9 Ultraviolet

You might notice that missing from the list of images is the ultraviolet region of the electromagnetic (EM) spectrum. Ultraviolet radiation begins just past the blue/violet region of the visible (optical) spectrum, and ends when X-rays take over. The boundaries between named regions can get a little blurred, especially if the broad-band regions (example: infrared) are further broken into sub-regions (example: near infrared and far infrared). One reference on EM waves says microwaves extend from about 1 millimeter to about 10 centimeters. In that case, the map of molecular hydrogen would fall into the category of microwaves.