Astronomers have spotted the largest known spiral galaxy - by accident ...
A team was looking through data from the Galaxy Evolution Explorer (Galex) satellite for star-forming regions around a galaxy called NGC 6872.
But they were shocked to see a vast swathe of ultraviolet light from young stars, indicating that the galaxy is actually big enough to accommodate five of our Milky Way galaxies within it.
The find was reported at the American Astronomical Society meeting in the US.
Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 spans more than 522,000 light-years, making it more than five times the size of our Milky Way galaxy.