UCSC prof’s work helps powerful new Vera C. Rubin Observatory capture secrets of deep space

UC Santa Cruz physics professor Steve Ritz had goosebumps the first time he saw a photo dubbed the “Cosmic Treasure Chest” produced this spring by the new Vera C. Rubin Observatory – both because of its beauty and the potential discoveries researchers will make from the data within it. 

The observatory uses the largest camera ever built – the size of a small car – with the fastest-moving telescope of its size on a mountaintop in central Chile, an area known for its clear skies. The “Cosmic Treasure Chest” photo is made up of 1,100 images and shows about 10 million galaxies from the Southern Hemisphere’s sky, appearing as glowing globs in bright reds, blues and white.

After the observatory’s first photos were made public this month, Ritz was amazed, relieved and emotional about all the effort so many people put in to reach this moment. He led the team that produced the images for the “First Look” event after first joining the observatory project in 2013. 

“I like to say these projects are almost impossible because if it were easy, you didn’t reach far enough,” he said.

Ritz said photos like the “Cosmic Treasure Chest,” which show such a vast amount of space with precision, are exactly what the telescope’s designers have sought to do for over two decades. For the first time, astronomers have a telescope that can detect real-time changes in the sky and observe faint objects deep in the universe in ultra-high definition. Ritz, who is one of the many UCSC researchers to have worked on the project, says these capabilities will allow for unpredicted discoveries and events, and questions never considered.

“The whole thing was designed for regions like that, to be able to explore deep into the universe, to see things that are really, really far away,” he said last week, sitting in front of his UCSC office computer displaying the image. “It was designed to see the whole sky and to look for lots of changes and to look at galaxies far, far away, as they say.” 

The Vera C. Rubin Observatory is a $810 million project funded by the U.S. Department of Energy and the National Science Foundation. Once it officially launches later this year, it will begin its primary function: to repeatedly scan the sky for 10 years from the Southern Hemisphere to create an ultrawide time-lapse of the universe, called the Legacy Survey of Space and Time. 

Originally called the Dark Matter Telescope, it was renamed in 2019 by an act of Congress after American astronomer Vera C. Rubin, who uncovered evidence for the existence of dark matter by observing the movement of galaxies and advocated for gender equality in science. (Dark matter doesn’t give off light, hence its name, and prevents galaxies from drifting apart. Despite decades of research, scientists still don’t know what dark matter is made of.)

UC Davis professor Tony Tyson, whom Ritz calls “the parent of the thing,” was part of the first group of astronomers and astrophysicists who dreamed up a telescope to better observe and understand dark matter and dark energy. Tyson, who also led efforts to raise money for the project, is the observatory’s chief scientist. After development of the telescope advanced, scientists realized the telescope they were designing would uncover much more than just observations of dark matter. 

The telescope is designed to look into four areas broadly: understanding dark matter and dark energy, cataloguing the makeup of the solar system, observing the changing sky and creating a map of the Milky Way. For example, scientists want to know how the solar system and Milky Way formed, and why some objects in the universe change over short time scales. 

Originally from New York, Ritz came to UCSC in 2009 and teaches introductory physics courses including “physics for everyone.” A distinguished professor of physics, he’s a member and former director of the Santa Cruz Institute for Particle Physics. Before UCSC, he was in Maryland, where he worked at Goddard Space Flight Center as project scientist for the Fermi Gamma-ray Space Telescope, which is still in orbit. 

Ritz began working on the Rubin observatory in 2013 as camera project scientist and later in 2022 as project scientist for the observatory’s construction – roles he said were similar. He’s been paired up with a project manager “to make sure the thing is successful” and is finishing soon. 

“One of the jobs of the project scientists is to look ahead to find opportunities, to make sure the science performance is protected,” he said. “And to even find opportunities for doing even better, and to make sure that’s all connected with all the science that the whole thing wants to do.”

In his role, for example, he decided that rather than having one company make sensors for the camera, which could be simpler than working with two different vendors, he realized that having two companies would be better, and faster. 

“You could argue it’s better to just be able to pick one company, but it takes time for them to make these very specialized sensors,” he said. “They’re not something you just go to Best Buy for.” 

This week, Ritz is at the observatory in Chile with his colleagues as they undergo a regular review by the National Science Foundation and the U.S. Department of Energy. The agencies have outside experts who run a panel asking the observatory’s team questions to make sure everything is on track. 

Ritz estimates that the telescope will be ready to launch in late fall, when it will begin the 10-year survey. For the first two years data is collected, the information will be available to U.S. and Chilean scientists, and other scientists with in-kind contributions and agreements with the U.S. agencies. 

Ritz said the data is limited to primarily the U.S. and Chile the first two years because of how much it cost those countries to build and run the project. Following those two years, the data will become public globally. 

People who aren’t professional scientists will also have opportunities to work with professional scientists who have projects using Rubin data through the Citizen Science Program in addition to a range of lessons and programs for educators. Ritz emphasized that one of the main missions is to engage the public to explore the universe. 

“That was something that was built in from the beginning,” said Ritz. “And, every school can have their own galaxy if they want.”

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