With so many bright lights out there, it’s a veritable surprise when we remember that most of intergalactic space is utterly empty. It contains about 1 particle per cubic centimeter on average.

Amidst the cornucopia of stars and galaxies sits a distant cluster of galaxies that exhibits a very notable behavior.  RX-J2248 (named for the ROSAT X-ray telescope, with which it was discovered) lives at a redshift of 0.35 and has hundreds of red old galaxies, as well as a massive amount of dark matter.

If we zoom in (inset, lower right), we can see the effect that this large amount of matter has on its immediate surroundings and on the fabric of space-time itself. In the center of the inset lies a yellow-ish, beautifully glowing bright central galaxy; this is the hub of RX-J2248. While most of its neighbors shine with a very similar hue, others are as blue as a clear daytime sky. These blue objects are actually distant galaxies, and don’t reside very near the cluster at all. They live far behind it, farther away from us and at higher redshifts.

So how can we see these galaxies? The cluster (galaxies, dark matter and all) has distorted space time: the light will still travel in a straight line, but this straight line is now in curved space. This is similar to how lenses in your eyeglasses distort images and bend the paths of light rays. For this reason, this peculiar phenomenon is called ‘gravitational lensing.’

This image represents the shape of things to come as the Dark Energy Survey gears up to begin its five-year mission. With strong gravitational lenses like RX-J2248, with thousands of supernovae and millions of galaxies and galaxy clusters, we will have the power to explore the nature of dark energy and its impact on our universe.

Written by: Det. B. Nord [FNAL]

Image created by: Nikolay Kuropatkin & Martin Murphy [FNAL]

Sometimes, big ideas need really big machines. Here, we see a rare close-up of the Dark Energy Camera (DECam) and most of its components. Over the course of about 10 years, hundreds of scientists and engineers from institutions across the world designed, built and calibrated the major components of DECam—an optical lens barrel, a hexapod, a filter changer, a shutter, CCD sensors and control electronics (from lower right to upper left).

In the image, DECam is not yet actually on the Blanco Telescope, which is in Chile. Before being installed there, it was assembled at the Fermi National Accelerator Laboratory (FNAL) in Batavia, Illinois in a test facility. The operations team performed tests to make sure that the multiple components came together and operated seamlessly before shipping all the components to their final location at the Cerro Tololo Inter-American Observatory (CTIO). Fermilab technician Kevin Kuk works on the last elements of assembly before testing.

As we plunge into a new era of science with big data, the needs for diverse skill sets and efficient communication between many scientists becomes increasingly clear. Last century, a few people around a table could design and create an experiment in a very short time, and with it make astounding discoveries. It is unclear how often this will happen in the future: our biggest questions require so many measurements with such high precision, that we need more and more people to work on them.  Welcome to a new day in science, welcome to the super-collaborative era.

Written by: Det. B. Nord [FNAL]
Image by: Reidar Hahn [FNAL]