Quasar
A Quasi-stellar Radio Source (Quasar) is a term used to describe the brightest and most distant objects in the known universe which emit up to thousand times the energy of our own Milky Way galaxy.
Quasars have a very high red shift which indicates extreme distance and age. The most distant Quasar ever discovered is a mind boggling 12.9 billion light years away and would have formed when the universe was approximately 770 million years old[1].
In early January 2013 a cluster of Quasars was discovered that measured 4 billion light years across making it the largest structure ever discovered in the universe[2]. Seriously - think about that for second...4 billion light years...
[edit] What are they?
The properties and formation of Quasars was historically controversial.
However, in recent times Quasars are believed to be formed by the accretion of material into supermassive Black holes[3]. Essentially, quasars are galaxies in the very early stage of their formation, where there's still enough infalling matter to feed that voracious black hole in its center. As the material swirls down the drain on its way to the event horizon, it heats up. A lot. The result is a hell of a lot of radiation across a wide variety of frequency bands.
[edit] Little Green Men
When quasars were first discovered, nobody really knew what they were. In 1963, Kardashev (of Kardashev Scale fame) speculated that the newly discovered quasar CTA-102 might be a radio beacon developed by high-tech space aliens. The Byrds even wrote a song about it:
“”C.T.A. - 102
We're over here receiving you Signals tell us that you're there We can hear them loud and clear |
| —"C.T.A.-102", from the album Younger than Yesterday |
If quasars really are artificial radio beacons, they are an awfully large and inefficient way to generate radio signals.