### definite unit | natural heavenly body:

Quasar
* All quasars have large red shifts.
* Most quasars are about the size of the solar system
  - larger than our solar system
  - the size of the solar system yet can be a trillion times brighter than the sun
* Some quasars are also great radio and gamma-ray emitter
  - as bright as a trillion suns
  - have the same structure as radio galaxies
  - show emission jets and extended emission features
  - vary in brightness over weeks or even days
* are a type of active galaxy
  - active galactic nuclei at cosmological distances
* are among the most distant extragalactic objects known
  - objects yet detected in the universe
  - distant, energetic objects ever observed
  - enigmatic objects in the universe
  - luminous objects in the sky
  - bizarre objects
  - brighter or dimmer or farther or closer than thought
  - compact powerhouses of light that reside largely at the outer reaches of the universe
  - compact, luminous objects powered by super-massive black holes
  - difficult to study because they are the active nuclei of distant galaxies
  - energetic beacons of light at the active cores of distant galaxies
  - energy sources
  - exceptionally bright objects located at the farthest reaches of the universe
  - extreme examples of active galaxies
* are extremely bright masses of energy and light
  - bright, small objects
* are extremely distant and luminous objects
  - objects in our known universe
  - faint starlike objects whose spectra are highly redshifted
  - farther away from Earth than any other known object in the Universe
  - galaxies with active and bright center objects, thought to be powered by black holes
* are galaxies with bright cores , probably powered by giant black holes
  - cores, most likely powered by giant black holes
  - extremely bright centres
  - huge black hole accretion disks that are much brighter than their host galaxy
  - just luminous active galactic nuclei
  - like galaxies and a cluster
  - located in space
  - no larger than our Solar System, but outshine galaxies of hundreds of billions of stars
  - point-like objects
  - powered by gas falling inward toward a central supermassive black hole
* are probably super giant black holes, which are devouring entire stars
  - small, powerful, extremely remote objects
  - so bright that they drown out the light from all other stars in the same galaxy
  - some of the most energetic objects observed in the universe
* are the bright cores of distant galaxies
  - bright, superluminal cores of very distant active galaxies
* are the brightest and most distant objects in the visible universe
  - brilliant, unresolved nuclei of active galaxies
  - energy of the gas spiralling in
  - extraordinarily bright centers of young galaxies
  - galactic cores with the holes in the shell
* are the most distant and luminous objects in the visible universe
  - cosmic objects known
* are the most distant distinct objects that astronomers have been able to detect
  - that astronomers have been able to directly detect
* are the most distant objects in the known universe
  - known, and yet they're the youngest
  - energetic and distant of all three objects
  - energetic, distant objects known in the universe
  - extreme example of monster black hole, highly luminous active galaxies
  - luminous class of objects in the universe
* are the most luminous objects in the sky
  - the universe and among the most distant objects known
* are very bright and very compact and their light is very red shifted
  - objects with a very high redshift
  - far away galaxies
  - mysterious objects
* are, in fact, the most distant objects to ever be detected in the universe.
* become even farther away and intrinsically brighter.
* can display light about millions of lightyears farther than stars
  - form from merging galaxies - common in the cores of clusters
* contraction of quasi-stellar object.
* drown out the light from all the other stars in the same galaxy because they are so bright.
* emit energies of millions, billions, or even trillions of electron volts
  - many different types of energy such as X-rays and rays
  - more or less constant power over all wavelengths from infrared to gamma-rays
  - tremendous amounts of light and microwave radiation
* give off huge amounts of energy.
* have prodigious luminosities
  - rapid light variations
* is Japanese
  - short for quasi-stellar radio source
* live in the center of host galaxies.
* look a bit like stars but are very different in many ways.
* look like any normal star through an optical telescope
  - stars but give off too much energy
  - very bright stars but actually are black holes at the center of forming galaxies
  - starlike when viewed through an optical telescope
* really have stellar dimensions, occasionally surrounded by nebulosity.
* reside at the centres of galaxies
  - in a variety of galaxies, from normal to highly disturbed
* seem to be always associated with galaxies
  - massive black holes, active in the early life of galaxies
* show infrared brightness correlated with their x-ray fluxes.
* tend to vary in brightness in a stochastic, non-linear nature.
+ Geoffrey Burbidge, Later career: 1925 births :: 2010 deaths :: English astronomers :: Astrophysicists :: English physicists :: English science writers :: Alumni of University College London
  * Later in his career Burbidge refused to accept the Big Bang theory which describes the start of the universe. Quasars are very bright objects with a very high redshift. The Big Bank theorists say that they come from places extremely far away in the universe. But Burbidge thought that quasars come from nearby galaxies, travelling near the speed of light, which explains their redshift. He thought they produced new matter as old matter was destroyed by reactions.