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Length scale
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<h2 id="examples">Examples</h2> <ul><li>The atomic length scale is ℓa ~ 10−10 m and is given by the size of hydrogen atom (<i>i.e.</i>, the <a href="/facts/Bohr_radius/vvP1lghl">Bohr radius</a>, approximately 53 <a href="/facts/Picometre/Cb54mVBX">pm</a>).</li> <li>The length scale for the <a href="/facts/Strong_interaction/JjRsKcLg">strong interactions</a> (or the one derived from <a href="/facts/Quantum_chromodynamics/3cA2ctyb">QCD</a> through <a href="/facts/Dimensional_transmutation/nlfQrbdu">dimensional transmutation</a>) is around ℓs ~ 10−15 m, and the "radii" of strongly interacting particles (such as the <a href="/facts/Proton/clCjepXP">proton</a>) are roughly comparable. This length scale is determined by the range of the <a href="/facts/Yukawa_potential/TmPzXYpx">Yukawa potential</a>. The lifetimes of strongly interacting particles, such as the <a href="/facts/Rho_meson/55vNvssd">rho meson</a>, are given by this length scale divided by the speed of light: 10−23 s. The masses of strongly interacting particles are several times the associated energy scale (500 MeV/<i>c</i>2 to 3000 MeV/<i>c</i>2).</li> <li>The <a href="/facts/Electroweak/QATz4dYF">electroweak</a> length scale is shorter, roughly ℓw ~ 10−18 m and is set by the rest mass of the <a href="/facts/W_and_Z_bosons/gAncY5XV">weak vector bosons</a>, which is roughly 100 GeV/<i>c</i>2. This length scale would be the distance where a Yukawa force is mediated by the weak vector bosons. The magnitude of weak length scale was initially inferred by the <a href="/facts/Fermi%2527s_interaction/uuzvty7m">Fermi constant</a> measured by <a href="/facts/Neutron/oRCM1geb">neutron</a> and <a href="/facts/Muon/BP2fLVIR">muon</a> decay.</li> <li>The <a href="/facts/Planck_length/4o04JYdD">Planck length</a> (Planck scale) is much shorter yet – about ℓP ~ 10−35 m, and is derived from the <a href="/facts/Newtonian_constant_of_gravitation/GdQ8tcBD">Newtonian constant of gravitation</a>.</li> <li>The <a href="/facts/Stoney_units/jqTc9Rge">Stoney length</a> (Stoney scale) is shorter yet – about ℓS ~ 10−36 m.</li> <li>The <a href="/facts/Mesoscopic_scale/QKWer6fG">mesoscopic scale</a> is the length at which quantum mechanical behaviours in liquids or solid can be described by <a href="/facts/Macroscopic/NLwPDtLe">macroscopic</a> concepts.</li></ul> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Orders_of_magnitude_(length)/YzL1bHGX">Orders of magnitude (length)</a></li> <li><a href="/facts/Extragalactic_distance_scale/Xae3hVvK">Extragalactic distance scale</a></li> <li><a href="/facts/Scale_height/vErWlen3">Scale height</a></li></ul>