Parsec
Videos
The parsec is a unit of length used to measure the large distances to astronomical objects outside the Solar System, approximately equal to 3.26 light-years or 206,265 astronomical units, i.e., 30.9 t
As observed by the Hubble Space Telescope, the astrophysical jet erupting from the active galactic nucleus of M87 subtends 20″ and is thought to be 1.5 kiloparsecs (4,892 ly) long (the jet is somewhat foreshortened from Earth's perspective).
Quasar
Videos
A quasar is an extremely luminous active galactic nucleus. It is sometimes known as a quasi-stellar object, abbreviated QSO. The emission from an AGN is powered by accretion onto a supermassive black
Artist's image of the accretion disc in ULAS J1120+0641, a very distant quasar containing a supermassive black hole with a mass two billion times that of the Sun
The Chandra X-ray image of PKS 1127-145, a quasar about 10 billion light-years from Earth. An X-ray jet extends at least a million light-years from the quasar. Image is 60 arcseconds on a side. RA 11h 30m 7.10s Dec −14° 49' 27" in Crater. Observation date: May 28, 2000. Instrument: ACIS
Hubble images of quasar 3C 273. At right, a coronagraph blocks the quasar's light, making it easier to see the surrounding host galaxy.
A cosmic mirage known as the Einstein Cross. Four apparent images are actually from the same quasar.