quasar
In either case, quasar is a contraction of ‘quasistellar,’ in reference to the fact that the visual appearance is starlike. [1]
… huge regions of radio emission, produced by the quasar, can stretch out to large distances outside the galaxy. [2]
Quasar, or Quasi-stellar Object (QSO), a starlike object displaying an unusually large red shift. [3]
LOS ANGELES - A team of European astronomers, glimpsing back in time to when the universe was just a youngster, says it has detected the most distant and earliest quasar yet. [4]
The highly energetic core of a remote active galaxy; quasars are the most luminous objects in the universe, capable of radiating over a trillion times as much energy as the Sun from a region little larger than the solar system. [1]
While there was initially some controversy over the nature of these objects’as recently as the early 1980s, there was no clear consensus as to their nature’there is now a scientific consensus that a quasar is a compact region in the center of a massive galaxy surrounding its central supermassive black hole. [5]
It is thought the infall of matter into the supermassive black hole can result in very hot regions where huge energies are released, powering the quasar (i.e., producing the emitted light, etc.). [2]
Most astronomers believe that the red shift of a quasar is explained by the Doppler effect that the shift is caused by the relative motion of the earth and the quasar away from one another. [3]
To scientists’ surprise, the black hole powering this quasar was 2 billion times more massive than the sun. [4]
Quasars were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar to galaxies. [5]
It appears galaxies may only act as quasars during the early stages of their lives, but it would still be for times of billions of years. [...] When radio telescopes were first turned on the heavens, point sources of radio waves were discovered (along with spread-out regions of emission along our Milky Way). [2]
Most quasars exhibit very large redshift s, suggesting that they are moving away from Earth at tremendous speeds (approaching the speed of light); they thus are some of the most distant known objects in the universe. [1]
Many astronomers believe that quasars represent an early stage in the evolution of galaxies such as our own. [6]
The first quasars were found because of their radio emission and were called quasistellar radio sources. [1]
Sources:
[1] quasar: Definition from Answers.com - Answers.com: Wiki Q&A …
[2] Frequently Asked Questions About Quasars
[3] HowStuffWorks “Quasar”
[4] Scientists discover brightest, earliest quasar …
[5] Quasar - Wikipedia, the free encyclopedia
[6] quasar - definition of quasar by the Free Online Dictionary …