Sunday, March 24, 2013

What is a Quasar? What is the Huge-LQG?

In my last post I wrote about Pulsars which are neutron stars. They are the rapidly rotating compacted remains of a dead star, that emit a stream of dust and energy in the form of light. When viewed from Earth, they appear to be pulsating.

So is a Quasar, more stars? Not exactly. The word quasar means, "quasi-stellar object" or "quasi-stellar radio source." They are similar to stars because they are extremely luminous. However, quasars are in a class of extragalactic objects that emit an immense amount of energy, in the form of light. This is infrared radiation coming from a compact source. Meaning they are high redshift sources of electromagnetic energy. They have a light signature and an energy signature. I know it sounds complicated. Maybe it's because quasars are the most complicated and interesting stellar objects in our universe.

Recently, the Huge-LQG (Large Quasar Group) has been discovered. It's a group of 73 quasars, which at some point were thought to be at the center of their own respective galaxies. It stretches 4 billion light years across (at its longest point). Our Milky Way Galaxy is only a small 100,000 light years across. To attempt to make some sense of the scale of this huge quasar group, imagine that it would take "tens of thousands of our own Milky Ways" to equal the enormous size of the Huge-LQG.

What does this all mean? There's a little something called the "cosmological principle", which states,"if viewed on a sufficiently large scale, the properties of the universe are the same for all observers." So, us little Earthlings thought that if you look out into the universe from any point, (on Earth), then space should look the same no matter the direction from which you're looking. But, now we have learned this object is simply too large to fit into the confines of the cosmological principle. It appears that our little corner of the universe, what we can see of it, is unique to itself.

Don't you wonder what else is out there? We should feel like a fraction of a fraction of a fraction of a grain of sand. We are only beginning to learn and understand this vast universe...and we have a long way to go!

Here is a link to the quasar cluster, "Biggest Thing in Universe Found."