Dark matter halos may leave twinkling wake in galaxies

Enlarge (credit: NASA, ESA, and M. Mutchler (STScI)) The Universe, according to cosmologists, is divided into three unequal portions. In the big bargain bin near the exit aisle you’ll find dark energy. Dark energy’s job is to push everything apart. There’s lots of it, and no one knows why. Then, next to to dark energy, […]