Orbits, eclipses & stellar evolution — the solar system, seasons and moon phases, Kepler orbits, stars, black holes, galaxies and getting a rocket to orbit.
Compare all eight planets on circular orbits and switch between compressed and linear AU spacing to see period and speed against distance.
Spin an enlarged Earth beside its orbit and see why a sidereal day differs from a solar day, with solar elevation and local solar time.
Tilt a globe through a circular year and read solar declination, day length, noon elevation and daily mean sunlight at any latitude.
Move the Moon around a plan-view Sun-Earth-Moon model and read the illuminated fraction, elongation and phase angle on an Earth-facing disk.
Vary lunar distance, inclination and node angle and watch umbra, antumbra and penumbra intersect or miss the target body.
Set eccentricity, semimajor axis and central mass on a Kepler ellipse and compare speed, swept area and orbital energy.
Scrub a five-stage tour from protostar to compact remnant for different initial masses beside a temperature-luminosity diagram.
Compare a supported clock near a nonrotating black hole with a distant clock and follow gravitational redshift of emitted light.
Separate the bulge, disk and halo and compare their contributions to a rotation curve with a movable radial probe.
Launch a two-stage rocket with a pitch program and check whether the integrated trajectory has a perigee above Earth.