Island Universe

The 1965 discovery of a faint but pervasive glow of cosmic microwaves, bombarding the earth from all directions in the sky, provided decisive evidence for a violent beginning of our universe in a hot “big bang.” Six decades onward, astronomers have mapped the structure and history of the expanding universe in exquisite detail, but we still do not know why the big bang occurred, or what physics prevailed in the billionth of a second that followed or preceded it. In the early 1980s, physicist Andrei Linde proposed the “eternal inflation” scenario, which posits that our own big bang is one of many, perhaps infinitely many, with each one seeding its own bubble universe. Josiah McElheny’s installation Island Universe depicts a patch of this hypothetical multiverse, with each of its five chandelier-like sculptures embodying a cosmos birthed by its own big bang.

When astronomers look beyond the stars of our own Milky Way, they find a universe filled with other galaxies, each one a swirling collection of billions of stars orbiting in their mutual gravitational pull and surrounded by a halo of invisible dark matter. The centers of galaxies harbor black holes up to a billion times more massive than our own sun. When these black holes are fed with gas, they light up as quasars, the most luminous objects in the cosmos. Thanks to the finite speed of light, astronomers can trace the history of galaxies and quasars by using telescopes as time machines, with the most distant objects seen as they were billions of years in the past.

In each Island Universe sculpture, time increases from the big bang at its hidden center to the “present” at its outer edge. The reflective central sphere marks the epoch when the cooling universe first becomes transparent to visible light, the origin of the cosmic microwave background discovered (on our planet, in our universe) in 1965. The clusters of glass disks and spheres trace the growth and transformation of galaxies, interspersed with the rare but brilliant lamps of quasars. In one of these sculptures, Heliocentric, the evolving populations of disks, spheres, and lamps track detailed astronomical knowledge of our own universe, following a mathematical relation that maps location in the sculpture to epoch in the cosmos. But eternal inflation allows each cosmic bubble to have a distinct history and even distinct physical laws. In Small Scale Violence, a clumpy early universe leads to rapid formation of quasars and collisions that transform ordered disk galaxies into chaotic spheroids. In Frozen Structure, a high proportion of repulsive dark energy arrests the growth of galaxies almost as soon as it begins, so the universe expands but the galaxies within it age quietly. In Directional Structure, the primordial universe expands more rapidly along two of its three spatial dimensions, creating a cosmos in which the galaxies themselves lie in a vast diskprimordial anisotropy creates a cosmos in which the galaxies themselves lie in a vast disk, like a super-galactic analogue of the Milky Way’s disk of stars. In Late Emergence, the early universe is smooth, so its first galaxies are just forming at its present day, a cosmos blooming into light. The viewer wandering among these sculptures traverses the “inflationary sea,” an exponential current that sweeps the expanding bubbles away from each other so fast that they will never meet.

In a prescient 1755 essay, the philosopher Immanuel Kant first proposed that the Milky Way is a disk of stars that we see, from the inside, as a band of light on the sky. He further proposed that nebulous blobs of light visible in the telescopes of the day were themselves enormous stellar disks, seen at unfathomable distances. Kant’s “island universe” hypothesis was finally confirmed in 1923, when Edwin Hubble used the 100-inch telescope at Mount Wilson Observatory to discover variable stars in the Andromeda Nebula, a revolutionary application of a technique devised by Harvard astronomer Henrietta Swan Leavitt. If the eternal inflation hypothesis is correct, then this “island universe” description applies again on a still grander scale: the trillions of galaxies that we see today and all of the galaxies we could ever see in the future comprise only a drop in the ocean of the multiverse.

David Weinberg Distinguished University Professor and Chair, Department of Astronomy, the Ohio State University August 2024

For a more detailed description of the science behind Island Universe, see “From the Big Bang to the Multiverse: Translations in Space and Time,” in Josiah McElheny: A Prism, ed. Louise Neri and Josiah McElheny (Skira/Rizzoli Books, 2010). The essay is also available on the web at http://arxiv.org/pdf/1006.1012