Astronomy Picture of the Day

Explanation: How far can you see? The Andromeda Galaxy at 2.5 million light years away is the most distant object easily seen with your unaided eye. Most other apparent denizens of the night sky -- stars, clusters, and nebulae -- typically range from a few hundred to a few thousand light-years away and lie well within our own Milky Way Galaxy. Given its distance, light from Andromeda is likely also the oldest light that you can see. Also known as M31, the Andromeda Galaxy dominates the centre of the featured zoomed image, taken from the dunes of Bahía Creek, Patagonia, in southern Argentina. The image is a combination of 45 background images with one foreground image -- all taken with the same camera and from the same location within 90 minutes. M110, a satellite galaxy of Andromenda is visible just below and to the left of M31's core. As cool as it may be to see this neighbouring galaxy to our Milky Way with your own eyes, long duration camera exposures can pick up many faint and breathtaking details. Recent data indicates that our Milky Way Galaxy will collide and combine with the similarly-sized Andromeda galaxy in a few billion years.