Limits RegistryPUBLIC RECORD
Limits RegistryAlcyoneus, a giant radio galaxy discovered in 2022 using data from the LOFAR radio telescope network, has jets and radio lobes spanning approximately 16.3 million light-years (about 5 megaparsecs) end to end — making it the largest known galaxy, roughly 100 times the diameter of the Milky Way. Its central galaxy itself is unremarkable; the record comes entirely from the enormous scale of its jet-powered radio lobes.
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Alcyoneus, a giant radio galaxy discovered in 2022 using data from the LOFAR radio telescope network, has jets and radio lobes spanning approximately 16.3 million light-years (about 5 megaparsecs) end to end — making it the largest known galaxy, roughly 100 times the diameter of the Milky Way. Its central galaxy itself is unremarkable; the record comes entirely from the enormous scale of its jet-powered radio lobes.
The greatest total physical extent of any known galaxy, including detected radio emission lobes.
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Permanent ID limitsregistry.com/limits/LR-LARGEST-KNOWN-GALAXY
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Limits Registry. LR-LARGEST-KNOWN-GALAXY. Largest known galaxy by size. 2026.