an eccentric orbit

fragment 1 (the first picosecond)

dark matter filaments

fragment 2

astrodynamics or celestial mechanics

north star (sky map 02h 31m 48.7s, +89° 15′ 51″)

fragment 3 (galactic background noise)

entropy as an arrow of time

the tides are not what you think they are

an astronomical radio source (gravity builds cosmic structure)