Sometime in May or June, as the southern hemisphere winter sets in beneath the skies of the Chilean Atacama desert, the Vera C. Rubin Observatory will open its dome and the largest digital camera in history will capture its first science-grade image of the cosmos. Under the Atacama’s pristine and stable atmosphere, Rubin will begin a 10-year mission to provide humanity with an extraordinary new vision of the cosmos with the Legacy Survey of Space and Time (LSST).
Twenty-four years in the making, the observatory is a brand new astronomical facility. To get a sense of what I mean when I say it will have the largest digital camera in history, imagine if the camera on your mobile phone were over 1.5 metres wide, 1000 times more powerful and weighed as much as a car. That’s LSSTCam, which (as of time of writing) is expected to capture photons from the Atacama sky for the first time on New Year’s Day. It is paired with one of the largest telescopes ever built – 8.4 metres across – giving us a brilliant new instrument for night sky observation.
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The fundamental science mission of LSST is to scan the entire night sky every few days, returning a time-lapsed high-definition recording of the universe. Using this data, the thousands of scientists around the world working on this project will be able to investigate questions of great cosmological significance. For example, as a member of the , I am excited to get high-quality data about our galaxy, the Milky Way, and its local galactic group.
You might wonder what looking at the local group could possibly have to do with understanding dark matter, which is a phenomenon we can’t see with a telescope. There are a few exciting science opportunities here. Rubin will search for evidence of extremely faint satellite galaxies that are gravitationally bound to the Milky Way and its neighbouring galaxy Andromeda. Understanding how many such galaxies there are in the neighbourhood will help us get a robust sense of which objects are gravitationally affecting our galaxy and its dark matter halo.
Rubin will also capture information about more than 10 billion stars and the dust that surrounds and produces them. This information will provide new insights into the structure and evolution of our home galaxy and its neighbours. Because we expect most, if not all, galaxies to be suffused with dark matter, we know that how stars are moving, where they are and even their formation rate is shaped by the presence of dark matter.
It will have the largest ever digital camera – imagine if your phone's camera were over 1.5 metres wide
Better understanding what we can see allows us to reverse engineer the behaviour of what we can’t see. This dataset will build on previous sky surveys, so when we talk about 10 years of data, we are really talking about 10 years of higher-definition data supporting a multi-decade mission to map our local galactic neighbourhood.
The beginning of scientific work with the Vera C. Rubin Observatory is a reminder that Earth is a multigenerational spaceship, filled with incredible scientific missions that take a long time to complete. In the 1960s, when Vera Rubin and Kent Ford began collecting the data that ultimately convinced the global astrophysics community that dark matter truly existed, the precursors to charge-coupled devices (CCDs), which behave like digital film, were in development at Bell Labs, New Jersey. At the time, it was unimaginable that we might one day have people-sized CCD cameras. Yet that is exactly what LSSTCam is.
At the time of Rubin and Ford’s work, scientists had no idea that the expansion of space-time was picking up speed. Today, understanding the nature of cosmic acceleration and whether it is caused by something called dark energy is a major driver of research in cosmology. The international collaboration that forms the LSST community will be working across borders to try to understand the fundamental structure of space-time.
I couldn’t be more excited for the Vera C. Rubin Observatory as a technological feat and a science mission. As someone who was first inspired to think about dark matter by a question from Rubin herself, I love being part of a project that honours her memory by furthering her endeavour to understand galaxies. I am also grateful that the Rubin community makes an effort to understand itself through an international lens. Since the project is hosted by the people of Chile, translating key documents, from our science glossary to our outreach materials, into Spanish has been a priority.
Like the European particle physics facility CERN, Rubin is offering an example of peaceful global cooperation. This is the kind of humanist vision we need to hold on to as we enter 2025.
Chanda’s week
What I’m reading
I’m enjoying Koji Suzuki’s sci-fi novel Edge.
What I’m watching
I’m pretty excited to watch season two of Silo, a sci-fi show about a working-class woman engineer.
What I’m working on
Digging into a new project on the effects of dark matter in the early universe.
Chanda Prescod-Weinstein is an associate professor of physics and astronomy, and a core faculty member in women’s studies at the University of New Hampshire. Her most recent book is The Disordered Cosmos: A journey into dark matter, spacetime, and dreams deferred
