Alright! So first off I am going to finish off my segment on Black Holes (for now.... dunh dunh dunnnnnnh).
So many depictions of Black Holes show pictures of a large, flat disc with a jet of energy flowing out of the middle.. Wait a second MrAstrowhat! Aren't Black Holes supposed to be Black?!
Yes they are! But! Let me explain. As matter approaches a Black Hole it first has to fall into its orbit. Now, with objects of such a high mass the gravitational pull is unbelievably strong. This causes the velocity of orbiting objects to be very high. As objects get closer to the center of the Black Hole the velocity increases. Knowing this, we can assume that when gas gets near the center, because its so light and the Black Hole is so heavy the gravitational force is FREAKIN HUGE! This will cause the gas to spin really fast and heat up to searingly high temperatures. As this happens radiation is emitted (usually as X-Rays). Now what does this have to do with the large disc that is clearly not black nor is it a hole. Well according to angular momentum (oh lord, here I go with the equations again) as friction builds up in the center (there is a lot of friction due to high velocity) the angular momentum moves outwards. To better explain this, think of spinning pizza dough. As you spin it it spreads out into a disc shape. I think thats a good explination..... I could be horribly wrong! Who knows!
Holy cow that is a huge paragraph! I hope I explained everything well enough! Like I have indirectly mentioned before, its a lot easier to explain verbally. Now these X-Rays that I mentioned are one of the big reasons we can detect Black Holes! But not only are there X-Rays... Oh no, there are also Gamma and Radio waves! These waves are all quite detectable and we have given a name to objects that emit these. Thats right, you all know where I am going with this! Quasi Stellar Radio Sources!
Quasi Stellar Radio Sources, or Quasars, are emitters of electromagnetic energy. They exist in a tight region around their own Black Hole and are fueled by energy from the accretion disc. Oh, I'm so glad I waited to write about accretion discs, this all ties together so nicely now!
Quasars, even though they may not be as visible as our sun or Betelgeuse, are actually the brightest entities in our known universe. Quasars from up to 28 billion light years away can be viewed through radio telescopes from our happy little home here on earth. This is one little proof of how bright they are.
Lets take my favorite stellar body for example. Quasar 3C 273, located in the constellation Virgo close to the star Porrima. It is semi-easily viewed through any small scale telescope but is still extremely far away. Now, if it was approximately 10 parsecs away (32.6 lightyears) it would be viewed to be as bright as our sun. In other words, its really big and really bright. A more scientific explanation of this would simply be a difference between apparent and absolute luminosity. Apparent luminosity is the luminosity of a stellar object as we view it from earth. The Absolute luminosity is the actual luminosity of the object if you decided to go give it a little visit and stand right in front of it.
So essentially Quasars have a high absolute luminosity and a low apparent luminosity.
Wow.... I think I just a whole paragraph to say "Quasars are really bright"...... It's probably because I tend to ramble off about things that aren't quite on the given topic or am worried about not explaining things properly.
Look! Thats proof right there! Anywho that is my blog for this week. I wish everyone the best of luck on the test on Friday :)
-MrAstrowhat
Food for Thought: Auriga, Orion, Gemini, Taurus, Cassiopeia, Perseus, Ursa Major, Pegasus, Andromeda, and Cetus. Learn them, know them, love them.
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