CHRONOSPHERE · a time machine for the night sky
kinematic snapshot · ballistic-valid
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Chronosphere

The constellations look permanent. They are not, and here you can watch them change.

Every star here is real. Each one is placed by its measured parallax and moves along its measured 3-D space velocity (Hipparcos and Gaia astrometry). Scrub through time and the sky changes as the kinematics dictate: nearby stars move quickly while distant ones barely stir, and brightness follows the inverse-square law, so approaching stars brighten and receding ones fade.

Travel through time

drag timelinescrub through deep time (with momentum)
← / →nudge ±1,000 yr  ·  for ±10,000 yr
Homereturn to now
Spaceplay / pause the slow "breathe"
T(or click the year) type an exact time, e.g. -30000 or 250k

Look around

scroll / swipepan across the celestial sphere
⌘/ctrl-scrollor pinch to zoom the field of view
click a staropen its kinematic dossier
/search for a star by name and fly to it

Motion includes a second-order galactic-tide correction from the MWPotential2014 model, verified against full galpy orbit integrations; the model error stays below 0.005 pc across the whole timeline. Beyond ±100,000 yr the band turns amber because measurement uncertainty (Gaia parallax and radial velocity, propagated over the extrapolation) starts to dominate, so figures out there are best estimates rather than certainties. No internet, no tracking: everything runs from this one file.

Data & sources

Stars: the HYG v4.1 database by David Nash / Astronomy Nexus (CC BY-SA 4.0), built on Hipparcos and Gaia astrometry; Gliese 710 uses Gaia DR3 astrometry, and published closest-approach estimates span 0.05 to 0.06 pc (Bailer-Jones 2022; de la Fuente Marcos & de la Fuente Marcos 2022). Constellation figures: the Stellarium modern sky-culture line set. Milky Way panorama: ESO/S. Brunier (CC BY 4.0). Galactic potential: MWPotential2014 (Bovy 2015), cross-checked against galpy. Star colours: B−V converted to temperature with the Ballesteros (2012) relation.

drag the timeline to travel · scroll to look around · click a star