ehj
ehj t1_j5ktegy wrote
Reply to I've started to animate my art to make it even more weird and this is the result by Krabonszcz
Love the colors!
ehj t1_j2t67me wrote
ehj t1_j2opwx3 wrote
Reply to A study on obese patients suggests the gut microbiome affects obesity levels. Microbial diversity decreased in obese subjects, and the reduction trend was correlated with the severity of obesity. by glawgii
So much confounding in that kind of study design. If not a randomized study, just disregard it - it's absolute junk science.
ehj t1_iue8jvz wrote
Having done research in the field of high energy radiation, I have not seen that this should be possible in practice. However if you can create a dense enough charged plasma, you can in principle reflect gamma rays. We are just not anywhere near being able to produce a plasma with a higher density than solid materials. Perhaps in some astrophysical extreme circumstances you can find something like this.
Edit: See e.g. this on the frequency below which reflection happens https://en.wikipedia.org/wiki/Critical_frequency
ehj t1_iu1hwov wrote
Reply to comment by sosodank in why can't a photon of appropriate energy enable P->N conversion? by sosodank
Momentum must be conserved, however this is not the explanation for the neutrino.
Neutrinos are part of the weak interaction. You correctly expect a positron on the right side of your reaction because of conservation of electric charge.. But why? Well conservation of electric charge is a consequence of the law of the force of electomagnetism. In radioactive decays the 'Weak' interaction comes into play and is in some ways similar to the electromagnetic force (and different in some ways and slightly more complicated). But it is similar in the way that there are also charges that must be conserved in the Weak interaction. In particular there is something called lepton number for each flavour of lepton which are the electron, muon and tauon. And this lepton number must be conserved.
But this comment on the neutrino and momentum conservation is indeed important, and it is an obvious question - why do we 'need' the neutrino. Historically we saw several types of radioactive decay and some of them (alpha and gamma) always had a fixed energy of the emitted particle e.g. gamma decay of an excited nucleus A*->A+gamma. Energy and momentum conservation of such a process where 1 particle turns into 2 predicts that the emitted particle will always have the same energy in every decay.
However for beta decays where an electron is emitted it was observed that the electron energy was a spectrum up to some upper energy - contradicting the 1 to 2 particle decay and therefore physicists postulated the existence of an additional very light particle being emitted in this decay such that the energy was split between the electron and the postulated 'neutrino' as this could explain the spectrum seen. This was how the neutrino was first discovered.
ehj t1_iu1b126 wrote
Well it actually can :) If you have a photon of the right energy (or several) you can turn a proton into a neutron+positon+electron_neutrino
see this paper which discusses this subject in the regime when absorbing several photons https://iopscience.iop.org/article/10.1088/1367-2630/abf705/meta
ehj t1_j83q7gl wrote
Reply to comment by TampaTrey in All the Way Up by The_Tree_Beard
Is a phenomenon that happens near the poles, and I dont know which city looking like this would have it.. faaake