Credit: B. Saxton (NRAO/AUI/NSF); GBO/AUI/NSF; NASA/ESA Hubble, F. Ferraro
Graphic showing locations of millisecond pulsars inside the globular cluster Terzan 5 in an optical image taken by the Hubble space telescope. Pulsars represented in blue are accelerating toward observers on Earth; those in red are accelerating away. These relative accelerations were derived by measuring minute changes in the speed of rotation of the pulsars.