Finding Our Place in the Universe

Finding Our Place in the Universe

How We Discovered Laniakea—the Milky Way's Home

By Hélène Courtois

Translated by Nikki Kopelman

How a team of researchers, led by the author, discovered our home galaxy's location in the universe.





How a team of researchers, led by the author, discovered our home galaxy's location in the universe.

You are here: on Earth, which is part of the solar system, which is in the Milky Way galaxy, which itself is within the extragalactic supercluster Laniakea. And how can we pinpoint our location so precisely? For twenty years, astrophysicist Hélène Courtois surfed the cosmos with international teams of researchers, working to map our local universe. In this book, Courtois describes this quest and the discovery of our home supercluster.

Courtois explains that Laniakea (which means “immense heaven” in Hawaiian) is the largest galaxy structure known to which we belong; it is huge, almost too large to comprehend—about five hundred million light-years in diameter. It contains about 100,000 large galaxies like our own, and a million smaller ones. Writing accessibly for nonspecialists, Courtois describes the visualization and analysis that allowed her team to map such large structures of the universe. She highlights the work of individual researchers, including portraits of several exceptional women astrophysicists—presenting another side of astronomy. Key ideas are highlighted in text insets; illustrations accompany the main text.

The French edition of this book was named the Best Astronomy Book of 2017 by the astronomy magazine Ciel et espace. For this MIT Press English-language edition, Courtois has added descriptions of discoveries made after Laniakea: the cosmic velocity web and the Dipole and Cold Spot repellers. An engaging account of one of the most important discoveries in astrophysics in recent years, her story is a tribute to teamwork and international collaboration.


$24.95 T ISBN: 9780262039956 184 pp. | 5.375 in x 8 in 69 figures


Nikki Kopelman.


  • A luminous behind-the-scenes record of a two-decade astrophysical feat.


  • This identification of Laniakea is a tour de force, and Courtois' account gives it life.

    Times Higher Education


  • Earth's cosmic address recently changed dramatically when astronomers realized we're located at the edge of a supercluster of galaxies far larger than previously imagined. Hélène Courtois, a key member of this mapping endeavor, beautifully presents both the science and the captivating story behind this startling discovery.

    Marcia Bartusiak

    MIT Professor of the Practice

    author of The Day We Found the Universe, Black Hole, and Einstein's Unfinished Symphony

  • In Finding Our Place in the Universe, Courtois weaves a scintillating narrative of astronomers wrestling with the largest structures in the universe. Chock full of whimsical illustrations and stunning photographs, it is a fascinating insider's glimpse into the craft of astronomy told by one of its true luminaries.

    Brian Keating

    Professor of Physics, University of California, San Diego

    author of Losing the Nobel Prize: A Story of Cosmology, Ambition, and the Perils of Science's Highest Honor.

  • Hélène Courtois is a friendly and unpretentious guide to our part of the Universe. Using her daily work and own career to illustrate science as a way of life, this brief book recounts how astronomers measure the flow of galaxies through the universe. Her carefully assembled measurements reveal a deep mystery through lacy maps: the underlying attraction of invisible dark matter

    Robert P. Kirshner

    Clowes Research Professor of Science, Harvard University

    author of The Extravagant Universe: Exploding Stars, Dark Energy, and the Accelerating Cosmos