Radio: Almost every dot is a whole galaxy far beyond ours.
Microwave: The oldest light there is, from just after the Big Bang.
Far infrared: Cold dust, a few tens of degrees above absolute zero.
Infrared: Warm dust, and stars hidden behind it.
Near infrared: Stars, seen through the dust that hides them from us.
Glowing hydrogen: Hydrogen gas made to glow by young, hot stars.
Visible: The sky as our eyes would see it through a telescope.
Ultraviolet: The hottest, youngest stars.
X-ray: Gas at millions of degrees.
Gamma ray: The most violent places in the universe.