The only *reason* that anyone gets a tattoo is because they think it'll look cool. - My ex-girlfriend's uncle
People ask me about my tats.
I got the fundamental constants done on my right forearm and did them in my own handwriting.
Physics constants are a good tattoo to get because they won't change. It's helpful to remember what domains of knowledge actually qualify as so true that you can get them tattooed on your body. There are very few of these, and physics and math are the real rigorous contenders.
There are seven fundamental physics constants that are exactly defined 2019 redefinition of SI base units
Euler's equation ties together the relationship between the three OG math constants: e, i, and pi.
Electromagnetism relies on mu and epsilon (TODO - type these weird characters). There's also the masses of the elctron, proton, neutron, and the gravitational constant, G.
And there are a few constants used all the time derived from the others - h-bar, the fine structure constant alpha, and the Stefan-Boltzmann constant.
Finally, we get down to brass tacks with Planck's constants, which define the smallest meaningful units of length, time, mass, temperature, and charge.
