Astronomers have long known that a spectacular barred spiral galaxy named NGC 6872 is a behemoth, but by compiling data from several space- and ground-based observatories and running a few computer simulations, they have now determined this is the largest spiral galaxy we know of. Measuring tip-to-tip across its two outsized spiral arms, NGC 6872 … Continue reading "Behold: The Largest Known Spiral Galaxy"