Messier 81, also known as Bode's Galaxy, is a classic grand-design spiral galaxy in Ursa Major lying about 12 million light-years away, with a disk spanning roughly 90,000 light-years.
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Messier 81, also known as Bode's Galaxy, is a classic grand-design spiral galaxy in Ursa Major lying about 12 million light-years away, with a disk spanning roughly 90,000 light-years. It forms a gravitationally bound pair with the nearby starburst galaxy M82, the two separated by only about 130,000-150,000 light-years, close enough that their mutual gravitational interaction has visibly disturbed M82's structure and triggered intense star formation there. M81's own spiral arms are well-defined and rich in star-forming regions, wound tightly around a bright, dust-free central bulge. Because the pair fits comfortably within a single wide-field frame, M81 and M82 are frequently imaged together, offering a striking visual contrast between M81's calm, orderly spiral and M82's turbulent, edge-on starburst disk.
