[HN Gopher] Beautiful nebula, violent history: Clash of stars so...
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       Beautiful nebula, violent history: Clash of stars solves stellar
       mystery
        
       Author : wglb
       Score  : 16 points
       Date   : 2024-04-12 00:55 UTC (1 days ago)
        
 (HTM) web link (phys.org)
 (TXT) w3m dump (phys.org)
        
       | denton-scratch wrote:
       | The authors don't say what the source of magnetism is, nor why
       | the merger triggered it.
       | 
       | Is it because of rotation, caused by the two stars spiralling in
       | towards each other?
       | 
       | But thinking about it, I don't know why a spinning blob of molten
       | iron should result in a magnetic field; if there's magnetism,
       | there should be electric current, and I don't know why a star
       | merger should result in a current. In fact, apparently I don't
       | know why either the Sun or the Earth has a magnetic field.
        
         | pfdietz wrote:
         | It's a common phenomenon in astrophysics for rotating objects
         | to amplify seed magnetic fields, in something called "the
         | magnetorotational instability". This is the source of strong
         | magnetic fields in accretion disks that form jets from
         | accreting black holes, neutron stars, and protoplanetary
         | systems.
         | 
         | https://en.wikipedia.org/wiki/Magnetorotational_instability
        
           | denton-scratch wrote:
           | Thanks - I only just realized I didn't understand this, when
           | I thought about it. I'm rather gratified that the answer
           | isn't simple and obvious; I didn't understand it because it's
           | beyond my intellectual capacity, not because I'm ignorant,
           | and I think that's an OK excuse.
        
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