Just in case you thought our galaxy was pretty big, it turns out that our neighbour Andromeda is huge…
The Andromeda galaxy, the most familiar of all the starry pinwheels in the sky and the Milky Way’s virtual twin, is three times the size astronomers had thought….the disc of the galaxy is actually three times larger than had been thought – 220,000 light years across, instead of previous estimates of 70,000 to 80,000.