Particle physicists set to invade the Dark Side.

Fermilab looks to the heavens.

Tom Diehl stretches his arms out and says, with relish: “It’s the biggest phenomenon in the universe and we don’t have a clue what it is!”

That pretty much sums up our situation with respect to dark energy, that mysterious thingamajig* that is thought to be causing the universe to expand at an ever-faster rate (as opposed to an ever-slower rate, like cosmologists once expected).  When dark energy was first reported in 1998, it was soon recognized as the biggest discovery in a generation.  But, as Diehl suggests, no one really knows very much about it.

This is not news. What is new is that some astronomical hardware tailor-made to study dark energy is now jumping off the drawing board and into reality.  And it’s happening at Fermilab, a place that is better known for looking at the smallest phenomena in the universe instead of the biggest.

Diehl himself is a living example of this shift. He’s a high energy physicist associated with “DZero”, one of the two main experiments at Fermilab that discovered the top quark in the early ‘90’s.  He’s always liked astronomy (ever since he helped run a planetarium at his undergraduate college in Maine) but he didn’t expect astronomy to reach out and grab him at Fermilab.  Now, with the leading edge of collider physics shifting to the Large Hadron Collier in Europe, researchers at Fermilab are searching for new ways to stay in business, and dark energy certainly fits the bill.

The Fermilab contribution is the Dark Energy Camera, which Diehl and his colleagues have just started building. Earlier today I watched as technician Michelle Jonas deftly assembled a CCD chip that will probably find it’s way into the completed camera (the chips have to audition to get in).  She’ll be working on making chips like this for the better part of the year, to create a camera that will ultimately deliver 512 Megapixel-sized images of the night sky (where 10 Megapixels is common for a household point-and-shoot). 

Meanwhile, in a nearby room, a large vacuum chamber serves as a prototype and for the one that will ultimately house the camera.  Why a put a camera in a vacuum?  Because it needs to be cooled to around -100°C to keep the signal to noise ratio up.  If the camera isn’t in a vacuum it will soon be encased in ice, as moisture in the air freezes around it.

When it’s completed, around the end of 2010, the camera will be shipped down to Chile and attached to the 4-meter Blanca telescope on Cerro Tololo. There it will survey distant galaxies, clusters and supernovae in an effort to accurately measure the effect dark energy is having on everything around us. By then the giant Tevatron accelerator that keeps most of Fermilab’s scientists employed will have been shut down.  With the Dark Energy Camera on line, at least a few of them will be looking upward instead inward.  The good news is that the universe presents tantalizing questions in every direction.

*I say THINGAMAJIG in recognition of the fact that dark energy is too poorly understood to categorize with a common noun.  It’s not a FORCE per say or a PARTICLE or even an ENTITY.  It may be a QUALITY of spacetime… but then again, maybe not.  It is most certainly a CONUNDRUM to science writers, who generally like using nouns whenever possible.  It’s yet another case where the universe seems specially designed to breakdown the laws of coherent communication.  You gotta love it!

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