Most interstellar matter is too cold to be observed optically. In which part of the electromagnetic spectrum might its radiation be detected?

Question

Quizplus · Accepted Answer

Interstellar matter, being cold, emits radiation primarily in the infrared part of the electromagnetic spectrum. This is because objects at lower temperatures emit most of their radiation at longer wavelengths, which are in the infrared range.

Most Interstellar Matter Is Too Cold to Be Observed Optically