This awesome video, courtesy of the European Space Agency, takes us through the optical, ultraviolet, microwave, and infrared wavelengths to reveal our neighboring galaxy Andromeda in quite literally every possible light.
Four telescopes teamed up to create this particular image - the Planck space telescope for microwaves, the XMM Newton satellite for ultraviolet, the Herschel probe for infrared, and a telescope down on the ground for the optical wavelengths that we're familiar with. Here's an explanation from the ESA of the various processes that went into creating this video:
Starting at the long wavelength end, the Planck spacecraft collects microwaves. These show up particles of incredibly cold dust, at just a few tens of degrees above absolute zero. Slightly higher temperature dust is revealed by the shorter, infrared wavelengths observed by the Herschel space telescope. This dust traces locations in the spiral arms of the Andromeda Galaxy where new stars are being born today.
The XMM-Newton telescope detects wavelengths shorter than visible light, collecting ultraviolet and X-rays. These show older stars, many nearing the end of their lives and others that have already exploded, sending shockwaves rolling through space. By monitoring the core of Andromeda since 2002, XMM-Newton has revealed many variable stars, some of which have undergone large stellar detonations known as novae.
Ultraviolet wavelengths also display the light from extremely massive stars. These are young stars that will not live long. They exhaust their nuclear fuel and explode as supernovae typically within a few tens of millions of years after they are born. The ultraviolet light is usually absorbed by dust and re-emitted as infrared, so the areas where ultraviolet light is seen directly correspond to relatively clear, dust-free parts of Andromeda.