Our Milky Way galaxy is just one part of a huge region of the Universe that includes what astronomers call a supercluster of galaxies. Now, that region of space has its own map and a name, "Laniakea." This is the Hawaiian word for "immense heaven."
Astronomers discovered that our galaxy was part of a supercluster of other massive galaxies by using the National Science Foundation's Green Bank Telescope.
We have finally established the contours that define the supercluster of galaxies we can call home," says lead researcher R. Brent Tully, an astronomer at the University of Hawaii at Manoa. "This is not unlike finding out for the first time that your hometown is actually part of much larger country that borders other nations."
Our new place in the Universe is part of a supercluster that contains 100,000 galaxies and is 500 million light years wide. That supercluster is made up of smaller local groups. Each group contains its own galaxies and clusters. And it's all connected by a cosmic web of filaments.
Laniakea Supercluster Preview from Daniel Pomarède on Vimeo.
To define our place on the map, researchers looked at how galaxies' motions affected other galaxies around them. Tully compared this to the behavior of water on Earth. Water flows in certain directions on Earth. For example, water knows, even on land, which way is downhill.
"Instead of downhill valleys that attract water flow, our Universe has something called the 'Great Attractor.'" says Tully. "This region serves as a gravitational focal point, influencing the motion of galaxies in the supercluster."
In their study, researchers clearly defined a supercluster for the first time. They mapped over 8,000 galaxies around the Milky Way and figured out where clusters separate. In the water example, this would be areas that flow into a different "valley" than other galaxies in the region. They discovered that the Milky Way sits on the outskirts of the supercluster now known as Laniakea.
Superclusters are the largest known structures in the Universe. However, it's possible that our supercluster is part of an even larger structure. Researchers hope to eventually look even further than Laniakea and chart tens of thousands of more galaxies and their regions of the Universe.
However, Earth has now claimed its place in the Universe, and within Laniakea.
