The name fits so well – Laniakea. It means ‘immense heaven’ in Hawaiian, and now it’s home. In the biggest sense of ‘big picture’ you can imagine.
Astronomers using the National Science Foundation’s Green Bank Telescope (GBT), among other telescopes, have determined that our own Milky Way galaxy is part of a newly identified titanic supercluster of galaxies they nicknamed Laniakea (Lah-nee-ah-KAY-uh).
The Milky Way’s always been in one gang or another. It’s a member in good standing of the Local Group, a gravitationally bound small cluster of some 54 neighborhood galaxies. It in turn, along with dozens of other clusters, are drawn by gravity to the granddaddy Virgo Cluster, which contains some 2000 galaxies 53 million light years away.
All these clusters are interconnected, linked into a web through mutual gravitational attraction. Taken together, they’re known as the Local Supercluster, and superclusters are the single biggest structures in the universe. Our Local Supercluster contains at least 100 different galaxy groups and stretches across 110 million light years.
Up till now we thought it was the biggest structure of which the Milky Way was a part. Not anymore.
R. Brent Tully from the University of Hawaii’s Institute for Astrophysics and his team studied the motions of galaxies in the Local Supercluster and discovered that we live in a MUCH bigger house than we ever thought.
By using the GBT and other radio telescopes to map the velocities of galaxies throughout our local universe, the team was able to define the region of space where each supercluster dominates. They found that superclusters are involved in a tug of war for galaxies – many are pulled into the supercluster while those near the edge are up for grabs.
By studying these streaming motions, Tully and team discovered that our historical supercluster home was itself part of a much larger supercluster I’m almost tempted to call the Local Superdupercluster (but I won’t). Doubtless the more poetic Laniakea was picked because of Tully’s Hawaii connections.
Meet Laniakea, the Milky Way’s home supercluster
“We have finally established the contours that define the supercluster of galaxies we can call home,” said Tully. He compared it to realizing for the first time that your hometown belongs to a much larger country bordering other nations (superclusters).
Not only do large galaxy clusters dominate the new landscape, but an enigmatic mass of distant galaxies called the Great Attractor is also a bona fide member.
It’s cool being part of something even bigger than we’d ever imagined. I just had a gut feeling the Milky Way needed more space.