IT MAY not be stamped in your passport, but everyone on Earth is now officially a citizen of Laniakea.

That is the name scientists have given the gigantic super-cluster of galaxies that contains our Milky Way. The word means "immeasurable heaven" in Hawaiian - an appropriate description for a structure 500 million light years across that contains 100,000 galaxies and a hundred quadrillion suns.

Laniakea itself forms just one corner of the observable universe. Scientists have long-known that galaxies are not distributed randomly but congregate together in clusters.

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Dr Brent Tully, from the University of Hawaii in Honolulu, led the team of scientists that mapped the super-cluster's boundaries from measurements of the velocities of local galaxies.

They wrote in the journal Nature: "We define a supercluster to be the volume within such a surface, and so we are defining the extent of our home super-cluster, which we call Laniakea."