X is a hard letter to write about

Ana muses about the letter X and x-treme astronomy

X is like a bull's eye, marking the exact spot where the arrow or scalpel should penetrate.
It swallows accompanying letters, like the 'e' in extra.
It's the default signature for those who can't yet read or who've suffered a serious stroke.
It can be penetrating, as in X-ray.
It's a choice for beginning names of new subatomic particles, which only a few scholars understand.
Curiously,  the light from a distant black hole is brighter than that of a visible star.