Quasars

PKS 1127-145 - 10 Billion light years from earth

This post is about the Quasar. When I was younger it was the quasar that made the papers much in the way that Black Holes tend to these days. Over the years though the light of Quasars began to dim has the light of the Black Hole intensified and these days they seem to be hardly ever mentioned.

The Quasar was, and still is, one of the greats of the heavens. The stats for these fellows is truly awe inspiring. In fact the numbers are so large that they really are way beyond comprehension.

A Quasar, or quasi-stellar radio source to give it its full title, are really energetic light sources often billions of light years away. To give you some idea of how bright these objects are, consider this...

The sun is about 8 light minutes away. It takes light about 8 minutes to travel the 150 million kilometers from Sun to earth. The nearest star is alpha century, which is about 4 light years away. It is so far that it is seen a star, one amongst many, granted it is a little brighter than most, but it is what we would call a regular star all the same.

If a Quasar was 33 light years away, 8 times the distance of Alpha Century, it would burn so bright as to be almost indistinguishable from the sun on a sunny day. It is thought to be as bright as two trillion (2x10¹²) suns. This is one of those numbers that is too large to grasp, it is genuinely massive.

The Sun itself radiates an incredible amount of energy every second of every day and yet a quasar takes this to an entirely different level. To try and give you some idea think of this,

A year is about 31 million seconds, 2x10¹² /31,000,000 = 65,000. A quasar gives off the same amount of light in 1 second as our sun does in about 65,000 years!

It is estimated that the Sun emits 3.3×10³¹ Joules of energy every second. Given E=mc², this amount of energy is the same as 3.6×10¹⁴ Kg of mass begin converted into pure energy every second. In 65,000 years this amounts to 7.4x10²⁵ Kg of mass. The mass of the earth is about 6 x 10²⁴ Kg.

In other words, if we could convert the entire earth into pure energy, then it would produce enough energy to keep a Quasar going for about 0.1 seconds!!!! That's 600 earths a minute. Talk about greedy!

Apart from the 0.1 seconds, which is actually over very quickly, the rest of the numbers discussed above are beyond out comprehension, suffice to say they really are huge.

So, we know that a Quasar is running on high octane, we also know that they are not that big. Once again, this is a relative thing. They are thought to be about the size of our solar system, which, lets be honest is pretty big. But considering how bright they burn, it is a small volume.


There are about 200,000 known Quasars and most appear to be upwards of 3 billion light years away. The furthest upwards of 10 billion years. If the Big Bang theory is correct then these older Quasars formed about 3 Billion years after the start of the universe.

They were first detected in the 1950s and measurements using the Doppler effect have shown that some are moving away from us at a tremendous rate, around 37% of the speed of light!

For several years after their discovery many theories tried to explain their brightness, antimatter or white holes, though it is now thought that it is due to the accretion disc energy mechanism. It is thought that at the center of each Quasar is a super massive black hole.

It is also thought by some that most galaxies, including our own Milky Way, have gone through a Quasar stage and are now quiet because they have run out of energy to feed into their central black holes to generate radiation.

I am not entirely convinced of the existence of black holes so I don't agree with some of this. That said, I do like the idea that our galaxy was once a Quasar. It's nice to think that our galaxy really was a bright shining object in its day.

I was brought up on Quasars, what is so cool about them is that there is no doubt they exist, you can see them with a telescope. They are beautiful, fantastic and utterly magnificient. I think that they are great.

Quasar, I salute you.