On Saturday, April 25, 2020 at 5:36:01 PM UTC-6, Brent wrote: > > > > On 4/25/2020 3:33 PM, Alan Grayson wrote: > > > > On Sunday, January 6, 2019 at 12:53:52 AM UTC-7, Brent wrote: >> >> To measure small things you need comparably short wavelengths. If you >> make a photon with a wavelength so short it can measure the Planck >> length it will have so much mass-energy that it will fold spacetime >> around it and become a black hole...so you won't be able to use it to >> measure anything. >> >> Brent >> > > I understand the BH issue. But suppose we want to measure the diameter of > a proton and use photons of large wave length, say of radio frequency. If > we're looking for a shadow on a screen, why won't the large wavelength > leave a discernible shadow of the proton? Or is it the back scattering we > look for? Same question; that is, why must the impinging wavelength be of > comparable length to measure a physical object of the same approximate > length? TIA, AG > > > If you use a wavelength that is not shorter than the dimension you're > measuring your resolution is just the wavelength. The waves refract around > the object so you can't resole edges. > > Brent >
That's what I was thinking; you get diffraction on the edges, which are then not well defined. But suppose you use a short enough wavelength to measure the diameter of a proton. How can get an actual measurement, given the tiny diameter? How is it done? AG -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/6e135412-ba7d-4422-8f6b-9ba42addcb52%40googlegroups.com.
