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The Engineer
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What are Quasars?

07/27/2006 2:24 PM

Rudolph Schild of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, US, led a team that observed a quasar situated 9 billion light years from Earth. A quasar is a very bright, compact object, whose radiation is usually thought to be generated by a giant black hole devouring its surrounding matter.

A well accepted property of black holes is that they cannot sustain a magnetic field of their own. But observations of quasar Q0957+561 indicate that the object powering it does have a magnetic field, Schild's team says. For this reason, they believe that rather than a black hole, this quasar contains something called a magnetospheric eternally collapsing object (MECO). If so, it would be best evidence yet for such an object.

http://www.newscientistspace.com/article/dn9620-my sterious-quasar-casts-doubt-on-black-holes.html

Fun Quasar Facts:

Quasars can be as bright as hundreds of galaxies
The first quasars were discovered in the 1950's
The name quasar comes from quasi + star
The brightest quasars are thought to consume 1000 solar masses (1000 suns) of material every year
All known quasars are many billions of years old.

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Guru
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#1

Re: What are Quasars?

07/28/2006 2:52 AM

Interesting story, but the jury is still out. In the article, it may appear as if the discovery puts the whole black hole theory in question. In reality it is just a different (possible) explanation for how quasars generate their immense radiation.

Some minor comments on your "Fun Quasar Facts:"

Quote: "The name quasar comes from quasi + star".
I believe its actually a contraction of quasi-stellar, but what the heck does it matter?

Quote: "All known quasars are many billions of years old."
True, sort of, but quasars do not have very long lives when compared to galaxies. This is because they 'eat' all the material available for fuel in a few billion years. Then the active nucleus dims out and it becomes a normal galaxy. That's the main reason why we see them only at large distances, when the universe was much younger.

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The Engineer
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#2
In reply to #1

Re: What are Quasars?

07/28/2006 10:18 AM

"I believe its actually a contraction of quasi-stellar, but what the heck does it matter?"

I looked around and your definitely right, it's a contraction of quasi-stellar.

I've done some looking around and I found my "All known quasars are billions of years old" is not entirely correct either. I came across this article from 1998 that talks about a quasar that is only 500 million lightyears away, check out the link below.

http://www.xs4all.nl/~carlkop/mark231.html

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Guru
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#3
In reply to #2

Re: What are Quasars?

07/28/2006 3:05 PM

I think the consensus is that quasars can be quite close by, but the majority is observed in the distant universe. This is because they were more usual when the universe was young and they do not live all that long. We see the young universe only at large distances because of the time it took light to travel to us. This does not mean that a quasar cannot form recently – it is just not as likely.

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