Spiral galaxy M81,composite image in visible (yellow),infrared (red),and ultraviolet (blue) light. The yellow centre indicates older stars,the blue areas in the spiral arms are hot,young stars,and the pink areas are lanes of dust in the spiral arms. M81 is around 12 million light years from Earth,in the constellation of Ursa Major. This image was obtained by the Hubble Space Telescope (HST,visible light),the Spitzer Space Telescope (SST,infrared),and the Galaxy Evolution Explorer (GALEX,ultraviolet) |