties either, this p...

About the Hubble Space Telescope


problem Even before NASA launched Hubble, engineers were hard at work building ... —the Wide Field Planetary Camera 2 (WFPC2)—meant for installation by ...... and quasars, the intensely bright, star-like objects appearing at galactic distances .... he called the cosmological constant Astronomers don't yet know whether.

Quasar Candidates in the Hubble Deep Field


study a wide range of questions in galaxy evolution and cosmology. ... for unresolved faint quasars and AGN in the crude combine images using a ... inconsistent with that of ordinary stars, 7 pointlike objects with colors consistent with quasars or .... The newly formed U300,B450,V606,I814 catalogs were matched using the ...

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Frequently Asked Questions in Cosmology


May 24, 2013 ... How can the oldest stars in the Universe be older than the Universe? ... Are quasars really at the large distances indicated by their redshifts? What about objects with discordant redshifts, like Stephan's Quintet? ... Thus for an accelerating expansion the supernovae at high redshifts will appear to be fainter  ...

Discovery that quasars don't show time dilation mystifies astronomers


Apr 9, 2010 ... (PhysOrg.com) -- The phenomenon of time dilation is a strange yet ... is that events occurring in distant parts of the universe should appear to occur ... ... at the same rate no matter their distance from the Earth, without a hint of time dilation. ... If these quasars were like the previously observed supernovae, an ...

The Odd Couple: Quasars and Black Holes | Institute for Advanced ...


Our own galaxy contains a few tens of billions of stars arranged in a disk; the nearest of ... 3C 273 with a faint optical source that looked like an undistinguished star. ... lines were redshifted—Doppler shifted by the cosmological expansion of the ... such as supermassive stars, dense clusters of ordinary stars or neutron stars, ...