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Astronomers discover the most distant known cluster of galaxies.
Astronomers peering at the most distant parts of the Universe have found the earliest known cluster of galaxies, formed only 800 million years after the Big Bang.
In astronomy, distant objects appear red, due to shifts in their light during the expansion of the Universe. The amount of “red shift” lets astronomers determine how far away they are, and thus how long their light has been travelling before reaching us. In this case, the galaxy cluster is 13 billion light years away, meaning its light has been travelling for 13 billion years.
The ancient cluster was spotted by an international team of scientists using a trio of the world’s largest ground-based telescopes – Subaru, Keck and Gemini – all situated atop Hawaii’s 4200-metre Mauna Kea volcano.
The finding is the “world record” for the most distant known cluster of galaxies, says Hideaki Fujiwara, the staff scientist in charge of public relations at the Subaru Telescope.
But it’s more than that, he says, because the discovery shows that galaxy clusters already existed when the Universe was only 800 million years old – 6% of its present age.
The cluster, which bears the arcane name Z66OD, contains 12 galaxies. One is a giant known as Himiko, which was discovered a decade ago and named for a mythological queen in ancient Japan.
The other 11 galaxies, the scientists say, could therefore be thought of as a “Queen’s court” attending the monarch.