A Hebrew University of Jerusalem researcher is part of an international team of astronomers that used new measuring techniques to describe our galaxy’s place in the universe. The researchers, including Professor Yehuda Hoffman from The Hebrew University’s Racah Institute of Physics, mapped our local supercluster of galaxies in new research appearing as the cover story of the prestigious journal Nature.
Superclusters are among the largest structures in the known universe. They are comprised of galaxy groups containing dozens of galaxies, and galaxy clusters containing hundreds of galaxies. These groups and clusters intersect, creating superclusters with poorly defined boundaries. A galaxy between two such structures will be caught in a gravitational tug-of-war, with the balance of the gravitational forces determining the galaxy’s motion.
By mapping the velocities of galaxies throughout our local universe, the researchers found that the galactic supercluster containing our Milky Way galaxy is 500 million light-years in diameter. They also found that it contains the mass of a hundred quadrillion suns in 100,000 galaxies. This is the first time the supercluster has been carefully mapped using these new techniques.
Led by University of Hawaii at Manoa astronomer R. Brent Tully, the team named the supercluster “Laniakea,” which means “immense heaven” in Hawaiian. The name honors Polynesian navigators who used knowledge of the heavens to voyage across the immensity of the Pacific Ocean. The name was suggested by Nawa‘a Napoleon, chair of the Department of Languages, Linguistics, and Literature at Kapiolani Community College, a part of the University of Hawaii system.
The research also helped clarify the role played by the Great Attractor, a mysterious gravity anomaly in intergalactic space that has perplexed astronomers for decades. See the video explaining the new findings.
The researcher team included Hélène Courtois (University Claude Bernard Lyon 1, France), and Daniel Pomarède (Institute of Research on Fundamental Laws of the Universe, CEA/Saclay, France).