ScienceShot: Mirrors of the Milky Way

Our home galaxy isn’t as unique as we thought. As galaxies go, the Milky Way is fairly typical. What makes it unusual are its two satellite galaxies, the Large and Small Magellanic Clouds, which are each less than one-hundredth the Milky Way’s mass and are about 160,000 and 200,000 light-years away, respectively. Now, a new survey reported in Monthly Notices of the Royal Astronomical Society reveals that having satellite galaxies isn’t so unusual after all; among galaxies between one-half and twice the size of the Milky Way, as many as 0.4% have two companion galaxies at least the size of the slightly-less-massive Small Magellanic Cloud. Of the two galaxy systems found that are most like the Milky Way and our companions, the closest match is GAMA202627 (image above), a spiral galaxy (within the large red oval) and its two satellite nebulae (within yellow ovals), a group that lies in the constellation Hydra. So much for being alone in the universe.

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