May
15
Exploring the cosmos at extreme energies, the Fermi Gamma-ray Space Telescope orbits the planet every 95 minutes. By design, it rocks north-south on alternate orbits to survey the entire sky. The spacecraft also rolls so solar panels point to the Sun for power, and the axis of its orbit precesses like a top, making a complete rotation every 54 days.
As a result of these multiple cycles, the paths of gamma-ray sources trace out complex patterns from the spacecraft’s perspective, like this mesmerising plot of the path of the Vela Pulsar. Born in the death explosion of a massive star within our galaxy, the Vela Pulsar is a neutron star spinning 11 times a second, seen as the brightest persistent source in the gamma-ray sky.
