The Vera C. Rubin Observatory will transform our understanding of the cosmos

ESA, NASA, K. SHARON/TEL AVIV UNIVERSITY AND E. OFEK/CALTECH

With its capacity to detect faint objects, Rubin is expected to increase the number of known asteroids and comets by a factor of 10 to 100. Many of them will be objects larger than 140 meters in diameter with orbits that pass close to Earth’s, meaning they could threaten our world. And it will catalog 40,000 new small icy bodies in the Kuiper Belt, the largely unexplored region beyond Neptune where many comets are born, helping scientists better understand the structure and history of our solar system.

“We’ve never had such a large telescopic image so wide and so deep.”

Anais Möller, Astrophysicist, Swinburne University of Technology, Melbourne, Australia

Outside our solar system, Rubin will see the telltale lights that signal the passage of exoplanets in front of their parent stars, causing them to dim briefly. It should also find thousands of new brown dwarfs, faint objects between the size of planets and stars, whose positions in the Milky Way may provide insight into how the environments in which stars are born affect the size and type of objects that can form there. It will discover never-before-seen dim dwarf galaxies orbiting our own and closely observe star streams, the remnants of star trails left behind after the Milky Way tore apart other, similar galaxies.

The facility will also look far beyond the Milky Way, cataloging some 20 billion previously unknown galaxies and mapping their positions in the long filamentary structures known as the cosmic web. The gravitational force of dark matter directly affects the overall shape of this network, and by examining its structure, cosmologists will gather evidence for different theories of what dark matter is. Rubin is expected to observe millions of supernovae and determine their distance from us, which is a way of measuring the rate at which the universe is expanding. Some researchers suspect that dark energy—which causes the cosmos to expand rapidly—may have been stronger in the past. Data from more distant, and therefore older, supernovae could help support or disprove such ideas and potentially narrow down the identity of dark energy.

SPENCER LOWELL

By almost all accounts, Rubin will be a monumental project, explaining the near-universal desire among those in the field to see it finally up and running.

“We have never had such a large telescopic image so wide and so deep,” says Möller. “It’s an amazing opportunity to really pinpoint things that are changing in the sky and understand their physics.”

Adam Mann is a freelance space and physics journalist based in Oakland, California.