Of course to aliens we are the aliens! And if they thought that the male and female were embodied in the personhood of a Trump and a May they may just as well ****** off back to their own solar system with gruesome tales of our planet at present.

Basic rules

A surd is a square root which cannot be reduced to a whole number.

Computing the eigenfrequencies of beams, or reciprocal lattice vectors & hence in various Fourier transforms. In this case, exact form is required, decimal expansion will not do. For the beam example, a numerical value can be computed for a given set of parameters, but if you want to know that frequency for *any* set of parameters, you need to know how to hand surds.

i think that the alien 'aliens" had somehow not computed the eigenfrequencies of beams, or reciprocal lattice vectors  and thus landed themselves on the earth in this absurd manner.