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 more than 140 meters in diameter with orbits passing near Earth’s, meaning they could threaten our world. And it will catalogue 40,000 new small icy bodies in the Kuiper Belt, a largely unexplored region beyond Neptune where many comets are born, helping scientists better understand the structure and history of our solar system.
“We have never had such a big telescope imaging so wide and so deep.”
Anais Möller, astrophysicist, Swinburne University of Technology, Melbourne, Australia
Beyond our solar system, Rubin will see telltale flickers that signal exoplanets passing in front of their parent stars, causing them to briefly dim. It should also find thousands of new brown dwarfs, faint objects between planets and stars in size, whose positions in the Milky Way can 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 look closely at stellar streams, remnant trails of stars left behind when the Milky Way tore other, similar galaxies apart.
The facility will also look far outside the Milky Way, cataloguing around 20 billion previously unknown galaxies and mapping their placement in long filamentary structures known as the cosmic web. The gravitational pull of dark matter directly affects the overall shape of this web, and by examining its structure, cosmologists will glean evidence for different theories of what dark matter is. Rubin is expected to observe millions of supernovas and determine their distance from us, a way of measuring how fast the universe is expanding. Some researchers suspect that dark energy—which is causing the cosmos to expand at an accelerated rate—may have been stronger in the past. Data from more distant, and therefore older, supernovas could help bolster or disprove such ideas and potentially narrow down the identity of dark energy too.
SPENCER LOWELL
In just about every way, Rubin will be a monumental project, explaining the near-universal eagerness for those in the field to see it finally begin operations.
“We have never had such a big telescope imaging so wide and so deep,” says Möller. “That’s an incredible opportunity to really pinpoint things that are changing in the sky and understand their physics.”
Adam Mann is a freelance space and physics journalist who lives in Oakland, California.
