Sea of stars. This vast, colourful portrait of our neighbouring galaxy, Andromeda, is a mosaic of more than 600 images that took the Hubble Space Telescope a decade to capture. Zooming in on different sections reveals millions of individually resolved stars, giving the galaxy an almost grainy appearance. Stars in the central part of Andromeda are relatively old and yellowish in colour, whereas younger, blue stars are found in the outer rim.
NASA, ESA, B. Williams (University of Washington)
