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Black Hole Jet

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jimmy1370

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<p>Please excuse my ignorance, but I have a question. Everything that I have ever heard about black holes is that nothing can escape from them. Not even light. Yet on the front page, the article talks about a black hole jet. Particles that are "spewed" outward at nearly the speed of light. How is this possible is even light can't escape?</p><p>&nbsp;And once again, I apologize if this is a stupid question.</p>
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Please excuse my ignorance, but I have a question. Everything that I have ever heard about black holes is that nothing can escape from them. Not even light. Yet on the front page, the article talks about a black hole jet. Particles that are "spewed" outward at nearly the speed of light. How is this possible is even light can't escape?&nbsp;And once again, I apologize if this is a stupid question. <br /> Posted by jimmy1370</DIV></p><p>Welcome to the forums jimmy 1370... good question.&nbsp;</p><p>This will only happen on black holes that have an active accretion disc.&nbsp; As matter starts falling towards a black hole, particles become highly energized.&nbsp; It is theorized the matter is somehow 'guided' toward the polar axes via a very strong magnetic field at relatavisitc speed resulting in plasma jets that are observed in the x-ray spectrum.&nbsp; Figuring out exactly how this happens is still an active area of research. </p><p>One thing they are fairly certain of, though, is this matter has never crossed the event horizon of the black hole and thus it is not escaping from within the black hole.&nbsp;</p><p>The only stupid question is the one never asked...</p><p>For other members:&nbsp; <font size="2"><strong>Here is a link</strong></font> to the article on SDC being referred to by Jimmy1370.&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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derekmcd

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<p>http://www.bu.edu/blazars/BLLac.html</p><p>Here's an excerpt taken from the original souce of the press release:</p><p>The supermassive black hole (with a mass of about 200 millions times that of the Sun, which corresponds to an event horizon that is about twice as large as the size of the Earth's orbit around the Sun) is just a very tiny black dot at the center. Surrounding it is an accretion disk of gas and dust from interstellar space that is slowly falling into the black hole while rotating around it in nearly circular orbits. (Despite the black hole's strong gravity, the gas has too much inertia because of the rotation of the disk to fall directly into the black hole. Instead, it swirls around until a process similar to friction slows it enough to fall past the event horizon.) The accretion disk contains a magnetic field that is twisted by the rotation (which is faster closer to the black hole). A coiled magnetic field creates a pinching force that focuses the plasma (charged particles that move together) into a narrow jet as it flows away from the black hole. (The magnetic field itself is probably kept from expanding excessively by pressure from a wind that we think surrounds the jet.) </p><p>We think that outbursts of radiation from blazars are triggered near the black hole, where some explosive event (such as "reconnection" of magnetic field in places where oppositely directed magnetic fields come in contact) shoots extra energy down the jet. This probably forms a shock wave that moves down the jet along a spiral path. The jet flow velocity increases with distance from the black hole, driven by magnetic forces. As the speed approaches the speed of light, the radiation is beamed more and more in the forward direction, similar to focusing a halogen flashlight. Since the jet points almost in our direction, the radiation from the shock wave gets most intense when the velocity reaches its maximum value, 0.98 times the speed of light. This actually creates an illusion that the bright knot of material made by the shock is moving 5 times faster than light travels. A few weeks later, after the emission has faded as the material in the shock expands and cools, we see a second brightening when the material is compressed by a stationary shock wave created by a pressure difference between the jet and the gas of the surrounding galaxy. </p> <p>The crucial aspect is what happened during the first flare. The polarization - which indicates the direction of the magnetic field - made about 1.5 rotations. So, that means that the blob passed through a coiled magnetic field. (In order to break the symmetry so that the polarization from different parts of the coil don't cancel, the blob needs to cover less than 100% of the width of the jet and it needs to follow a loose spiral path.) We surmise that the reason for the rise in brightness is the acceleration of the blob as it passes through the region of coiled magnetic field. All of this is exactly what was predicted by theorists, especially Nektarios Vlahakis (U. Athens, Greece) and Arieh Konigl (U. Chicago). But previous observations did not have frequent enough VLBA imaging combined with polarization observations and closely spaced measurements of the radio, visible, and X-ray brightness to fill in enough pieces of the puzzle to determine what is happening physically in the jets.</p><p>&nbsp;</p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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weeman

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Please excuse my ignorance, but I have a question. Everything that I have ever heard about black holes is that nothing can escape from them. Not even light. Yet on the front page, the article talks about a black hole jet. Particles that are "spewed" outward at nearly the speed of light. How is this possible is even light can't escape?&nbsp;And once again, I apologize if this is a stupid question. <br />Posted by jimmy1370</DIV><br /><br />A black hole's gravity is only inescapable if the matter/light is beyond the event horizon. Any matter/light that is outside of the event horizon still has the chance of escaping the black hole's grasp. This is why it is possible for us to see large jets spewing out from black holes. <div class="Discussion_UserSignature"> <p> </p><p><strong><font color="#ff0000">Techies: We do it in the dark. </font></strong></p><p><font color="#0000ff"><strong>"Put your hand on a stove for a minute and it seems like an hour. Sit with that special girl for an hour and it seems like a minute. That's relativity.</strong><strong>" -Albert Einstein </strong></font></p> </div>
 
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gammarayburst

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Please excuse my ignorance, but I have a question. Everything that I have ever heard about black holes is that nothing can escape from them. Not even light. Yet on the front page, the article talks about a black hole jet. Particles that are "spewed" outward at nearly the speed of light. How is this possible is even light can't escape?&nbsp;And once again, I apologize if this is a stupid question. <br /> Posted by jimmy1370</DIV><br /></p>Jimmy, The explanation that the jets are caused from matter entering the event horizon is just a theory.&nbsp; Fact is many black holes have these jets and yet appear to be inactive.&nbsp; Conjecture : Since magnetic fields affect electrons and light/plasma is made of electrons then the only logical explanation would be magnetic poles are the only places where these electrons can escape.<br />
 
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derekmcd

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<p><BR/>Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>Jimmy, The explanation that the jets are caused from matter entering the event horizon is just a theory.&nbsp; Fact is many black holes have these jets and yet appear to be inactive.&nbsp;&nbsp; <br /> Posted by gammarayburst</DIV></p><p>&nbsp;</p><p>The theory say nothing about matter <strong><em>entering</em></strong> the event horizon.&nbsp; Additionally, stating "is just a theory", is a common misperception of what a scientific theory really is.&nbsp; There is a <u><strong><em>huge</em></strong></u> difference between the use of the word between non-scientific folks and those that study the sciences. </p><p>Also, you state as fact that inactive black holes have plasma jets.&nbsp; Could you site a source for this fact?&nbsp; I don't believe this to be true.&nbsp; I can't picture any mechanism that would allow this.<br /> </p> <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>
 
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MeteorWayne

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Replying to:<BR/><DIV CLASS='Discussion_PostQuote'>&nbsp;The theory say nothing about matter entering the event horizon.&nbsp; Additionally, stating "is just a theory", is a common misperception of what a scientific theory really is.&nbsp; There is a huge difference between the use of the word between non-scientific folks and those that study the sciences. Also, you state as fact that inactive black holes have plasma jets.&nbsp; Could you site a source for this fact?&nbsp; I don't believe this to be true.&nbsp; I can't picture any mechanism that would allow this. <br />Posted by derekmcd</DIV><br /><br />Well since the plasma jet defines "active" it seems rather self evident <img src="http://sitelife.space.com/ver1.0/content/scripts/tinymce/plugins/emotions/images/smiley-smile.gif" border="0" alt="Smile" title="Smile" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>
 
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