2 ms·
Eh, kind of. It depends on the photon. A human is not transparent to visible light: if they were, we'd all be see-through. But we are substantially transparent
by adhesive_wombat 5y ago
Eh, kind of. It depends on the photon. A human is not transparent to visible light: if they were, we'd all be see-through. But we are substantially transparent to gamma rays. The same goes for baryons like protons: proton beam therapy can reach deep into humans, but alpha radiation (which is 2 protons and 2 neutrons, so not much "bigger") will be stopped by the first layer of skin.
From the an OMG particle's perspective, at that speed, due to Lorentz contraction factor of 300 billion, a human is only a few picometres across.
- MayeulC 5y agoCan the interaction also be approximated using the wavelength? E=hc/λ -> λ=hc/E -> λ=1.239/(1.4e15)=8.9e-16 μm Vanishingly small, about 900 yoctometers, or seven orders of magnitude smaller than a proton. No wonder we appear like empty space for the first few cascading reactions. Now, could dark matter just be photons with absurdly high energy?
- beecafe 5y agoNo, because dark matter concentrates around mass, which requires it to be able to be at rest to normal matter.