It's not pejorative. It's literally true. Whatever it is, it does not couple to electromagnetism; it cannot radiate or absorb light. It's not just a matter of a higher or lower frequency. The only handle we have on it (indeed, the only one we can have) is gravity. That's how it was first inferred, and that's how this map was made.
"It's not pejorative. It's literally true. Whatever it is, it does not couple to electromagnetism; it cannot radiate or absorb light. It's not just a matter of a higher or lower frequency. The only handle we have on it (indeed, the only one we can have) is gravity. That's how it was first inferred, and that's how this map was made."
It is pejorative, because "light" and "dark" carry, in all human cultures, weighted values that goe beyond, and even long precede the mundane scientific knowledge and understanding of the properties of phontonic and other energy wavelengths.
"Dark" while scientifically meaning that our human photonic receptors do not receive photon input from something, carries a deeper meaning, culturally as "dark" places are dangerous or, at a minimum at least pose some level of risk and at a maximum are "evil", bad and everything opposite of "good" (which is associated with light). Thus "dark" always carries a subjectively pejoritive value.
To say that "dark" matter does not "absorb" "light" is an error, for we do not really know that. In fact it may "absorb" light so thoroughly, as part of the attributes whereby it seems to not radiate or reflect light.
It would be more accurate and less pejoritive if the missing matter was referred to simply as "hidden"; hidden from we who do not yet have the eyes, technical or otherwise, to "see" it.