How to Look Back in Time

In an old experimental hall previously used for particle physics experiments, a team of French engineers are checking the filters on what will be the largest digital camera ever built. It’s October 2021, and I’m seeing the camera during its assembly at SLAC National Accelerator Laboratory in Menlo Park, California. When this high-resolution imager is finally put to work, it will give us breathtaking views of the deep universe.

The instrument is the Legacy Survey of Space and Time (LSST) Camera . The 3.2-gigapixel (3.2 billion pixel) camera will eventually be installed at the Vera Rubin Observatory on a Chilean mountaintop, where it will image half of the southern sky every three days. It will give astronomersastrophysicists, and cosmologists complete portrait of that region of the sky about once a week. “We will see dimmer objects than people have looked at before in an area on the sky,” said astrophysicist Aaron Roodman, lead scientist for camera assembly and testing. “People have done things deep, but they’ve been in tiny regions of the sky.” The new telescope will be able to look far, far into distance—and therefore the past—over a huge region.