Mapping the Cosmic Frontier30th October 2017
First came the talks. It was the year 2000, and scientist after scientist stood on the stage in Berkner Hall at Brookhaven National Laboratory and told us that something strange was happening to the universe. Supernova explosions from as long as seven billion years ago were not as bright as they should be. Giant sheets and filaments of dark matter were being mapped, and they did not form the structures they should.
Theorists had a model that should explain all these effects, but the results of their calculations were 120 orders of magnitude too large. In fact, it looked like the expansion of the universe was running away, not slowing down the way it should if the universe was filled with matter.
The best the physicists could do was provide a label for what was happening: Something strange called “dark energy” was wreaking havoc. They declared figuring out just what dark energy is as the most pressing problem in fundamental physics.
Then came the plans for experiments: A new satellite that would find hundreds more supernovae; a giant telescope with a camera the size of a minivan that would make a movie of the whole sky showing the positions, colors, and shapes of billions of galaxies.
Then came the dealmakers. Well-connected physicists were approaching the U.S. Department of Energy with a proposal to study dark energy.
“You know something about sensitive detectors and the electronics, don't you?” they asked us. “Would you be interested in joining a collaboration to build the world's biggest camera to study the most important question in physics?”
It didn't take more than a few nanoseconds for us to say yes. Our Lab director generously agreed to support us in the endeavor. It was the summer of 2004.
Since we were a small group at Brookhaven, we recruited talented friends from universities we'd collaborated with in the past. The pieces were now in place to begin designing.
We gathered a group of about 20 in our large conference room and ordered lots of coffee, stood in front of the whiteboard sketching, arguing, erasing. When it was finally over the basic architecture of the custom silicon chip that would read out 3.2 Gigapixels of cosmic data was on the board in green, red, and blue marker.
Smartphone cameras snapped and the group dispersed to do its work.
Now, nearly 14 years later, people working in a cleanroom in the Physics building are churning out production modules that will live at the heart of the Large Synoptic Survey Telescope (LSST) camera when it begins its survey of the skies over northern Chile sometime in 2022.
As astronomers analyze the hundreds of petabytes of images our camera will produce, new understanding of the nature of dark energy will emerge. LSST will track cosmic movements over time, providing some of the most precise measurements ever of our universe’s expansion, potentially offering clues to understanding the cosmic anti-gravity behind its acceleration.