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Author Topic: Space Thread  (Read 130200 times)

Akura

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Re: Space Thread
« Reply #3000 on: April 14, 2019, 08:15:26 am »

On the same subject, almost... KSP plane - make it bigger, loads of engines, a lot of wing, and don't forget the wheels.

That looks like they welded two planes together at the wingtip.
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wierd

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Re: Space Thread
« Reply #3001 on: May 01, 2019, 03:47:59 am »

My hokum senses are tingling!!

https://www.livescience.com/65344-quantum-vacuum-gamma-rays.html

Faster than light charged particles?  MASSIVE particles!?  No no no no no no.

Oh, what's that? Local spacetime is distorted so that photons cant travel at the same speed?  But that is still the local spacetime medium, not a photon exchange medium! How?  What?
« Last Edit: May 01, 2019, 03:50:17 am by wierd »
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Kagus

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Re: Space Thread
« Reply #3002 on: May 01, 2019, 05:23:05 am »

Aren't particles by definition massive? It's not much mass, but I thought particles were the ones with the physical bits.


Then again, I am utterly without an education, so I probably shouldn't be talking.

wierd

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Re: Space Thread
« Reply #3003 on: May 01, 2019, 05:48:27 am »

Photon is a point particle (that can also behave as a wave, but meh) that is massless. 
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Arx

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Re: Space Thread
« Reply #3004 on: May 01, 2019, 08:04:41 am »

Oh, what's that? Local spacetime is distorted so that photons cant travel at the same speed?

I am the first to admit I'm not a quantum physicist, nor did I especially enjoy my quantum-adjacent courses, but I've read through the paper and I'm pretty sure that's never claimed. What is claimed is that strong magnetic fields polarise quantum fluctuations (not new), that polarisation causes an effect on protons similar to that of a dielectric medium (i.e. reduction of phase velocity) (not new), and that as a result it seems reasonable to claim that a charged particle in a vacuum can, supposing it is within a powerful enough magnetic field, emit Cherenkov radiation the way one would expect in a dielectric medium (a completely logical follow-on to the previous statements).

Nowhere does it posit that c is exceeded, nor that this really changes anything other than presenting a potential explanation for some currently murky astronomical gamma ray emissions. Especially, the result you seem to be taking particular offense to (light in a vacuum behaving as though in a dielectric medium) seems, although I could be wrong here because I'm reading papers I barely understand, to be decades old:

Quote from: Markland and Shukla, 2006
It has  been suggested  that the nontrivial refractive  index  due  to  photon–photon  scattering could induce a lensing effect in the neighbourhood of a magnetar (Shaviv et al., 1999).

The general interactions between photons and nonlinear QED effects in vacuums have been researched since the 70s or before, too.

I'm sure if I hunted more I could find older results or understand the topic better, but like I said, I don't particularly care for quantum.

Oh, and as for

How?  What?

The paper is on arxiv and presumably, to a physicist in the field, explains those quite adequately.
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