Astronomers just found the largest galaxy ever

A new paper describing the galaxy's discovery has been accepted for publication in the journal Astronomy & Astrophysics.

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Researchers from Leiden University have discovered the largest known radio galaxy ever, about 16.3 million light-years in length, or about five megaparsecs. The giant plumes of plasma visible in the photo, visible in bright orange, glow with radio light and are likely the result of a supermassive black hole at the center of the galaxy. The black holes at the center of a galaxy can create two jet streams, ejecting material out of the galaxy and emitting radio waves, creating scenes like those seen here.

These kinds of astronomical observations are only viewed from Earth, and hence they do not contain any depth information. Therefore, it is difficult to know how far the galaxy's sphere of influence expands in the third dimension. Still, at more than 16 million light-years across, the radio galaxy is comparable to one hundred Milky Ways in a row.

The massive structure has been named Alcyoneus, after the son of Ouranos, the Greek primordial god of the sky. It is located three billion light-years away and yet is as large in the sky as the moon. Astronomers are unsure how it reached this size, as its black hole and stellar characteristics seem to be less than average compared to smaller galaxies.

You can read more from the paper here.