Andromeda seen in a new light

The new infra-red image of the Andromeda galaxy (top) shown above the well known visible image. © NASA

The Andromeda galaxy is one of the closest and most studied galaxies outside our own galaxy, the Milky Way. In many ways, it is thought to be very similar to our galaxy and is therefore of particular interest to astronomers. Now, thanks to NASA, we can see the whole of Andromeda in infra-red light, and in much greater detail than has been possible before. The top image was made by joining together 11,000 separate images taken over 18 hours using NASA's Spitzer Space Telescope. Now that is alot of cutting and pasting!

When we look at stars or even everyday objects, our eyes see them in the optical or visible part of the electromagnetic spectrum. Infra-red radiation is a special kind of "light" emitted by warm objects, but which our eyes cannot see. On Earth, infra-red cameras are used to search for people who are lost, because our warm bodies appear to shine more brightly on such cameras. Other types of electromagnetic radiation include radio waves, x-rays, ultraviolet light and gamma rays. By looking at the Andromeda galaxy in the infra-red, we can see vast dust structures and some stars that cannot be seen in normal 'visible light' pictures.