First stars powered by dark matter annihilation?

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docm

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http://www.physorg.com/news122034732.html<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p><b>First stars might have been powered by dark matter<br /><br /><i>For a long time, scientists have assumed that the very first stars were powered by fusion, in processes similar to what goes on in present day stars. But a new theory is emerging to challenge that view. “The first stars were different in a lot of ways,” Katherine Freese, a theoretical physicist at the University of Michigan, tells PhysOrg.com.</i></b><br /><br /> Freese, along with Douglas Spolyar at the Unversity of California, Santa Cruz and Paolo Gondolo at the University of Utah in Salt Lake City, posit that dark matter annihilation was the source of energy that powered the earliest stars, formed about the time the universe was between 100 and 200 million years old.<br /><br />If they are right, some of what we know about stellar formation – and the formation of the universe itself – could be called into question. Their work appears in Physical Review Letters with the title “Dark Matter and the First Stars: A New Phase of Stellar Evolution.”<br /><br />“Annihilation means that matter goes into something else,” Freese explains. She says that everything has a partner opposite – matter and anti-matter, electrons and positrons. When these opposites meet, their identity is lost and the energy goes elsewhere. “Dark matter particles are their own anti. When they meet, one-third of the energy goes into neutrinos, which escape, one-third goes into photons and the last third goes into electrons and positrons.” <br /><br /><font color="yellow"><b>“In order for a star to form, in order for its matter to collapse into a dense object, it has to be able to cool off,” Freese continues. “We noticed that in the first stars something was competing with the cooling. The stars couldn’t collapse down small enough to get fusion going. But they were still</b></font></p></blockquote> <div class="Discussion_UserSignature"> </div>
 
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brellis

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I've been rereading Hawking's "Brief History". He describes the 1-in-100 or more chance of anti-matter appearing.<br /><br /><font color="yellow">“Dark matter particles are their own anti. When they meet, one-third of the energy goes into neutrinos, which escape, one-third goes into photons and the last third goes into electrons and positrons.”<br /></font><br /><br />It sounds too simple - a double negative explains the fusion process of 1st generation stars! <div class="Discussion_UserSignature"> <p><font size="2" color="#ff0000"><em><strong>I'm a recovering optimist - things could be better.</strong></em></font> </p> </div>
 
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robnissen

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I have two problems with this research. First, is the one you identified:<br /><br /><font color="yellow">“Dark matter particles are their own anti. When they meet, one-third of the energy goes into neutrinos, which escape, one-third goes into photons and the last third goes into electrons and positrons.” </font><br /><br />I don't believe there is even one fact in that statement, I think everything in that statement is nothing but [perhaps well-informed] speculation. Is there any evidence that 1) <font color="yellow">“Dark matter particles are their own anti.</font> and 2) <font color="yellow">When they meet, one-third of the energy goes into neutrinos, which escape, one-third goes into photons and the last third goes into electrons and positrons.”</font>I don't think so. <br /><br /><br /><br />Second:<br /><font color="yellow"><br />“We noticed that in the first stars something was competing with the cooling. The stars couldn’t collapse down small enough to get fusion going. But they were still giving off energy. They were in a phase we hadn’t discovered before.” </font><br /><br />I don't believe we have ever seen first generation stars, so how can they possibly know that the first generation stars weren't getting "small enough."
 
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MeteorWayne

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I'd tend to agree Rob.<br />Since nothing has been shown to be dark matter in the first place.<br /><br />Perhaps earlier in there is something descibing what they suspect dark matter to be which might lead to those results.<br /> <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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docm

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They can't even test their theory until the JWST is up, so.... <div class="Discussion_UserSignature"> </div>
 
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MeteorWayne

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If an article shows up as to what they suspect dark matter to be, I'd be interested.<br /><br />I mean so far, the only evidence for it so far is gravitational effects, yet here they are predicting it's it'sown antiparticle, and what happens to the resultant energy.<br /><br />So what do they think dark matter is?<br /><br />I suppose it will come out eventually, too bad the physorg article didn't include a link to a preprint. <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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mindopener9

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Dark Matter doesn't even exist, if a new theory proves to be correct. Dark Fluid rules!!!!! <div class="Discussion_UserSignature"> We must progress and expand, or we will stagnate and die. </div>
 
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halman

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docm,<br /><br />When something falls into a gravity well, it is accelerated. Is the increase in velocity an increase in the energy in the system? If the system is constantly experiencing an increase in the total amount of energy, isn't it going to have to expand, unless mass is to became heavier? And what happens to matter which is accelerated past the speed of light while falling into a black hole? Is this the source of the energy 'jets' that we see coming out of the cores of some galaxies? <div class="Discussion_UserSignature"> The secret to peace of mind is a short attention span. </div>
 
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derekmcd

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<blockquote><font class="small">In reply to:</font><hr /><p>When something falls into a gravity well, it is accelerated. Is the increase in velocity an increase in the energy in the system?<p><hr /></p></p></blockquote><br /><br />I don't think the energy of that 2 body system is increased due to tidal forces and the conservation of energy. Take, for example, a gravity assist with a spacecraft. There is no actual energy (speed) increase of the craft relative to the planet. As it approaches the planet, it borrows some energy and as it passes by, the energy is return. Only it's velocity and speed is changed relative the sun.<br /><br /><blockquote><font class="small">In reply to:</font><hr /><p>And what happens to matter which is accelerated past the speed of light while falling into a black hole? Is this the source of the energy 'jets' that we see coming out of the cores of some galaxies?<p><hr /></p></p></blockquote><br /><br />Matter does not reach light speed approaching a black hole. Matter can not be accelerated to the speed of light. It can, however, achieve very high speeds outside the event horizon in an accreation disc becoming an ionized gas and being shot out in x-ray jets at the magnetic poles of the black hole. <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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