Department of Energy

Dark Energy Cam: Fermilab Expands Understanding of Expanding Universe

March 12, 2012

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Researchers at Fermi National Lab team stand beside the 570-megapixels, five-ton Dark Energy camera, which will be capable of measuring the expansion of the universe - and developing better models about how dark energy works. | Photo by Reidar Hahn, Fermi National Lab

Researchers at Fermi National Lab team stand beside the 570-megapixels, five-ton Dark Energy camera, which will be capable of measuring the expansion of the universe - and developing better models about how dark energy works. | Photo by Reidar Hahn, Fermi National Lab

Breaking down is often an essential part of building up. Athletes break down their muscles during hard workouts to build stronger ones for better performances. Construction workers tear down ruins to build skyscrapers. And scientists find flaws in accepted theories and use them to build even better models of how nature actually works.

“Creative destruction,” is the term that Joseph Schumpeter coined for the process, which he applied to economics. But scientists at Fermi National Accelerator Laboratory (Fermilab) are applying it in a rather more literal way through their work in leading the Dark Energy Survey (DES).

The Dark Energy Survey is "designed to probe the origin of the accelerating universe and help uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion with high precision.”

Let’s back up and break that down. About 80 years ago, an astronomer named Edwin Hubble discovered that the universe was expanding. And for the next 50 years or so, scientists figured – based on well-founded evidence – that gravity would gradually slow the expansion down.

However, in 1998, two independent teams of scientists, one of which was led by Dr. Saul Perlmutter of Berkeley National Laboratory, announced that instead of slowing, the universe was actually expanding at an accelerating rate. That made precisely no sense – the equivalent of seeing a shot basketball slowly rise to the top of its arc . . . and then shoot rapidly into the sky – but it seems to be the way the universe began working some five billion years ago.

Dr. Perlmutter and two others won the 2011 Nobel Prize in Physics for this discovery of the accelerating expansion of the universe, which scientists believe is being driven by a mysterious force called dark energy. And that’s what the Dark Energy Camera (DECam) is designed to examine.

The DECam is the largest digital camera ever built, with 570 megapixels, mirrors about three feet across, and a weight of between four and five tons, which puts it in the range of an elephant. DES researchers – yes, Dr. Perlmutter is on the team – recently began shutting down the high-powered Blanco telescope at the Cerro Tololo Inter-American Observatory in Chile, so they can install it.

When it sees first light later this year, the camera won’t examine dark energy itself. Rather, it will look at dark energy’s effects on large scales, on the galaxies racing away from one another across space and time. That will allow the members of the Dark Energy Survey team to make their most accurate picture of the universe yet, and perhaps poke a few holes in today’s popular theories along the way.

That’s the exuberant and sometimes painful process of creative destruction at work. And that’s an essential element of the efforts of the Energy Department's Office of Science: Providing world-class tools to researchers peering deeply into the darkness, breaking down incomplete theories and building a better understanding of our world and universe.