Making Photons Pt 2

Previously, we covered the long wavelengths of the electromagnetic spectrum, from radio waves to visible waves, from hundreds to billionths of a meter.  This is where things can start to literally get painful.  Time for a bit of the ol' ultraviolet. [I am not sorry for doing that]

UV light, as you might expect, has a higher frequency (shorter wavelength) than visible light, ranging from 10-400nm.  This takes more energy than visible light, but is created in similar fashion - excited electrons in atoms or molecules dropping states.  Because of the higher energy requirement, these drops simply must be larger than those for visible light.

Fun Fact: high-energy UV light can literally break your DNA.  FUN!

X rays!  Now these sci-fi celebrities know how to do some damage.  Ranging from .01-10 nm, these still use electrons, but in a slightly different way.  Recall how the difference in energy of excited states is equal to the energy of the photon.  In order to make x rays, first accelerate the holy hell out of some free (unbound) electrons, then smash them into nuclei [note: at this size, nothing actually ever touches anything - 'smashing' thus implies getting them really really close together until their repulsive forces push them apart].  This sudden negative acceleration produces photons, like not wearing your seat belt in a car crash and flying through the window.  This is called bremsstrahlung, German for 'braking radiation'.

X rays are capable of ionizing - completely removing - an electron from the inner shell of an atom.

Our final stop through the EM spectrum is with gamma rays, the highest-energy photons*.

*By which I mean naturally-occurring photons.  The difference between x rays and gamma rays today is a matter of source: x rays are made by the behavior of electrons.  Gamma rays are generated right in the nucleus itself, by excited or unstable protons.  We can make them right here on Earth with things like radioactive nuclei, and they're a staple of all of the most violent and powerful events in the universe.

So, have you noticed?  For radio waves we rapidly changed the current of electrons, for microwaves, we rapidly changed the magnetic field.  Infrared is generally created by vibrating molecules (coated in electrons),  with visible light created by de-exciting electrons, similarly to ultraviolet light.  X rays are produced in extreme interactions between electrons and others, or with nuclei, and gamma rays come from the heart of the atom itself.

It's all electrons! (*ahem* and protons) You need an electric charge (positive or negative) to create electromagnetic fields.  You also need charge to detect these fields.  With no charge, you become completely blind to any and all electromagnetic processes.  What a sad state of affairs that would be.